Rotten window cill. How to treat ?

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I am repainting my bay at the moment and the bedroom cill looked great, just needed a sand, but when i got going i found soft wood.

I ended up raking out a lot of area and the photos will show what i have now got. The channel to fill is 50mm deep.

How do you tackle a repair like this ?

I was thinking the post can be filled with the wood repair fillers, but the channel is different.

Do you try fit in some treated timber to fill the space and then fill around it with the wood fillers?

any tips appreciated.
 

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Ok great. What do you think about putting some treated timber into the large area. It would just need to much filler i reckon.
 
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Yes, you can glue pieces of timber into the frame/cill, you could shape to match or just leave it below the surface and have a scrim of filler over it.

Andy
 
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Trevor Bayliss,

Cut or chisel it square and use a bit of timber to put in the slot. If not possible plain a bit of wood and Gorilla Glue it in place. Use a wee bit of filler in the gaps and plain it square to the existing frame. Not forgetting to put a dab of paint on to stop it rotting again ;)
 
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The belt and braces way to splice in the new timber would be to use epoxy resin. Unlike 2 pack filler the epoxy allows for expansion and contraction. Epoxy resin is much more expensive though.

The two main brands are

http://www.chemfix.co.uk/products/timbabuild-wood-repair/ and

https://www.repair-care.co.uk/

The former is the less costly of the two. Both have their own proprietary application guns for their twin tubes. RepairCare however do sell an epoxy in a regular sized tube. It costs about £25 for 180ml.

https://www.repair-care.co.uk/product/dry-flex-4-2-in-1/

Assuming that your cuts are accurate, it should be just about enough. You have to be very methodical when you mix it, far more so than when working with 2 pack filler. ReparCare recommend that you wet prime the old surfaces to be glued with their expensive Dry Fix liquid but if the old wood is sound you can skip that.
 
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When I had one done, I obtained a piece of teak from a local boat builder, and the carpenter cut away all the damaged wood, and used a router to trim it back to a long square edge that the new piece slotted into all the way along the sill, with a drip.

The join is not invisible, but a very neat job, and I think better than patch repairs.

Not everyone can get teak, but hardwood sills are widely available.

I've tried wood filler repairs in the past. They don't last long. Windows are very exposed to weather.
 
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Agreed. In fact I can't think of a better tool.
My Mrs didnt need one, she got fed up of waiting for me me to do one so. She dug out the rot,treated,then hardener ,then chicken wire ,filled most of the way with sand cement Sbr mix and made good when dry with a tub of putty. I was a little horrified but hate to admit it still looked pretty good a few years later when I replace all the windows .
 
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Thanks all

luckily I have a multi tool so will go on with it this weekend

I was wondering if the stixall product will hold the new spliced wood in place ?

then will the small bits with filler
 
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Yes, Stixall will glue it in place as long as you hold it in place with masking tape while it 'goes off'.

Andy
 
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I think better than patch repairs.

Agreed, if most of the sill is rotten then replace it but if the damage is localised epoxy resin is fine. I wouldn't splice in a 2cm squared piece of timber, I would just use epoxy resin.

You raise a good point about hardwoods. Three years ago I repainted a hardwood timber conservatory. It had quite a lot of localised rotting. I spliced in with softwood and epoxy. Everything is still sound (no hairline cracks) but I can see that the softwood expands and contracts at very slightly different rates to the hardwood.

The next time that I have to do one, I will buy a portable bandsaw and some teak.
 
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