Rubber roof insulation

I have a unique 1965 home that has a large Central room with a wood ceiling that the roof board directly affix to (no gap to hold insulation or create an air barrier). I recently had the tar and gravel roof replaced with rubber membrane, after the fact they casually mentioned that there had been insulation under the tar and gravel but never said anything else about it.

Since the replacement my main room has been considerably warmer than the rest of the house (traditional insulation) and I’ve just found out that no insulation was added or replaced when my roof was replaced meaning there is just two layers of wood and the rubber membrane between me and the outside world.

Is this a normal practice with rubber roofs? Do they have some kind of amazing natural insulation? I live in an area that gets well below freezing in the winter and I can only imagine all my heat escaping through the roof.

Sounds like the roofer didn’t understand your homes construction. The insulation should have been placed under the new material. A simple closed cell ISO of 1" is about R6. You can double it for every inch. I’m sorry they didn’t insulate it for you.

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At this point you need to look up IRMA or Inverted roof membrane assembly. Without insulation you will have a condensation problem, big black ants, and rotten wood. Too many idiots in roofing nowadays.

Paint Gaco over it.
It will reflect the heat instead of absorbing it.

After painting it with Gaco,
Even on the hottest day, you can stick your hand on the surface and it will not be hot.
Warm, yes ofcourse.

I’m pretty sure, at a minimum, R30 insulation is required.

According to the IEC R-30 is only required for new construction or buildings being renovated.

This is a renovation situation.

The OP is facing a condensation problem, yes, even without an attic. gaco is not the answer to everything. It will disbond if there moisture in the system. it has no insulating properties. it will not adhere to mod bit with aluminum paint on it, even though the rep said it would. Once it’s installed, it’s gaco forever.