Design Narrative.pdf

AE Replace Roof Building 69 and 139 Project No. 542-23-201

DESIGN NARRATIVE

For Bid Submission

1400 Blackhorse Hill Road Coatesville, PA 19320

May 01, 2025

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission VA Project # 542-23-201 05/01/2025

TABLE OF CONTENTS

1.0 Project Overview 3

1.1 Executive Summary 3

1.2 Project Understanding 4

2.0 Architectural Design Approach 7

2.1 General 7

2.2 Assessment of Existing Conditions – Building 139 7

2.3 Assessment of Existing Conditions – Building 69 22

2.4 New Roof Design Recommendations – Low-Sloped

Roof Areas (Buildings 139 and 69)

2.5 New Roof Design Recommendations – Steep-

Sloped Roof Areas (Buildings 139)

2.6 Skylights 36

2.7 Natatorium Enclosure 38

2.8 Code Abstract 39

2.9 Calculations 40

3.0 Electrical Design Approach 40

4.0 Mechanical and Plumbing Design Approach 41

5.0 Structural Design Approach 43

5.1 Building 139 43

5.2 Building 69 44

5.3 Structural Design Criteria 45

6.0 Site Design Approach 45

7.0 Construction Phasing 47

7.1 Phasing Plan Development 47

8.0 Contract Administration 47

9.0 Hazardous Material Survey 48

10.0 Construction Cost Estimate 48

11.0 PA SHPO Submission 48

Appendices Appendix A Project Schedule Appendix B Catalog of Roof Mounted Equipment/Penetrations Appendix C Specifications Index Appendix D Environmental Report Appendix E ICRA / PCRA

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

1.0 Project Overview

1.1 Executive Summary

The Pettit Group, LLC (Pettit) has been contracted by the U.S. Department of Veterans Affairs (VA), to provide A/E services at the Coatesville VA Medical Center, 1400 Blackhorse Hill Road, Coatesville, PA 19320 for Project No. 542-23-201 Pettit will conduct this work under Contract Number 36C244D0067 Task Order 36C2442N0419.

The Pettit Group will be working with the following companies to deliver this project to the Coatesville VAMC:

The Pettit Group: Architectural Design

Contract and Project Management

Quality Control

Keast and Hood: Structural Design

NEI: Mechanical Design

Electrical Design

Plumbing Design

TTI: Hazardous Material Investigation Services

OCMI: Cost Estimating Services

Garland Co.: Roofing Consultant

The Coatesville VAMC Team has been identified as follows:

Elizabeth Wilson Contracting Officer (CO)

Vanessa Chmielewski Contract Specialist

Michael Wilcox Contracting Officer Representative (COR), This For Bid Submission includes architectural, mechanical, electrical, plumbing and structural drawings.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

1.2 Project Understanding

The property is located at the southwest intersection of East Kings Highway and North Calin Road, outside the incorporated limits of Coatesville in Chester County. The site is an existing VA Medical Center.

As per the General Scope of work provided in Attachment B (Requirements For A/E Services for Construction Documents and Construction Period Services to Replace Roof Building 69 and 139 Project No. 542-23-201 At the VA Medical Center, Coatesville, PA, our understanding of the project is as follows:

This project provides design service for a demolition, abatement, repair, and replacing of the roof of buildings 139 and 69 at the Coatesville VA Medical Center. The Pettit Group will fully investigate and provide an accurate plan to perform the required services to fully and efficiently repair and replace the designated roofs for each building.

Building 139: Patient Dining Hall

These services denoted in the design created and provided by the Pettit Group will fully encompass the abatement of any asbestos, lead, and other hazardous materials and the replacement and repair of the roof of Building 139 in its entirety including both the pitched asphalt shingle and the flat (low slope) EPDM roofing. This will include the protection and preservation of the existing facilities.

There are skylights on the flat (low slope) EPDM roof that were to be removed. The scope of work has been modified by the Coatesville VAMC to no longer require the skylights to be replaced. The existing skylights will be removed in their entirety. The remaining voids left by the existing skylights will now be in filled and covered with roofing membrane. The existing lightning protection will be removed and replaced with code compliant protection equipment.

• Demolish the current pitched asphalt shingled roof of Building 139 as well as the flat (low slope) EPDM roof section over half of the building space.

• Due to a change in scope by the Coatesville VAMC there is no longer a requirement to provide temporary freezer plans for the food storage space that will be affected by the changing of the rail curbs on the roof. (Alternates noted in the body of this document)

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

• Phasing plans will be developed with assistance from the CVAMC to phase temporary relocation of refrigerated and frozen goods within the existing kitchen utilizing existing walk in cooler and freezers.

• Provide plans for new curb rails for equipment with proper maintenance clearances taken into amount.

• Repair structural damage due to leakage and age as needed and required for Building 139’s roof structure. (Interior building work is outside the scope of this project)

• Replace pitched asphalt shingle roofing as well as the flat (low slope) EPDM roofing of Building 139 with pitching to ensure proper drainage.

• Remove the lightning protection on the roof and replace it with code complaint lightning protection equipment for Building 139.

• Due to a change in scope by the CVAMC, there is no longer a requirement to remove, repair the surrounding area, and replace the skylights above the patient dining hall in Building 139.

• The voids in the roof where the skylights currently are located will be infilled and add roofing material applied over the substrate similar to the adjacent conditions.

• The existing sconce lighting in the skylight lightwell are to be removed, with remaining surfaces patched and repaired as necessary.

• New pendant fixtures are to be installed in the existing lightwell utilizing existing circuitry.

• Drywall areas adjacent are to be repainted as noted in construction documents.

• New walking pads to be added to access required equipment.

• Remove two trees alongside the building that have their limbs resting on or hanging over the roof of Building 139.

• Protect the integrity of the equipment that is to be preserved on the roof that will be removed and reinstalled to replace the roof of Building 139.

Building 69: Physical Medicine and Rehabilitation, KT, OT, PT, Audiology, Speech, Prosthetics

For building 69, these services denoted in the design created and provided by the Pettit Group will fully encompass the abatement of any asbestos, lead, and other hazardous materials and the replacement and repair of the roof of Building 69 in its entirety but not limited to its flat (low slope) EPDM roofing. This will include the protection and preservation of the existing facilities.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

There is dunnage on the flat (low slope) EPDM roof that will be removed and the area around it repaired while considering the structural integrity of the roof when performing this task. The lightning protection of the building will be removed and replaced with code required protection equipment.

The Coatesville VAMC has identified existing exhaust fans that are no longer in service which will be removed. Any voids remaining will be infilled and covered with roofing material.

The glazed natatorium will have targeted repairs identified to further ensure it is water tight. This is also a change in scope as directed by the Coatesville VAMC.

This project will provide complete and functional systems in accordance with the Department of Veterans Affairs (VA) requirements, Technical Information Library (https://www.cfm.va.gov/til/spec.asp), industry standards and all applicable code requirements. This applies to each system and every system, which is affected by this project, even if only partially modified. The systems and equipment will maximize energy efficiency to the extent practical.

• Demolish the current flat (low slope) EPDM roof of Building 69 while preserving the integrity of the building.

• Repair structural damage due to leakage and age as needed and required for

Building 69’s roof structure. (Interior work is excluded from this project scope.)

• Replace the (low slope) EPDM roofing of Building 69 as well as any damaged equipment or structure damaged during demolition. All new roofing to be pitched to ensure proper drainage.

• Investigate the space for asbestos, lead, and any other harmful materials as well as creating a plan to abate it within Building 69’s construction zone as applicable.

• Remove the lightning protection on the roof and replace it with code required lightning protection equipment for Building 69.

• Investigate the structural effect of removing the dunnage on the roof of Building 69 and how it can be efficiently and safely done with minimal impact on the structural integrity of the building.

• Walking pads to be installed to allow access to required equipment.

• Protect the integrity of the equipment that is to be preserved on the roof that will be removed and reinstalled to replace the roof of Building 69.

• The glazed natatorium will have targeted repairs identified to further ensure it is water tight.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

2.0 Architectural Design Approach

2.1 GENERAL

Technical disciplines include but are not limited to architectural, structural, mechanical, electrical, abatement of ACM if any are encountered, and construction cost estimating.

The design will comply with VA-adopted codes and standards including VA Directives, Design Manuals, Master Construction Specifications, Design Criteria and other Guidance on the Technical Information Library (http://www.cfm.va.gov/til/).

2.2 Assessment of Existing Conditions - Building 139

The purpose of this evaluation is to detail the conditions of existing roofing materials;

assess performance of present design and detailing; and provide recommendations for improved performance of the new roof design.

Low-sloped (EPDM) and steep-sloped roof sections

The low-sloped roof areas include the main roof level, which is the largest contiguous area of roofing. This area contains 3 roof monitors (clerestory spaces that allow daylight into the interior) which are situated approximately 10’ higher in elevation but otherwise share similar features to the main roof. A separate roof area at lower elevation to the southwest of the main roof covers a portion of the lobby space and runs follows the corridor connecting buildings 139 with buildings 57 and 58. One additional roof section adjacent to the loading dock on the west side of the building also has a low-sloped roof. Black EPDM membrane is installed over all of the existing low-sloped roof areas of the facility.

The two steep-sloped roof sections of the building are both roofed with asphalt shingles. The first area is the penthouse mechanical room and the other is located along the southwestern perimeter of the facility, covering the connecting corridor between 57 and 58 as well as the entrance lobby.

Field:

The existing roof membrane is a 60 mil, single-ply EPDM membrane fully adhered (glued) to the underlying insulation.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

• The typical complete assembly is as follows:

• Steel Deck

• Plastic Vapor Barrier

• Gypsum Thermal Board

• Tapered Polyisocyanurate Insulation (1/8” per foot slope)

• 60 mil EPDM

This image shows Insulation Assembly from roof core, showing gypsum board on the left and polyisocyanurate on the right

Since the insulation is tapered, the R-value varies across the roof and cannot be calculated exactly. On the main roof area, the insulation thickness starts at approximately 2” or 2 ½” and gains 1” every 8’ moving out from the valleys. The high points vary from 5-6” thickness, potentially thicker in localized areas but often thinner in narrower areas of the roof. The average thickness of the insulation is estimated to be less than 5”, and therefore falls a little short of the current code minimum for R-30.

All roofs share similar construction, with one exception being the roof elevation adjacent to the loading dock which also has a ½” wood fiber cover board installed between the EPDM membrane and the polyisocyanurate insulation.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

This image shows a typical area of the roof, the roof is a black EPDM membrane with marginal slope.

The membrane material itself is in fair condition overall, however there is some damage to the membrane in the form of punctures. This is one of the major downsides of a single ply membrane, they are easily damaged by foot traffic, dropped tools, etc.

A more durable roof system utilizing a multi-ply modified bitumen will be specified for the new roof.

The seams of the roof are adhered with splice tape which generally provides a reliable bond but can fail at T-joints and other interruptions in the continuity of the seams.

Patches are applied over these areas and some other locations. These may have been original to the roof or applied as a repair. Most of these are properly adhered however some are failing where water accumulates due to poor drainage.

This image shows two peeling seams in two locations at the wall flashing.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Organic debris piles were observed in multiple locations (leaves, branches, etc.).

Even with a new roof installed, routine maintenance should include clearing of debris from the roof on a regular basis, to prevent accumulation and issues such as clogged drains.

Example of accumulated organic debris

Drainage:

The existing roof system has tapered insulation installed to create slope to the drains, however the layout of the tapered slope is not well matched to the roof drain layout.

The plan fails to incorporate all of the drains on the roof, so some of the roof drains are essentially rendered inactive because they are not situated in low points.

This image shows the roof drain located within cricket

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

A comparison of the original drawings to the existing conditions reveals that the tapered design for the current roof departs from the original tapered layout when the building was constructed. When the roof was replaced, the new installation favored a 2-way slope configuration, reorienting some of the prevailing slopes.

A more effective drainage layout is needed. The design for the new roof will be to properly incorporate all internal roof drains into the tapered insulation plan. The existing tapered installation provides 1/8” slope which is 50% less than the required minimum ¼” per foot, so that will also be changed to improve overall roof slope. The new roof will be designed to have ¼” per foot slope and ½” crickets to expedite drainage and prevent ponding conditions.

An example of poor slope resulting in ponding water.

Crickets between the roof drains are too shallow in several areas. The minimum ratio of distance between drains to cricket width is 3:1 but several of the crickets fall short of that minimum.

There are overflow scuppers cut through the parapet walls in various locations around the roof perimeter. These provide emergency overflow capacity and should be maintained. One of these was improperly closed in during the last roof project and should be re-opened with the new roof installation. Others are installed but not properly sealed against water intrusion from the exterior side.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Image of a “Forgotten" overflow scupper at southwest corner of the main roof area.

This is another overflow scupper, with no exterior trim to seal against water intrusion

This is an example of an existing internal drain. It is recommended that all drains be replaced with new cast iron units with the roof replacement project.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Perimeter Conditions:

The prevailing perimeter condition is a parapet wall with a limestone coping. When the building was originally constructed, the first roof system was installed before setting the stone copings on the parapet wall. This old EPDM flashing beneath the stones is still in place and the building waterproofing is dependent upon it. Unfortunately, it is failing in numerous locations where exposed; and can be expected to also have splits where it is concealed.

Figure 1: Here is one of several examples of the old flashing membrane split with a direct path for water entry into the building. The new roof cannot rely on this material.

Figure 2: These are the original limestone copings, cracks existing in both the joints between stones as well as the mortar bed in which the stones are set.

Where the roof meets a masonry rising wall, there is typically a through-wall flashing in place at the brick veneer. This condition can be found at the penthouse wall, at the elevation change between the main roof and the lower-level hallway roof, and at the roof monitors. In general, the through-wall flashings appear to be performing properly, however the height that these flashings are set into the brick will be a problem with the new roof, which will have a

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission thicker base layer of insulation and a steeper pitch once converted to ¼” per foot slope. With the new roof design, these will be raised to prevent water infiltration.

This shows the rising wall from the loading dock roof area with a two-piece through-wall counterflashing receiver and insert.

A unique condition exists specifically at the clerestory/monitor walls. The brick walls are exhibiting signs of moisture within the masonry. This can be attributed to the limestone copings leaking at the joints above, where mortar has cracked, and potentially absorbing water on the face as well. At the base of each wall, there is a through-wall counterflashing which provides a barrier to this water getting down into the interior space. Unfortunately, similar to other areas, this flashing is too low and will be designed to be raised to prevent water intrusion.

The dark colored mortar joints are an example of areas of moisture within the masonry working its way back

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

One other rising wall condition to note is at the intersection with the adjacent buildings.

Where the roof of Building 139 meets Building 58, there is a reglet style flashing cut into the wall. This is also too low but is much simpler to raise since this is a mass wall.

Reglet mounted counterflashing set in the wall at the junction with building 58.

The final perimeter condition for the low-sloped roof areas is the intersection of the membrane roof with the shingle roof at the hallway connector between 57 and 58. The flashing membrane between the shingle and EPDM roofing is dry rotted, cracked, and failing.

Cracking flashing membrane along length of shingle roof intersection, sealant is applied over the cracks but is ineffective.

The penthouse rising wall is a brick wall with a through-wall flashing similar to the roof monitors and other rising wall conditions on the facility. The door threshold is a solid curb with EPDM flashing run over the curb and terminated inside. This will be designed to be further protected from foot traffic with a metal sill plate installed over the finished roof membrane to prevent damage to the roof on the edge of the step.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Projections and Equipment:

There are a number of condensers on the roof set on free-standing supports. These are functional but not as stable as supports anchored to the structure and flashed into the roof system. With the new roof system, the insulation height will be increasing in numerous areas.

New supports will be designed to be to create the proper height. The orientation of the supports, wherever possible, will be aligned with the roof slope to allow water to drain through.

Typical condenser set on freestanding rails.

Each condenser is served by refrigerant pipes and wiring that is routed through the roof.

These penetrations are made watertight with pitch pockets. Some of the sealant was poured around the insulation and is not properly sealed to each pipe. These are also aging so the sealant is in need of replacement. Existing pitch pockets will be replaced with a roof penetration housing curb to provide lower-maintenance for the pipe penetrations.

Pitch pocket for condenser penetrations through roof

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

The roof has a perimeter warning line and fall protection railings set up on the roof. These are freestanding on weighted bases which are a good option for the roof to prevent unneeded penetrations and flashings into the roof. These will be noted to have a protection pad set beneath each stand to prevent potential damage to the roof membrane.

This shows one of the stands set on the roof without any protection pad beneath it.

The remaining projections through the roof include plumbing stacks, powered ventilators, gravity vents, and some other miscellaneous equipment – all of which are standard rooftop projections. Some pieces of equipment will need to be raised with the new roof but they do not pose any significant challenges, except some potential electrical work to extend wiring where needed.

This image shows an exhaust fan on a standard curb and a round projection with a cap, obsolete equipment curbs can and should be closed in with the new roof.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Steep-Sloped Roof Areas – Review of Existing Conditions

Field:

Building 139 has two steep-sloped roof areas – the penthouse and the corridor/entrance lobby roof area. The age of each section is unknown but the shingles are different styles so the installations were likely from different timelines. The penthouse roof appears to be older.

The penthouse composition is a steel roof deck with a nailboard insulation on the decking (this is a composite of insulation and plywood). The roof is an asphalt shingle over an underlayment membrane. The corridor/lobby roof is a similar composition of asphalt shingle over membrane underlayment on a plywood deck. The penthouse roof has 8:12 slope, the shingle roof on the lobby is a 6:12 and the corridor area is a 4:12 pitch. On the penthouse roof, there are some concerns with ridging that can be observed through the shingles. This is an indication of warping of the plywood substrate. It can be caused by improper fastening leaving a loose or unsecured edge, or by water infiltration or overheating due to poor ventilation which is warping the wood. The corridor roof is not exhibiting this problem.

This shows the penthouse roof, some of the ridging effect can be observed across the field.

The corridor roofs are in better condition than the penthouse roofs, the substrate poses less of a challenge for asphalt shingle performance than the steel penthouse structure

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

There is no concern with moving water due to the steep slopes, but the penthouse roof lacks any control of water exiting the roof since the design does not incorporate gutters. Water spills off the roof edge to the lower roofs surrounding the penthouse. The corridor and entry roof does have gutters on the exterior facing roof edges. These also have screens to keep leaves and other debris out of the gutters.

The shingle roofs on the corridor drain towards the front into gutters, on the opposite side down onto the low-sloped roof area.

Perimeter Conditions:

The penthouse roof perimeter is in poor condition. The fascia, original to the building, is loose in at least two locations. When this roof was last replaced, the new shingles were installed without any drip edge detailing at the eaves and rakes. The shingles are properly overhanging the edge, so most of the water drips off the roof. However, this condition leaves open the possibility for some volume of water to track backwards beneath the shingle and into the structure. Without the drip edge, the wood blocking and edge of the plywood deck are exposed to repeated wet conditions. This is suspected to be a contributing factor to the fastener failure of the decorative fascia.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Detached fascia on the west elevation.

Another example of loose fascia and missing drip edge detail.

The existing assembly is 2” thick above the steel deck. With the plywood nailer, there is at most 1.5” of insulation within the system. This equates to an R-value of 8.6 or less if there is an air gap in the assembly. The penthouse may not require the typical R-30 standard due to its use and the nature of the space. If that is required, the new roof can be designed with increased insulation.

The penthouse roof edge overhangs the penthouse walls by several feet. Below this overhang is a metal soffit panel with small circular vents cut in. The ridge appears to be vented but not the hips. With the steel decking and solid wood at the eave as observed where the fascia is loose, it is unclear if or how air flows into the space below the shingles where needed to remove excess heat build-up. The corridor roof is also vented at the ridge and has vented soffit at the overhangs.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

The corridor roof has no projections. There is lighting protection cable running across the roof and the clips are fastened through the shingles, which is a poor detail but will only allow very minor water intrusion. The penthouse roof projections include pipe stacks through the roof and vents on curbs.

An example of several projections through the penthouse roof including some pipe penetrations and gravity ventilators on curbs. Crickets are required behind the large vent curbs.

This shows two flashing techniques, the smaller pipe has a premanufactured pipe boot, the larger has a sleeve with a rain collar above - both details are dependent on caulk applied as a repair.

Lightning arrestor clips are attached through the shingles with sealant beneath.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

2.3 Building 69: Assessment of Existing Conditions

The low-sloped roof areas include a large main level roof area, separated roughly down the center by an expansion joint. There is also a small canopy over a loading dock area on the east side, and a separate, higher elevation roof area in the northwest corner of the building.

Black EPDM membrane is installed over all of the existing low-sloped roof areas on this facility and all roofs appear to be of similar vintage. The adjacent shingle roof area on a connecting corridor and the therapy pool enclosure structure are not part of this project and evaluation, except may be mentioned where relevant for tie-in details.

Low-Sloped Roof Areas – Review of Existing Conditions

Field:

The existing roof membrane is a 60 mil, single-ply EPDM membrane fully adhered to the underlying polyisocyanurate insulation. The typical complete assembly on the main roof area is as follows:

• Steel Deck

• Tapered Polyisocyanurate Insulation (1/16” per foot slope)

• 60 mil EPDM membrane

Insulation Assembly from roof core, showing two layers polyisocyanurate. Note the discolored foam on the right side – this is the top of the core and the foam is deteriorated from high heat due to proximity to the black roof surface.

There is some slight variation on the other two roof sections which each have 1/8” tapered insulation. The canopy on the east side is a wood deck instead of steel deck.

The main roof area is tapered, however the slope is very low – measured at 1/16” change per foot. On this roof, the average thickness of the insulation is estimated to be between 3 and 4 inches, which would correspond to an R-value between 17 and 23. The goal with the new roof will be to achieve an R-30 or higher to meet code and improve energy efficiency.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

This image shows a typical area of the roof, the roof is a black EPDM membrane with poor slope.

Puncture through the roof membrane.

In addition to noted damage to the roof surface, there are some locations where the insulation is warped due to water absorption and subsequent deformation.

Warped insulation due to past water damage.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

The membrane material itself is in poor condition overall. Similar to Building 139, there is some damage to the membrane in the form of punctures and cuts. This is one of the major downsides of a single ply membrane, they are easily damaged by foot traffic, dropped tools, etc. A more durable roof system utilizing a multi-ply modified bitumen assembly will be specified for the new roof.

Because this is an older roof system, there is also evidence of seam issues. Unlike Building 139’s roof, these seams are glued and sealed with lap sealant on the outside edge. Glued seams are not common anymore because they were less reliable seals. There are examples of broken-down lap sealant on the roof now and lifting seams, especially T-patches and other reinforcing patches around drains and other key areas.

This shows loose edges of patches around a drain flashing target membrane.

Several feet of seams have been coated to resolve previous issues with seam integrity.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

This roof does not have as many concerns with debris as Building 139, but there are some areas of accumulation and dirt caked around roof drains.

Example of accumulated organic debris

The original drawings from 1960 show a built-up roof design, which was most likely a coal tar pitch system. Coal tar is the only roofing product approved in the building code for slopes less than ¼” per foot, due to its unique chemistry and characteristics as a waterproofing product.

The existing roof system has tapered insulation installed to create slope to the drains, however the tapered slope is too shallow, resulting in poor overall slope which falls short of minimum design standards. The new roof will have tapered insulation following a similar layout, except it needs ¼” per foot slope to more effectively move the water.

The roofs have 2-directional slope with crickets located in the valleys

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

The center of the cricket follows the true low point of the roof. The drains are offset from the low point. This is typically due to structural members obstructing the plumbing.

Larger sumps will be incorporated in the new design (8’x8’ wherever possible) in order to overcome the drain placement offset from the true low-point in the roof.

The loading dock canopy slopes towards the building to a single roof drain.

Perimeter Conditions:

The roof perimeter at the exterior edges is a metal fascia flashed into the roof with a fascia extender. There is some damaged or loose fascia extender, both on the north side of the building as well as the loading dock.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

This is the typical exterior edge as viewed from the ground. A metal fascia integral to the roof system and one extender that sits below it. There is a gap at each window bank where the stucco façade is recessed.

There are two small rising wall details, where the canopy roof meets the main roof and where the building elevation changes at the northwest corner. These two walls have existing brick exposed masonry with a through-wall counterflashing set in the brick. With increased height of tapered insulation, these flashings will be eclipsed by the new roof. The new roof detailing will include membrane flashing all the way up the wall terminating under the adjacent fascia.

At the pool enclosure, the pool wall is flashed with EPDM membrane that terminates beneath a sill under the glass curtain wall.

Lastly, there is a small intersection with the shingle roof on the corridor roof section that connects to Building 69 at the southwest corner.

The curb detail where the pool enclosure meets the flat roof area is flashed with membrane terminated beneath the sill.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Intersection of adjacent building shingle roof and Building 69 roof membrane. Replacement of the roof will necessitate some disturbance and patching to the shingle roof to create a watertight transition.

A large number of projections through the roof are obsolete and will be removed with the new roof project. This includes steel dunnage, capped curbs, unused rails, and capped pipe projections through the roof.

This is a view looking east, several obsolete projections can be seen including unused curbs, rails, and the steel dunnage in the background

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

There is very little clearance between the steel and the roof. This is likely the reason why such a shallow tapered insulation system was selected when this roof was installed. Removal of the dunnage clears the way for proper tapered design.

Existing equipment still in use will remain with the new roof system. This includes exhaust fans and plumbing stack penetrations through the roof, passive vents, and convenience outlets on posts that are flashed with pitch pockets. Raising equipment will be necessary in some locations with the new tapered insulation system. Some of the plumbing stacks or pipes through the roof have boots which are pulled down and not properly shedding water.

This may be from movement of the pipes. All pipes through the roof which are active and in use will be stabilized as needed with pipe deck clamps to prevent settlement and disruption to the flashings.

Pipe penetration through roof with a collapsed pipe boot.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Obsolete pipes wrapped with tape/sealant to be removed.

2.4 New Roof Design: Low-Sloped Roof Areas (Building 139 and 69)

Roof replacement encompasses a complete tear-off of all membrane, flashings, and insulation down to the structural roof deck followed by installation of a complete new roofing system including all insulation, flashings, and accessories.

On Building 139, the existing roof assembly includes a gypsum board directly on the roof deck. This is a design choice to increase fire rating of the roof assembly and should be maintained. The new roof assembly will start with a 5/8” gypsum board laid over the metal decking. There is also a vapor barrier membrane installed currently. A new vapor barrier that also functions as an air barrier will be installed on top of the gypsum thermal board. This will be a self-adhesive and self-sealing membrane so that it continues to function as an air barrier after subsequent layers of roof insulation are fastened in place.

Building 69, since it does not have kitchen space, does not currently have these design elements and they would not be required for the new roof system. An air barrier directly on the roof deck of building 69 is an option for enhanced energy efficiency.

The standard system will include ¼” tapered insulation to enhance the drainage. The added slope on the roof, along with good sumps at the scuppers and crickets between, will make a drastic improvement to the roof drainage performance. This will also bring these roof designs in line with the VA’s standards for design as well as building code requirements for slope in the roof. The new insulation will provide some improved thermal performance as well, providing some energy savings payback after the roof is completed. An R-value average of 30 or more will be the target for each building.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

This chart shows how R-value increases provide diminishing returns, and there is very little benefit to going above the code-required R-30. Air leakage reduction is just as important and additional air sealing measures provide a 1:1 payback.

The increased height of insulation will be a challenge due to restrictions at the rising walls with flashing heights. The new design will include new through-wall flashings. Without one of this change, there will be leaks that occur behind the wall flashings. These modifications are needed at the three brink monitors located on the roof of Building 139.

New through-wall flashing involves removal of brick veneer to access the wall cavity, installation of the new flashing detail, then replacement of the bricks to close the wall upon completion.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

New roof insulation will be mechanically fastened to the roof decking. The fastening pattern will be based on ASCE 7-16 methodology and the roof system manufacturer’s system testing.

This is a code requirement and is vital to ensure that the new roof is properly designed to withstand uplift during severe weather. The new roofs will be more resilient and resistant to catastrophic failure, which is currently a concern especially with Building 69. After the new polyisocyanurate insulation is installed, the final layer of insulation is 1/2" cover board. This will consist of gypusm, perlite, or wood fiber. The cover board is denser than the insulation and provides a beneficial substrate for the new roof membrane.

There are many options for new roofs but the best is modified bitumen. It is more durable than EPDM or any other single ply system, is thicker and heavier so naturally has better wind resistance, and has a good track record for durability, longevity, and is less prone to leaks through the multi-ply system. The roof assembly would include an 80 mil thick base layer and a 155 mil surface layer. The base sheet and the cap sheet are both manufactured with SBS modified asphalt, a mixture of asphalt and rubber polymers that enhance flexibility. Fiberglass and polyester scrims within the sheets are manufactured to infuse strength and stability into the membranes. The end result is a strong, thick and durable waterproofing system. The redundant nature of the 2-layer construction provides extra protection against potential leaks. The overall thickness of the system and the durable membranes make the roof difficult to puncture or cut, so it is not prone to damage like the current roof systems. The membranes are installed using zero-VOC adhesives with virtually no odor, so the re-roofing process will not have disruptive odors. Membranes that incorporate recycled content would be selected to in pursuit of sustainability objectives. The roof surfacing is a factory applied granule. This is beneficial as it gives better traction than a single-ply membrane and is often preferred by many facility personnel that access the roofs for maintenance.

New roof assembly detail for proposed roof system.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Along with the new roof, new flashings at all perimeter and curbs will be installed. This would include new 2-ply membrane flashings and new perimeter metal. All of the new perimeter metal will be a .050 aluminum, kynar finished metal coping caps or fascia. This will last the life of the roof system and provide a clean finished aesthetic for the building. Only ANSI- SPRI ES-1 tested and approved metal edge products that are designed to perform through severe weather will be utilized. The edge metal should be sourced from the same manufacturer as the roof membrane to obtain a complete system warranty covering both components together. The new roof would be warranted for 30 years with a No Dollar Limit, Edge-to-Edge warranty that covers both the roof membrane and the perimeter metal.

The typical perimeter detail at Building 139 will be a metal coping cap installed over the existing parapet wall.

The typical edge condition at Building 69 will be a new fascia. Fascia extenders (not shown) will also be necessary. Note the air barrier continuity to the outside edge.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

It is best practice to install new cast iron roof drains with a new roof system. This will include new cast iron bowls, clamping rings, strainers, and hardware.

Specific details for each roof area will be developed to address flashing conditions for projections and equipment. The condenser supports on Building 139 are one specific area that is called out for improvement. Instead of the existing rail curbs free-standing on walkway mats, the new rail curbs can be installed attached to the deck and flashed into the roofing system.

Typical equipment rail support detail. The base will be elevated on wood blocking where the insulation thickness requires additional height for clearance.

Another potential upgrade for consideration in place of the standard pitch pocket flashing detail for condenser refrigerant piping and control wiring by installing roof penetration housings.

Figure 3: Roof penetration housing example.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

Alternative Roof System Options:

The above-described roof system can be finished with a bright white surface coating as the final surfacing for enhanced reflectivity and UV shielding which may further contribute to energy efficiency. This coating would enhance the surface resilience of the roof system mentioned above and lead to longer life expectancy because of the extra protection from weathering and UV radiation.

A third option to consider is a hybrid system utilizing a thermoplastic membrane installed over a modified bitumen base sheet. The replacement would be nearly identical to the first option, with a complete tear off to the deck, followed by new insulation with drainage improvements via tapered insulation, a cover board, and the modified bitumen base sheet. The difference is in the final layer, which in this case is a smooth, thermoplastic KEE membrane in place of the mineral-surface modified cap sheet. The KEE membrane has a smooth, white reflective surface and the seams are welded to create a strong, monolithic final layer. This installation can be completed with a 2-component foam adhesive which is low-odor process that won’t create issues inside the facility.

Note Regarding Existing Roof Restoration Compatibility:

It is a good idea whenever possible to review options for restoration of an existing roof, rather than a complete tear-off. Unfortunately, the general condition of all low sloped roof areas on the two facilities do not lend themselves to restoration products. Almost none of these roof areas have functional drainage design. It is irresponsible to restore a roof with ponding conditions or otherwise inadequate drainage – even if the products specified claim to resist ponding water. A secondary concern with restoration is that the underlying membrane adhesion cannot be guaranteed. Older EPDM roofs exhibit a loss of adhesion over their lifespan for numerous reasons. One of which is the high heat of the black surface that deteriorates the underlying insulation and weakens the overall bond and wind resistance of the roof. Catastrophic failures often occur to aged EPDM roofs where the wind resistance has fallen below the needed threshold. These roofs are not good candidates for repair or restoration and the plan for replacement is justified.

2.5 New Roof Design : Steep-Sloped Roof Areas (Building 139)

The shingle roofs are scheduled for replacement and can be replaced in-kind with new asphalt shingle roofing. That process would involve tear-off down to the plywood substrate of each roof section. The corridor and lobby roofs will be replaced with similar architectural shingles over an underlayment. The penthouse roof will require replacement of the entire

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission nailboard assembly with a new vented nailboard to have a successful roof installation. This offers the opportunity for increased insulation thickness if there is a need for further insulation over the penthouse space. Proper detailing, such as the inclusion of trim at the eaves, rakes, and other flashing details, will provide better performance than the existing roof. The existing soffit and fascia can be maintained with repairs to the loose pieces.

2.6 SKYLIGHTS

The existing dining hall (Building 139) currently has two large multi-pane skylights which measure 52’-9”x5’-10”. These appear to be originally installed skylights and are exhibiting signs of failure. The gaskets/seals are failed or failing and surface caulking over them has not been successful. The membrane flashing detail at the skylight curbing appears to be a similar condition to the parapet wall, where the old roofing membrane was flashed to the curb before the skylights were set in place. When the facility was reroofed, the new membrane was sealed to the old roof flashing. This original roof is not viable any longer but still is being relied upon. There is a counterflashing extension providing some protection over this detail but the problem won’t be fully resolved until the new roof installation is complete and a new skylight is installed or one of the options below is implemented.

This shows the skylight with condensation on the panes, the gaskets have failed and sealant applied to the surface is needed to stop water infiltration

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

These skylights are currently blocked off with a fixed canvas sheet, so the skylight and the sky beyond are no longer visible from the interior of the building.

Existing interior view of the skylights

The dining hall is well lit with natural daylighting currently with no additional light provided from the skylights. With the skylights not offering natural light currently the Coatesville VAMC has directed Pettit to omit the skylights.

Existing daylighting conditions in the Patient Dining Hall of Building 139.

The design will be developed to infill the existing skylights with light gauge framing and roof over the former opening with similar roofing materials. On the interior of the dining hall the design will be developed to infill with drywall and painted white. The voids in the roof where the skylights currently are located will be infilled and add roofing material applied over the substrate similar to the adjacent conditions. The existing sconce lighting in the skylight lightwell are to be removed, with remaining surfaces patched and repaired as necessary.

New pendant fixtures are to be installed utilizing existing circuitry. Drywall areas adjacent are to be repainted as noted in construction documents.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

EXISTING PROPOSED

2.7 Natatorium Enclosure

It was visually observed on the interior of Building 69 that there was water damage in the pool area where the glass enclosure meets the building. Also in the ceramics studio which is also on this same connection line. It was noted by staff that on days of heavy rain that the infiltration is visibly noticeable. (See figure below : The heavy redline indicates the line of water infiltration observed.

Coatesville VAMC, Coatesville PA AE Replace Roof Building 69 and 139 For Bid Contract Document Submission

As these images show there are other contributing factors to potential water ingress during wet weather:

• Seals at sill failing directly above where the building and roof meet

• Vertical downspouts draining directly where the building and roof meet. These should be extended or diverted

• Connections at gutters failing directly above where the building and roof meet

• There is also a window that needs to be replaced.

There was no visible condensation in the glass panels which is a good indicator that the seals are still intact.

2.8 Code Abstract

All work shall be designed, furnished and installed in accordance with the following codes:

• VA TIL PG 18-15 Volume C - A/E Submission Instructions for Minor and NRM Construction Program. dated November 2008

• VA TIL PG 18-3 – DESIGN AND CONSTRUCTION PROCEDURES dated September

• VA TIL CODES, STANDARDS & EXECUTIVE ORDERS 1-1 TOPIC 1 – CODES,

STANDARDS AND EXECUTIVE ORDERS

• VA TIL PG-18-1 - MASTER CONSTRUCTION SPECIFICATIONS

• VA TIL PG-18-10 - DESIGN MANUALS

• VA Directives,…