Rats in cavity walls, question about block work

[Snuffy88]

Got a rat problem which I would appreciate any advice on please. I noticed lots of chew marks in some food in one of my lower kitchen cupboards, they’ve been climbing in over the back rather than using the doors. Can even see the claw marks on the walls which is gross.

I had a look behind the kickboards and the obvious thing that stuck out were these gaps in the blockwork. Could feel the breeze from the cavity.

Put some traps out and set up a motion activated camera and lo and behold it showed its head in the gap.

My questions are:

1. Are there any reasons for gaps in the blockwork like that? Is this pattern of gaps likely to extend along the first floor?
2. Any advice on where to best position the traps. I know you’re supposed to put perpendicular to walls, but when I know where they’re coming from shall I just surround the gaps? Take it I’m best trying to kill them off before sealing them in?
3. How best should I fill those gaps? I know wire wool can be a short term fix, but the gaps are probably too large for that and would prefer a more permanent solution.

I’m also going to do a thorough look for any other external entry points to block. Difficult given I live in a first floor flat in a terrace.

 

[Mr Chibs]

Gaps are possibly where the joists for the floor are (if it's a suspended floor) if they are they will be all along the room, something like 400mm apart.

You won't be able to use expanding foam, will be difficult to get in, and they might eat through it.
I think I would cut some plywood squares and glue over the gaps, with a good adhesive. They can gnaw through some meshes.

Something like this.

I'm sure you'll get some more ideas.

Good luck

 

[^woody^]

Sack the cat.

First floor flat implies that there is a landlord for the block. If so it's their responsibility.

Alternatively, as these are not aerial rats ie squirrels, then they are getting in from the flat below or adjacent, in which case involve your council under there Statutory Nuisance powers to enforce action by those neighbouring owners within 21 days.

 

[Deluks]

Poke some mortar into the holes. Or stuff them with wire wool or one of those metal brillo pads, then pump in a few squirts of silicone to hold it in place.