Need for insulating steam pipe in wall cavity beyond putting back bat of R19 wall insulation?

JimmyNJ

Hi everyone,

I recently had a new radiator installed and the riser goes through an exterior wall cavity that had a bat of R19 fiberglass insulation in it. I was wondering if anyone had any opinions on whether it is necessary to wrap the pipe with 1" fiberglass pipe insulation in addition to putting the bat of R19 back? The rule of thumb is probably that you can't have enough insulation on a pipe but my concern is that it may be difficult to put the sheet rock back if the pipe (1 /1/4") has both pipe insulation and "regular wall fiberglass insulation" around it. I put some of the insulation back and right now I would need to press it down a bit for the sheet rock to that will go over the opening to be flush with the rest of the wall. If opinions are that covering the pipe with the bat of R19 that was in the wall cavity to begin with is sufficient then I will probably lean on going that way.

ChrisJ

Jimmy,
Surrounding the pipe by fiberglass batts is probably fine.

However, just to be safe can you share some pictures of how this piping was done?

JimmyNJ

Hi Chris,

Thanks for the input. See attached pics. The pipe is currently exposed in the basement but will get it wrapped in 1" fiberglass pipe wrap today.

To help clarify the pics.

1. Take off piping from main
2. piping in basement before it goes vertical into wall cavity
3. Riser in wall (I had put the R19 back in)
4/5. Riser going horizontal (pitched back to riser) in ceiling to radiator in Master bedroom
6. picture of wall opening for radiator riser pipe (with the R19 bat covering the steam pipe).

ChrisJ

Looks good to me.

JimmyNJ

So you think just the wall insulation will be okay Chris?

ChrisJ

I don't see why not.
@Hatterasguy thoughts?

HydroAirJoe

My first inclination would be to keep the pipe on the warm side and wrap in in pipe insulation. But this would compress the batt reducing it's R-value. If you are worrying about drywall, have you considered having it spray foamed?

JimmyNJ

HydroAirJoe said:

My first inclination would be to keep the pipe on the warm side and wrap in in pipe insulation. But this would compress the batt reducing it's R-value. If you are worrying about drywall, have you considered having it spray foamed?

At this point I am not considering the extra expense of having area of the wall spray foamed. What I did so far was taking the batt and opening it like a book in the middle and putting the un-faced part behind the pipe and then the other half with vapor barrier around the pipe facing the family room. I may take a piece of the section of batt down which faces the room and just see how badly the batt insulation would be compressed + would I even be able to get sheet rock flush in the opening with 1" pipe-wrap.

ChrisJ

Spray foam + steam pipe is the stuff nightmares are made of.

I'd just loosely fill the area with the fiberglass as you have and seal-er up.

You'll be fine.

JimmyNJ

Thanks for your thoughts on this Chris - I believe that is exactly what I will end up doing.

HydroAirJoe

Does the steam pipe get hotter than 240 degrees?
If so you could not use a product like Tiger Foam closed cell and u should just have to live with the fiberglass.