How to replace exterior window trims and flashing?

[MiCCAS]

Hey legends!

I'm keen to replace my existing aluminium exterior window trims with wood, but at a bit of a loss on how to do this as there is quite a gap in the weatherboards behind it. The existing trims are 120mm.

I'm also trying to understand what I need to do with flashing as these windows do not have eves covering them.

 

  

This is what I'm aiming for:

 

[EricL]

Hello @MiCCAS 

Thank you for sharing your question about replacing your window trims. Under ideal conditions aluminium steel does not rust or corrode making it the perfect trim for outdoor windows. I suspect that if the trim and dividers are painted in white it will look exactly like that window finish you were dreaming of.

However, if you still wish to replace the trim, I recommend making sure that it is H3 treated so that it can withstand outdoor use. I also recommend using Zenith 8G x 35mm Galvanised Countersunk Rib Head Metal Screws or similar. To fasten the window trim to the aluminium frame. In regards to the gap, I propose using Selleys 430g White No More Gaps Exterior Gap Filler.

I suggest having a look at these discussions to give you more ideas:

• How to D.I.Y. window mouldings? by @Emily1
   
• How to add exterior window trim?

If you need further assistance, please let us know.

Eric