A E Answers to further bidder Questions 12-20-11.pdf

SOLICITATION IFBPO6171200001

REPLACE ROOFS – PHASE I

PROJECT 6A1S

THE FOLLOWING FURTHER CLARIFICATIONS ARE PROVIDED A RESULT OF ADDITIONAL CLARIFICATION REQUESTED:

4. 075500-2.1.C indicates tapered insulation. No slope is indicated. Please clarify slope of tapered insulation system.

CLARIFICATION: Roof elevations are indicated at roof high points, roof drains/overflow drains and scuppers.

REQUEST FOR ADDITIONAL CLARIFICATION: Do the elevations (thicknesses) reflect top of insulation or top of roof deck?

Some of the slopes created by the thicknesses shown may not be possible. Standard available slopes are 1/8"/FT.

1/4"/FT. & 1/2"/FT Non Standard slope is 3/8"/FT.

Further Clarification: The slopes shown are the top of the insulation. We need to maintain as close as possible to the 1/4” slope per foot to get the water off the roofs. Slopes that are less than this will be rejected.

5. 072200-2.1.C.6 indicates an average R-30 requirement. Please clarify if this R-30 requirement is based on each individual roof area or the project in total.

CLARIFICATION: Per Section 07 22 00/2.1/C.B. : Thermal Resistance: Average over entire roof R-value of 30, but maybe greater to achieve roof slope requirements for drainage.

REQUEST FOR ADDITIONAL CLARIFICATION: Based on this response I assume answer is "project in total". Correct?

Maintaining a specific 2" minimum thickness may or may not achieve the overall Avg R 30. Particularly when you consider some max thicknesses may not be met when using standard available slopes.

Further Clarification: Each roof area should have an average of R30.

10. 075200-3.2.H.4 Indicates a minimum 1/8" per foot slope and a minimum Y" per foot at Valleys. May I suggest that these two slopes are reversed. It is physically impossible to achieve a valley slope of Y" per foot with a structural slope of 1/8" per foot.

CHANGE: The drawing show a design of a 1/4" per foot slope. Section 07 52 00/H./4. Should be revised to read: Minimum Slope: 1/4 inch per foot.

11. If the slopes as indicated above are reversed and the structural slope is required to be Y" per foot it may still be impossible to achieve a slope of 1/8" per foot in the new valleys created by the new tapered insulation and crickets. Valley slope will be dictated by the available area or length to install the crickets and may not be large enough to accommodate sufficient length to achieve the 1/8" per foot valley. Can this requirement for valley slope be changed to maximum slope achievable within the spaces allocated?

CHANGE: The drawing show a design of a 1/4" per foot slope. Section 07 52 00/H./4. Should be revised to read: Minimum Slope: 1/4 inch per foot.

REQUEST FOR ADDITIONAL CLARIFICATION: The minimum slope is 1/4"/ft. but thicknesses shown on the plan take precedence which means some slopes will be greater than 1/4"/ft. Correct? The tapered layouts as shown on the plans may have to be changed. Changes will be a result of attempting to maintain a single slope on each roof area.

Currently the slopes that result from thicknesses shown vary considerably and many of the slopes do not exist or are not available.

Clarification: We need to maintain as close as possible to the 1/4” slope per foot to get the water off the roofs. Slopes that are less than this will be rejected. The minimum 2” thickness is at the scupper to ensure that water will flow off the roof and thru the scupper. In several instances the scuppers were above the roof level. This minimum thickness will ensure the water goes into the scupper.

REQUEST FOR ADDITIONAL CLARIFICATION: Also keep in mind that bidders will have to assume all roof decks to be dead level for quote purposes unless shown otherwise.

Clarification: We have assumed that the concrete roof decks are level.

GENERAL CLARIFICATION:

There are several issues we are trying to address.

First, this is a retrofit project and we are trying to use as much as possible existing scuppers. The original installation did not put the scuppers equidistant from each other or even in similar locations on identical roofs. Hence the different heights and lengths of crickets

We need to maintain as close as possible the ¼” per foot slope to prevent the ponding that has occurred on the roofs over the past decade and caused numerous roof leaks. We also need to maintain an average of R30 on each roof.

The 2” minimum insulation is at the location of the scuppers to ensure that the water does actually flow into the scuppers. In several instances the scuppers were about 2” above the roof so that there was at least two inches of water on the roof before it could drain off.

The goal as with any reroofing project is to improve the U value (R30 average), get the water off the roof hence ¼” slope per foot and use as much as possible the existing drainage system. In this instance the scuppers.