Site visit minutes to post.doc

20 April 2009 SUBJECT: Site Visit Minutes

REFERENCE: Repair STRATCOM Roof

SOLICITATION: FA4600-09-B-0004

A A site visit was accomplished in connection with this solicitation, FA4600-09-B-0004, Repair STRATCOM Roof, Bldg 500. The site visit was held on 9 April 2009 at 0900. All contractors were given until 15 April at 1600 to submit questions in writing. Prior to the site visit conclusion, all prospective bidders were afforded one last and final opportunity to ask questions.

B Below are a list of questions and answers from the prospective bidders, or issues brought up by the Government.

KHA RESPONSES IN RED TEXT BELOW.

GOVERNMENT RESPONSES IN BLUE TEXT.

1. Section 075200 Modified Bitumen Roofing System- A. Scope calls for this system to be installed over the (LCIC) System

• The Roofing Schedule on Sheet A.2 shows all roofs over LCIC to be TPO Roofing System

• Clarify where Modified System is to be installed

KHA Response: See portion of spec section 07 52 00 pg.1 below:

“SCOPE

Extent of built-up roofing (BUR) system work as indicated on the Drawings and by provisions of this Section is defined to include roofing and accessories integrally related to roofing installation at existing concrete roof deck areas shown on the Drawings. This work occurs only below areas shown on the Drawings to receive lightweight cellular insulating concrete (LCIC) system.”

Also see detail 3/2.5. The BUR is only used below LCIC system as a temporary waterproofing system until LCIC and new membrane is installed.

2. Section 075200 B. Products- Roofing System refers only to a SBS Glass Torch Base Sheet. No Surface Cap Sheet is mentioned. In order to receive a 20 Year Warranty over Lightweight Concrete there needs to be a mechanically Fastened Base sheet, SBS Torch Base and SBS Torch Cap Sheet.

• Clarify what is the entire system to be used

• What are the weight and type of sheets are to be used

• See Attachment of a sample assembly of 20 Year Modified Roofing system over LCIC

KHA Response: Also see detail 3/2.5. The BUR is only used below LCIC system as a temporary waterproofing system until LCIC and new membrane is installed. Study drawings and specs closely. Believe the information requested is all included. A/E feels the warranty requirement should be eliminated; discussed this with Bruce McCauley on 4/16/09; he agreed. Since we’re only installing part of an assembly, we won’t be able to get a warranty.

3. Section 075423 Membrane Roofing system- B. Products Page 6, Roof Insulation- There is not a thickness given for the polyisocyanurate 4’ 0” x 8’ 0” Boards. Provide Thickness of Insulation and number of layers to be used with the TPO System

KHA Response: Insulation thickness information is on Roofing Schedule on Sheet 2.0.

4. An existing Vapor Barrier is listed under to Existing Roof System. What is the material of the existing vapor barrier and how is it attached to the deck?

KHA Response: Existing vapor barrier information is on the Roofing Schedule on Sheet 1.0. A/E believes in most cases it is hot-mopped. Removal Plan/Legend on Sheet 1.0 says to remove loose felt material.

5. Is any work required on the Existing Copper Standing Seam Roofs on the main roof Area?

KHA Response: Not sure what copper standing seam roofs are referred to …. at louvered hoods? If that’s the question, no work is done to them.

6. Will there be access to the green roof area from the ground level?

KHA Response: As shown on Sheet 0.0, this roof area is only about 2 feet above the ground. As shown on Sheet C1.2, there is access to this area at ground level.

7. What is the approximately time for security background checks and clearance for employees who will be working on site

Gov’t response: AF Form 75 (base passes) will take about 4 hours, and expect the contractor badge for building 500 another 4 hours.

8. What are the working hours especially for the Demolition?

Gov’t response: Hours of operation are 7:30 am - 5:00 pm excluding Saturdays, Sundays and Federal Holidays.

9. Will there be an on site staging area for material and equipment?

Gov’t response: According to 1A-3, #11 "Delivery and Storage of Material" - The contractor shall use only established roadways, entrances and exits as prescribed by the Government Construction Representative. Materials and equipment shall be stored only in designated areas and shall be transported directly to and from the construction site under strict regulations as prescribed by the Government Construction Representative. Materials quantity receipt shall be given to the GCR upon delivery of materials to job site. All items of stored materials, containers, vehicles and other equipment shall be removed from the base prior to final payment.

10. Are there any restrictions for Roof Access with Cranes? Set up areas?

Gov’t response: I believe the crane will be set up in the courtyard in one maybe two different locations. The set up area should be in the courtyard as well. I don't believe Command Security will allow for cranes to be on the grassy areas of USSTRATCOM

11. The existing roof drains are an older style. Will there be new roof drains or roof drain inserts?

KHA Response: Replace the strainers but use the existing drains.

12. Will the contractor be allowed to have cell phones, 2-way radio's or cameras on the jobsite?

Gov’t response: Those devices are not allowed “inside” the building. Mark Oestman, Command Security, said cell phones and two way radios are acceptable “on the roof” while photography must be coordinated with Merle Alexander’s office.

13. In Section 075423-3 Line item 23 - you refer to "standard for polyvinyl chloride sheet roofing". ASTM D 4434 Type 2 Grade 1 is a PVC Not TPO. Is this correct?

KHA Response: delete the following portion of spec section 07 54 23 pg. 5:

“TPO MEMBRANE

TPO membrane for all roof areas shall be as described in paragraph above titled “Description of System”, and shall conform to ASTM D 4434, “Standard for Polyvinyl Chloride Sheet Roofing”. Classification: Type II, Grade 1. Membrane color shall be white. Membrane roll width shall be 6-10 feet.

TPO membrane flashing for all roof areas shall be 60 mil fiberglass-reinforced TPO membrane manufactured by the primary roofing membrane manufacturer.

ASTM Test

Min. ASTM

Parameters

Method

Rqmnt.

Solar Reflectance %

E903

Elongation at Break of Fabric, min.,% D751

Seam strength, min., lbf/in.

D1876

Tearing Resistance, min., lbf

D751

Low Temperature Bend, max., deg. F D2137

-40

Accelerated Weathering

G26

Test (Xenon Arc)

Cracking (7x mag.)

None

Discoloration (by observation)

Negligible

Crazing (7x mag.)

None

Linear Dimensional Change, max., % D1204

1.0%

Static Puncture Resistance, 33 lbf D5602

Pass

Dynamic Puncture Resistance, 7.3 ft-lbf D5635

Pass”

Replace with the following:

“TPO MEMBRANE

TPO membrane for all roof areas shall be as described in paragraph above titled “Description of System”, and shall conform to ASTM D 6878, Standard Specification for Thermoplastic Polyolefin Roofing.” Membrane color shall be white. Membrane roll width shall be 6-10 feet.

TPO membrane flashing for all roof areas shall be 60 mil fiberglass-reinforced TPO membrane manufactured by the primary roofing membrane manufacturer.

Parameters

Test Method

Min. Rqmnt.

Solar Reflectance, %

ASTM C1549

Breaking Strength, min., lbf

ASTM D751

Elongation at Break, min.,%

Seam strength, min., lbf/in.

Tearing Strength, min., lbf

Brittleness Point, max., deg. F

ASTM D2137

-40

Weathering

ASTM G151

Pass

Linear Dimensional Change, max., %

ASTM D1204

1.0%

Puncture Resistance

FTM 101C, Method 2031 265”

14. We have spoken to all manufacturer's you have listed and they require a fleece back sheet over the light weight concrete for better adhesion. Is the membrane meant to be fleece back over the light weight?

KHA Response: Membrane must be approved by the manufacturer for use in this application over LCIC. If that means fleece-backed, then that’s what it must be. I checked with several manufacturers on 4/16/09, and they do agree that it must be fleece-backed.

15. For our portion that we are bidding we will need a 2" water hook-up. Is there a fire hydrant or other source of water with a 2" hook-up that we can use close to the building?

Gov’t response: There are several hydrants for hook up.

16. On the roof schedule the pour LCIC portion is listed a 1/8" slope. Would 1/4" per 1" be acceptable?

KHA Response: 1/8”/ft. slope was selected due to not wanting to raise equipment curb heights, penthouse door sills, etc.

17. Is there an average R-value or minimum R-value required for the LCIC portion of the roof?

KHA Response: Desired overall average LCIC ‘R’ value is 30. The limiting factor for this project, however, is matching the existing roof edge construction height, which is not to be altered. See detail 3/2.5. Also see Roofing Removal Schedule on Sheet 1.0 which lists the average existing insulation thickness. The LCIC is essentially replacing the existing insulation thickness in the same slope and shape.

18. What are the roof drains set at (height above the deck) on the LCIC portion of the roof? Will they change or stay the same?

KHA Response: Varies greatly in different areas. Some = 2 ½”, some = 8”. Contractor will have to field verify. Intent is to not redo roof drains, unless they’re broken or non-functioning.

19. Is the lightning protection system a design build?

KHA Response: Yes, it’s a performance spec.

20. Does the light weight concrete have a minimum thickness?

KHA Response: Desired overall average LCIC ‘R’ value is 30. The limiting factor for this project, however, is matching the existing roof edge construction height, which is not to be altered. See detail 3/2.5. Also see Roofing Removal Schedule on Sheet 1.0 which lists the average existing insulation thickness. The LCIC is essentially replacing the existing insulation thickness in the same slope and shape.

21. Does the modified bitumen require a 20-year manufacturer's warranty? This system to be installed UNDER the lightweight.. Why would a 20-year be required?

KHA Response: A/E feels the warranty requirement should be eliminated; discussed this with Bruce McCauley on 4/16/09; he agreed. Since we’re only installing part of an assembly, we won’t be able to get a warranty.

22. Since the existing EPDM roof already has a 20-year warranty, can repairs be made without obtaining a 15-year warranty?

KHA Response: This roof area is already about 5 years into its’ 20-year warranty, hence the requirement for 15 year warranty. Government must answer the rest of this question re: whether contractor can “repair” the existing membrane under the original warranty.

23. Section 075200 – Modified Roofing

This roofing only happens under the LCIC concrete system as stated under scope for this work.

20-yr warranty is not available for this application.

KHA Response: A/E feels the warranty requirement should be eliminated; discussed this with Bruce McCauley on 4/16/09; he agreed. Since we’re only installing part of an assembly, we won’t be able to get a warranty.

Drains will be 3” to 4” above concrete deck when roofing is torn off. How is lead flashing and roofing to be tied into drain?

KHA Response: Lead flashing is not needed in conjunction with modified bitumen membrane installation.

25. Page 10 of Drawings

Item I of roof schedule says “see note 1”, which says that this roof is Option 1. What is Option 1? Can’t find on bid sheet.

Is roof to be bid with base bid and then bid with green roof?

KHA Response: Apparently the Option for the green roof system (that was designed by us as an Option) was changed afterward to be part of the Base Bid. Government should issue appropriate information to the bidders to clarify this.

26. For the LCIC portion of the work, for a direct adhered TPO roofing sheet without a nail down base sheet on top of the LCIC portion the NVS system;

Siplast, Inc. needs to be change to an Insulcel system: Siplast, Inc. per manufacture suggestion. We are requesting for the Insulcel system from

Siplast would be an approved substitute for Spec section 03 52 16.13.

Please see attachment for data sheet.

KHA Response: This manufacturer and product appear to be satisfactory substitutes.

27. As to access to the roofing for removal and material loading, can we get defined roof access locations.

Gov’t response: The way we went up (A wing) is the only way to the roof