Isopolyisocyanurate and radiators

David_5

You can do what you ask. It is ok for the insulation to touch the radiators but the radiators work better with more air space. You could use aluminum duct tape to seal insulation joints.

David

Sevenoaks

Foam insulation board touching radiators

Hi. Most of our forced hot water radiators are recessed in a metal lined spaces in brick exterior walls (which have no insulation). All of these recessed systems are beneath windows. This is vintage 1946 construction. While working on the wall insulation problem as we can, we want to line the radiator metal recess spaces with Super Tuff-F (polyisocyanurate) with the foil side facing inside, next to the radiator.

Is it okay if the radiator touches the foil? Or worse, is it okay if the radiator pushed into the foam board slightly? The board is only 1/2" thick but that also seems to be about or less than the clearance in the back of the radiator.

The radiators are two-pipe and changing the plumbing would also mean that the front covers (also metal) won't fit any more.

Please let me know what you think. We consume so much oil for 2400 sq ft (including a basement that the great old cast iron boiler keeps very comfortable); and we need to do as much DIY as possible.

Happy Holidays and thank you for your help, Bobbie.

P.S.
If its okay to go this way, should the foam board sections be taped together? If yes, with what?

And should we try to line the top of the metal recess with the foam board too? If yes, what kind of adhesive would be safe to use near the radiators that would hold the board in place? Thanks again.

Paul Pollets

Air space

2" air space works beat for radiator enclosures. See radiator topics in Hot Tech Topics

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