Industry standard guidelines for applying a tarp to a flat roof in bad weather

Hey there,

I had a roofing contractor begin work on my flat roof a few days before what turned out to be a major rain storm. Right before the storm, he nailed down a tarp over the roof and left for the day. The storm hit at midnight and by 4am we had massive breaches of water coming in to our master bedroom and flowing down inside the walls to the living room below. I got up there an it was essentially a 4" deep swimming pool over the entire roof.

I was told by a roofing inspector that the roofer didn’t follow acceptable roofing guidelines for tarping a roof for bad weather, and there should have been some kind of structure built to raise the level of the tarp to allow for the shedding of water off the roof, avoiding the swimming pool effect. Also it was obvious that the roofer didn’t provide any way for the pooling water to flow through the downspouts.

Does anyone have a link to a document from any kind of roofing association in North America that could show even some basic guidelines for how to achieve the kind of temporary structure that would raise a tarp like the inspector was talking about? Any kind of tarping-for-bad-weather guidelines at all? This was a couple years ago and the inspector is unreachable.

Thanks so much in advance.

Industry Standards are “never remove more than you can cover before the end of the day”. That said, flat roofers use tarps to cover material, not roofs.


Amen. Tarps are for absolute emergencies only in my opinion. We cover everything every day regardless of forecast.


Most tarps are not water proof enough for that kind of use, it is also very difficult if not impossible to seal a tarp to prevent leaks on anything without at least 1:12 slope.

Bottom line is temporary roofing should always use some kind of waterproof membrane, such as EPDM or TPO, it should be sealed around all penetrations, and it should allow for adequate drainage. I am not able to find something right away. But contact a local company that specializes in commercial flat roofs and just ask if they could help you out, sounds like you might be in a prolonged legal fight. There should be someone in your area who would be willing to act as a professional witness.

Thanks so much for your reply.

You are correct, this is going to a small claims trial. The roofer (he’s not a real roofer - he’s a silicone guy who wanted to sell me a ‘peel and stick’ roof - but of course had to screw down plywood across across the entire roof first turning it in to swiss cheese) is saying in the official legal reply that he ‘followed standard industry practice’ for tarping the roof. Maybe the reason I can’t find it is because there is none. I guess the onus is on him to provide some kind of document - but I’d love to get ahead of the game.

He’s also saying that because he’s not a real roofer he doesn’t have to follow any sort of building code, which sounds so absolutely ridiculous, but then it turns out judges have accepted this kind of argument in the past.

Thanks again. I will call the real roofers we were lucky enough to find to come in and save the day.


Have fun with that! IF he has any insurance, they can deny on the basis of negligence.

He does have insurance. They may indeed wash their hands of him, particularly when they find out he and his labourers were on my roof with torches with no hot work insurance.

He’s got 11 or 12 trucks with his name on them running around town, and advertises on local tv. The guy is making money hand over fist. We’re not worried about him being able to pay for the damages if the court sides with us. But I’m in no way over-confident that we’ll win, even though we got royally screwed by his incompetence.

You could file with your insurance and let them subrogate the damages.

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The roof inspector, not sure what that is, gave you poor information. Darkthirty is correct. There is no roofing standard for installing a tarp. ARMA roofing practices spiral I have behind my desk, doesn’t even mention the word tarp. (tarpaulin) Never tear off more than you can secure and always seam it to the unremoved area.

You now have a warning to anyone that will listen when replacing a flat roof.

Thanks for the reply. Here we’ve got the Roofing Contractors Association of British Columbia which I guess is like an accreditation guild for roofers. They have a list of accredited ‘observers/consultants’ who provide inspections and oversight to seemingly mostly commercial projects. The guy we hired is an engineer and has been with the association since it’s inception in the 60’s. Dude was pretty old. Maybe getting a little loose with his facts.

He was recommended by the new roofing contractor who came in and saved our asses before the real rain came. Theyre the biggest contractor in our region and usually do malls and high rises etc. Our neighbour happened to know a guy who worked with them and called him over, he was really worried about us. Everyone in the neighbourhood was appalled at what what was happening on our roof (and in our house) as it was dragging for weeks. Got the inspection done the day before an army of guys came, built an elevator on the side of the house, and tore every last bit of shit the first guy put on, and installed a roof of the highest quality.

In the end we’ve spent quadruple what the original scope of work was to cost. And of course, we were uninsured for any of the damages - when we bought the house the insurance company added a clause to our policy that any damage caused by water that came in through the roof would not be covered. Why? Because it needed a new roof… They didn’t like the age (27 years). There was not a single leak. It was ugly, but it kept water out. Of course until buddy took a big deposit from us, came to the house and filled the roof full of thousands of holes right before a huge storm…

A tarp on a flat roof that ponds will not work.
You would need to build a pitch so the water runs off.
We just use a ladder, making our own gable roof, teepee roof of some kind.
You cant allow ponding on the tarp.
I Learned the hard way more than once.
Even with full ice and water shield installed already….and brand new tarp…

Build a roof out of just about anything for the tarp not to pond anywhere on the flat roof and it can survive a long storm.