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Commercial Roofing Solutions from The Garland Company

Can you diagnose these TPO blisters?

This 7 to 9 year old TPO has been repaired many times. It was originally black, but the manufacturer stepped up at some point and paid for the coating (which is not doing a lot of good, as you can see here). In fact, we’ve never seen anything that looks quite this bad.

So what went wrong? We’ll never know for certain but here are four probable causes:

  • Wet primer or glue when installed
  • Overheating the patch material
  • Incompatibility of the patch material
  • Poor installation and cleaning of membrane

At first the Garland rep asked to analyze this roof thought it might be a reaction from the coating being applied to the repair material.  However, the uncoated patches are also blistering. In fact, 85 to 90% of the repairs are experiencing the same blistering/ bubbling issues. It would be nearly impossible for even the worst roofing crew to screw up every patch.

Here’s our best guess: the patch material/ primer was not compatible or was in some way faulty. What do you think?

One Response to Can you diagnose these TPO blisters?

  1. Joe Mellott
    Joe Mellott November 30, -0001 at 12:00 am #
    Good call on the “best guess”. There may be another issue to consider. White surfaces do not get as hot as darker surfaces. In colder climates, its possible that excessive condensation can form under white single ply roofs (like TPOs). This situation can be made worse due to vapor drive and single layer, non-staggered insulation. The vapor driven from the inside of the building can cause subsurface condesation and perhaps blisters of this nature.

    Check out this early article posted in a number of publications. It is something to consider.

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