New bifold threshold

[pudding]

Morning all,

 

Attached below is the general detail of our foundation/slab/timber frame wall. In this wall we're planning on a 3.6m triple glazed bifold door. Question is how to position the door and reduce thermal bridging. Builders will be pouring a slab next week I think (racing along v quickly, too quickly almost!) so before that really I need to come up with any requirements for the door thresholds. Options in my mind include

 

1. Simply placing the door on the edge of the concrete slab/inner leaf, with a 190mm cill from the door, spanning over the 100m cavity EPS, but I think this would be the worst thermally, but in the grand scheme of things perhaps not awful?

2. Using some 12/15mm ply to create a box (already doing this for cills/jambs/heads for other windows) that then projects 50mm over the cavity/EPS, and shifting the bifold 50mm out into the cavity/EPS layer

3. Using Compacfoam somehow, perhaps as in the GBS detail, but that then requires those blocks to be ordered and threaded bars, and quite a bit of effort and prep with the pour, so could delay things a bit

4. Using Compacfoam in some other way that doesnt require threaded rods set into the slab?

5 ???

 

 

Any bright ideas would be great.

Edited June 2, 2020 by pudding

[pudding]

This is one idea I have, using a 100x50 Compacfoam block. On the edge of the shuttering for the RC slab pour, a 50x50 batten is attached, creating a 50x50 rebate. The compacfoam can then sit in this rebate, and then in order to attached it to the slab, it is screwed to 15mm ply, which is then bolted to the edge of the slab. Look any good? Lot of faff for not much gain? Not going to work for some reason? Ta.

 

[Miek]

Does the slab have to be over the top of the inner course? Can you not continue the lightweight block up to the sole plate to create a thermal break? 

 

Maybe use a course of foamglass perinsul below the timber sole plate? 

 

These details should be known before you started IMO

 

 

[gc100]

I think normally windows bridge the internal and external walls across the void. The frame itself should have a thermal bridge inside. You might be over thinking it as the frame and window u value is so much higher than the brick etc that the effect will be minimal whatever you do around this.