I want to block the big hole behind the basin

[Dimyself]

Hi,

Try to stop mice, I want to block the big hole behind my basin, but don't know how difficult it will be. Please give me your advice!

1. Is this easy to uninstall and reinstall Part 1?
2. Is this OK to use cement plaster to block the big hole?

Thanks a lot in advance.

 

[bernardgreen]

Part one is likely to be supporting much of the weight of the basin.

 

[JohnD]

do you mean that where the pipes go through the wall, the hole for the pipes has been left with gaps? If so, take the basin off and fill the wall. You could possibly also fill the gaps on the other side of the wall.

 

[Burnerman]

Look upwards from Part 1.....can you see some nuts, often around 10mm threads (17mm spanner?) If you can, these support the basin and you can slit through the silicone that seals between the basin and the semi pedestal with a stanley knife. The pedestal screws will be under those white plastic caps so if you undo those, the semi should come free.
You should now see where you need to fill.....maybe with expanding foam?
John

 

[KenGMac]

Hate to chuck a spanner in but?

If you have a close look at the hole that is to be filled, the feed pipework has at least one in line stop valve, generally called a ball O fix It is a small shut off valve that would allow you to stop the flow of water to the tap if you need to change a tap washer.

if you block up this hole then access to the valve will be denied, indeed both the hot and cold feed pipes will in all probability have such devices fitted, just cant see the second pipe.

As fix, how about using a piece of plywood cut to slip over the hole you could then use silicone [which is a good glue] to set the ply in place, hole blocked, no more mouse runs from that source.

As an aside are you sure that the little furry ones are accessing the house via this hole? I can see no indications of any fraying of the edges of the plasterboard to indicate this is a mouse highway, normally if mice are using this as access I would expect to see rub marks, minor scratch marks and similar to indicate a mouse run?

Ken.

 

[Dimyself]

Before I read your advises, I would like to show you the BIG HOLE!

 

[JohnD]

I will guess that the hole is behind the basin and goes into a plumbing duct or void behind the wall. Take the basin off to fix it.

If you truly have mice in the duct or void, you will need to block it with a material they cannot easily gnaw through. As it is behind a basin it needs to be water resistant.

Get the smallest piece you can find of Hardibacker board. It is sold in places that sell tiles. A broken piece would do. It is a cement-based board. It is possible to cut and drill it. Cut it to be a close fit round the pipes and drill through it to screw to the wall. Buy the smallest amount you can find of sand and cement or mortar mix, make it up with a little water and about 5% PVA adhesive so it is stiff, not runny. You can use it as filler and use a filling knife to pack it round the pipes and any remaining cracks. Mice will not gnaw it and it will not burn or be damaged by damp.

Other fillers, and expanding foam, mice can bite through.

I have a feeling that it is a new build or conversion. It does not seem to be fire-stopped to prevent the spread of smoke and flame, which is very bad if it is in flats.

 

[Dimyself]

JohnD:

The wall behind the basin is some kind of hard paper! There are at least 3 layers hard paper. The mice cannot go through pipes, they enjoy running between the paper walls.
When the people install the new basin, probably they just tear a big hole to let the pipes go through......
I think you advice is correct, I will try.

Thanks a lot!