Sealing bottom of tall window….anything missing?

[Harry0013]

Hi all,

I have had some tall windows put into new living room extension as pix below.

My very basic question is …. What goes beneath these windows. I would like something that seals the heat in best.

I have been told that the skirting around the room will cover but think that something is missing.

Thanks in advance!

 

[Swwils]

Is that the exterior brickwork?

 

[Harry0013]

Is that the exterior brickwork?

Yes that is the exterior brickwork! I need advice on how best to insulate this and finish to a nice level.

I was thinking maybe there is a standard way to finish this ?

Appreciate your thoughts.

 

[Mr Chibs]

Is it only single skin brickwork under the window?

If so, it might have been better to add a decent thickness of PIR foam to this skin, before screeding.

Is it liquid screed...? are you having UFH?

 

[Swwils]

Move the windows / doors or insulate the reveals.

Unfortunately the 8mm edging strip used is also lacking, but a bit late now.

 

[Harry0013]

Is it only single skin brickwork under the window?

If so, it might have been better to add a decent thickness of PIR foam to this skin, before screeding.

Is it liquid screed...? are you having UFH?

Yes Mr Chibs, it’s single skin. I wish I had indeed put in the PIR against this skin.
It is liquid screed and the ufh is underneath.

Wondering how the base of these windows could be finished off.

Thanks.

 

[Harry0013]

Move the windows / doors or insulate the reveals.

Unfortunately the 8mm edging strip used is also lacking, but a bit late now.

Thanks Swwills. I cannot move the windows now. How best to insulate the reveals? - any ideas would be helpful.


Thanks

 

[Mr Chibs]

When you say reveals, are you talking about the gaps around the edge of the screed, if so, expanding foam is your only easy option.

There should have been and upstand of PIR and the foam expansion strip along all the walls, this stops heat leeching out of the slab and also copes with the contraction/expansion of the screed as it warms and cools.

You are probably advised to have a decoupling membrane on your screed if you are going to tile it (not needed for wood.)

 

[Harry0013]

When you say reveals, are you talking about the gaps around the edge of the screed, if so, expanding foam is your only easy option.

There should have been and upstand of PIR and the foam expansion strip along all the walls, this stops heat leeching out of the slab and also copes with the contraction/expansion of the screed as it warms and cools.

You are probably advised to have a decoupling membrane on your screed if you are going to tile it (not needed for wood.)

Thanks for the response.

I am where I am.

In terms of reveals I was talking about the base of the windows. Do I put the skirting across the bottom- or something else as standard?

 

[Mr Chibs]

What are you putting down as flooring?

As for the window edge,

If its tile, just go up to the window frame and leave 5mm and fill with a matching silicone.
Engineered wood, do the same, or cork expansion strip or matching wood bead.

The walls just need skirting boards, expanding foam may be useful to fill any large gaps.

 

[robinbanks]

You are probably advised to have a decoupling membrane on your screed if you are going to tile it (not needed for wood.)

Only part of your post I don't necessarily agree with, especially if the screed was dried using the UFH

 

[robinbanks]

I am where I am.

Do you have a picture of the UFH pipe layout before the screed was poured? I find it very unlikely that the installer would have piped all the way to the edge of the room so it's still be possible to run a stihl saw round and cut 50mm off the edge of the screed and replace it with a strip of PIR, then shoot the tiles over it

No one is going stand a stiletto heel right against the wall (and really not in this window alcove) and shove with enough force to break a 50mm tile overhang, except maybe at an entrance (if you're worried about it leave the screed butted up to the edge at a door)

Stihl saw or grinder would easy clip the edge off that screed; it cuts like sandstone does. Wear a mask and run a vacuum cleaner next the the cutting wheel exit point, or do a wet cut if you can wait for the screed to dry again (It soaks water up like a sponge, take a while to dry throuroughly. Do moisture tests before installing floor covering, the simplest one being to put a piece of cling film over a section overnight. If the screed goes darker where the film is, it's still drying)

 

[robinbanks]

Do I put the skirting across the bottom- or something else as standard?

Really depends on how you want it to look. I think skirting would look odd. I ran my flooring up to the window. If there is a bit of a lip that the window is sat up on and you're installing thin floor covering like LVT that wouldn't sit higher than the lip, consider using self levelling to ramp the screed a little up to the lip. No one will notice

If that were my install and it were a single skin brick I'd definitely look at whipping the bricks out under the window, putting some insulation in to half the skin width and then putting them back in. It should have been done before window install but you are where you are. If the window has only been foamed and screwed in and not finished it'd likely be as fast to take out the beads, the glazing, the screws, cut the foam, sort the base out and put the window back. If the window has a sill you might be able to get enough working room just by removing the glass, undoing the screws retaining the sill and sliding/wriggling it out