Cat Flap in Cavity Wall

vaderag

I've seen a few older threads on this but they all seem to be closed so hope I'm okay adding a new one.

We have a PetSafe microchip cat flap and want to stick it through a cavity wall. We have builders in and they're prepared to do it, but say we need the tunnel. It's a 300mm wall and the cheapest I can find the tunnel pieces are £10 per 5cm so looking at over £60!!

I've seen people posting about using plywood / tiles etc, but i cannot find any pictures anywhere!

Is anyone able to share some pictures?
Thanks

Artytarty

You can use anything really, some vinyl tiles would work or even plywood.
It doesn't need to be plastic or metal.

suki1964

We just made it out of wood

Just a cube that fits in snug is all that's needed

vaderag

And did you guys attached the cat flap to the wood or the cat flap to the wall?
And do I need to worry about damp?

Mistral001

Cavities provide a dual function. As well as providing some heat insulation, they also drain away any moisture that gets through the outer skin of brickwork and prevent that moisture reaching the inner skin of brickwork. Thus you have to assume that the cavity will be damp. Strickly speaking you should use materials that will be resistant to moisture. Also there should be a means to prevent water travelling along the top and bottom of cat flap "tunnel" and across the cavity.

vaderag

Mistral001 wrote: »

Also there should be a means to prevent water travelling along the top and bottom of cat flap "tunnel" and across the cavity.

Could you please advise what you mean by this?
I mean, the 'official' adaptors don't seem to have anything like this?

jfdi

We had this done years ago......it’s a square tunnel made out of plywood. The frame for the doorway is fixed to the brickwork. When we’ve replaced the catflap we just got another one the same size, so could use the existing holes with a bit of sealant in!
No damp. Not neatened on the inside either, as it’s hidden between kitchen units!

Mistral001

vaderag wrote: »

Could you please advise what you mean by this?
I mean, the 'official' adaptors don't seem to have anything like this?

Usually there is small ridge running around the outside of box or tunnel. It just forms a barrier or "drip" to prevent water crossing the cavity. Alternatively a stepped DPC can be put above the box, but it is only practical to install this during the construction of the house.

The following shows a box for a vent in a cavity wall where you can see two plastic ridges approx. in the centre of the box:

https://www.amazon.co.uk/Rytons-Cavity-Through-Draught-Ventilator/dp/B00S2OJKRK/ref=pd_lpo_sbs_60_img_2?_encoding=UTF8&psc=1&refRID=S1BVHYKXBZZ0X0C0EF8Z

suki1964

Two cat flaps, one on either side of the wall, you only need the expensive one on the outside, bog standard basic inside

What you can do is make your cube, then cover it with a bit of DPC before fitting it

Ours was in for 3 years and we never had a problem with damp