Door cill detail for MBC passiv raft foundation

[RedRhino]

Dear Community, 

We are struggling with the last piece of our Rationel window & door order and would appreciate help.

We are going from pillar to post with MBC, Rationel and our architect unable to specify a small but critical detail. 

For balance I would say we are very happy with great service from all three agencies on all aspects but we are stuck on this one. 

 

The MBC timber frame is going to be battened and counter battened to affix brick slips creating an offset that will extend down to 150mm above ground. 

We plan to sheath the EPS insulation from 150mm down to below ground using aluminium sheet. Thank you to the Self Build forum for helping us learn of that solution. 

 

But what about beneath the door cills? They are cantilevered out from the door frame and need structural support. We have received the detailed drawing attached but no one as yet can say quite what should be below the cill or how it is fixed. 
Thank you in advance. 

[Mr Punter]

I can't work out what the materials are.  What are they where you don't have a door?

[RedRhino]

Drawing annotated : )

 

[MikeSharp01]

We used a structural polystyrene from Green Building Store. Compacfoam

[RedRhino]

  On 07/12/2024 at 10:56, MikeSharp01 said:

We used a structural polystyrene from Green Building Store. 

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Thanks @MikeSharp01, it looks like this product: https://www.21degrees.com/compacfoam/
May I ask, did you use this just under the cills or all around the perimeter? 

[Russell griffiths]

I’ve used a product called kingspan green gaurd in the 500 kpa spec. 
why only a thin piece though. 
I would take it full depth of your insulated raft, so it bears down onto the stone the raft sits on, fully adhered to the outside insulation. 
 

bit confused though, if you are covering the insulation in aluminium, then why does the door cill project out so far that you need this support, wouldn’t the door be set further back in the frame. 
 

do you have a section drawing showing frame position and cladding location. 

Edited December 7, 2024 by Russell griffiths

[MikeSharp01]

  On 07/12/2024 at 11:04, RedRhino said:

Thanks @MikeSharp01, it looks like this product: https://www.21degrees.com/compacfoam/
May I ask, did you use this just under the cills or all around the perimeter? 

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We just used it where we needed the load bearing capacity, everywhere else we used PU or EPS100 if we could not get the right PU section. Cutting compacfoam is hard. They say you cannot cut it with a circular saw - I say you can't! I did find my hot wire did it on full power going slowley. 

[Mr Punter]

The weight of the frame is mostly resting on the 200mm polystyrene.  You could extend this or move is outward by 74mm and finish with the same ali sheet you propose elsewhere.

[Conor]

I would not be installing a door frame on EPS. Use compactfoam or similar and set directly under the frame to act as a door block.

 

[Russdl]

Why is the door set so far out? It’s going to protrude beyond the timber frame. 
 

Our detail involved threaded bar into the slab which allowed a GRP angle to be bolted to the slab that took the weight of the door. That puts the door further back in the frame. 
 

I can post some detail when I get home if you’re interested. 

[Russell griffiths]

  On 07/12/2024 at 20:30, Conor said:

I would not be installing a door frame on EPS. Use compactfoam or similar and set directly under the frame to act as a door block.

 

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I think we talked about this a while ago, and it was found that the downwards load was so small there was no problem sitting either heavy sliding doors or windows onto eps or xps. 
the weight divided over the area was tiny. 

[Adrian Walker]

I would and have used solid Foamed Glass.