# Question about TPO with polyiso to prevent heat from coming in my commercial building



## robarrington (7 mo ago)

Hi everybody. I live in Tampa Bay, Fl and have a 3,000 sq ft single story office building with a flat roof. Right now it's just modified bitumen over light concrete. My R value must be hovering somewhere around 0. I shot the underside of my roof inside my building with an infrared thermometer the other day and it was 110!!! I have a small new addition with TPO over polyiso and that reads 79. In the main part of my building where it's 110 up in the ceiling, my air conditioners cannot keep up this time of year. They are fighting a losing battle. Soooo, time to get a new roof to fix my problem.

I have one quote to do sloped polyiso from about 8" down to 2" with tpo over it for $60k. For 3,000 sq ft, does this quote seem reasonable? Also, what if I forget the slope and just put a couple inches of polyiso over the whole roof with tpo on top? If I did that, how many inches of polyiso would you recommend to rectify my problem?


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## andy (Oct 30, 2011)

That's not a horrible price...might be kinda cheap. ISO is expensive, tapered ISO is stupid expensive. I've done TPO work in Florida, from sale to install as recently as 2018/19. Another question is material lead time.

I'd recommend getting another quote or two and go from there.

Any way to find out how much your addition has on it?

I always shoot for r-60 if the budget allows. Beyond that you get diminished returns


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