[Walason]

Am installing 18, 500 square feet of 1.5' poli-iso or OSB decking in 4x8 sheets over old failing BUR. Ten fasteners (screws and 3" plates) per 32 square foot sheet. Building is flat with four drains at the long sides; two per side. Roof is 212' x 88'. 10” parapet around all four sides. Poli-iso/OSB is only being used as a divorcing material as we are going over old BUR. After above mentioned work, we are sealing joints, and applying a butyl based elastomeric set into polyester fabric for strength. Have done hundreds of these roofs; coatings are 90+ % of my work. Have done almost 180,000 square feet of roofing for this customer, and he insists on this system as it hasn't failed him in the past 14 years I've been installing roofing for him. No tear off, and very profitable.

My question/concern is the night stop or seal; sealing off the edge of where my mechanics stop laying the OSB/poli-iso at the end of the work day, and over night from water infiltration caused by rain. The BUR is blistering, ridging, and cracking, so it is slightly uneven. It is not smooth BUR, but has a layer of small stone we blow off with a tow behind compressor. In the past we have used expandable foam and sealed it in our mastic caulking, then removed the next morning and proceeded work from there. However this type of install can be (and has been) a disaster, as you well know if it rains during the overnight their is good likelihood of rain water getting under the recent installed OSB/poli-iso and leaking into the building through all those new fastener holes - absolute disaster and impossible to control if it happens.

I really don't want to do this job, but this customer has been my largest for 14 years now, and he really does want it.

I'm not looking for suggestions of how to roof the building, but how to install night stops and your experiences regarding the rain issues. Once the poli-iso/ OSB is down it is sealed before moving too far ahead on the top surface and along the three sides, so again all I 'm worried about is where we stop working for the day.

Sincere thanks !

 

[Ed the Roofer]

Try this product that is sold at ABC Supply and other fine roofing supply houses.

http://www.mulehide.com/acrobat2/pds/SEAL-FAST TAPE TEMPORARY ROOF SEALER.pdf

It works.

Ed

 

[Walason]

Ed, thank you. Is this stuff similar to "Quik Seal 7" sold at Bradco Supply ? Looks like dry oatmeal ? Greta idea, and thank you again.

 

[Ed the Roofer]

Probably the same compound.

Once it gets wet, it turns into a malleable clay/putty like substance.

Ed

 

[AaronB.]

What about spudding the tie in and sealing with an appropriate asphalt product? that's typical roofing basics.

 

[Grumpy]

I am no longer a fan of elastomeric board systems and have removed them from our service offerings. MAJOR FAILURES. Even one manufacturer warned me about board systems saying "watch out on the board systems." I've done 3, all to spec, with manufacturer inspections and approvals, all 3 have had some major problems. No problems with the resurfacing systems however.

If i were still doing board systems I would definetly NOT go over just ISO. I always went over a product called secure rock, which is basically dens deck. Iso doesn't offer enough compressive strength. Hail will rip the roof apart, IMO. I also didn't install fully reinforced, but installed with butyl taped seams. That's the primary failures in these systems, the taped seams.

When I did board systems, the largest was 250 squares. For our night seal we simply used a 6" butyl tape adhered on one side to the board and adhered on the other side to the existing roof. But it was a smooth roof over the half we luckily staged out as our center for night sealing purposes. In your case this wouldn't work. I'd try some 2-part sealer laid on nice and thick before screwing down the edge of the board. You could probably also use a fibered elasto-mastic beneath the board in lieu of the 2-part.


Aaron what asphalt product is appropriate to be mixed with an elastomeric system? certainly some spudding will be required no matter what product is used. Maybe even some torch priming to remove some surface dust after spudding.

 

[Walason]

Aaron and Grumpy: Your comments and ideas are great, and I appreciate them.

Aaron- thank you. I hadn't thought about using an asphalt product to seal the tie in at the old roof level, as normally asphaltics are not compatible with butyl coatings or Poli-iso, however your suggestion will work as the two will not be in contact (if I understand you).

Grumpy, I do coatings/elastomerics almost exclusively- a little shingle work as that is how I started almost 20 years ago. You mentioned "fully reinforced systems". That is the only system we would install over ISO or even OSB. From what you described, I can COMPLETELY understand the failures you experienced with butyl taped seams (OMG- What a f- - -ing nightmare!)

The idea of using butyl tape on the seams as a night seal is something I actually was aware of, but had forgotten about. Great suggestion- thank you. Like you said, it won't work for this job, but certainly reminded me of what should've been obvious to me.

What product do you recommend for the 2-part sealer ? I don't know of this .

You also mentioned a fibered elasto-mastic installed underneath the board stock before screwing down the edge. What have you used or suggest ?

Chicago is my wife's favorite city in the world. Never been there myself. She has told me of "The Magnificent Mile". I correspond with someone in Oak Park.

Thank you again Aaron and Grumpy.

- Kirk

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