Insulating pipes

deyrup

Thanks everyone for all your help answering my questions. I was reading We Got Steam Heat and it recommends that insulating your pipes. It looks like my pipes at one time had asbestos insulation and most of it got stripped out so the pipes are no longer insulated.

I measured the diameter of the cast iron pipes with calipers and they don't match up with the diameter of the pipe insulation sold; the outer diameters of the pipes were 1.6" and 2.4". Does that correspond to 2" and 1-1/4" pipe insulation?

Is a plumbing supply storer the best place to find insulation?

Is there something that insulates the elbows on the pipes? They seem bigger than anything I have seen online for pipe insulation.

Is it ok to put the insulation over the asbestos or do I need to get someone to remove it, and in general is adding insulation a job I can do for myself?

I can insulate everything in the basement, but what about the pipes that go up through the floors, are those usually not insulated?

Is the tube here the main vent? I read that often a lot of problems can be traced to a main vent being replaced with a plug or getting clogged. Is there a way to test if it is working properly?

Jamie Hall

1.6 is 1 1/4 nominal -- but that seems a little small. Are you sure? 2.4 is 2 inch nominal. Which is the sizing fiberglass insulation is sold by.

And, so long as you don't disturb it (much) just slap the fiberglass right over what you have there. No problem. Insulation can be had for fittings as well.

Don't worry about the risers in the wall. Not worth the effort.

A plumbing supply store may have it -- you want 1 inch -- but there are on-line supply houses as well.

And yes, that little tube is probably what passes for a main vent. Even if it's working -- and unless it's been abused it probably is -- it's also probably not as big as you would like to have. Try a Gorton #2. You have have to get some bushings or reducers to match the thread size.

Zipper13

I just started insulating mine yesterday (~50' of main, 10 tees, 4 unions, a couple 45s and 90s. Spent about 3 hours and I'm probably just shy of halfway done (had to cut to fit a lot to make clearances with other pipes and obstacles).

I've seen some people only get the sleeves and leave the fittings bare, but I don't care for the exposed fiberglass ends, so wanted all the seams and fittings sealed up tight so that added to the time commitment. There are separate insulated fitting covers that you can get to insulate the elbows and tees. It would have been much quicker with an extra set of hands too.

I got everything at buyinsulationproducts.com. they have a sizing chart based on circumference or diameter. my mains measures about 2.4 (~2 3/8") in outside diameter and I ordered the "2x" size sleeves and the "#11" size fitting covers, I think. bigger selection and better price than my local home improvement store.

deyrup

@Zipper13 Is there a bit of give in the insulation the larger pipes seem to range from 2.375"-2.4", which is a little bit bigger than the recommended size for 2" insulation. I am wondering if I need to choose the 2.5" insulation.

Is it easy to cut for smaller sections?

How much of a difference is 1" vs 1.5" is it enough to justify double the price? Looks like I need about 40' of insulation.

Zipper13

the fiberglass sleeves I got are cut in half the long way and have a heavy paper wrap on the outside that closes up with double stick tape. this shows it pretty well (fast forward to about 10:20 ): https://youtu.be/qhO9ZRsEcmU?t=628 the insulation itself is significantly more rigid and dense than fiberglass batting that you'd put in a wall, but there is absolutely some good squish in it for sure.

for me the added price for 1.5" or 2" thickness didn't make sense. As has been explained to me by others here, twice as thick doesn't equate to twice the heat retention; there are diminished returns on thickness and the prices add up fast!

the 1" thickness is just a hair deeper than my razor blade goes so I had to cut from the outside first then open it up and give another cut from the inside. but a fresh sharp box cutter slices through it no problem to cut to length.