# Best Way to Waterproof a Flat Metal Roof?



## theHisO (Nov 29, 2015)

i am limited in my commercial roofing experience but being fairly intelligent or observant as a contractor, i have come to the realization that the subs i have used in the past don't know much either so i am reaching out. I have a 9' x 12' flat sheet metal roof over a freezer at a resturant that is outside and due to crappy application and some shifting in foundation, is leaking like a sieve. it looks like someone tried to fix the flashing where it attaches to the main building with spray foam from a can lol. So for one, i take pride in being and honest contractor and also in learning anything i don't know and informing my clients of the same. This guy owns a lot of restaurants and i am sure properties so i want to do what's right. he grew a restaurant from one into many on his own and he is an italian from up north originally but been in texas over 20 years. I want to know any opinions on how you would approach this from a contractor point of view. I most likely will do the work myself with a helper. re-roof it? is there a coating i can apply? should i remove the foam or just cover it? i'll attach pics and thank you for any input. this is my first post on here so be gentle


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## Jsp404 (Nov 9, 2015)

I have done a couple freezers which I install TPO fully adhered and T-bar all around The outside edge. Flash a minimum of 8 inches on to the main building apply water block behind the flashing T-bar np1 counter metal to cover t-bar and caulk.


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## flatroofrepair (Dec 25, 2015)

Just out of curiosity please can you post more pictures of the completed flat roof please? It would be really good to see how you accomplished this small project.

Hope you got more work from the Italian


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## AlexLarson (Feb 15, 2016)

*Answer*

Hi there.
You have to remove the foam and start from scratch. Think about any liquid ribber protective coatings http://liquidrubber.ca/ this one is not bad at all.​ Thanks God I used this product a couple of years ago and it was wonderful. First time in years my roof is not leaking on my warehouse. As for me, liquid rubber is the way to go on most types of flat of low slope roofs


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## Beetlejuice (Aug 31, 2016)

I am familiar with metal roofs but not so much with freezer roofs. Anything you apply over top you will need to take into consideration of trapping any moisture (condensation). This could lead to bigger problems down the road. You will need to replace the mastic on the wall with the proper wall flashing. I would definitely consult with the manufacture before applying any products.


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## sammismith (Jul 28, 2016)

I would remove the foam first just to be on the safe side. Not an expert, but that makes sense for this type of project.


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## FLroofing (Nov 27, 2016)

Fully adhered TPO with ISO is the best option, judging by the photos provided (alluding to the budget) you could probably use HydroStop to waterproof it. You will need to add some sort of counter flashing with NP1 against the wall.


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## Dimensional (Mar 29, 2016)

Leaking metal roof can be a nightmare for any home owner. Repairing it yourself is possible if you have do it yourself skills. But if you don't, it is best left to a professional - Roofers Austin


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## TucsonRubberizedCoatings (Feb 21, 2019)

It looks like you've got your work cut out for you with that project. Your first step should be to have those leaks repaired, so that they don't give you any trouble in the future. After that, I would recommend a siliconized roof coating to extend the life of your roof. This type of coating will guard your roof against water damage and water-related damage, which includes rust, mold, mildew, and water stains. A siliconized roof coating will also help protect your metal roof from solar radiation. Good luck!


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