Winterizing a Roof Under Construction
I’m building a small addition(16×16) in Zone 6A. The roof is a .75/12 pitch, and will be an unvented assembly with EPDM over polyiso. I’ve had delays with construction and it appears that cold weather will soon become an obstacle for the EPDM installation.
I’m looking to install some sort of temporary covering/coating on the roof deck (3/4″ Advantech) that will be weather-tight for the winter. Ideally the covering would be: weatherproof, cost friendly, reliable, and either easily removed or acceptable to leave in place before completing the roof install in the spring. I’m looking for any product recommendations that would be suitable. (or any alternate suggestions)
My current leaning is to coat the roof with Prosoco Cat 5 (12 month exposure rating), which seems to check all of the boxes but is a little pricey for temporary mitigation. I do like that it will not trap moisture.
Thanks in advance.
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Many types of roofing underlayment are rated to be exposed for some period of time waiting for the final roofing material (shingles, etc.) to be installed. Just look at what the rating is for whatever you want to use. The 12 month rating you mention for the Prosoco product is pretty long though, I doubt you'll be able to find anything rated for longer than that.
EPDM is OK until the temperature gets too low for it to be formed. You probabably have a least another month or so before it gets cold enough for that to really be a problem. I'd try to rush things a long a little so that you can get your permanent roof up this season if at all possible.
Bill
The simplest is to tape the seams of the deck with zip tape (which you should in any case as the air barrier) and put on a heavy duty tarp (10mils or thicker). Make sure to nail it down with 1x2s so the wind can't get under the edges.
If it is a simple flat roof something that size is a 1/2 day install. Not sure it is worth while to put on a temporary roof.
I've also used I&W as temporary roof for low slope. This can be left under the EPDM, you do have to make sure that the I&W can't come into contact with the EPDM at the edges after the install.
Attached is an image and text from the Huber ZIP installation manual.
Source: https://www.huberwood.com/zip-system/roof-sheathing
On page 30 of their manual, Huber explains that an ice-shield product can be applied over the ZIP sheeting. I expect that you could install a peel and stick product and avoid nails. It would have to remain in place when you finish the roof so I don't know if that would be acceptable to have under the Polyiso. Here is an example of one peel and stick synthetic ice-shield (from a random internet search).
https://www.ftsyn.com/platinum-htsa-underlay/
If I may, I would recommend calling Huber (Zip) and they advertise their phone number on their website for technical assistance. "Call a specialist at 1.800.933.9220 ext. 2716"
https://www.huberwood.com/technical-support
I would think that a simple tarp would work but then you are punching a ton of holes in you ZIP to install strapping with nails. I could see doing this on a house built to code minimum standards. If you have ZIP, you are someone who is building above and beyond code. Of course, when you remove the strapping and nails in the spring, you will need to repair each and every single nail hole with ZIP liquid flash (or tape?) I suggest that any additional holes create risk for future water and/or air leaks.
I have called manufacturers in the past many times and I am always surprised how much they know their product and how genuinly interested they are in wanting to help. Who knows, maybe Huber would tell you to just leave the ZIP sheets exposed - only they could tell you that.
Thanks everyone. As always - some great ideas.
Best case the stars will align and I'll get the EPDM on before the temps get too cold. Of course life gets in the way so contingency plans are nice.
I'll weigh the bare bones- tape/tarp option and I&W shield. Though I'm concerned about the reliability of tarping for the winter/early spring without having leaks. I tarped diligently for the most recent storm (2" rain, 50 mph gusts) and had a leak.
I'll see if Huber has any recommendations as well. As mentioned by mr reference, many of these manufacturers have great tech support just a call away.
I'll let you know what path I go with. Thanks again.