How to fill timber window gaps?

Vand

We have timber window frames with aluminum windows that, in some places, have large gaps of up to 8mm - see photo below.

(red line inserted to highlight the areas of gap)

We're going to be repainting these windows. My question is, what would be the best approach for filling these gaps?

My guess would be to have some strips of hardwood cut at bunnings to pack in the gaps flush with the aluminum frame, and then finishing with gap filler. If that's the best approach, I'm not sure of the most cost effective but appropriate piece of wood I should be using in that case, especially since they need to be in wet areas too (assuming this rules out laminated wood)?

My fallback will be to add some quad, but I'd like to try a more "flush" gap fill first and if that doesn't turn out well I can always add the quad afterwards to hide the poor attempt. 

MitchellMc

Hi @Vand,

I can't see any particular need to try and fit timber in the gap. You can pack the gap with Moroday 6mm x 5m White Gap Filler Rod and fill directly over that with Selleys 480g White 3-in-1 Silicone Sealant. The sealant is designed for wet areas and is paintable. 

Ensure the filler rod is pushed sufficiently far back into the gap so it's not proud of the surface. A flat scraper will come in handy for this. Tape up the timber and aluminium surfaces on either side of where you'll run the bead of silicone. Once you've applied the bead, dampen a finger in water and smooth the bead out. You can then remove the tape.

Please let me know if you have any questions.

Mitchell