Need to replace a rotten windowsill

Barack Obama

Hi. We are not in our house too long and it turns out that the windows were never fitted properly in a bedroom and constantly leaked with rain. The windows have since been fixed but I need to replace the rotten windowsill.

I have a decent table saw so I'm happy to do this myself. The long run will be fine but I'm a bit concerned about the end pieces because these go into the wall. I'm just looking for some advice with the plastering - should I bite the bullet and saw away an inch of it and then look to get it re-plastered afterwards or is there a way that the plaster can be left untouched?

Thanks!!

antiskeptic

Barack Obama wrote: »

Hi. We are not in our house too long and it turns out that the windows were never fitted properly in a bedroom and constantly leaked with rain. The windows have since been fixed but I need to replace the rotten windowsill.

I have a decent table saw so I'm happy to do this myself. The long run will be fine but I'm a bit concerned about the end pieces because these go into the wall. I'm just looking for some advice with the plastering - should I bite the bullet and saw away an inch of it and then look to get it re-plastered afterwards or is there a way that the plaster can be left untouched?

Thanks!!

I'd remove the larger piece first and see how well the smaller piece is fixed in. Unless it's nailed to the underlying blockwork, I imagine you could tap it loose.

I'd trim the plaster above and below the wood away by a few mm using a stanley knife or some such - right back to the blockwork. That way pulling the wood - even roughly - won't also pull chunks of plaster away from the wall. Fit the new (gluing it down with Tec7 or panel adhesive) then fill in the gap you've cut with a bit of Polyfilla.

If nailed, you'll have to try to split the wood along a centreline on which the nail lies using a chisel.

Barack Obama

Great - thanks for the tips antiskeptic

Been looking for where to buy the wood for a new sill. Do you know if Woddies or B&Q carry this stuff?

Buford T Justice

Doubt it, but most builders providers will stock windowboard. BTW, I doubt you'd get away without making a hash of some of the plasterwork.

Barack Obama

Grand - thanks. I just noticed that there is a Chadwicks in Lucan so I can pop in there

jack of all

If you want to use solid wood get some laminated pine board 25- 28mm thick, being laminated it will resist cupping and is more dimensionally stable. Otherwise use moisture resistant MDF, it's cheap enough and easy to paint. If at all possible I'd recommend biscuit jointing the mitred corners, this will ensure a strong joint which will resist opening up. Use a good panel adhesive when fixing the boards and if at all possible try and back prime any boards with an oil based primer; it's never done on site but it will help control movement and durability of the wood. The existing plaster will be damaged when you remove the old boards but small areas like this are easily repaired with minimal skill. Use bonding as a "scratch" coat and finish in skimcoat. After priming the wood use a good acrylic caulk in the corners, undercoat and topcoat for a good finish.

heffo500

We were told in construction studies that the window sill is on the outside and the one on the inside is actually called a window board. don't know how true this is. And that job you want undertake should be handy enough just have small bag of plaster at the ready.

Buford T Justice

Yes, inside is windowboard. If you're skill level for filling is low, then use bonding as a scratch if the hole is big, and something like Gyproc promix as a finish. It'll need a few coats as it shrinks when it dries out, but its much easier to work with thank skim, especially in small areas.