Wet roof deck and new roof installation

Hi all. i’m a homeowner. i have some new construction that my GC didn’t finish before christmas and then went on vacation. it rained several times and the roof deck got wet. It was tarped, which was a joke- poured buckets through it and then i’m sure the moisture was trapped underneath. to make things worse yesterday it snowed and now it’s 18 degrees. i’m not sure it will make it above freezing tomorrow. he’s telling me he’s coming out here to lay the felt and asphalt shingles. my understanding is the felt is being nailed and the asphalt is then glued. it’s a flat roof. can this happen on wet wood? he has a heater and wants to heat from below within the new construction but the physics doesn’t make sense to me. anyway… is this a bad idea? there’s only more rain in the future… it’s not going to get a chance to dry out. can someone put my mind at ease? thanks.

The plywood or osb board should be inspected before applying any kind of roofing or underlayment and replaced as/if needed. It sounds like you would be surprised that the wood can get wet a few times before any permanent damage is done. Buckling and warping would reveal wood that needs replaced while wood that is just a little wet will dry out and be fine.

He might need to take the tarp off of the top and run the heater underneath for a half or full day and put a dry tarp back on it just for over night. Then he could come back the next morning to install the roofing with everything dry or mostly dry. You would need 2 sunny days of above freezing weather. Having heat underneath from the heater and heat above from the sun should dry it out for the most part.

Obviously, the existing tarp job was not done properly. If there aren’t two decent weather days in the near future, then he should have a roofer do a professional tarp job to keep any further water out until such time as the work can be performed.

they’re up there right now putting it on. I feel like there’s not much to be done about it. they said it was “mostly dry” though i don’t understand how’s that’s possible given water was dripping through to the interior from the roof and it’s been below freezing :frowning:

it hasn’t been wet long enough to rot, what I was/am concerned about is water getting trapped under the felt and having mold issues or buckling or whatever may happen down the road. but we have nothing but more rain in the future after today so they are rushing to get it done.

I honestly wish I was there right now to help.
God bless every roofer out there working in this cold!

I felt HORRIBLE for them today. it was so cold and i can’t believe they said they were going through with it. grateful on one hand but still very skeptical on the other. never got above 25 today. didn’t see any heat guns. freezing rain tomorrow- guess we’ll see (in a few years) if the adhesive stuck.

Nailed felt and adhered asphalt. First of all, if it’s adhered asphalt, I hope they are nailing a “base sheet”. Secondly, adhesives aren’t meant for 18 degrees. It needs to be 45 or higher for 4 hours after installation. Give me some more details to make sure you didn’t just get a faulty roof.

nailed felt and then self adhered Certainteed SA. well under 40 degrees the day of installation yesterday plus freezing rain today and 37. back into the teens for the next few days. I told them this was a bad idea, he insisted it was fine.

If they actually did put 15# or 30# felt down your in trouble. Your supposed to use a tough base sheet meant for the job and use metal cap nails to fasten the crap out of it. Then you adhere the cap sheet to the base sheet(which is secured to the decking). If you adhere it to felt, the wind will pull the cap sheet, breaking the paper felt and letting the whole roof section come loose.

Also adhering under 45 degrees is a bad idea and against manuf. specs. If you accept the installation, keep an eye on the seams for separation to deter leaks.

OK, not being the professional I used the wrong term I think. I am pretty sure I saw a box that said nail base. do they use that and then felt or does that replace the standard felt?

they’ll be here tomorrow and will have a discussion. at the very least i’m thinking this is good for now and will at least allow them to start working again on the rests of the addition, which has been held up due to no roof and weather. maybe I have them replace it again when this is all done?

Wet roof is problem because there are so many different types of roofs in use today, specifying a flat roof coating isn’t easy. Different substrates require different coatings. A coating’s adhesion might depend as much on the substrate’s characteristics as on the coating type. In general, it is more difficult for coatings to adhere to hard, smooth, chemically inert surfaces and easier on rough, irregular, chemically active surfaces.

Yes nailbase is good. No felt is used. Temperature is your main issue assuming the deck was mostly dry.

That would be Certainteed Flintlastic SA Nailbase, which is a mechanically fastened (nailed) base sheet. Then you apply the Flintlastic SA Cap to the above mentioned Nailbase, there should be no felt used at all.

First, identify wet areas in the roof. To do so, one of three types of moisture surveys should be completed: infrared, nuclear or capacitance. None of these actually measure moisture. Instead, they measure the effect moisture has within the roofing materials.

Youmatch the type of moisture scan with your roof since each moisture scan works differently. Infrared surveys measure the heat retained or lost in insulation that has become damp. Ballasted roofs aren’t good candidates for infrared surveys because the rock itself retains a lot of heat, giving potentially false readings. Nuclear moisture surveys measure hydrogen atoms in the roof, meaning that any membrane with a large hydrogen chemical component will send positive readings. Water is a good conductor of electricity, and capacitance surveys measure electricity traveling through the roofing material. This won’t work on a roof with wet or ponded areas, and may require modified instruments on EPDM roofs.