View Full Version : foam pipe insulation

11-06-2007, 01:58 PM
I'm going to insulate my 1/2" cpvc in my basement. I'm using this balck rubberized foam (like armaflex). Problem is that it is not pre slit. What is the best way to slit it to get a straight line and then seal it? I thought about laying it on the floor and laying a 2x4 edge along the center line and cutting along the 2x4, then taping it with black electrical tape on the ends and in the middle. Thoughts?

11-06-2007, 02:47 PM
The best way to do that would be to return the stuff you have now and buy pre-slit, pre-glued insulation. I'm sure that is not what you wanted to hear but it's better than futzing around.

I'm sure you can get a fairly straight cut by flattening the insulation under the edge of a straight board and then making a horizontal cut along the length of the piece.

Sealing it is another problem. A single strip of tape along the length of the cut would provide the best seal. Electrical tape in 3 places may leave gaps depending on how the insulation fits the existing pipe.

11-07-2007, 03:12 PM
thanks chh, but i can't find pre slit/self sealing...and I have called 3 different major suppy houses here in Atlanta...so I guess I am stuck with slitting and taping it.

11-07-2007, 03:54 PM
That's too bad. The big boxes have it around here. The plumbing supply guys sent me to an insulation specialty outfit when I needed some for odd sized pipe. They had just what I needed but it was $$$ about 5x the big box store.

11-07-2007, 05:43 PM
If you cut it there is a contact cement to glue it together, just like the precut stuff.

11-08-2007, 08:55 AM
hj, what is the contact cement and where can I get it? thanks

11-08-2007, 11:11 AM
if it truly is made for that outside diameter, it will hold its shape very well for a long time after you cut it, and the minor gap of 1/64th" will not be a significant source of heat loss compared to the heat loss at elbows where you will need to cut custom pieces and tape them a lot. So, just cut it any way you like, and tape it enough to make you feel good about its looks, and work on the corners bends and elbows most.


11-08-2007, 01:54 PM
thanks david...that is what i will do.