# Flat Roof Resurfacing - Where to start?



## adamgram (Sep 2, 2010)

I am interested in info on what is involved in recoating a flat roof. It is the roof of my house, which is a 2 story row house in Philadelphia. The front part of the roof has a pitch towards the street and is tiled, then the back is flat with a slight pitch to the back of the house for drainage. The flat part is about 20'x20'. 

I installed a roof hatch the other weekend with the help of my Dad, who has built several roofs before but has no experience with flat roofs.

The roof is in good shape, there are no leaks and no major cracks on the surface, but I want to resurface it now because I have plans to put solar panels on the roof.

I'm not sure where to begin, there are a few pictures attached. I read a few things about different types of roof systems but I'm not sure what mine is or how to resurface it. I saw there are a variety of Henry roofing products available at the local hardware store numbered 201, 203, etc. Would these be acceptable to resurface an entire roof?

Any information you could point me towards would be helpful, thanks.


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## Grumpy (Dec 12, 2003)

Read this page on my site as it will explain some of what you need to know about low slope roof restoration options.

Flat Roof Coatings 

If you want to go with a traditional membrane: Flat Roofing Options

BTW no pictures were attached that I can see.


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## adamgram (Sep 2, 2010)

Thanks for the link, I got some good info out of it. I've been reading about all these different types of flat roof systems: modified bituman, single-ply, TPO, etc, and the different types of coatings you can put on top, and I guess my biggest question is does the system that is installed already affect what type of coating I should use? I don't know how to tell what type of roofing material is there now, do I need to know this before I pick a coating?


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## Slyfox (Jun 13, 2008)

adamgram said:


> Thanks for the link, I got some good info out of it. I've been reading about all these different types of flat roof systems: modified bituman, single-ply, TPO, etc, and the different types of coatings you can put on top, and I guess my biggest question is does the system that is installed already affect what type of coating I should use? I don't know how to tell what type of roofing material is there now, do I need to know this before I pick a coating?



Yes you do.
The wrong coating applied will not only not help but it can cause additional issues.


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## adamgram (Sep 2, 2010)

Slyfox said:


> Yes you do.
> The wrong coating applied will not only not help but it can cause additional issues.


Thanks for the info. So how do I figure out what was used before? I'll try again to post the pics.


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## Grumpy (Dec 12, 2003)

If you post a pic we can likely tell you. 

Like Sly said you need to know what's there now because what ever you put back may not be compatible. For example put a TPO directly in contact with an asphalt based roof and it will yellow through in a few years. Another example, most elastomeric coatings require a primer over EPDM before coating, some don't require a primer over EPDm, but do over PVC, so it's important to know what is there now and research the installation instructions thuroughly before applying any material.


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## adamgram (Sep 2, 2010)

Okay I will try this again. I had to shrink the picture so it is under 100 MB. Hopefully you can still make it out. Thanks for your help!


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## Grumpy (Dec 12, 2003)

I can't really tell but from the overall age and appearance I can guess that the roof is a smooth built up roof, possibly asphalt, that has been coated. 

Based on what I am seeing and using my experience I can tell you that roof is likely already in excess of your local building codes. What I see here in chicago, that roof owuld be 3-4" thick of coal tar and asphalt built up no less than 3-5 layers of roofing. If I am right your only option, within code, would be to apply an elastomeric roofing system. However the existing coating may complicate things and you'll have to do pull tests before you apply any other coating to ensure the new coating will stick to the existing. 

Infact after 2nd look I can se an area that has been blown off or something, where you see a 2nd layer beneath. most building codes only allow for two layers. tear it off or install a liquid applid system.


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## OldNBroken (Jun 11, 2008)

Looks like snowcoat. If it is then the minute you coat it with another material it will begin to loose adhesion and lift from the substrate. One of the unforeseen consequences of using that crap. Have seen it more than once on more than one type of surface.


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## adamgram (Sep 2, 2010)

Thanks again for the input guys. I have some more photos uploaded to Flickr that you can see through the link below. It includes a few pictures of the section of the roof we cut out when putting in the roof hatch. It is a black material with a white coat on top, and the roofing material is about as thick as the wood decking itself, a little less than one inch.

http://www.flickr.com/photos/[email protected]/?saved=1


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