Recently had a field-mouse in the kitchen. Didn't take long to catch it -
but I was initially puzzled as to how it had got into the house. We have
UPVC doors front and back, and all the airbricks around the house are
Eventually I found what I am sure is the access point. My CH boiler (and gas
meter) is located in the attached garage. The flow and return pipes from the
boiler, and also the gas pipe, enter the house from the garage via a hole in
the garage/house wall 3" above floor level. This brings the pipes into the
house beneath the suspended floor in the hall. The hole through which the
pipes pass is over-large and certainly big enough to allow a mouse to crawl
through the hole alongside the pipes and hence then have the run of the
house. Mice can easily get into the garage because the gap below the garage
door is wide enough to allow a mouse to squeeze under!
Clearly I need to seal the hole - but I am concerned about still allowing
for expansion and contraction of the CH pipes. I don't, for example, just
want to fill the hole around and between the pipes with mortar because the
constant expansion and contraction of the pipes could eventually cause a
leak. I then thought of silicone - but am not sure how silicone sealant
would deal with the extremely hot outflow pipe from the CH boiler.
Anyone any bright ideas as to how to seal this hole up without risk of
damage to the CH pipes?
Silicone sealant should be fine - even the stuff they use for glazing is
good for 190C. Most of my ovenware is silicone. However, I'd get a
stainless steel "wire-wool" pot scourer or two and push them in around
the pipes and then apply the sealant to them whilst filling the hole.
Rodents will eat sealant - but find the pot scourers a tad less
However, I'd use standard builder's PU expanding foam. Push the tube
into the gap, here and there and a little squirt and it's done. IME,
rodents won't eat the stuff...YMMV.
(Living near a water course on Dartmoor, I get the lot trying to get in,
uninvited- water voles, badgers, otters, foxes, mice, rats, grokkles,
adders, frogs, toads, you name it...) - just having to contend with
field mice would be *luxury* :) ).
My sign on the field gate saying, "Warning - LIVE FIRING. Authorised
personnel only beyond this point" seems to work a treat.
Mind you, why they are quite so put off, I couldn't say - my pottery
kiln isn't *that* dangerous...
It's a tourist to Cornwall (and in Devon they're called Emmets [or possibly
the other way round]).
It's generally used by the indigenous population of both counties as an
*INSULT* to those that make the 'great South West' holiday tour every year
and whose cash probably keeps several thousand people in jobs (albeit
Thanks everyone for your suggestions - I reckon the expanding foam is
probably the best bet. I did also consider making an aluminium template in
two pieces that would fit close enough around the pipes to keep the mice
out - but give enough room for expansion. I could just screw that to the
wall - but the foam would be a lot easier!
old brillo pad should be fine if you give it a quick spray with wd40 or such
mousies can't gnaw through it.
If you smear a drop of _proper_ hot pepper sauce on the inside they won't
even go anywhere near it. Google for Mad Dog 357 sauce. About 180 times
hotter than tabasco. Lasts for years. Handle with care. Seriously.
Bypassing all the jokes and innuendos, generally speaking, compo (sand &
cement) is quite sufficient.
Recently removed 30 year old boiler installation in my own home, with
pipework local to boiler encased in cement. No leaks, not even any pipe
If you want to take precautions split a length of overflow pipe and slip
that over the pipe before you entomb it. Do two pieces at 180 degrees if
pipe is too large in diameter.
If you do not encase a fitting, or some other irregular feature within the
cement closure the pipe will not be firmly held and will move within the
cement by expansion. This can be demonstrated by the fact that after 30
years my encased pipes could be tapped out of their "prison" by a few light
taps with a hammer.
I still have 30 year+ pipes encased with no probs.
I'd go with expanding foam but..... you say your air bricks are intact, so
they might be but I bet a field mouse could get through one of the holes - I
actually watched a house mouse come out of one in our house shortly after we
moved in. The house had been empty for 9 months prior to us moving in and we
could hear mice scuttling about but couldn't figure out how they got in. I
was in the garden one afternoon and saw this little beastie crawl out of the
air brick hole!
Not all that surprising, I saw a documentary about rats some weeks back and
it was said that a rat can get through a half inch gap under a door!
Persistant little sods
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