Wind tunnel under bay window

Skindel

I pulled up a floor board new to my steam radiator in my bay window. There is no insulation below it and the wind is howling through. Two questions. If I put in fiberglass insulation, how close to the steam pipe can I get? Can I put a foam insulation sleeve around the steam pipe?

KC_Jones

Fiberglass insulation is what you use on steam piping. Do not use any foam on the steam piping at all it will melt. The fiberglass is what you need to stand up to that heat.

Skindel

Thanks. Glad I asked! I was about to go to the hardware store and try it. Can the fiberglass touch the pipe or do I need to leave a space?

wcs5050

Can you stop that draft somehow?

Abracadabra

Skindel said:

Thanks. Glad I asked! I was about to go to the hardware store and try it. Can the fiberglass touch the pipe or do I need to leave a space?

yes.. the fiberglass can touch the steam pipe, it is actually preferable to touch the steam pipe. You don't want any air. Fill all the air space with firberglass

Gordy

Is this a cantilevered bay window?

I don't know the access but I would seal with caulk, and or spray foam first then the fiberglass. Fiberglass alone won't stop the cold air.

Skindel

It is a cantilevered window. Thanks for the help. It's really hard to access as it's under 100 year old tongue and grove flooring with layers of poly. I tried to find gaps to seal with spray-in but couldn't find any. I'll pack it with as much fiberglass as I can. I figure anything will be better than the newspaper insulation that I've found along the edges. Thanks!

BobC

All fiberglass battens do is filter the air, it does nothing to stop air movement. You have to find a way to stop the air movement through he box with caulking or spray foam before adding insulation to that space.

Fiberglass pipe insulation is much denser than house fiberglass insulation and actually will stop air flow but that will do nothing to control air infiltration through the open space at the base of the bay..

Bob

Skindel

Good to know. Maybe I can get another board up tomorrow and find a way to stop the air flow.

KC_Jones

You might also consider looking around on the outside of the house. You are looking for any cracks or openings that will allow air to come in. Keep in mind it might not be one big opening, but a whole bunch of little ones that add up to a lot of air.

SWEI

Any chance you can find a way to shove a carefully cut piece of 1-1/2" or 2" sheet foam into the cantilever? If so, you should be able to drill a few strategically located holes in the surrounding woodwork and use canned spray foam to seal it into place.

BobC

They make an acoustic fiberglass panel that comes in 2X4 ft 2" thick sheets. It is stiff but not really rigid so it might be easier to fit into place than sheet foam. It could be held in place with spray foam and augmented with regular fiberglass once the wind tunnel is tamed.

Bob

Larry_52

KC_Jones said:

Fiberglass insulation is what you use on steam piping. Do not use any foam on the steam piping at all it will melt. The fiberglass is what you need to stand up to that heat.

Not to start a war but I have used closed cell foam for sill plate sealing and in one instance on my own dwelling had it in direct contact to a steam pipe to a radiator. The area is visible in the basement and after 3 years there is no breakdown of the foam. I would probably not recommend great stuff in a can, but closed cell foam or any fire block rated foam will do the job and stop the air which fiberglass lacks.

tim smith

I would put fiberglass pipe insulation on pipe tape joints well then you could maybe foam in under bay totally. That way you get best of both worlds. Do a little research first on foam and moisture/vapor problems first.

vaporvac

Perhaps after the winter you can attack it from the outside and use a vapor barrier of some sort. Just be sure whatever foam use use is fire-rated. Many aren't and the fumes will get you before you even realize what happened.

Skindel

Thanks everyone. I tried building a foam board wind barrier, wrapped the pipes in fiberglass tubing, and layered some more fiberglass in the area. I'll try to tackle the wind issue in the spring. I also used a car jack to lift my radiator and put wood blocks under the radiator, so the slope of the pipes is better. Hears hoping for quiet pipes and nights.

BobC

Let us know how it works out.

Bob

Skindel

For the first time in two years I do not have severe water hammer that lasts five minutes. I still have the sound of boiling water in the radiator, but I don't worry about that waking my downstairs tenant, so it's acceptable, though I'd take suggestions on how to stop that. Thanks for the help.

BobC

You said you raised that radiator on blocks, use a level and check the radiator itself has pitch back towards the supply pipe.

It could also be the radiator valve flapper has cracked and is partially blocking the passage of water. I would not mess with that until spring.

Bob

Fred

Check the pressure also. Do you have a 0-3PSI pressure gauge on your boiler. I had a boiling water sound on one of my radiators and it turned out the pigtail that the pressuretrol is mounted on was plugged with gunk and letting the boiler build excess pressure. Sometimes when you have that excess pressure, it makes it difficult for the condensate to return to the boiler. Cut-in should be .5PSI and Cut-out pressure should be no more than 1.5PSI. If you have a grey colored Pressuretrol, set the scale on the outside at .5PSI and inside the unit there is a white dial. Set it to 1. That gives you a cut-out of 1.5PSI (.5 + 1)