Pomme de Terre Roof Replacement Solicitation Q and A 20210621.pdf

Pomme de Terre Roof Replacement Questions and Answers

Question 1: The specification is calling for Extruded Polystyrene Board Insulation for both the tapered and non-tapered insulation. Extruded is very uncommon for low slope roof applications. Expanded Polystyrene (EPS) is common in roof applications and meets the same ASTM requirements, would EPS be acceptable?

Answer: After reviewing the Contractor's attachment it does not state which EPS system they are requesting to use. I recommend that if the Contractor desires to use an EPS system , the minimal is a type 2, but a type IX is preferred.

Question 2: Sheet A-400 “typical tapered roofing section ¼” per foot” appears to be a polyiso tapered system. Please advise whether an EPS tapered system or hybrid tapered system is desired.

Answer: As far as the system the EPS is a single placement system and the hybrid is a duel placement system. Either is acceptable for these applications.

Question 3: Drawing A-401 is calling for ½”/ft slop on the office roofs. According to the record drawing the roof deck is structurally slope. Is the intent to have tapered insulation over the structurally sloped deck to achieve the ½” per foot slope? This will raise the south end approx. 20” on low roof and 17” on high roof

Answer: It is the intent to provide additional positive drainage to both the upper and lower roof regardless of the structural decking slope. The north end of the roof has a tendency to pond water, which we are attempting to eliminate. The 1/2"/ft can be reduced to a 1/4"/ft with an additional insulation slope on the southern side of no more than 2' of the roof. This is to prevent a shear face that faces the south.