Using expanding foam near gas/water pipes (to keep mice out)

achan

Hello,

I’m seeking solutions to stop mice entering my kitchen

Occasionally (at least once a year) get vermin underneath my flat kitchen cabinets and I have to get pest control in to set traps. They’ve previously mentioned that there are holes in the wall, where pipes come into the kitchen and that as long as there’s an entrance vermin is likely to return. 

And once again today, I’ve seen droppings underneath the cabinet right at the back near the wall…(tough to clean 😰) 

The pipes / hole in the wall is right in the corner and far to reach so it’ll be difficult to fill it. It’s also next to the gas meter so there’s gas pipes nearby. I think there’s also the water pipe beside it. 

1. If I can reach it using extra long tube, is it safe to use expanding foam next to gas and water pipe? I’m aware that Brillo pad / copper mesh with the expanding foam would be more of a deterrent.

2. Would I be causing myself issues in future if those pipes that I encase in expanding foam need to be replaced? I understand expanding foam is a nightmare to remove. Is there a better solution to this? 

Thanks 🙏 

subjecttocontract

Expanding foam is ideal for sealing holes in walls, the secret is not to use to much.

ThisIsWeird

You can also get supposedly mouse-repelling type. I used a few cans last year on mil's new place - no meece in the hoose yet, but a huge family of very cute voles under her decking...

p00hsticks

if you can reach it, another option I've heard of is to use wire wool to block the holes 

chrisw

1. Perfectly safe.
2. The foam is difficult to remove from surfaces but if the pipes need removing in the future it can be cut very easily with a knife so not really an issue.

FreeBear

Around the water pipe, expanding foam isn't a problem. Around a gas pipe, it could be....

Current Gas Safe rules says a pipe should pass through a wall through a non-combustible material. So sleeveing the hole with metal for the gas pipe to pass through is OK. A plastic sleeve is not, nor is plugging the gap with expanding foam apparently. Whilst this isn't an issue for most people, if you ever need a Gas Safety certificate, it might fail the inspection.

ThisIsWeird

FreeBear said:

Around the water pipe, expanding foam isn't a problem. Around a gas pipe, it could be....

Current Gas Safe rules says a pipe should pass through a wall through a non-combustible material. So sleeveing the hole with metal for the gas pipe to pass through is OK. A plastic sleeve is not, nor is plugging the gap with expanding foam apparently. Whilst this isn't an issue for most people, if you ever need a Gas Safety certificate, it might fail the inspection.

I can think of a scenario where this could happen. Um, actually, no I can't. If the GS fellow drops to their knees and begins to pull off a unit plinth, then...

When I did this job, access was abysmal - there were large wastes pipes running along the under-unit void making it a 'mare. But I bought a large wad of steel wool from SF, pulled out large tufts of it, and then used a long stick to push it along the floor and in to the gaps and holes as best I could - which was not very well. Then I used the 'mouse' foam and full arm stretch - a very unpretty job.

If you reckon you can poke a stick in to the gaps first, then consider the wire wool as the first barrier, and then the foam on top.

achan

Thank you all. Good to know what’s considered best practise, legislation and practical reality. I think I will try to poke wire wool or copper mesh into the hole(s) and then foam on top. This is assuming I can extend the foam spray to around a meter (intending to use homemade plastic tube extension). Good to know it can be a very unpretty job. I guess I can only do that I can with my short arms!

FreeBear

achan said: This is assuming I can extend the foam spray to around a meter (intending to use homemade plastic tube extension).

One tip - Get yourself a cheap foam gun or two off Amazon or ebay, and use the gun grade cans. Much easier to control, and you can fit a bit of hose on the end quite easily. The cans of foam with the built-in nozzle/applicator are very much an all or nothing affair and next to impossible to control the amount of foam coming out of the business end.

Second tip - If you need to inject foam in to a small space, whack a nozzle from a tube of mastic on the end of the gun.

Third tip - Acetone or nail polish remover is the best stuff for keeping the gun clean - I strip mine down and soak the parts after use.

Eldi_Dos

achan said:

Thank you all. Good to know what’s considered best practise, legislation and practical reality. I think I will try to poke wire wool or copper mesh into the hole(s) and then foam on top. This is assuming I can extend the foam spray to around a meter (intending to use homemade plastic tube extension). Good to know it can be a very unpretty job. I guess I can only do that I can with my short arms!

Another possible alternative is to get some neoprene tape and create a loose fitting grommet around the pipes ( sticky side out) and slide this along pipes and use a thin palate knife or spatula to push into holes around pipes.
If need be attach palate knife to pole to give extra reach.