How best to repair a rotten timber frame?

[SirGalahad]

I have a hard wood window frame in the bathroom and I think overtime the splashes from the sink has caused part of it to rot. About 5-7 inches long, 2 inches wide and about 1-2 inch deep.

The sink is level with the bottom of the window sill.

So what is the best way to repair this?

1) Remove all the old rotten wood
2) Apply rotten wood hardeners
3) Fill with expanding foam
4) Then finish with an epoxy based wood filler
5) Sand down and varnish over.

Is Ronseal wood hardener and Ronseal Wood filler appropriate?

 

[chris1982]

Instead of the expanding foam, I'd use timber pieces.

 

[SirGalahad]

Instead of the expanding foam, I'd use timber pieces.

What glue is best to use? Will it need to be done in 2 stages?

1) remove old timber and then apply treatment - day1
2) glue in new timber piece - day 2
3) finish with epoxy wood filler - day 3

Can it be done quicker?

 

[Mr Chibs]

If you didn't put any treatment on, you could do it in one day... does depend on how bad it is.

I'm finding Gorilla glue is very strong for wood, plus it expands very slightly [bit like foam] so might help.

I'd use car body filler instead of wood filler, it's the same but cheaper for a much larger tub.
As mentioned fill with timber pieces to pack out.

 

[Doggit]

I'm not sure how long the Ronseal rotten wood hardner takes to set, but there are 5 minute wood glues, and even the normal ones will only take about 20 minutes or so on a hot day. The body filler will go off in about 10-15 minutes depending on how much hardener you use, but if you're using Ronseal wood filler, make sure you start sanding as soon as it's hard, otherwise it can be a bugger if left too long. I'd avoid the foam though, as you'll have a weak spot in the frame. But you could bed the wood pieces in with the filler rather than wood glue.

You've basically got a good idea of how to handle the situation.