Wood hardener/sash windows

Likely, yes. If you've chosen a wood which rots easily - like most you'll find today - any filler, no matter what, won't last that long.

Ronseal wet rot wood hardener will soak into the rotted section and make it rock hard. If the windows are out so much the better as they can be laid flat and the hardener, which has the consistency of water. may penetrate further by gravity. A two part car body filler to fill the large voids will last maybe 5+ years. A few (stainless) screws into the hardened wood will give the filler a "key". The seal (putty) to the glass has to be good as any water running behind the putty will hit a waterproof barrier (the car body filler) and likely run towards the inside of the window and towards untreated soft wood.

The thinner cracks may be more of a problem to fill to last 5+ years.

In my experience sand down any excess filler when it has gone hard to the touch and not necessarily after 24 hours after curing more.

Perhaps I should have used MDF, or old pallets, or balsa. No, silly me I used unsorted Swedish redwood. Pah. Tch.

Re the actual job, I'll paint it with polyester resin, over the wood hardener, and add a bit of chopped strand glass to make it a little stronger.

I saturated it :) I think it will take rather longer than the two hours (it says on the tin) to dry.

That's the problem. This was one of the first windows I made. The whole thing was made, glazed and finished before being lifted bodily and pushed into the aperture. That was a long time ago now! It was never maintained.

I'll give it a go. If I have to replace the top sash meeting rail and do some splicing then - oh, well. I might even have some of the original mouldings, I made a bit too much back then.

I think I would remove as much of the damaged wood as possible until you reach relatively sound wood. Try to leave the surface as flat as possible. Harden the remaining wood and then splice in a fresh piece of wood that would bring the thickness back to what it was originally use the epoxy filler to both glue in place the spliced timber and to compensate for any gaps. Finally a couple of screws driven in from the backside into the fresh timber should make it all secure before filling in any imperfections.

I did this on a couple of windows at my last house the repairs lasted ten years before we replaced with UPVC and the repaired sections showed no further rot when they were taken out.

Richard

I've got lots of sash windows here - all original Victorian. About 140 years old. And no rot.

Did have a bigger windoiw fitted to the kitchen, made from modern treated wood. Only a few years later, that's when I found out Ronseal hardener and filler is at best a short term fix. Before replacing the window with PVC.

I'm having some double glazed sashes made for the living room bay window. They're not using Swedish redwood.

Not unusual, given *maintenance*.

Yes, MDF's got a lot going for it. So they are not using what was almost certainly used originally (you can look it up).