Correct, or best economical pipe insulation for larger pipes?

Mike T., Swampeast MO

For the mains in my gravity system I used 1" thick Armaflex made for 2" pipe. This was NOT split. I split myself and wrapped securing the ends with duct tape (sorry). Tees/elbows were a bit tricky but once you get the knack you can do a nice job.

Then I wrapped with heavy rubber 3-M "arc-proofing tape" that I bought for a song at an auction. I suspect such would be expensive if bought normally, but surely you could find something similar. Probably not utterly necessary to overwrap but I found it looked a lot better, made it virtually immune to impact damage and made the tees & elbows much neater.

For the smaller pipes, I used the appropriate size Armaflex, split and sealed the seam with duct tape.

Al Roethlisberger

Correct, or best economical pipe insulation for larger pipes?


I have an 80ish year old hot water home heating system, and at one time the entire system was insulated with asbestos.

Most of that is gone now, certainly all of it in the basement where the pipes are exposed.

I would like to reinsulate these pipes, but being an old gravity system, all of my pipes are quite large, the smallest being 1.25", going up to 4" pipe.

I had hoped I could use the inexpensive black closed-cell foam insulation one can get just about anywhere. This is the stuff with the adhesive already along the seam, so you just split it, put it on the pipe, yank the adhesive cover, and squeeze. But looking around, these seem to only go up to about an inch in diameter.

I found a product from Johns Manville called Micro Lok which is a vinyl coated fiberglass product that will accomodate my pipes, but it is a bit pricey. If that is all there really is these days, that's fine, but I thought I'd check.

So, I was wondering what you recommended for the DIY guy who wants a quality job, but not spend a fortune.

Thanks
Al

Brad White_9

Moulded fiberglass

is the default insulation of choice. It has the same k value within a decimal point as the black rubber and comes in all sizes. A one-inch thickness is a good place to start although model energy codes may dictate thicker. If you go to a mod-con boiler you can do very well, the temperatures will not be very high for very long most seasons.

Mike T., Swampeast MO

For the mains in my gravity system I used 1" thick Armaflex made for 2" pipe. This was NOT split. I split myself and wrapped securing the ends with duct tape (sorry). Tees/elbows were a bit tricky but once you get the knack you can do a nice job.

Then I wrapped with heavy rubber 3-M "arc-proofing tape" that I bought for a song at an auction. I suspect such would be expensive if bought normally, but surely you could find something similar. Probably not utterly necessary to overwrap but I found it looked a lot better, made it virtually immune to impact damage and made the tees & elbows much neater.

For the smaller pipes, I used the appropriate size Armaflex, split and sealed the seam with duct tape.