Wood Fibre to prevent Thermal Bridging - How to handle joins

[Lears]

Hi all,

 

Looking for some advice on an old stone property I'm currently renovating. After lots and lots of research, the plan is to use 60 or 80mm or woodfiber as IWI and lime around the exterior walls. However, in addition the renovation, we're replacing a conservatory with a proper extension, likely a timber frame build that we'll likely to make as efficient as possible in terms of u value (the hashed wall).

 

I'm struggling to figure out the best way to insulate around the join between old and new however. You can see below where I've added woodfibre to the 450mm stone wall section (solid grey) and provisionally, I've added the same to interior on the kitchen side as well on the assumption that cold could bridge through the stone wall and into the house.

 

I haven't put woodfibre around the whole interior section of stone wall assuming that it wouldn't be an issue but now I'm wondering if thats just a thermal bridge risk that I need not take and in fact, I should just put woodfibre around the entire section. The dotted lines are just where an RSJ will be going in where we're removing a wall.

Any advice would be greatly appreciated. 

 

Thanks

 

 

[jfb]

What you have drawn does a decent job of mitigating thermal bridging I would say. Belt and braces would be to go round the internal section and join the IWI up. Can be done with curved corners to soften the edges if you want a less modern feel or else you’d have to use a plastic corner bead. It wouldn’t take much effort given what you are doing already.

[Lears]

1 hour ago, jfb said:

What you have drawn does a decent job of mitigating thermal bridging I would say. Belt and braces would be to go round the internal section and join the IWI up. Can be done with curved corners to soften the edges if you want a less modern feel or else you’d have to use a plastic corner bead. It wouldn’t take much effort given what you are doing already.

Thanks jfb, that's pretty much where I'm at to be honest. Given it's a rubblefilled stone wall, there's a good chance leaving it exposed won't look great anyway and given we're already doing 95% of all the walls anyway, feels like we might as well just wrap around.