Best way to fix these gaps around the window frame?

[GeddyMortgage]

Hi all,

I've noticed our recent rear extension has been getting colder / retaining heat worse than the rest of the property, so decided to investigate the doors and windows.

On closer inspection noticed a lot of draught coming in through gaps between the the higher up fitted window frames and the walls of the reveals (images below).



My question is, should I be using caulk or a silicone sealant on these? visually, I'd be happy enough with using a clear silicone if that's the most effective option to stop the draughts? You'll see on the photos but they're mostly 1-2mm, apart from the slightly bigger chunks where it looks a little more cracked.

and lastly sorry if a stupid question, but when sealing, are you supposed to seal these gaps in the frame too?




thanks so much, I checked the exterior btw and that does appear to have a brown sealing between frame and window. So hoping this is just an interior quick fix!

 

[Koolpc]

Where you got gaps in the plaster around the windows i would open them up and pump in low expanding foam. Then cut back and fill.

The frame gaps can be filled with good frame sealant.

 

[GeddyMortgage]

Where you got gaps in the plaster around the windows i would open them up and pump in low expanding foam. Then cut back and fill.

The frame gaps can be filled with good frame sealant.

thanks @Koolpc

By gaps do you mean the larger chunks missing or for all the gaps between the frame and plaster in the images above? Also what would you finish that with? Caulk or sealant ?

And by frame gaps do you mean on the last image above?

 

[GeddyMortgage]

I’ve also noticed this inconsistency between the window / frames. Anyone know what this black sticky out bit is and whether that could be contributing to the draught?




The frame on the other side of the room doesn’t seem to have a this..?




Thanks agaib