Insulating a Home With a Flat Roof

andrewscharff asks,

You've mentioned Insuladd on your show, but haven't been able to find anything positive about it online. Do you have personal experience with the product? In a related question, I often hear you talking about how insulating the roof is so important; however, I have a 3-story 1910 city rowhouse with a flat roof. Any ideas on how to better insulate this type of roof?

Our Answer

I don’t have experience with paint as an insulator. I've heard a few reports of it working, but personally have never seen evidence that it’s super effective.
In terms of your home in particular, flat roofs are the hardest type of roof to insulate because it's all enclosed. The only way to do it right is to remove the ceiling, or to remove the roof from the outside. If you take either of these routes, be sure not to use fiberglass insulation. Use spray foam insulation instead. It's very effective. You'll feel the difference and see it reflected in your utility bills, too.

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