Att_01_Specifications_Volume_1.pdf

HAMPTON NATIONAL HISTORIC SITE

TOWSON, MARYLAND

PRESERVE HISTORIC STRUCTURES

HAMP

326087

PROJECT SPECIFICATIONS

VOLUME 1

NATIONAL PARK SERVICE (NPS)

DENVER SERVICE CENTER (DSC)

05/29/2024

SEAL:

ST

ATE OF MARYLANDJA

MES R. LONG

PROFESS I ONA L ENG I NEERREG I S T ERED

NO . 16 0 3 9

05/29/2024

HAMP- 326087 00 01 10 - 1

TABLE OF CONTENTS

TABLE OF CONTENTS

VOLUME 1 OF 2

PROCUREMENT AND CONTRACTING REQUIREMENTS

DIVISION 00 -- PROCUREMENT AND CONTRACTING REQUIREMENTS

00 01 10 - TABLE OF CONTENTS

SPECIFICATIONS

DIVISION 01 -- GENERAL REQUIREMENTS

01 10 00 - SUMMARY OF WORK

01 26 01 - CONTRACT MODIFICATION PROCEDURES

01 27 00 - DEFINITION OF CONTRACT LINE ITEMS

01 31 00 - PROJECT MANAGEMENT AND COORDINATION

01 32 16 - CONSTRUCTION SCHEDULE

01 32 33 - PHOTO DOCUMENTATION

01 33 23 - SUBMITTAL PROCEDURES

01 35 13.22 - ARCHEOLOGICAL PROTECTION

01 35 23 - SAFETY REQUIREMENTS

01 35 25 - EXPLOSIVES

01 35 91 - HISTORIC PRESERVATION TREATMENT PROCEDURES

01 40 00 - QUALITY REQUIREMENTS

01 42 00 - REFERENCE STANDARDS

01 50 00 - TEMPORARY FACILITIES AND CONTROLS

01 56 39 - TEMPORARY TREE PROTECTION

01 57 19.11 - INDOOR AIR QUALITY MANAGEMENT

01 57 19.12 - NOISE AND ACOUSTICS MANAGEMENT

01 57 23 - TEMPORARY STORM WATER POLLUTION PREVENTION

01 67 00 - PRODUCT REQUIREMENTS

01 73 29 - CUTTING AND PATCHING

01 73 40 - EXECUTION

01 74 19 - CONSTRUCTION WASTE MANAGEMENT AND DISPOSAL

01 77 00 - CLOSEOUT PROCEDURES

01 78 23 - OPERATION AND MAINTENANCE DATA

01 79 00 - DEMONSTRATION AND TRAINING

01 81 13 - SUSTAINABLE DESIGN REQUIREMENTS

01 90 00 - ACCEPTANCE OF WORK

01 91 14 - TOTAL BUILDING COMMISSIONING

DIVISION 02 -- EXISTING CONDITIONS

02 41 00 - SELECTIVE DEMOLITION

02 41 13 - SELECTIVE SITE DEMOLITION AND REMOVALS

02 81 00 - TRANSPORTATION AND DISPOSAL OF HAZARDOUS MATERIALS

02 82 00 - ASBESTOS REMEDIATION

02 82 13 - ASBESTOS ABATEMENT

02 82 16 - ENGINEERING CONTROL OF ASBESTOS CONTAINING MATERIALS

02 82 33 - REMOVAL AND DISPOSAL OF ASBESTOS CONTAINING MATERIALS

02 83 13 - LEAD HAZARD CONTROL ACTIVITIES

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02 83 33 - LEAD-BASED PAINT REMOVAL AND DISPOSAL

DIVISION 03 -- CONCRETE

03 30 00 - CAST-IN-PLACE CONCRETE

03 30 53 - MISCELLANEOUS CAST-IN-PLACE CONCRETE

03 35 11 - CONCRETE FLOOR FINISHES

DIVISION 04 -- MASONRY

04 05 13.10 - RESTORATION MORTARS

04 05 13.91 - MASONRY POINTING

04 20 00 - UNIT MASONRY

DIVISION 05 -- METALS

05 12 00 - STRUCTURAL STEEL FRAMING

05 12 13 - ARCHITECTURALLY-EXPOSED STRUCTURAL STEEL FRAMING

05 52 13 - PIPE AND TUBE RAILINGS

DIVISION 06 -- WOOD, PLASTICS, AND COMPOSITES

06 03 12 - HISTORIC WOOD REPAIR

06 10 00 - ROUGH CARPENTRY

06 16 00 - SHEATHING

06 20 00 - FINISH CARPENTRY

DIVISION 07 -- THERMAL AND MOISTURE PROTECTION

07 13 00 - SHEET WATERPROOFING

07 14 00 - FLUID-APPLIED WATERPROOFING

07 21 00 - THERMAL INSULATION

07 31 29 - WOOD SHINGLES AND SHAKES

07 46 23 - WOOD CLAPB SIDING

07 56 00 - FLUID-APPLIED ROOFING

07 61 00 - SHEET METAL ROOFING

07 62 00 - SHEET METAL FLASHING AND TRIM

07 92 00 - JOINT SEALANTS

07 92 01 - EXTERIOR JOINT SEALANTS - SITEWORK

DIVISION 08 -- OPENINGS

08 03 52 - HISTORIC TREATMENT OF WOOD WINDOWS

08 11 13 - HOLLOW METAL DOORS AND FRAMES

08 14 33 - STILE AND RAIL WOOD DOORS

08 31 00 - ACCESS DOORS AND PANELS

08 71 00 - DOOR HARDWARE

08 80 00 - GLAZING

08 91 00 - LOUVERS

DIVISION 09 -- FINISHES

09 01 10.15 - PAINT AND COATING REMOVAL

09 01 24.91 - STUCCO RESTORATION

09 03 20 - HISTORIC TREATMENT OF PLASTER

09 21 16 - GYPSUM BOARD ASSEMBLIES

09 30 00 - TILING

09 65 00 - RESILIENT FLOORING

09 68 16 - SHEET CARPETING

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09 91 00 - PAINTING AND FINISHING

DIVISIONS 10 - SPECIALTIES

10 28 00 - TOILET, BATH, AND LAUNDRY ACCESSORIES

DIVISION 11 -- EQUIPMENT (NOT USED)

DIVISION 12 -- FURNISHINGS (NOT USED)

DIVISION 13 -- SPECIAL CONSTRUCTION

13 34 13 - GLAZED STRUCTURES

DIVISION 14 -- CONVEYING EQUIPMENT (NOT USED)

VOLUME 2 OF 2

DIVISION 21 -- FIRE SUPPRESSION

21 13 16 - DRY-PIPE SPRINKLER SYSTEMS

DIVISION 22 -- PLUMBING

22 05 00 - COMMON WORK RESULTS FOR PLUMBING

22 05 23 - GENERAL-DUTY VALVES FOR PLUMBING PIPING

22 05 29 - HANGERS AND SUPPORTS FOR PLUMBING PIPING AND EQUIPMENT

22 05 53 - IDENTIFICATION FOR PLUMBING PIPING AND EQUIPMENT

22 05 93 - TESTING, ADJUSTING, AND BALANCING FOR PLUMBING

22 07 19 - PLUMBING PIPING INSULATION

22 0800 - COMMISSIONING OF PLUMBING & DOMESTIC HOT WATER

22 11 16 - DOMESTIC WATER PIPING

22 11 19 - DOMESTIC WATER PIPING SPECIALTIES

22 13 16 - SANITARY WASTE AND VENT PIPING

22 13 19 - SANITARY WASTE PIPING SPECIALTIES

22 13 19.13 - SANITARY DRAINS

22 14 14 - STORM DRAINAGE PIPING

22 14 23 - STORM DRAINAGE PIPING SPECIALTIES

22 14 29 - SUMP PUMPS

22 33 00 - ELECTRIC, DOMESTIC-WATER HEATERS

22 42 00 - COMMERCIAL PLUMBING FIXTURES

DIVISION 23 -- HEATING, VENTILATING, AND AIR-CONDITIONING (HVAC)

23 05 00 - COMMON WORK RESULTS FOR HVAC

23 05 23.12 - BALL VALVES FOR HVAC PIPING

23 05 23.14 - CHECK VALVES FOR HVAC PIPING

23 05 29 - HANGERS AND SUPPORTS FOR HVAC PIPING AND EQUIPMENT

23 05 48 - VIBRATION CONTROLS FOR HVAC

23 05 53 - IDENTIFICATION FOR HVAC PIPING, DUCT AND EQUIPMENT

23 05 93 - TESTING, ADJUSTING, AND BALANCING FOR HVAC

23 07 13 - DUCT INSULATION

23 07 19 - HVAC PIPING INSULATION

23 08 00 - COMMISSIONING OF HVAC & HVAC CONTROL SYSTEMS

23 11 23 - FACILITY NATURAL-GAS PIPING

23 21 13 - HYDRONIC PIPING

23 21 16 - HYDRONIC PIPING SPECIALTIES

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23 23 00 - REFRIGERANT PIPING

23 31 13 - METAL DUCTS

23 33 00 - AIR DUCT ACCESSORIES

23 34 13 - FANS

23 52 13 - ELECTRIC BOILERS

23 81 26 - SPLIT-SYSTEM AIR-CONDITIONERS

23 81 29 - VARIABLE REFRIGERANT FLOW HVAC SYSTEMS

23 82 39.16 - PROPELLER UNIT HEATERS

DIVISION 26 -- ELECTRICAL

26 00 50 - COMMON WORK RESULTS FOR ELECTRICAL

26 05 19 - LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES

26 05 26 - GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

26 05 29 - HANGERS AND SUPPORTS FOR ELECTRICAL SYSTEMS

26 05 33 - RACEWAYS AND BOXES FOR ELECTRICAL SYSTEMS

26 05 43 - UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL

SYSTEMS

26 05 44 - SLEEVES AND SLEEVE SEALS FOR ELECTRICAL RACEWAYS AND

CABLING

26 05 53 - IDENTIFICATION FOR ELECTRICAL SYSTEMS

26 09 23 - LIGHTING CONTROL DEVICES

26 24 16 - PANELBOARDS

26 27 26 - WIRING DEVICES

26 28 13 - FUSES

26 28 16 - ENCLOSED SWITCHES AND CIRCUIT BREAKERS

26 43 13 - SURGE PROTECTION FOR LOW-VOLTAGE ELECTRICAL POWER

CIRCUITS

26 51 00 - LED INTERIOR LIGHTING

26 52 13 - EMERGENCY LIGHTING

DIVISION 27 -- COMMUNICATIONS

27 05 28 - PATHWAYS FOR COMMUNICATIONS SYSTEMS

DIVISION 28 -- ELECTRONIC SAFETY AND SECURITY

28 20 00 - VIDEO SURVEILLANCE

28 31 00 - INTRUSION DETECTION

28 31 11 - DIGITAL, ADDRESSABLE FIRE ALARM SYSTEMS

DIVISION 31 -- EARTHWORK

31 00 00 - EARTHWORK

31 10 00 - SITE CLEARING

31 11 00 - CLEARING AND GRUBBING

31 20 00 - EARTH MOVING

31 22 19 - FINISH GRADING

31 23 00 - SITE EXCAVING, BACKFILLING, AND COMPACTING

31 23 19 - DEWATERING

31 25 00 - EROSION AND SEDIMENTATION CONTROL

31 50 00 - EXCAVATION SUPPORT AND PROTECTION

31 60 00 - UNDERPINNING

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DIVISION 32 -- EXTERIOR IMPROVEMENTS

32 01 13.63 - CHIP SEAL

32 01 16.71 - COLD MILLING ASPHALT PAVING

32 01 17.61 - SEALING CRACKS IN ASPHALT PAVING

32 01 17.71 - PARTIAL DEPTH PATCHING OF ASPHALT PAVING

32 01 17.72 - FULL DEPTH PATCHING OF FLEXIBLE PAVING

32 11 00 - BASES COURSES

32 11 23 - AGGREGATE BASE COURSE

32 12 13.13 - ASPHALT TACK COAT

32 12 16.01 - MINOR ASPHALT PAVEMENT

32 12 16.13 - ASPHALT FOG SEAL AND BLOTTER

32 14 16 - BRICK PAVING

32 14 40 - STONE PAVING

32 15 42 - RIVER ROCK

32 15 43 - STONE FINES PAVING

32 17 23 - PAVEMENT MARKINGS

32 31 29 - WOOD FENCING AND GATE

32 91 19 - LANDSCAPE GRADING

32 91 19.13 - TOPSOIL PLACEMENT AND GRADING

32 92 00 - TURFS AND GRASSES

32 92 19 - SEEDING

32 93 00 - PLANTING

32 94 13 - LANDSCAPE EDGING

DIVISION 33 -- UTILITIES

33 01 30.73 - MANHOLE REHABILITATION

33 01 30.74 - SEWER REPAIRS

33 10 00 - WATER UTILITIES

33 34 00 - SANITARY UTILITY SEWERAGE PIPING SYSTEMS

33 39 00 - SANITARY UTILITY SEWERAGE STRUCTURES

33 40 00 - STORM DRAINAGE UTILITIES

33 40 20 - WARNING AND TRACER TAPE

33 46 00 - SUBDRAINAGE

DIVISION 34 -- TRANSPORTATION

34 01 00 - MAINTENANCE OF TRAFFIC

END OF SECTION 00 01 10

HAMP 326087 01 11 00 - 1

112723 SUMMARY OF WORK

NPS DSC Division 1 Specifications National Park Service (NPS) - Denver Service Center (DSC) | 11-27-23

By using NPS DSC Division 1 Specifications, you acknowledge you read, understand, and will format edits according to NPS DSC Division 1 Specifications Instructions.

HAMP 326087

SECTION 01 11 00 - SUMMARY OF WORK

PART 1 - GENERAL

1.1 SUMMARY

A. Section includes the following:

1. Work Covered by Contract Documents

2. Work Under Other Contracts

3. Government-Furnished Materials

4. Construction Contractor Use of Site

5. Public Use of Site

6. Occupancy Requirements for Buildings

7. Conduct of Operations

8. Work Restrictions

9. Special Construction Requirements

10. Soils Investigation Report

11. Additional Reports

1.2 WORK COVERED BY CONTRACT DOCUMENTS

A. Project Location: Hampton National Historic Site, 535Hampton Lane, Towson, MD 21286., B. The Work consists of:

1. Rehabilitation of the historic Enslaved Quarters #2.

2. Rehabilitation of the historic Enslaved Quarters #3.

3. Removal of the 1948-era addition to the historic Overseer’s House. Rehabilitation of the

Overseer’s House, and reconfiguration of the accessible entrance to this structure.

Building system improvements for the Overseer’s House, including sprinkler, domestic water and mechanical systems.

4. Rehabilitation and accessibility improvements at the Work Yard situated between Enslaved

Quarters #2, Enslaved Quarters #3 and the Overseer’s House.

5. Rehabilitation of the historic Mule Barn.

HAMP 326087 01 11 00 - 2

6. Improvements to the interconnected Fire Alarm and Intrusion Detection systems for the

Overseer’s House, Mule Barn, Enslaved Quarters #1, Enslaved Quarters #2, Enslaved

Quarters #3 and the Dovecote Bathroom.

7. Rehabilitation of the historic Dairy.

8. Rehabilitation of the historic Long House Granary, including replacement of the existing non-historic entrance stair for accessing the second level.

9. Rehabilitation of the historic Hampton Mansion, including rehabilitation of the stucco, rehabilitation of the exterior historic brick walk to accommodate accessibility requirements, replacement of the existing, non-historic visitor entrance ramp for the

Hampton Mansion, rehabilitation and repainting of the exterior woodwork and wood windows, and limited interior rehabilitation at the Hampton Mansion.

10. Regrading at the historic Domestic Service Cluster of structures east of the Hampton

Mansion to address detrimental water-run off conditions. Rehabilitation of the historic

Domestic Service Cluster buildings.

11. Rehabilitation of the historic Ice House, as well as lighting upgrades to the Ice House interior.

12. Rehabilitation of historic Greenhouse #1 and upgrades to accommodate future use, including architectural and building systems upgrades.

13. Rehabilitation of historic Greenhouse #2 and upgrades to accommodate future use, including architectural and building systems upgrades.

14. Rehabilitation of the historic Garden Maintenance Building and upgrades to accommodate future use, including addition of a toilet room, as well as other architectural and building systems upgrades.

15. Rehabilitation of the historic Caretaker’s Cottage, and upgrades to accommodate future use, including, including addition of a toilet room, as well as other architectural and building systems upgrades.

16. Addition of interconnected Fire Protection and Intrusion Detection systems at Greenhouse

#1, Greenhouse #2, the Garden Maintenance Building, and the Caretaker’s Cottage.

17. Rehabilitation and improvements to the Green Metal Building.

18. Improvements to the interconnected Fire Protection and Intrusion Detection systems at the

Green Metal Building, the Collections Storage Building and the Pole Barn.

19. Road maintenance and repair work throughout the Park.

20. Site work including Erosion and Sediment Control requirements and Stormwater

Management improvements.

C. Project will be constructed under a single prime contract.

HAMP 326087 01 11 00 - 3

1.3 CONSTRUCTION CONTRACTOR USE OF SITE

A. General: Construction Contractor shall have limited use of site for construction operations. Limit use of premises to areas within the Construction limits indicated on drawings. Do not disturb portions of Project site beyond areas in which the Work is indicated.

B. Work Plan: Hampton National Historic Park (Park) will remain open to visitors and employees throughout construction. The Park needs to maintain safe access for visitors as well as maximum visitor access to buildings and interpretive portions of the Park throughout the project. Submit a work plan detailing how construction will be completed to maintain safety while maximizing visitor use throughout the project. This work plan should be reflected in the baseline schedule.

C. Storage of Materials: Confine storage of materials to staging areas shown on plans.

D. Parking: Confine parking to staging areas shown on plans on Farm side of Park. Confine parking to lower Visitor’s Lot on Mansion Side of Park.

E. Stockpiling: Confine stockpiling to staging areas shown on plans.

F. Preservation of Natural Features:

1. Prevent damage to natural surroundings. Restore damaged areas, repairing or replacing damaged trees and plants, at no additional expense to the Government.

2. Provide temporary barriers to protect existing trees and plants and root zones.

3. Do not remove, injure, or destroy trees or other plants without prior approval. Consult with

Contracting Officer (CO) and remove agreed-on roots and branches that interfere with construction.

4. Do not fasten ropes, cables, or guys to existing trees.

5. Carefully supervise excavating, grading, filling, and other construction operations near trees to prevent damage.

G. Driveways and Entrances: Keep driveways and entrances serving premises clear and available to

Government employees, and emergency vehicles at all times. Do not use for parking or storage of materials.

1. Schedule deliveries to minimize use of driveways and entrances.

2. Schedule deliveries to minimize space and time requirements for storage of materials and equipment on-site.

H. Construction Camp: Establishment of a camp within park will not be permitted.

I. Hauling Restrictions: Comply with legal load restrictions in hauling of materials. Load restrictions on park roads are identical to state load restrictions with such additional regulations as may be imposed by the Park Superintendent. Information regarding rules and regulations for vehicular traffic on park roads may be obtained from the Office of the Park Superintendent. A special permit will not relieve Construction Contractor of liability for damage which may result from moving of equipment. Hauling allowed on Park roads only as identified in drawings, unless otherwise specifically permitted by the Park Superintendent.

HAMP 326087 01 11 00 - 4

1.4 PUBLIC USE OF SITE

A. Construction Contractor shall conduct his operations to ensure the least inconvenience to public.

[Road] closures may be permitted, when required, upon specific approval of Contracting Officer for a maximum of 4 hours.

1.5 OCCUPANCY REQUIRMENTS FOR BUILIDINGS

A. Existing Buildings

1. Partial Government Occupancy: Government will occupy premises during entire construction period, with exception of areas under construction. Cooperate with

Government during construction operations to minimize conflicts and facilitate

Government usage. Perform Work so as not to interfere with Government’s operations.

Maintain existing exits, unless otherwise indicated.

a. Maintain access to existing walkways, corridors, and other adjacent occupied or used facilities. Do not close or obstruct walkways, corridors, or other occupied or used facilities without written permission from Contracting Officer.

1.6 CONDUCT OF OPERATIONS

A. Construction Contractor shall conduct his operations in conformance with rules and regulations promulgated by the Secretary of the Interior for the National Park Service, and applicable park rules and regulations prescribed by Park Superintendent.

B. Work on Saturdays, Sundays, may not be performed unless stated in the Work Restrictions below or without prior consent from the Contracting Officer. Submit requests 2 calendar days in advance of the work to the Contracting Officer for approval. Work on Federal holidays or at night shall not be permitted.

C. No signs or advertisements (except those specified herein) shall be displayed on the construction site or within the park unless approved by the Contracting Officer.

1.7 WORK RESTRICTIONS

A. On-Site Work Hours: Work shall be generally performed during normal business working hours of 8:00 a.m. to 4:30 p.m., Monday through Friday, except when otherwise indicated.

1. Weekend Hours: If permitted per section above, 8:30 a.m. to 4:30 p.m.

2. Early Morning Hours: Early morning hours shall not be permitted.

3. Hours fornoisy activity: 8:00 a.m. to 4:30 p.m., Monday through Friday.

B. Existing Utilities

1. Existing Utilities: Notify Contracting Officer and utility companies of proposed locations and times for excavation.

2. Construction Contractor shall be responsible for locating and preventing damage to known utilities. If damage occurs, repair utility at no additional expense to the Government.

HAMP 326087 01 11 00 - 5

3. If damage occurs to an unknown utility, repair utility. An equitable adjustment will be made in accordance with the Changes clause of the contract.

C. Existing Utility Interruptions: Do not interrupt utilities serving facilities occupied by Government or others unless permitted under the following conditions and then only after arranging to provide temporary utility services according to requirements indicated:

1. Notify Contracting Officer not less than two business days in advance of proposed utility interruptions.

2. Do not proceed with utility interruptions without Contracting Officer’s written permission.

3. Hours and length of Utility Shutdowns: Utility shutdowns may not persist for longer than one business day, unless otherwise approved in writing by Contracting Officer.

D. Nonsmoking Building/Tobacco Use/Vaping: Tobacco use and vaping is restricted to staging areas only, and is not permitted elsewhere in the work site or Park.

1.8 SPECIAL CONSTRUCTION REQUIREMENTS

A. Project Management and Communication Software: Software administered by NPS shall be used to manage communication and document sharing during construction.

1. See Section 01 31 00 "Project Management and Coordination" for requirements on using

NPS project management and communication software.

1.9 SOILS INVESTIGATION REPORT

A. The report Report of Geotechnical Study: Hampton National Historic Site prepared by Froehling

& Robertson, Inc. is available, an appendix with this package.

B. In case of conflict between report and drawings or specifications, the drawings and specifications govern.

1.10 ADDITIONAL REPORTS

A. The report Asbestos-containing Materials & Lead-based Paint Survey Reportprepared byArc

Environmental is an appendix with this package.

B. In case of conflict between report and drawings or specifications, drawings and specifications govern.

HAMP 326087 01 11 00 - 6

PART 2 - PRODUCTS (Not Used)

PART 3 - EXECUTION (Not Used)

END OF SECTION 01 11 00

9017 Red Branch Road, Suite G Columbia, Maryland 21045 T 410.825.4131 F 410.321.7384 www.fandr.com

VIRGINIA • NORTH CAROLINA • MARYLAND • DISTRICT OF COLUMBIA

A Minority-Owned Business

Report of Geotechnical Study

Hampton National Historic Site (NHS)

Towson, Maryland

F&R Project No. 75C0022

Prepared For:

GWWO Architects

1215 E. Fort Avenue, Suite 24

Baltimore, Maryland 21230

Prepared By:

Froehling & Robertson, Inc.

9017 Red Branch Road, Suite G

Columbia, Maryland 21045

April 19, 2024

FROEHLING & ROBERTSON, INC.

Engineering Stability Since 1881

9017 Red Branch Road, Suite G

T 410.825.4131 I F 410.321.7384

9017 Red Branch Road, Suite G Columbia, Maryland 21045 T 410.825.4131 F 410.321.7384 www.fandr.com

VIRGINIA • NORTH CAROLINA • MARYLAND • DISTRICT OF COLUMBIA

A Minority-Owned Business

April 19, 2024

Mr. John G. Bernet

GWWO Architects

1215 E. Fort Avenue

Liberty Building, Suite 24

Baltimore, MD 21230

Reference: Report of Geotechnical Study

Hampton National Historic Site (NHS)

535 Hampton Lane

Towson, Maryland

Dear Mr. Bernet:

This report presents the results of the subsurface exploration program and the geotechnical engineering analyses performed by Froehling & Robertson, Inc. (F&R) for the above-referenced project. Our services were performed in general accordance with F&R Proposal No. 2375-00340R1 dated November 8, 2023.

The report presents our understanding of the project, reviews our exploration procedures, describes existing site and general subsurface conditions, and presents our geotechnical evaluations and recommendations.

We have enjoyed working with you on this project, and we are prepared to assist you with the recommended quality assurance monitoring and testing services during construction. Please contact us if you have any questions regarding this report or if we may be of further service.

Sincerely, Dawn M. Appelbaum, P.E. Hasan M. Aboumatar, PhD, P.E.

Senior Geotechnical Project Engineer Senior Engineer/Branch Manager

Professional Certification I hereby certify that these documents were prepared or approved by me, and that I am a duly licensed professional engineer under the laws of the State of Maryland.

License No 29553. Expiration Date: 12/31/2025

GWWO Architects Hampton National Historic Site

F&R Record No. 75Z0202-0001 April 19, 2024

Page - i -

SECTION PAGE

EXECUTIVE SUMMARY

1.0 PURPOSE & SCOPE OF SERVICES

2.0 PROJECT INFORMATION

2.1 SITE DESCRIPTION

2.2 PROPOSED CONSTRUCTION

3.0 EXPLORATION PROCEDURES

3.1 SUBSURFACE EXPLORATION – SPT BORINGS AND PAVEMENT CORES W/AUGER BORINGS

3.2 VACUUM EXCAVATED TEST PITS

3.3 LABORATORY TESTING

4.0 REGIONAL GEOLOGY & SUBSURFACE CONDITIONS

4.1 REGIONAL GEOLOGY

4.2 SUBSURFACE CONDITIONS

4.2.1 General

4.2.2 Surficial Materials

4.2.3 Existing Fill

4.2.4 Piedmont Soils

4.3 GROUNDWATER

4.4 LABORATORY TEST RESULTS

5.0 GEOTECHNICAL DESIGN RECOMMENDATIONS

5.1 PAVEMENT CONSTRUCTION

5.2 STORMWATER MANAGEMENT (SWM) FACILITIES

5.3 VACUUM EXCAVATED TEST PIT OBSERVATIONS

6.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS

6.1 SITE PREPARATION

6.2 STRUCTURAL FILL PLACEMENT AND COMPACTION

6.3 SURFACE WATER/GROUNDWATER CONTROL

7.0 CONTINUATION OF SERVICES

8.0 LIMITATIONS

Page - ii -

APPENDICES

APPENDIX I

Site Vicinity Map (Drawing No. 1)

Boring Location Plan (Drawing No. 2)

Pavement Core Location Plan (Drawing No. 3)

Test Hole Location Plan (Drawing No. 4)

APPENDIX II

Key to Boring Log Soil Classification

Unified Soil Classification System

Laboratory Test Results

F&R Boring Logs (B-1 through B-6)

Vacuum Excavated Utility Test Hole Logs (TH-1 through TH-3)

APPENDIX III

Utility Locating Maps and Designating Sketches

APPENDIX IV

GBA Document “Important Information about Your Geotechnical Engineering Report”

Page - 3 -

EXECUTIVE SUMMARY

This Executive Summary is provided as a brief overview of our geotechnical engineering evaluation for the project and is not intended to replace more detailed information contained elsewhere in this report. As an overview, this summary inherently omits details that could be very important to the proper application of the provided geotechnical design recommendations.

This report should be read in its entirety prior to implementation into design and construction.

The project consists of various site improvements at the Hampton National Historic Site

(NHS), including stormwater management (SWM) facilities and new pavement areas.

The subsurface exploration program was performed on March 20, 2024, and consisted of one

(1) soil test boring designated as SWM-1 and four (4) pavement cores with shallow auger borings designated as C-1 through C-4. The test borings were drilled to depths ranging from approximately 5 feet to 6 feet each below existing grades. Below the surficial topsoil or existing asphalt pavement, the borings encountered Existing Fill and undisturbed Piedmont soils the termination depths.

Our scope also included three (3) vacuum excavated test holes, designated as TH-1 through

TH-3. The purpose of the test holes was to locate existing pipes associated with the onsite geothermal well field, as well as an existing electrical line in the Domestic Service Cluster area.

Page - 4 -

1.0 PURPOSE & SCOPE OF SERVICES

The purpose of the subsurface exploration and geotechnical engineering evaluation was to explore the subsurface conditions in the area of the pavement areas and stormwater management (SWM) facilities and provide geotechnical engineering design and construction recommendations that can be used during their design and construction. In addition, our scope included vacuum excavated test pits to locate existing utilities.

F&R’s scope of services included the following:

Visiting the site to observe existing surface conditions;

Coordinating utility clearance with Miss Utility;

Reviewing readily available geologic and subsurface information relative to the project site;

Completion of one (1) soil test borings to a depth of 6 feet below the existing ground surface for the planned SWM facility;

Completion of four (4) pavement cores with shallow auger borings to a depth of 5 feet below existing grades for the pavement areas;

Completion of three (3) vacuum excavated test pits to locate buried utilities;

Preparation of typed Boring Logs;

Performing geotechnical laboratory visual classification of soil samples;

Performing a geotechnical engineering evaluation of the subsurface conditions with regard to their suitability for the proposed construction;

Providing recommendations for pavements;

Providing recommendations for design and construction of stormwater management (SWM) facilities;

Providing recommendations regarding the placement and compaction of fill materials, including an assessment of the suitability of the on-site soil for re-use as structural fill; and

Preparation of this geotechnical report by professional engineers.

Our scope of services did not include a survey of the boring locations, quantity estimates, preparation of plans or specifications, or the identification and evaluation of wetland or other environmental aspects of the project site.

Page - 5 -

2.0 PROJECT INFORMATION

2.1 Site Description

The project site is located on the grounds of the Hampton National Historic Site (NHS) at 535

Hampton Lane in the Towson area of Baltimore County, Maryland (See Site Location Plan, Drawing No. 1, Appendix I). The site is split into two areas: the main portion of the Hampson NHS is located on the south side of Hampton Lane and the Hampson NHS Farm is located on the north side of Hampton Lane.

2.2 Proposed Construction

Project information was provided via email correspondence from GWWO Architects. The provided plans depicted the existing and proposed conditions, as well as the requested soil boring locations for the proposed stormwater management (SWM) facility, as well as the general area of the requested vacuum excavated test pit locations for existing buried utilities.

Based on the provided information, we understand that the project consists of various site improvements at the Hampton NHS and the Hampton NHS Farm. At the Hampton NHS site, the existing private roadway located to the southeast of the main parking area will be replaced with new asphalt pavement. Proposed grading information was not provided at the time this report was prepared; however, we have assumed that no grade changes are planned.

The provided plan also indicates that several stormwater management (SWM) facilities are planned at the site Hampton NHS Farm. Specific details regarding the SWM facilities were not provided at the time this report was prepared; however, we understand that subsurface exploration was only required for the proposed rain garden (SWM Option 1) and that the facility bottom will be less than 4 feet below existing grade.

3.0 EXPLORATION PROCEDURES

3.1 Subsurface Exploration – SPT Borings and Pavement Cores w/Auger Borings

The subsurface exploration program was performed on March 20, 2024, and consisted of one (1) soil test boring designated as SWM-1 and four (4) pavement cores with shallow auger borings designated as C-1 through C-4.

All soil test borings were performed using a rotary drill rig (as described below). The soil test borings were drilled to depths ranging from 5 feet to 6 feet each below existing grades.

The locations of the borings are shown on the attached Boring Location Plan (Drawing No. 2) and

Pavement Core Location Plan (Drawing No. 3). The boring locations were staked in the field by

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F&R utilizing GPS techniques and the provided site plans. Surface elevations at the boring locations were estimated from available topographical information. Given that some minor shifting of pre-staked locations may have occurred during drilling, we recommend that the test boring locations and elevations shown on the attached Boring Location Plan, Pavement Core

Location Plan and Boring Logs be considered approximate.

The soil test borings were performed in accordance with generally accepted practice using a track-mounted Dietrich D-50 rotary drill rig equipped with an automatic hammer. Hollow-stem augers were advanced to pre-selected depths, the center plug was removed, and representative soil samples were recovered with a standard split-spoon sampler (1 3/8 in. ID, 2 in. OD) in general accordance with ASTM D 1586, the Standard Penetration Test. For these tests, a weight of 140 pounds was freely dropped from a height of 30 inches to drive the split-spoon sampler into the soil. The number of blows required to drive the split-spoon sampler three consecutive 6-inch increments was recorded, and the blows of the last two increments were summed to obtain the

Standard Penetration Resistance (N-value). The N-value provides a general indication of in-situ soil conditions and has been correlated with certain engineering properties of soils.

The test borings were advanced through the soil overburden by soil drilling procedures to the planned termination depths. Subsurface water level readings were taken in each of the borings immediately upon completion of the drilling process, and then backfilled with auger cuttings

(soil). Periodic observation of the boreholes should be performed to monitor subsidence at the ground surface, as the borehole backfill could settle over time.

Representative portions of the split-spoon soil samples obtained throughout the exploration program were placed in glass jars and transported to our laboratory. In the laboratory, the soil samples were evaluated by a member of our engineering staff in general accordance with techniques outlined in the visual-manual identification procedure (ASTM D 2488). The soil descriptions and classifications discussed in this report and shown on the attached Boring Logs are based on visual observation and should be considered approximate. A copy of the boring logs are provided and classification procedures are further explained in Appendix II.

Split-spoon soil samples recovered on this project will be stored at F&R’s office for a period of 60 days. After 60 days, the samples will be discarded unless prior notification is provided to us in writing.

3.2 Vacuum Excavated Test Pits

The test pit exploration program was performed on March 20, 2024, and consisted of three (3) vacuum excavated test holes to attempt to locate existing underground utilities. The test holes were excavated by Insight, LLC under the supervision of F&R personnel. The test holes were

Page - 7 -designated as Test hole TH-1 through TH-3. The locations of the test holes are shown on the attached Test Hole Location Plan (Drawing No. 4).

Our field observations of the vacuum excavated test pits are included in Section 5.3 Vacuum

Excavated Test Pit Observations.

Prior to excavating the utility test pits and performing the pavement cores/auger borings, existing buried utilities were located in the field by Insight, LLC. Copies of their utility locating maps and designating sketches are included in Appendix III of this report.

3.3 Laboratory Testing

Representative soil samples were tested in our laboratory for Water Content (ASTM D 2216), #200 Sieve Wash (ASTM D 1140), Atterberg Limits (ASTM D 4318), Hydrometer Gradation (USDA)

Moisture Density relationship (ASTM D 698) and California Bearing Ratio (AASTHO T 193) to substantiate the visual classifications and assist with the estimation of the soils’ pertinent engineering properties. The results are shown in Section 4.4 and in Appendix II.

4.0 REGIONAL GEOLOGY & SUBSURFACE CONDITIONS

4.1 Regional Geology

The project site is located in the Eastern Piedmont Physiographic Province. The virgin soils encountered in this area are the residual product of in-place chemical weathering of the rock underlying the site. The typical residual soil profile consists of silty to clayey soils near the surface

(where soil weathering is more advanced), underlain by more sandy silts and silty sands that generally become denser with depth down to the top of parent bedrock. The boundary between soil and rock, referred to as “weathered” or “decomposed” rock, is not sharply defined. This transitional zone can contain highly weathered materials and boulders of more resistant rock.

Based on the results of the test borings and our review of the Geologic Map of the Towson

Quadrangle dated 1974, the project site is located in an area underlain by the Cockeysville Marble

Phlogopitic metalimestone member (cpl), which is described as the following: fine- to medium-grained, white to bluish-white calcite marble interlayered on a millimeter- to centimeter-scale with fine- to medium-grained, purplish, phologopitic calcite marble or calc-schist with feldspar, scapolite, muscovite, quartz and very minor diopside and tremolite.

4.2 Subsurface Conditions

4.2.1 General

The subsurface conditions discussed in the following paragraphs and those shown on the attached Boring Logs represent an estimate of the subsurface conditions based on interpretation

Page - 8 -of the boring data using normally accepted geotechnical engineering judgments. The transitions between different soil strata are usually less distinct than those shown on the boring logs.

Sometimes the relatively small sample obtained in the field is insufficient to definitively describe the origin of the subsurface material. In these cases, we qualify our origin descriptions with

“possible” before the word describing the material’s origin (i.e. possible fill, etc.). Although individual soil test borings are representative of the subsurface conditions at the boring locations on the dates shown, they are not necessarily indicative of subsurface conditions at other locations or at other times. Data from the specific soil test borings is shown on the attached

Boring Logs in Appendix II. A subsurface profile, which is a composite of the boring data, is included in Appendix II.

Below the surficial materials, the borings generally encountered Existing Fill and undisturbed

Piedmont soils. These materials are generally discussed in the following paragraphs.

4.2.2 Surficial Materials

Surficial organic soils were encountered in Boring SWM-1. F&R has not performed any laboratory testing to determine the organic content or other horticultural properties of the observed surficial organic soil materials. Therefore, the term surficial organic soil is not intended to indicate a suitability for landscaping and/or other purposes. The surficial organic soil depth at the boring location was recorded during the subsurface exploration program to be approximately 8 inches.

We note that the transition from surficial organic soil to underlying materials may be gradual, and therefore the observation and measurement of surficial organic soil depths is subjective.

Actual surficial organic soil depths should be expected to vary.

The surficial materials encountered in Borings C-1 through C-4 generally consisted of approximately 2.5 inches to 3.5 inches of asphalt pavement.

4.2.3 Existing Fill

Existing Fill was encountered below the asphalt pavement in Borings C-1 through C-4. The

Existing Fill materials were generally classified as Sandy GRAVEL (GW) and exhibited loose relative densities. The Existing Fill generally extended to depths ranging from approximately 1 to 2 feet below existing grades.

4.2.4 Piedmont Soils

Piedmont soils were encountered under the surficial materials or Existing Fill in all borings. The

Piedmont soils were generally classified as Clayey SAND with Silt (SC-SM), Silty CLAY (CL) and

Sandy CLAY (CL). The sampled soils were generally brown and gray in color, with moisture contents visually characterized as moist. The N-value in the granular soils was 4 blows per foot

(bpf), indicating loose relative densities. N-values in the cohesive soils ranged from 4 bpf to 8 bpf, indicating soft to firm relative consistencies.

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4.3 Groundwater

The test borings were monitored during and after drilling operations to obtain short-term groundwater information. Groundwater was not encountered in any of the borings to the depths explored.

It should be noted that the location of the subsurface water table could vary by several feet because of seasonal fluctuations in precipitation, evaporation, surface water runoff, local topography, and other factors not immediately apparent at the time of this exploration.

Normally, the highest subsurface water levels occur in the late winter and spring and lowest levels occur in the late summer and fall.

4.4 Laboratory Test Results

As discussed in Section 3.3, laboratory testing was performed on selected soil samples collected during our subsurface exploration. The results from the laboratory testing are included in the table below.

Source

Sample

Depth

(Feet)

Natural

Water

Content (%)

Liquid Limit/

Plasticity Index

% Passing

No. 200

Sieve

USCS

Class.

USDA

Class.

C-1 1’-5’ 35.6 41 / 20 74.0 CL --

C-4 1’-3’ 21.7 36 / 18 78.9 CL --

SWM-1 2’-4’ 26.9 -- 90.2 CL Clay

5.0 GEOTECHNICAL DESIGN RECOMMENDATIONS

5.1 Pavement Construction

We understand that the proposed development will include the replacement of the existing private roadway located to the southeast of the main parking area with new asphalt pavement.

Proposed grading information was not provided at the time this report was prepared; however, we have assumed that no grade changes are planned. Details regarding the anticipated traffic conditions were not provided. Based on our experience with similar projects, we anticipate that the majority of the traffic will consist of automobiles; however, delivery truck and trash truck traffic, along with automobile traffic can be expected.

Based on the pavement core and boring results, the existing asphalt pavement ranged from approximately 2.5 inches to 3.5 inches in thickness. A layer of Sandy GRAVEL (GW) fill was encountered below the asphalt in Borings C-1 through C-4 and ranged in thickness from approximately 8.5 inches to 21.5 inches. Below the Sandy GRAVEL fill, the undisturbed Piedmont soils were classified as Silty CLAY with little Sand (CL).

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F&R obtained a bulk sample of the Silty CLAY subgrade soils and performed California Bearing

Ratio (CBR) testing on the bulk sample. The results of the CBR indicated that the Silty CLAY subgrade soils should exhibit a value of 2.9 when compacted to at least 95 percent of the maximum dry density, as determined by the Standard Proctor test (ASTM D 698).

We anticipate that final pavement grades will be close to or will match the existing pavement grades. Based on the boring results, the existing Sandy GRAVEL (GW) fill appears to extend to a minimum depth of 12 inches.

The following design values were used for our analysis:

Standard-duty traffic loading 25,000 equivalent single axle loads (ESALs)

Design life 25 years

Reliability 85 %

Variance 0.45

Initial serviceability 4.2

Terminal serviceability 2.0

CBR Value 2.9

Our design analysis was based on methodology from the American Association of State Highway and Transportation Officials’ (AASHTO) Guide of Design of Pavement Structures, 1993. Based on the assumptions and methodologies presented above, we recommend the following:

Remove the upper 5 inches of existing asphalt pavement/Sandy GRAVEL (GW) material, then place new asphalt on the remaining 7 inches of Sandy GRAVEL (GW) fill. The recommended pavement section is shown in the table below.

PAVEMENT SECTION STANDARD-DUTY

LAYER Material Type

THICKNESS

(INCHES)

Surface

Course

Hot Mix Superpave

(Surface-9.5MM) 2.0

Base

Course

Hot Mix Superpave

(Base-19MM) 3.0

Subbase

Course Existing Sandy GRAVEL (GW) Min. 7.0

Pavement subgrades should be evaluated by a geotechnical engineer prior to placement of the base course. If excessive subgrade movement is observed, appropriate improvements such as

Page - 11 -undercutting and/or in-place stabilization will be required at that time. Any undercutting should be replaced with CR-6 material.

It is recommended that areas subjected to excessive starting and stopping motion or concentrated loads (such as a dumpster area), be supported with concrete pavement. For such areas, we recommend the pavement be constructed of 6-inch thick, air-entrained Portland cement concrete having a minimum compressive strength of 4,000 psi with 6 inches of aggregate base.

The pavement sections provided above have been developed for conventional post construction traffic conditions. Since the supportive qualities of these pavement sections for their respective uses are reliant upon full construction of the subbase, base, and surface courses, partial construction of either of these sections to facilitate construction traffic may result in subgrade and pavement failures, due to the inadequate supportive qualities of an incomplete pavement section and the heavy concentrated loads associated with construction traffic. Excessively heavy, repetitive construction and/or permanent traffic loads, heavy static loads, and (especially) poor drainage conditions could cause failures. Specific problem areas, should they occur subsequent to construction, will have to be remedied on a case by case basis.

5.2 Stormwater Management (SWM) Facilities

Based on the provided information, several stormwater management (SWM) facilities are planned at the Hampton NHS Farm site. Specific details regarding the SWM facilities were not provided at the time this report was prepared; however, we understand that subsurface exploration was only required for the proposed rain garden (SWM Option 1) and that the facility bottom will be less than 4 feet below existing grade.

The subsurface conditions within the planned SWM rain garden were evaluated with Boring

SWM-1, which extended to a depth of approximately 6 feet below existing grade. Groundwater was not encountered in Boring SWM-1 to the depth explored. Bedrock was not encountered in

Boring SWM-1 to the depth explored. The details regarding the soil strata for the SWM boring can be seen on the boring logs in APPENDIX II.

Laboratory testing consisting of soil gradation by hydrometer (USDA classification) was performed on a representative soil sample recovered from Boring SWM-1. The laboratory test results indicate that the tested soil in Boring SWM-1 (from approximately 2 feet to 4 feet below existing grade) generally consists of Silty Clay Loam per the USDA classification.

5.3 Vacuum Excavated Test Pit Observations

F&R personnel observed the excavation of three (3) vacuum excavated test holes to attempt to locate existing underground utilities. The test holes, designated as Test hole TH-1 through TH-3, Page - 12 -were excavated by Insight, LLC. The locations of the test holes are shown on the attached Test

Hole Location Plan.

Based on the provided information, the purpose of the test pits was to attempt to locate existing pipes associated with the onsite geothermal well field, as well as an existing electrical line in the

Domestic Service Cluster area. Prior to the start of excavation, the locations of the test pits were identified by first measuring from known locations as shown on the plans titled “Mechanical Site

Plan, Sub Sheet Number M9.1” by Henry Adams, LLC. dated of June of 2004 and “Alternative

2/Micrograding” by GWWO, Inc. that was undated. Then a vacuum extraction drill was used to advance a 1 foot square hole to the desired depth. Copies of the test hole logs are included in

Appendix II. The results of the test pits are described below:

Geothermal Well Area

Test Hole TH-1 (geothermal water line): The test pit was extended to a depth of 2.9 feet below existing grade. The soil removed consisted of a brown to orange brown Silty CLAY (CL). A HDPE pipe tee, approximately 1.5 inches in diameter, was encountered at this depth. The main line of the pipe ran in a north-south direction. The short end of the tee ran to the west.

Test Hole TH-2/3 (geothermal water line, electric line): The test pit was extended to a depth of

2.9 feet below existing grade. The soil removed consisted of a brown to orange brown Silty CLAY

(CL). A HDPE pipe tee, approximately 1.5 inches in diameter was encountered at this depth. The main line of the pipe ran in a north-south direction. A second plastic pipe approximately 1.25 inches in diameter was encountered at a depth of 2.4 feet. This pipe also ran in the north-south direction and appeared to be an electrical conduit. The details regarding the HDPE geothermal water line are described on test hole log TH-2 and the details regarding the plastic electrical conduit are described on test hole log TH-3 in Appendix II.

Domestic Service Cluster Area

At the direction of the onsite Hampton NHS personnel, a vacuum excavated test pit was not performed to locate the electric line due to the soft ground conditions, which may not have been able to support the vacuum excavation truck. The provided plan indicated that an electrical line was installed in this vicinity at the site. A radio transmitter was then attached to a nearby transformer and the signal was traced along the line to an area in front of two storage sheds. The transmitter indicated that the electrical line may be at a depth varying from approximately 2.9 feet to 3.1 feet below the existing ground surface. The approximate locations of where the measurements were obtained are indicated on the attached Test Hole Location Plan.

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6.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS

6.1 Site Preparation

During the site preparation operations, positive surface drainage should be maintained to prevent the accumulation of water. After stripping, areas intended to support new pavement and/or new fill should be carefully evaluated by a geotechnical engineer. At that time the engineer may require proofrolling of the subgrades with a 20 to 30-ton loaded truck or other pneumatic-tired vehicle of similar size and weight. Proofrolling should be performed during a time of good weather and not while the site is wet, frozen, or severely desiccated. The purpose of the proofrolling is to locate soft, weak, or excessively wet soils present at the time of construction.

The proofrolling observation is an opportunity for the geotechnical engineer to locate inconsistencies intermediate of our boring locations in the existing subgrade. Any unsuitable materials observed during the evaluation and proofrolling operations should be undercut and replaced with compacted fill or stabilized in-place. The possible need for, and extent of, undercutting and/or in-place stabilization required can best be determined by the geotechnical engineer at the time of construction. Once the site has been properly prepared, at-grade

6.2 Structural Fill Placement and Compaction

Based on the boring data, structural fill may be constructed using the non-organic on-site soils or an off-site borrow source having a classification of GW, GP, GM, SW, SP, SM, SC, CL or ML as defined by the Unified Soil Classification System (USCS). All fill materials to be used on site should have a maximum liquid limit (LL) of 40 and plasticity index less than 15. Other materials may be suitable for use as controlled structural fill material and should be individually evaluated by the geotechnical engineer. Controlled fill should be free of boulders, organic matter, debris, or other deleterious materials and should have a maximum particle size no greater than 3 inches. In addition, we recommend a minimum Standard Proctor (ASTM D 698) maximum dry density of approximately 100 pounds per cubic feet for fill materials.

Predicated on the boring and laboratory results, and the recommendations provided above, the best time for construction of the structural fills and compacted subgrades would be during the warmer, drier months of the year, such as from late April through early October. During this time frame, on-site soils that are wet of optimum can usually be dried to near optimum levels with relatively little effort. If grading is performed during the colder, wetter months of the year, such as late October through early April, and suitable dry materials are not available on site, then off-site drier borrow sources will likely be necessary.

Page - 14 -

Fill materials should be placed in horizontal lifts with a maximum height of 8 inches loose measure. New fill should be adequately keyed into stripped and scarified subgrade soils and should, where applicable, be benched into the existing slopes. Where construction traffic or weather has disturbed the subgrade, the upper 8 inches of soils intended for structural support should be scarified and re-compacted. During fill operations, positive surface drainage should be maintained to prevent the accumulation of water. We recommend that structural fill be compacted to at least 95 percent of the Standard Proctor maximum dry density (ASTM D 698). In confined areas such as utility trenches, portable compaction equipment and thin lifts of 3 to 4 inches may be required to achieve specified degrees of compaction.

In general, we recommend that the moisture content of fill soils be maintained within three percentage points of the optimum moisture content as determined from the standard Proctor density test. Excessively wet or excessively dry soils should not be used as fill material without proper drying or wetting.