How to fill (and what to use) around window frames?

[DIYNotIan]

Hi all

You've helped me fantastically with the decorating of my windows and re-sealing the individual panes.....

I wondered if I could ask once more for you help, this time with how to reseal around the frames themselves (where they join the wall).

I've removed as much of the old pink putty as possible, leaving a reasonably sized gap.... Sometimes mortar (is that the right word?) came out too..... Was I right to take out as much as possible?

Here's how they are looking now......

Two at the sides:

Untitled

• DIYNotIan
• 18 Sep 2012
• 1

Untitled

• DIYNotIan
• 18 Sep 2012
• 1

Two at the Top of the window:

Untitled

• DIYNotIan
• 18 Sep 2012
• 1

Untitled

• DIYNotIan
• 18 Sep 2012
• 1

What I need to know is what procedure to now follow for re-filling / sealing them up and making them watertight for winter....

Huge thanks

Max

 

[Burnerman]

For small gaps, sealant is perfect, for large gaps, mortar is needed first.
Looking at your particular job, I'd go for a thick bead of sealant pushed well into the gap, but leaving just enough proud for you to smooth over with a damp finger.
The sealant tube nozzle is cut to provide you with the size of bead that you need....don't spare it!
Very thin fillets of mortar are all very well, but they do tend to crack if too thin so you're back to square one.
Obviously the gap at the top of the window is the worst one, but your frames do seem to be overhung and therefore protected from driving rain somewhat.
John

 

[DIYNotIan]

your frames do seem to be overhung and therefore protected from driving rain somewhat.
John

Unfortunately that didn't stop some of them leaking last winter!

OK - well some of the gaps might be a little bigger than those I've shown, but not by much... So I'll stick with sealant only. As per my other thread, you recommended Dow Corning 791 - so I'll see if I can get hold of some of that.

I've got a decorator here doing the work... Should I make sure the sealant goes all the way in (and totally fills the gap depth-wise)? If it doesn't and leaves empty space at the back/deepest part, will that cause major problems or be ok?

Cheers

Max

 

[andywhy]

I would wait till the painting/varnishing is done as most sealants aren't overpaintable.

You could seal the bulk of the larger gaps before painting, aiming to leave it flush or slightly below the face of the frame. Make sure you don't get any smudges on the frame as the finish won't stick!

You could use thin slivers of timbers to pack the gaps slightly, less sealant required

 

[JohnD]

you could also use expanding foam. Clean out any dust first, and spray with water to make the surface moist so it sets faster and stronger.

Tape cling film to surfaces adjacent and underneath, since it will bulge or drip out and is extremely sticky. If you tack a wooden batten over the gap, that will force it to expand backwards into the depth of the gap, but the injection nozzle will enable you to place it deep. If you drill holes in the batten and fix it before injecting, you can inject through the holes and the batten will leave a flat surface. Wrap the batten in cling-film or it will be stuck in place. I did this and decorated the batten before fixing, to match the windowframe, it looks fine.i

You can cut the foam flush with an old breadknife when fully set, and apply silicone or paint the surface. It must not be exposed to sunlight as this degrades the exposed surface. It will also stick the frame firmly in place. It is very good for preventing draughts.

 

[Burnerman]

DC 791 will adhere to almost anything, and as its available in brown, over painting doesn't really matter (it will over paint after a week or so).
No primer is required before using the 791 in your case but as already suggested, back fill those gaps with something......if you can get the sealant in for around 20mm or so, there won't be any more problems.
John

 

[DIYNotIan]

Hi again

The decroator is not doing this work anymore - I'll be doing it instead

I've just re-read through the posts (thanks for those), but since writing I have been out to take a closer look at things.

As the photos show, the gaps vary quite considerably. Where I've managed to get all the old stuff out the depth is around 70mm. Width wise the gaps are anything between 1mm and 5mm, perhaps going up to 8mm/10mm on much rarer occasions.

Above the frames (as in the picture) the gap between the brick and wood is around 25mm. Should I look to fill this whole area or just between the mortar and wood?

Or on the other hand should I look to remove all the mortar even if it is still fairly well stuck in place (not sure what counts as "loose"!).....

And should I be looking to treat all areas the same way, or should I have different approaches depending on the size and depth of the gaps (sealing the 1mm gaps vs 20mm+ gaps)?


Huge thanks guys

Max

 

[andywhy]

Hi

I'm no professional but I wouldn't fill a 20mm gap with just sealant. If you're not used to working with the stuff then you may be left with a very sticky and uneven mess!

Some sort of beading may be the answer. If I were doing it to my own house I would glue in timber strips slightly proud from the face and make flush before decorating the windows and sealing

 

[Burnerman]

As above - the sides of the frames can use sealant no problem, but as for the top......check that the cement bond on the bottom of the brick is sound.
If it is, trowel in as much sand / cement mix as you can - poke it in with a stick if it helps. If it isn't, it'll have to be chopped away with a bolster chisel.
If you can finish the pointing with a gentle slope outwards, so much the better to cast water away.....if you can't, let the pointing dry and then run a bead of sealant against the timber.
John

 

[DIYNotIan]

Hi again

OK, I've been looking at all kinds of different sealants and trying to choose one. They all seem to say in their tech specs that the minimum width should be 5mm. Some of my gaps are as small as 1mm width so I'm not sure which of the products will be suitable.

The gaps are quite deep in places (up to 70mm) and I was planning on using a low expanding foam as a backing. I've bought a can of it, but the trouble is the applicator tube is too big for most of the gaps I have, and I fear that without being able to get the tube into the gaps I'm going to make an almighty mess!

So what's the best way to fill small gaps around frames (in the 1 - 5mm region)?

Cheers

Max