Reply To: POLYURITHENE FOAM COATING TO ROOFS

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#291911
Jerry Peck
Participant

Hi Sylvan,

You stated “If the decking is in good condition and they only are looking to remove trapped moisture I have found installing sheet metal vents (almost like a Swiss Cap) will work but it can take years (depending on ambient temperatures and huminidity levels to allow all the moisture to evaporate BUT it will stop blistering on BUR systems so it should work here as well.”

The above questions were referring to the foam roof systems, which are coated with a ‘special’ elastomeric coating (do not have a BUR system over them.

The foam is the roof system and needs to be replaced.

I suspect you were thinking of rigid foam insulation board, used as roof deck insulation, over which BUR systems are installed.

Even then, the wet area should be cut out and removed (including cutting out and removingthe wet foam insulation board).

If the wet area is allowed to stay and the ‘dry out takes years’, if the roof structure is single concrete tees or twin tees, there could be water related problem in the tees (spalling); if the roof structure is steel bar joists, galvanized steel decking, a gypsum or lightweight concrete deck poured in place, there could be damage to the gypsum or concrete, and most likely rusting or corrosion to the steel decking (I’ve seen this stuff almost completely rusted away); and if the roof structure is wood with wood decking, the decking will wood decay away, as will the wood trusses.

Then you added “Doing a complete rip up can really get into big bucks which may not be in the budget at this time.”

You are correct, but leaving the wet roof in place is like the adds on TV with the FRAM oil filters “You can pay me now, or pay me later.” Paying later ALWAYS costs more. Think of it as a loan with interest compounding – the interest is the damage which begins to occur, the compounding is time. The longer the interest is left to take its course, the higher the total due becomes.

Then you asked “Suppose they put a layer of 3/4 CDX or even wonder board with vents to help remove trapped moisture using probes or similar moisture seeking devices to find the hot spots and then just cover the existing with say and EPDM or other single ply system and treat the older lower roofing membrane as added insulation?”

You (not YOU in particular, but using YOU as in the plural for everyone) are not allowed to roof over or re-cover a wet roof. All moisture must first be dried out. Every code and manufacturer’s specs I read are specific on that.

You then added “This could give them about 8-10 years relief time to budget for a complete rip off.”

Well, technically they could (would be against code though), but if they did, their end cost could be considerable higher due to the long term water damage to the structure.

snip (I snipped out some of your message)

You ended with “The one great quality no one menthioned is this system does not have fish mouths but it does seem to have its share of alligatoring.”

Well I’ll be! You mean there is a ‘good quality’ to this roof system?

True, there are no fish mouths as this is spray or roller applied as a continuous roof coating, however, I’ve never seen the top protective coating applied anywhere near as thick as required, much less as thick as need for proper protection. Remember, these roofs are installed where there is required access to mechanical equipment and the roof coating does not withstand foot traffic well or dropped tools. One crack, hole, puncture, etc. and the roof is leaking.

In case you haven’t guessed, I have yet to find a redeeming quality for these foam roof systems.

Take care.

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