Expanding foam to fill holes in wood

Remove the foam - it will always be spongy, cos that's what it is.

If accessible enough, cut out the rotten section & join new timber in.

NT

If it is structural, I'd certainly not be using foam. Threat the wood, cut out the rot or whatever, make sure you can still have enough left to be strong enough to hold it up!. Really I'd not want to use foam cosmetically this way. Brian

Didn't see the original message, but yes, dig out the foam and any remaining rotten wood, use Ronseal wet rot wood hardener to harden up the wood surrounding the cavity, and then Ronseal wood filler to fill it.

Chris? advice is probably ok for small areas- the Ronseal stuff is good. However, if the holes are large enough to weaken the structure, you need to replace the wood. You don?t want the thing falling down on someone or your car.

It's a light weight expanding foam designed to fill holes/voids and not to form a structural repair on a supporting beam or leg. The cured foam is full of air pockets and will be easily pushed in with a finger. Any excess can easily be cut away with a saw or knife.

As others have written you may have been better off using the Ronseal Wet Rot hardener on first on the damaged/rotten wood