Foam roof separation - substrate or application problem


Have an adobe style house with a flat roof. Four separate elevations, so four separate sections of roof. Had a spray foam roof put on because the house is older, with lousy insulation. Three sections are ok, but the 4th is having pretty major problems. Foam was applied over an underlying modified bitumen roof.

At some point a few months after the roof was complete, I had a leak. Roofer’s employee repaired a separation against a higher elevation wall. Foam was mostly applied against the underlying roof which went up the wall 6" or so. Above that is stucco. No more leaks but the separation has been expanding slowly ever since. At the guy’s last visit, he threw a bunch of caulk in the separation and said he’d be back to do a more thorough repair. Never came back. Now I have a separation of about 1-2.5" along about 30 feet of wall. That same section of roof is showing signs of lesser separation on two other edges. Looks like the underlying roofing is being pulled away from the wall, though in other sections the foam is pulling away from the roofing. Foam seems to be shrinking away from the wall.

Roofer is blaming the underlying roofing and says it’s not a warranty issue. I’m not convinced and wonder is it’s an application problem. It was quite windy that day (if that matters). Their equipment looked filthy and their compressor barely ran. Could have been a problem with too thick of a foam application per pass? Off-ratio mix? Partially clogged nozzle?

I’ll pay for the repairs if it’s a substrate problem, but for a variety of reasons, I don’t trust what he’s saying… Any help would be appreciated.


where you located?

Northern New Mexico (Los Alamos). About 7400 Ft. elevation so we get all four seasons.

It sounds like an application issue to me. I love SPF. It really is a great product. One of the major issues it has though is preparation. The surface it is being bonded to needs to be thoroughly cleaned and properly primed to accept the foam application. If not or if there were mix issues you could experience the problems you are having.

Also if the foam is running up the wall for 6" did by chance they cover the stucco weep flashing? And if they did, did they coat the stucco wall to prevent it from soaking up water? Top to bottom left to right? Any Contractor should be able to tell you that stucco acts as a sponge allowing water to flow through its substrate and get exhausted out through a metal flashing at the bottom, which is hopefully flashed properly over what ever membrane is beneath it. In your case it sounds to me like the contractor sprayed foam over the weep effectively funneling moisture from the stucco wall under the foam membrane. This trapped moisture WILL cause havoc, including not allowing the foam to bond to the existing membrane.

And while I am thinking of it another preparation issue with foam is scanning for moisture. The system is monolithic so any existing moisture in the original system is now trapped. As it finds it way out it will bubble the foam and cause other system failure. The foam will also bubble from new moisture being forced under it from the stucco.

Thanks. I appreciate the information. It’s really a challenge to find good trustworthy contractors around here.

Previous roof ran up the wall ~6" and the foam was applied up to that point, though in a few spots where the stucco was contacted a bit, it got pulled off the wall… It’s an older house and there is no stucco weep flashing there. I don’t recall that they primed anything or did anything else to prepare except for a quick cleaning of the surface.

I’m sure water got underneath.


I am a Roofing contractor in Business for 24 yrs. I don’t install spray foam roofing and I never would. I believe it cost people money and does not work. That is my honest and humble opinion. The problem with the whole idea is that you usually are going over a roof that is leaking so when you spray the foam you are trapping the moisture. I have seen many examples of this same problem over the years some bubbles as big as 4 ft. high well maybe only 3 ft. :). I know its not a joke but use proven methods and don’t experiment with your customers thats my motto!

I would have to agree that trapped moisture can be a problem. In fact one of the problems that keeps me in business. As I said before the original roof membrane needed to be scanned for moisture and any places where moisture is detected cut out so as not to trap it. Unfortunately most contractors do not do this and jgbnm is past this point.

I would suggest you do what you have done. Attempt to have the contractor fill in the gaps. I would have them spray some more foam in the gaps to fill them and coat over it. I would also suggest having the stucco wall coated with an elastomeric emulsion top to bottom, left to right to seal the wall and make it water shedding.

But if as you said the contractor is unwilling to come out and correct their work you might have some issues. I am not familiar with the rules and laws in New Mexico as far as what to do when a contractor fails to perform their job. So I can not be much of a help there.

All this being said I am not a foam salesman or installing contractor. I am a Consultant who performs diagnostic tests and inspections on all types of roofs. I believe that SPF is a good product as long as it is correctly installed. It is one of the most sustainable and easy to maintenance. It offers the advantages of being monolithic and having high insulative properties. As with any roof it all comes down to preparation and installation.

Thanks for the feedback.

Essentially, the contractor is saying that it’s my fault and the underlying roof was the problem and it’s not his job to ensure the underlying roof is in good enough condition to accept the foam roof. He wants to charge me for the repairs… It’s a 100 mile trip for him to get to my house and I suspect he’s struggling for business in our crappy economy.

I just can’t get him to explain to me why the foam is now 2+ inches away from the wall. I could understand a small gap developing that needed to be resealed but slowly shrinking away from the wall for a year? I don’t get it.

I’m concerned that if I get it fixed, it will just pull away from the wall again and I’ll be back to square one.


Hello Jon,
The reason that the spray foam shrinks is that weather it is opened or closed cell it all must be ionized as it is sprayed through the machine. This application process infuses moisture into the roof system.As a result two physical challenges start to deteriorate the system. First is the effect on the foam itself, as the moisture content drys out within the system the product tends to not only shrink and pull away from the wall the more dangerous situation is what you can’t see, and that is it pulling up from your roof. The second physical challenge is the moisture deteriorates the coating used to prevent moisture from getting in. As a result the trapt moisture lifts the coating from the surface of the foam. You must remember the fact is every other white paint out there is just a surface coating. Final Flat Roof is the only Kevlar reinforced bonding agent that exists on the market today. We become a structual attachment to the foam with a cellulas bond thus can never be removed. The NM climate is a very unique atmosphere when it comes to roofing.

I am not here to make any enemies, but my best advice to you honestly is to stop wasting your time and money on spraying foam over anything its just never going to work in my opinion. Even if say you go over a dry roof and the foam does stick to all the old flashings, drains etc… that are never replaced! The insulation itself is not waterproof so what is your waterproofing? Answer is a coating of some sort and they are always the best according to the sellers. Never have I seen a Foam system that worked out, It is a way to escape the tear off of the old roof which is necessary to get the moisture out, Replace the old flashings, any damaged wood etc… it is appealing cause it saves money, but it will never work out in the long term. Show me a project with this spec that worked out none here in Los Angeles that I know of. I mean 5 Years no problems no leaks Bubbles etc… I am following this because I have lost large Jobs to these spray foam Systems, Have been told If I sprayed foam I would get the work. It will not happen would not do that to my customers!

I’m going to have to disagree with you prsystems. I am a Roofing and Weatherproofing Consultant in Los Angeles. I have no particular allegiance to any product. I specify according to my clients needs and requirements. I have seen SPF systems that were properly prepared and applied lasting beyond their warranty dates, 12 years no problems. I have seen many that have been recoated in the tenth year twice and are now going on 30 years old. Conversely I have seen them fail in 5 or 6 years. I have also seen a brand new BUR completely worthless in one year. Everything comes down to preparation and application. Each Roofing System (the System with SPF is the foam and coating you would never specify the one without the other) has strengths and weaknesses.

Any recommendations I have given here are based purely on personal opinion. I see no need to waste the money spent and tear everything up. But again I don’t live in NM nor do I have anybody I could trust to help the homeowner there.

I’ve seen blisters and bubbles in asphalt BUR, CTP, EPDM and other roofs; I take it you don’t install those either!

I Actually do install Built up roofing, Torch (APP), methods which have been around for years I am just saying that. The specs that I use and the manufacturers all recommend! Is the removal of old deteriorated roofing materials the specs I have seen with foam are cover it all with foam but you could be right maybe when they cover rusted flashing and wet roofing its not the material but the contractor doing the work. And the times I have come across a foam system is at the problem stage but since you are in CA.Los Angeles I welcome you to prove me wrong and show me a foam system that is 10 years old as you say and problem free. Thats sprayed foam with a coating over it. On a flat roof! Sorry homeowner we will work this out but I still am at this point standing by what I say. Get rid of the foam :). Its an opinion would you sell it to your MOM guys Common? What about height of flashing? As I think this particular customer has experienced should the roof to wall flashing have been raised up or is painting the wall the best fix? Hey we actually need to follow up on this guys Texas is far away but lets do get together here in Los Angeles.

I’m saying there is a place for most types of roofing applications, and that not all roof systems are good in all applications. Personally, I prefer spray-foam for beneath the roof deck, cold-floors, exterior walls, etc., but not on the roof. However, I have seen well maintained SPF roofs last well over 15 years here in Houston.

Remember, blisters in an SPF roof are going to be caused by one of two things; either there was moisture present during application, or the applicator sprayed into rising foam. Since closed-cell is, well, closed-celled, it doesn’t wick water. So water penetration generally isn’t very deep on an SPF roof unless there was structural movement or something that fractured the SPF. Sunlight, birds, and algae, can damage an SPF, but if properly maintained it isn’t a bad roof system; I just wouldn’t want one; at least not yet. :mrgreen:

I Think we lost the homeowner guys GOODNIGHT! I will follow up on this I have been making calls lets talk Fallan.