25-N0817C Addendum #2.pdf

INVITATION TO BID

25-N0817C Alaska Veterans & Pioneers Home – Roof Replacement

Issued: March 26, 2025

ADDENDUM NO. 2

Information in this addendum takes precedence over original information. All other provisions of the document remain unchanged.

Note to Bidders: Bidders are required to acknowledge this addendum on the bid form.

This addendum consists of:

1. Addendum No 2 document consisting of 2 pages

2. Contractor Questions

3. Attachments:

• Addendum No. 2

4. Last Day for Bidder Questions: April 2, 2025

5. Bid Deadline remains April 8, 2025 @ 2:00 PM

Contractor Questions

1. Question: Contractor is requesting approval to use EPS as a substitute for Polyiso in this roofing system? EPS provides cost saving measures to the project while still meeting R-value and fire rating requirements. Please advise.

Response: Polyiso insulation was specified to provide a higher R-value with less thickness. This helps coordinate interface with flashing at existing walls and roofs. Roof Assembly R2 has a listed R-44 with 6.75” polyiso. EPS has a listed R-value of 4 per inch. This would require approximately 11” of EPS. Roof Assembly R3 has 8” of polyiso for R-52. This would require approximately 13” of EPS. That’s a difference of 4-5” for both assemblies. That would significantly change the detailing and interface with existing walls and roofs. Please use the polyiso to maintain the thinner roof assembly and detailing.

2. Question: I have a question about the metal roof panels. Can Bryer TBC Superseam roof panels be used in lieu of clip loc?

Response: Alternative roofing manufacturers and products are generally acceptable, provided that they provide a similar appearance to the existing roofing panels when viewed from ground level. Similar appearance should include a vertical rib of 1.625”-2” at 8” o.c. and 2 striations in the flat. Products should meet the requirements of the specification. Shop drawings should cover all conditions noted in the drawing set. Coordinate snow guards and any accessories with any variation in profile for the roofing panel.

Clarification: Products on this project must comply with BABAA Certification. Products and Submittals that do not comply with BABAA Certification will be rejected.

3. Question: In an effort from this contractor to both the owner and the designer, I would like to reach out with the following statement: The clip rib basis of design of roofing panel has long been walked away from as a result of consistent insurance claims, and design deficiencies that we have seen in the field over the past decade. In Palmer with the extreme winds, and driving snow and rain, I would urge to consider this type of panel as a basis of design. I understand the initiative of a “similar panel” with a trapezoidal seam, however, only a true standing seam design with a floating clip produces a truly “watertight” roof, as evidence from your specification request for an ASTM E2140. While an aesthetic design appearance often is communicated in remodel projects as to “match existing”, the features of the design for the eye are often lost to details that detract from the overall scope and intent of the project. Please note the following:

1. The general public cannot tell the difference between a 1 5/8” seam trapezoidal rib, from a 2” rib. Rib spacing at 8” on the existing roof shows as linear vertical flowing lines. The architect may consider a 90-degree rib, for a “thicker’ reveal at each panel joint. It should be noted that most standing seam metal panels are 16-18” but can come “striated” or “pencil ribbed” throughout width of the panel to create a “vertical line reveal” moving upward of the panel.

Response: See response to question #2 above.

2. Excessive snow guards- The current snow guard layout on the Palmer roof completely detracts from any design elements that would be desirable from a “similar panel” – it looks like a checkerboard. I would recommend and engineered Snow guard system, that is rib attached (via an S-5 style clamp) that utilizes 2, or 3 rows. This would allow the vertical reveals to “speak”. On a standing seam, this also mean there are no penetrations for the snow guard system.

Response: See drawings for locations of new snow guards. See Specification 07 72 53 Snow Guards for snow guard system basis of design.

3. This recommendation is given as a concern to both the owner and the design team, as the budget given, may not be applicable to achieve your basis of design. The excessive roof curbs, and broken nature of the roof ( limited panel lengths) leave gaps in available manufacturer’s warranty regarding approved installations. You may find your desired panels become expensive, as they must be fabricated in the lower 48, and late design clarifications of flashing systems and CA will lead to change orders. The curb detailing vs. manufacturer standard details available will lead to excessive custom fabrication, as a “clip-lok” panel, regardless of manufacturer is not designed for this type of application.

Response: See drawings for detailing. Flashing details have been referenced to basis of design manufacturer’s standard installation details. Contractor’s shop drawings should cover all conditions noted in the drawing set.

4. Question: Clarifications and Addendum Questions:

07-41-13-4 2.1- Performance Requirements

B.) ASTM E1646 has no described test-pressure difference required. Please clarify.

Response: 2.86psf.

C.) ASTM E2140 Hydrostatic-Head resistance is stated as a requirement. The basis of design product does not meet this testing requirement, nor will any non-standing seam product meet this requirement. This changes the availability of “similar roofing profiles” and leaves the interpretation too loose without the filing of substitution requests, or a redefinition of the basis of design.

Response: Delete ASTM E2140 Hydrostatic-Head resistance as a requirement.

D.) Wind uplift rating is stated as UL 580 test, given as a UL90 rating, but ASTM E1592 supersedes this rating as structural test. Performance requirement for UL-90 is typically stated for wind uplift testing, which is ultimately ASTM 1592 structural pullout strength, which is less stringent than the ASTM 1592, which is also specified. UL90 is also given for follow up testing for panel configuration.

Is follow-up testing required? When will if be required? And from what entity? The panel manufacturer(s) has requested clarification on this requirement.

Response: Correct, the two tests are different testing agencies. UL 580 is for testing roofing over substrate and UL 90 is the highest testing pressure but is a minimum installed design standard. ASTM 1592 is structural panel test based on the design loads noted on the structural drawings. The basis of design product listed both tests in the reference specification. For UL 580/UL 90, follow-up testing is not required for this project.

5. Question: Will the architect consider, with a substitution request approved “similar roof panels” prior to the bid? The contractor understands that they are responsible for providing manufacturer BABAA certifications and the substitution requests do not need to be previously certified by the architect with the review as a part of the contractor’s submission.

Response: See response to question #2 above.

Note that if contractors propose roofing products that they will self-roll or roll on-site, the requirements for BABAA will still apply. In that case, it will minimally require certification from the coil and coating manufacturer(s) and a self-certification from the contractor (see sample signature form in Spec 00 10 00 BABAA Requirements).

ATTACHMENTS:

1. 25-N0817C Addendum #2.pdf

END OF ADDENDUM 2

Issued: 3/26/2025