ICF and Wall Plate

[Renegade105]

Hi,

 

on an ICF build, wall plate needs to be set on top of the ICF core, was thinking of using a mixture of 1) acoustic flex sealant, 2) airtight foam, 2) mechanical fixings to clamp it all down.

 

what’s you’re recommendation here?

 

will have attic truss and slate tile with spray foam insulation

[Russell griffiths]

Wall plate doesn’t need to be airtight, just bolt it down. 

What is your airtight strategy between the roof/ ceiling and walls. 

[Conor]

Nothing under, as we used a SIPs type roof system, we used airtight foam between the wall plate and panels. then foam in the gap and finally a good wide strip of airtight paint at the join between wall and roof panel. Obviously totally different from what yu are doing!!

[Renegade105]

Hi,

 

so planning on Spray Foam open cell, then an air tight membrane underside of truss and down onto internal ICF Leaf…tricky to detail as the rafters will be there every 600mm. Hoping spray foam will help here.

 

thanks,

 

 

[Renegade105]

Just now, Conor said:

Nothing under, as we used a SIPs type roof system, we used airtight foam between the wall plate and panels. then foam in the gap and finally a good wide strip of airtight paint at the join between wall and roof panel. Obviously totally different from what yu are doing!!

That’s really tidy.

 

what bolts are those? Did you screw them down into set concrete ?

[Conor]

9 minutes ago, Renegade105 said:

That’s really tidy.

 

what bolts are those? Did you screw them down into set concrete ?

Yes. wall plate was something like 150x100mm C24. The guy doing the roof had them chamfered and planed to suit in his workshop.

 

Yeah, they are something like 200x10mm thunderbolts driven in to the set concrete. Every 600mm I think.

 

They spent a lot of time chiseling away and filling in the top of the concrete core. When you're doing your last pour, make sure the guys trowel and float the top of the concrete nice and smooth and flat. I think the two guys spent at least a full day tidying up. If I'd known that was needed, an extra hour with a float when the concrete was wet would have saved me £500 of extra labour.

Edited March 5, 2023 by Conor

[Iceverge]

47 minutes ago, Renegade105 said:

o planning on Spray Foam open cell, then an air tight membrane underside of truss and down onto internal ICF Leaf…tricky to detail as the rafters will be there every 600mm. Hoping spray foam will help here.

 

 

Sounds like a warm loft. 

 

Tricky with a trussed roof. 

Is there an option there for an cut roof. 

 

Alternatively a hybrid/warm roof with taped OSB sarking above the trusses forming your airtight layer and more insulation above it.