How to fill this gap between weatherboards and window?

[jeremy8]

Any advice as to what I can do to fill this gap on our renovation?

 

 

[JacobZ]

Hi @jeremy8,

Many thanks for your question and welcome to the Bunnings Workshop community, it is fantastic to have you join us.

It looks like you've removed an architrave around the window, is that correct? 

Do the other windows around your house have architraves around the windows? 

I ask because the best way to solve this issue is likely to copy what has been done elsewhere on your property.

If the other windows use architraves, I suggest using a suitable timber such as this 66 x 11mm 5.4m H3 Treated Pine FJ DAR Primed LOSP then sealing between the architraves and weatherboards with a paintable external gap sealer such as this Selleys 430g White No More Gaps Exterior Gap Filler. Once sealed, you can paint the timber and sealant with a suitable external paint to match.

You might like to check out How To Install Architraves, How To Silicone a Gap and How to paint trims for some guidance on this process.

Let me know if you have any further questions.

Jacob
 

[jeremy8]

Thanks Jacob,

I just purchased this house so I’m kind of trying to fix up what the former owner did. 
Do you think the gap is too big for silicone?  I’m wondering whether to use some expandable foam ?

[JacobZ]

Hi @jeremy8,

It's important that you do this correctly because this gap will allow rain to get into the timber framework of your home. This will promote mould, increase the potential for rot and cause you a great deal of pain down the line.

Unfortunately, you can't use expandable foam to fill this gap as there is no waterproof expandable foam. I also wouldn't suggest simply using silicone as the gaps in some sections are far too wide to accommodate it.

You can see from the location of the paint on the timber window that there was originally an architrave around the window. I suspect the former owner removed this intending to replace it, but they clearly didn't get to it.

I'd suggest having a look at the other windows around the home and emulating what has been done there. There will likely be an architrave using a timber profile such as the 66 x 11mm 5.4m H3 Treated Pine FJ DAR Primed LOSP that I mentioned earlier. 

Once this architrave is installed, you can seal around it using an exterior gap filler such as Selleys 430g White No More Gaps Exterior Gap Filler. Make sure to seal any gaps that would allow water to get in. This will give you a much better weather seal than just applying silicone to the gap as it is.

Let me know if you have any other questions.

Jacob

[jeremy8]

Great, thanks mate,

so essentially fit the architrave then silicon the gap - got it!  Thanks again!

[JacobZ]

Hi @jeremy8,

Yep, that's it.

Keep us in the loop if you need a hand as your job commences. I'd be more than happy to assist further if needed.

Jacob