How to caulk window frames?

Joshuam08

Hi all, I saw a Bunnings “how to caulk your window frame” instructional video appear recently so I thought I’d take a look at my window frames. My window frames have rubber seals on all sides so assumed they didn’t need caulk but did notice in some areas I can see the house wrap (green film) behind the rubber seal so it’s obviously not properly sealing against the brick. My question is should I be caulking the gap between the rubber and the brick, or should I be trying to do a really thick bit of caulk between the brick and the actual window frame? We don’t notice any draught around the window inside but obviously would like to stop water etc getting in.

It’s hard to get a photo of the tiny gap but the attached photo is just to show the seals.  

JacobZ

Hi @Joshuam08,

If you're looking to create an airtight, fully waterproof seal, then the caulk would need to go over the rubber seal and extend from the brick wall to the aluminium frame. This is because the rubber is naturally flexible and will expand and contract due to changes in temperature. If you were to try and seal between the rubber and the wall, there's a good chance your caulk would pull free from one of the surfaces it is attached to. 

As you have black frames, I'd suggest using a black sealant such as Selleys Black Flexiseal Polyurethane Construction Sealant or Sika Black Sikaflex 11FC Purform.

Start by taping off the window frame and brick wall using painter's tape. This will ensure you get nice, clean lines and the sealant does not go where you don't want it to.

Make sure you cut the nozzles so the opening is just wider than the gap, as the bead of sealant needs to fully span the gap and attach to both the brick and the frame.

Once the sealant is in place, strike it off with a Silicone Scraper, using the roundest corner available. Make sure you wear old work clothes and you have a bucket of water and rags handy, as this stage can get a bit messy.

Once the sealant has been struck off and tidied up, pull the tape to create your nice clean finish.

Let me know what you think, and if you have further questions, please don't hesitate to ask.

Jacob