Best way to insulate window frame

[Iamshirl]

On windy days, you can practically feel the draft sneaking around the frame, and in the winter it’s like the cold air is pooling in that corner of the room so I’m guessing the original insulation around the frame is either thin, settled, or just never done right in the first place. My main concern is sealing it up properly without causing future problems like trapping moisture or messing with the frame expansion there. Tips and suggestions on the best way to handle this ?

 

[purdil21]

On windy days, you can practically feel the draft sneaking around the frame, and in the winter it’s like the cold air is pooling in that corner of the room so I’m guessing the original insulation around the frame is either thin, settled, or just never done right in the first place. My main concern is sealing it up properly without causing future problems like trapping moisture or messing with the frame expansion there. Tips and suggestions on the best way to handle this ?

Pull the trim and seal the gaps with low expansion spray foam so it fills voids without bowing the frame. Then pair that with a good caulk on the inside and outside joints, and you’ll cut the draft without trapping moisture

 

[slvr22_bd]

On windy days, you can practically feel the draft sneaking around the frame, and in the winter it’s like the cold air is pooling in that corner of the room so I’m guessing the original insulation around the frame is either thin, settled, or just never done right in the first place. My main concern is sealing it up properly without causing future problems like trapping moisture or messing with the frame expansion there. Tips and suggestions on the best way to handle this ?

I second @purdil21's suggestion. Make sure the low-expansion, low-pressure foam sealant you're using is specific for windows and doors. This is your critical air seal that won't distort the frame. After that, seal all the visible joints by using a quality exterior caulk, like silicone or polyurethane outside, and a flexible interior caulk where the trim meets the frame or wall.

 

[birds.of.a.feather]

Don't seal both sides airtight, the interior tight, exterior needs to breathe outward for moisture and also, if the window frame itself is leaking, new weatherstripping or it might just be toast

 

[Iamshirl]

Thank you all for your wonderful suggestions. What caulk do you recommend for the exterior? I've heard things about silicone as opposed to acrylic latex for longevity.
Also, should I be worried about painting over it later or does most exterior caulk take paint fine?

 

[Vertesol Eustache]

On windy days, you can practically feel the draft sneaking around the frame, and in the winter it’s like the cold air is pooling in that corner of the room so I’m guessing the original insulation around the frame is either thin, settled, or just never done right in the first place. My main concern is sealing it up properly without causing future problems like trapping moisture or messing with the frame expansion there. Tips and suggestions on the best way to handle this ?

I agree with others here, the perimeter around the frame is likely needs to be resealed. I would remove trim and spray foam low-expansion for windows and doors or use backer rod and caulk. That way no drafts but you won't force pressure on the frame or moisture inside.