I have a flat roof project (BUR needs replacement) that consists of about 60,000 sqft of retail space and 15,000 sqft of non-climate controlled ministorage. Location is about 50 miles inland from Gulf Coast, so high heat/humidity, hurricane prone area.
Was planning on using Sarnafil to recover, but their tech dept is saying we must put their insulation (polyiso) down over the old asphalt BUR to get a 20 year warranty. This adds significantly to the cost.
The retail space BUR already has insulation (lightweight insulating concrete over metal deck)
We have used Sarnafil before on property in Utah & they did not have the insulation requirement (due to different climate perhaps)
(i) It seems wasteful to use insulation on non-climate controlled ministorage. We don’t need it to stay cool (and have no insulation right now), just need to keep water out. Is there another system that could be recommended for this application.
I have briefly looked into spray on polyurethane foam, and EPDM, but so far my due diligence does not lead me to have much confidence in the longevity of these systems.
(ii) On the retail space, the extra insulation has some value in reducing the tenants’ electric bills, but still may be overkill for the application given that we already have lightweight insulating concrete under old BUR.
(iii) Are there any pitfalls to recover an existing roof that I should be aware of. The contractor will be scanning the roof for trapped moisture,and Sarnafil has OK’ed it with 20 year warrantee.