Gap above window frame, what do i need to do b4 painting?

[kilo_4que]

Hi guys, I prepping my walls today before i add the first mist coat of paint on a fresh plastered wall but have realised that above the window frames there is a approx a one inch gap all the way across the width of the window frame. By gap i mean this part has not been filled in with any plaster or anything, what would you guys suggest i do about it i.e. fill it with.

I have some photos which i can upload tomorrow but in the mean time please do provide some suggestions

thanks

 

[JohnD]

you could use expanding foam. It holds the frame in place, goes stiff so you can cut and sand it, and protects against draughts. Clean the gap throughly first, and moisten with a water spray. You can paint or fill it once hard and you can cut it with a breadknife. It will grip whatever it touches.

If you have not used it before:

It can be very very messy and sticks almost irremovably to hands, gloves, glass, windowsill. carpets, clothes, shoes, specacles, eyeballs, skin, fingernails etc, so mask off well and cover everything. Have some spare gloves so you can change them as soon as you get foam on them. If you have not used foam before you will not believe me but it is incredible.

Buy a can of "Foam Eater" to clean up the dried problems at the same time you buy the foam. Inject it into the gap with the nozzle and let it expand outwards. Excess foam can drip out. Spraying it with water helps it cure faster and puts a hard skin on it.

Once you have learned to take care it is a good product.

 

[kilo_4que]

wow you great man lol

so this stuff, can it be sanded down to a smooth finish or would it need topping with some form of filler?

Also when you say add water, shall i just keep a spray bottle with water in it and spray that on as i am adding the foam stuff

Finally what specific product would you recommend, something i could buy from Screfix

cheers

 

[JohnD]

It will bulge out like an omelette, I would spray when finished, unless you see a sticky drip and want to harden it

I have found a good method is to cover surrounding surfaces with clingfilm, then nearby with masking tape and newspaper

If injecting through a drilled hole, you can stick masking tape over the hole, then puncture it for the nozzle, this protects the surface round the hole. It is possible to fasten a batten (wrapped in clingfilm) over the gap, and inject through holes, and then it will harden flat against the batten, which saves cutting back. If you do not wrap the batten in clingfilm, it will be very very difficult to remove afterwards.

As you have not used it before you wil probably put too much in, so you will have to cut it back with a breadknife, then sand smooth or use a filler before decorating. Or you could fix trim or architrave round the window to cover it. It must not be exposed to sunlight as this degrades it, but you can paint it with gloss for protection.

It will also escape round the back, to the outside of the house round the window or into the cavity.

I have found the Polycell foam to have a better texture than the cheap own-brand ones (they can form big gas bubbles inside which leave voids). you canb get it in the high stret.

Once you gave started a can, it will probably not be usable on a second day

 

[Kes]

For occasional use get the cans with the plastic 'gun' attached, not just the spray tube. After use the tube is bent back and plugged into a stopper on the gun. I used to use the cans once then throw away, but with these guns you can use all the contents of the can weeks later.

I also need to go around all my windows to seal them. It's amazing how much rain can get into a house through a small gap.

 

[kilo_4que]

Wow this stuff does sound very messy indeed,

I am thinking of using a batten with holes as you said to cut the sanding down time.

Btw guys, is this the same stuff window fitters use between frames?