DIY Dave: Repairing and painting a rotten window sillBy DIY Dave
August 11, 2012
You know what it is like – you don't go out in the back garden often and when you do, there is always something needing to be done.
Had the ivy not grown up and over the window sill, you'd have seen it sooner – before it got this bad.
You just had to task your teenager with removing the ivy didn't you? Now you have and there is no ignoring the rotten window sill.
From the image above, you will see there is 'good wood' around the rotted area and lots of loose, flaking, old paint.
You will need:
A chisel or old and wide screw driver.
A tub of 'High Performance' Wood Filler (Ronseal do one and so do others)
Clean flexible filler knife (plastic or metal as you prefer)
Computer Controlled Robotic Arm
A small piece of wood (on which to mix the filler)
Various grades of sand paper
Firstly you must sand or scrape or wire brush off all flaking and loose paint.
Gouge and chip out all soft and rotten wood with an old but wide screw driver or an old wood chisel and then brush out any dust and loose material from the area.
Mix an amount of the filler and hardener with a spatula or stick.
TIP: Lolly sticks are good for mixing or those stirring sticks some cafe type places give for stirring coffee.
TIP: This stuff will set hard quite quickly so don't get distracted or pop off to the shops or anything daft like that until you have filled the rotten part of the sill.
Daub (technical term) the filler into the wood and press firmly with the spatula / filler knife so the filler is forced well into the wood grain and leaves no air pockets.
Smooth the filler to the contours of the original window sill (you can leave this a little proud of the original wood as we shall be sanding it down later).
TIP: Don't leave the filler too proud of the original contour of the sill as you don't want to be out there all night sanding the filler back down – just leave enough to be able to sand a nice smooth surface and to make any repair invisible after painting.
Leave the filler to harden (read the tub as this will specify the drying / hardening times, although it is around 30 minutes).
Either use the Computer Controlled Robotic Arm to prod the filler to test it's hardness or poke it (gently) with a screw driver.
Filler not hard? Not good – leave it a while longer to harden.
Filler hard? Good – carry on.
Wrap some coarse grade sanding paper around a flat noggin of wood and carefully smooth the worst of the roughness from the repaired area and then swap to a medium grade and then to smooth/fine grade as the filled patch begins to blend with the original wood.
TIP: Often you will only properly see if all lumps and bumps have been sanded from the filled patch and the edges have blended perfectly with the original wood, once a coat of primer is brushed over the whole area as a single colour is easier to see bumps than when you have a patchwork of colours from wood / filler and what have you.
If, once you prime the wood, there is still sanding to be done, don't forget to allow the primer paint to fully dry before sanding as unless it is fully dry, it will immediately clog the sand paper.
So, once smooth and invisible after primer – paint with undercoat and top coat as usual – give it a couple of coats of top coat as it is outside and open to all weathers.
Well done – have a cuppa and a custard cream.
I am limited to a single image here although I'll try to put additional images of each stage of the repair on my blog at DiYDave.tumblr.com