Help- trying to Re-Insulate thru a Wall

marcusjh

So - we're having a mouse issue - and I've been covering the basement soffits (not sure if that's what they're called or not… ?) that adjoin the house to the addition which was installed in the early 70's. This last one has a steam pipe going through it (photos attached) plus a bx cable. The only thing that was between the addition and the house on this one was a really thin layer of fiberglass (no craft paper), which is deteriorating badly.

I was going to use rigid foam - but Google is saying 'No, don't do that' - So I'm playing with the idea of a new piece of fiberglass, using a split piece of wood (expanded half/hole on either side to accommodate the pipe, and bx cable), then stuffing some stainless scrub pads between the hole and the pipe, and then covering the whole thing with carpenters mesh (which is what I did with the other soffits).

But my gut keeps saying there's another way - and I don' t know what it is - - Suggestions? Should I just use a new piece of fiberglass, put the mesh over it, and call it a day?

I'm guessing when they installed the piping, the pieces of metal under the pipe was to act as a heat-sink?

Thanks!

Jamie Hall

What is the objective of the exercise? Keep mice from wandering around? (good luck with that…) Prevent draughts? Insulate something? The pipe? The house"

Your options change depending on what you want to do…

Not sure what the metal shims are all about — maybe to make it easier to let the pipe slide and eliminate a noise from that.

What are the dimensions of the cavity?

DCContrarian

If the steam pipe is going through the wall I'd presume that both sides of the wall are conditioned space. If that's the case, you don't really want to insulate the wall, you want to insulate the boundaries of the conditioned space.

This is something that even pros get wrong all the time — figuring out where the boundaries of the conditioned space are.

Jamie Hall

That's why I asked what the objective of the exercise is…

EBEBRATT-Ed

Remove the insulation and pound steel wool in around the pipe then stuff insulation in there.

marcusjh

The cavity is 6 x 9.

The objective is to keep the rodents and the cold out. I know that the ideal thing is is to seal the crawlspace area under the addition, but it's compromised (two areas that the cold is coming in, and one is hard to get to), so I need to insulate this cavity for now until I can raise the money to seal the crawlspace. I know the mouse issue sounds like a lost cause, but they're getting into the pantry, and we need to do something. These areas are where the most activity has been, so I suspect it's the likely point of entry

Steel wool is flammable - but those stainless scrub pads are made with thicker strands - I dunno if those have been used in that way, or not….? Maybe a new square of fiberglass, and then a pc. of aluminum sheet metal to cover that~?

Larry Weingarten

Hi, Look up "copper mesh pest control". It's a way to keep the mice out. I'd look at sealing the bottom with it and then using blown insulation to fill the cavity. It's commonly done by poking a hole somewhere near the top and stuffing the blower hose down, pulling the hose up as the cavity fills. Then patch the hole you made. Mice are pretty persistent, chewing through 2x lumber, so I'd cover a bigger area than just the obvious mouse freeway with the copper mesh. 🐹

Yours, Larry

marcusjh

Thanks Larry! The cavity leads to a huge crawl space under the addition to the house - I forgot about copper mesh! I've been stuffing some #3 coarse steel wool in some of the other areas, but the copper mesh will work around the heating pipe. I was looking at getting a chain mail scrub pad last night, but the mesh would be much easier to work with in a smaller area. Thanks again!

DCContrarian

My preferred method of keeping mice out is a mix of steel wool and spray foam. Mice can gnaw through wood pretty easily, but they don't go around making random holes in buildings, they find promising opening and make it bigger. The steel wool keeps them from chewing, but if you don't seal the hole air tight they'll be drawn by the smells and even the warmth of the inside and just make another hole. I find that they tend not to chew into spray foam. The added bonus is that any hole in your house that a mouse could come through should be sealed air tight anyway.

The key to keeping mice out is to secure the perimeter. Unless your crawl space is up on piers and exposed on the bottom, I don't see any point to trying to make the spot where the basement joins the crawl space the perimeter. If they can get into the house, trying to keep part of the house mouse-free is a losing battle. You want to keep them out of the whole house. That means making your foundation the security perimeter. In modern construction there should only be a handful of holes in the sill joist, you need to go around the house and find them and fill them. A mouse can get through a hole the size of a dime.

It helps to know your enemy. There are two types of mice that typically infest houses, house mice and field mice. House mice eat our food and can live their entire lives inside the house, the only way to get rid of them is to kill them. Field mice do not generally eat our foot, they use our houses only for nesting, they need to go outside several times a day to find food and water. If you can block every opening into your house they will stop being a problem.

marcusjh

Larry -- - the steam pipe is iron, and the mesh is copper…. would there be a galvanic corrosion issue? I have this happening on the side of my Weil McLain boiler where the copper piping is touching the sheet metal housing.

DC - Thanks for the info. I can't use spray foam around the heating pipe because it's flammable. I've already used hardware mesh to block initial access to the other cavities -but I will be putting 2" rigid foam against it with the spray foam around the edges to seal it up.

DCContrarian

I don't think your steam pipe is going to catch the house on fire. But OK, here's the fireproof version: Get a short piece of PVC sewer and drain pipe. Slit it and slide it over the steam pipe. Support it so that it's centered, and fill the space between the two pipes with mortar or concrete. Then fill around the PVC with the foam and steel wool. Hardware cloth is good too, especially in concert with foam.

Again, unless the crawl space is on piers, I think you're wasting your time trying to seal between the crawl space and the basement. If the crawl space is on a foundation, you want to be sealing between the foundation and the framing of the house. It's a much more defensible boundary.

marcusjh

No can do on that pvc, as it's hitting the beam at the bottom.

Getting the crawl space correctly sealed is the next big project, but I can't do it myself - we'd need to spend upward of 4k, which we don't have at the moment.

DCContrarian

https://forum.heatinghelp.com/discussion/comment/1811292#Comment_1811292

You can seal against mice without doing a complete encapsulation. All you need to do is go around and look for holes big enough for a mouse to go through, shove some steel wool in and spray with foam. It's maybe $20 worth of materials. There's probably a couple holes by the HVAC guy, one hole by the cable guy and one hole by the internet guy, one hole for each outdoor faucet.