# Hail Damage to TPO



## Terminallance

Hi all, new to the roofing business, less than a year in.

I had a project in april with a blow off of a TPO roof. The church had two roofs stacked in top of eachother like one mushroom over a smaller one.

Anyway, there was issues of the facia and soffit rotting away, and when we tore the rest of the TPO off we found basically a swimming pool of water underneath. 

I went back to the sub roof today to look for hail hits, and I found these brown yellowish round discolorations about 6-12 inches in diameter, and in the center there were inch gashes where the outer layer had cracked open.

I believe water came underneath these cracks and formed said brownish discolorations, much like water does to ceiling sheetrock. There are about 100 over the surface of the roof. Everywhere there is a discoloration, there is a crack in the outer layer. 

Does this sound like hail to anyone? I'm not at all familiar with identifying hail damage on TPO roofs. 

Also, will the underlaying surface absorb water and distribute it along the facia and soffit that are rotting away


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## 1985gt

Can you post some pictures?


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## Terminallance

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## Terminallance

A lot of the spots that have discoloration will rub off with just a light touch. The outer layer is literally rotting away. 

My theory is that hail originally weakened it, caused a tare and then water got underneath and rotted it. 

I looked under the entire structure today and water is dripping off the sofit, where it should be just rolling over the side or evaporating. Same pattern over the soffit with discolored and chipped TPO.


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## 1985gt

Do you have any pictures a bit further back? To me that looks like a SPF roof with a coating. 

That is typically what a SPF roof looks like when the coating starts cracking and such. Hail damage on these types of roofs will be round strikes and indented pretty good.


TPO although I can't say I've personally seen a hail damaged TPO, but I have seen hail damaged PVC, and I would expect it would act similar. There would be a circle where the impact is then spiderweb cracks around it.

As for the roof you are working on, if it is a SPF roof and I suspect it is, they spray insulation down similar to ISO compounds and coat the whole roof with elastomer or other types of coatings. What happens is once the coating is cut/broke, messed up and allows water to enter the insulation and it acts like a big sponge. Now if the spray foam contractors are anything like ours here, they went right over what is most likely an old BUR roof. So leaks will only show up on the outside edges of the roof, around penetrations (sometimes) and anywhere where the old BUR/old roofing system had problems before hand. 

Now people will tell you that you can recoat them. I've never had much luck or the will to recoat the failing roof. Generally there is so much moisture trapped in the insulation that it will cause a lot more damage. The remedy here is to tear it off, all layers, and put a real low slope roof system on. 

That is a problem with these systems the contractors come in and get the job because it's cheaper,but fail to tell the building owners that once the roof goes bad again it will be 2-3 times more expensive to reroof it due to the two roof systems on it. In fact we charge more some times for tearing off SPF roofs as they suck to tear off most of the time.

Here is a fairly good example of what the spray foam roofs look like.










I don't have any I can find with damage to the PVC roofs but TPO roofs should be in rolls of 5-7-10-12' wide or something like that. There will be a definite seam.


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## Terminallance

I'll try to get more pics. If this is true, then myself, and the adjuster miss diagnosed the upper roof. 

What you're saying makes complete sense tho. I remember seeing multiple roof types underneath the other tare off. 

Thanks for your reply.


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## Terminallance

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## Terminallance

We replaced the top with modified bitman. The base structure is still what we called "TPO" both us and the adjuster. There aren't many roofs like this in this region. In fact, we would have had to get a crew from 300 miles out just to do the job had we gone back with TPO.


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## Terminallance

So in your opinion, is it harder to replace a spray foam roof or a TPO roof?


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## Terminallance

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## Terminallance

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## Terminallance

Pics right after the storm.


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## buildpinnacle

Based on the pics you are posting, it looks to me like the roof is a smooth surfaced built up roof with an elastomeric coating. How did you and/or the adjuster get TPO out of that?


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## Terminallance

Scratch that, it was going to be replaced with TPO. It was in april.

What does hail look like on the surface of those?


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## 1985gt

Yeah white coated smooth mod is what it looks like to me. The close up shot was a bit hard to tell. 

As far as hail damage on a modified roof. IDK I've never seen it happen. Most of them around here are a 3 ply felt with a smooth or granular mod cap sheet. Hail the normal size we get here just bounces right off of them.


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## Fregeau

*storm resistance with pvc instead of tpo and puf coating*

Storm resistance has been tested in lab and in the field with success using Sika Sarnafil membrane in the past.
I would suggest to have a look at the following site:
http://usa.sarnafil.sika.com/downloads/repository/submittal/literatures/high_wind_brochure.pdf
it might just give you a glance of other ways of using single ply membranes in high wind situations.
As for hail resistance (resistance to impact and puncture, tested EN 13583) I would suggest:
tha.sika.com/dms/getredirect.get/th01.webdms.sika.com/337
and
nzl.sika.com/dms/getredirect.get/nz01.webdms.sika.com/178
I've used those membranes and those made from Protan in Norway, and never had any problem in very severe and nordic weather.
Trust my own experience.
Claude Fregeau, architect, Canada.


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## Roofer Louisville Guy89

was the felt paper installed.


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## wfduggan

Looks more like a coated asphalt.


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## wfduggan

1. Looks like a white coated BUR.
2. Why does the hail damage even mater? it blew off.
3. how was it attached I see no fasteners.
4. My guess is that the roof is old and the asphalt is old and brittle. The coating was probably put on to fill theleaking cracks. The stains you're seeing are probably where it was leaking prior to the the coating. When you have two roof systems, you end up with a water bag when the top roof starts failing and leaking.


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