B09_Questions and Answers_Amd_0002.docx

List of the contractor question 9/3/2020

Specifications

2.1 A 1 c

Air Barrier: Vapor Retarder SA 31 self-adhered air barrier/vapor retarder, 31 mil nominal thickness.

Question: The PVC roof material acts as a vapor barrier; can vapor retarder SA 31 be removed to reduce cost and installation time?

Answer: No the air barrier/vapor retarder cannot be omitted and shall be included in the bid proposal and work.

Specifications

2.1 B

1. Uniform, self-adhered fiberglass-reinforced flexible sheet compound from polyvinyl chloride (PVC) with plasticizers and modifiers, conforming to ASTM D4434.

2. Factory applied pressure-sensitive adhesive backing and siliconized polyethylene release liner.

Question: Some reputable PVC roof manufactures do not make a pre-adhesive product. Would using bonding adhesive spread evenly on the surface be acceptable rather than using a self-adhering Product?

Answer: Yes, a low-VOC water-based bonding adhesive spread evenly on the surface in accordance with the manufacturer’s recommendations is acceptable rather than using a self-adhering product.

Specifications

2.7 B Polyisocyanurate Board Insulation

Boards shall be 4 feet by 4 feet as manufactured by Atlas Roofing Corp, … Question: May 4’ X 8’ boards be used instead of 4’ x 4’ to reduce time for installation and fastening? Contractor note: Typically, 4X4 is only for glued boards.

Answer: Yes, 4’ x 8’ insulation boards are acceptable. Ensure that factory preformed, tapered insulation boards are used where required as indicated in the specifications.

SOW 1.2 A 16 Roof System Roof will be built up (raised) approximately 5 inches above the existing profile. Two outside edges of the existing roof canopy are almost flush with the coping/parapet.

Question: Would that be acceptable?

Answer: It is acceptable that the new roof will be flush with the coping/parapet.

The roof build up on the front canopy will exceed the height of the existing parapet.

Question: Would the BLM like to raise the parapet at this location, reduce the amount of insulation, or eliminate the insulation at this location?

Answer: Insulation will not be required on front canopy.

Items not in the SOW or specifications Question: The SOW does not address scuppers. New scuppers will be required to adequately bond the PVC. Should new suppers be included in bid proposal?

Answer: Yes, include PVC clad metal scuppers. PVC clad metal used for scuppers shall conform to the ‘Clad Metal Flashing’ portions of the specifications. There are eight scuppers on the roof. Scuppers shall be incidental to bid item 10.

Question: You are asking for roof drains, which the roof has none. Technically, those are roof scuppers. Do you want us to provide collection boxes and downspouts as well as new scuppers? The scuppers will need to be replaced with PVC clad metal in order to provide proper bonding with the PVC roof. However, the downspouts and collection boxes could be standard aluminum or steel.

Answer. Yes, include PVC clad metal scuppers. PVC clad metal used for scuppers shall conform to the ‘Clad Metal Flashing’ portions of the specifications. There are eight scuppers on the roof. Scuppers shall be incidental to bid item 10. Do not include collection boxes or downspouts.

Question: Insulation will be tapered down from 4” to meet location of existing scuppers. Is this acceptable?

Answer: Yes, it is acceptable that the insulation taper down from 4” to meet the location of the existing scuppers.

Question: In order to avoid building up (raising) the parapet at the roof areas with crickets, would use of 2-inch insulation instead of 4-inch insulation at cricket areas (down drainpipes areas) be acceptable? Answer: Yes, 2-inch insulation instead of 4-inch insulation at cricket areas (down drainpipes areas) is acceptable.

The existing stink pipe will need to be raised to meet the code since we are raising the profile of the roof.

Question: Will contractor be required to extend vent pipes as necessary to meet code requirements? Answer: Extend vent pipes as required to meet applicable code requirements.

Question: The pricing schedule states on item #8 Installation of 2" Polyiso (2 layers required) 1500 sq ft. The roof is 7500 sq ft so the total would be 15,000 sq ft.

Answer: Yes. The quantity for item #8 shall be 15,000 square feet.

Question: How and where bid should be submitted. Can you send this info?

Answer: The bid shall be submitted via email to legonzalez@blm.gov

3--The spec says we are to reuse metal flashing. However, the metal flashing will not be able to be salvaged in order to provide the manufacture NDL warranty. This includes the parapet caps. Can you require replacement of the parapet cap as well? This will provide the best product.

Answer. Much of the metal flashing is not suitable for reuse. Please include replacement of parapet cap.

4--Are we replacing any of the standing seam metal roofing shown in the photos?

Answer. No.

5--Can you extend the bid a couple more days so we can get answers to these questions.

The date has been extended till 09/15/2020 @ 1600 PST