Blockwork for foundation

[Kelvin]

We’ve started in the ground so have been discussing the foundations with the groundworks company. He pointed out a flaw in the blockwork design. Our house is two rectangles joined together with a continuous blockwork wall below the soleplate where the rectangles join. There are three doorways between the rectangles and the blockwork runs continuously under them. They’ve said because the blockwork is continuous it will create three cold spots because there will be a break in the insulation layer at each doorway. Ordinarily they leave gaps in the blockwork to accommodate this.
 

I’ve raised this with the timber kit company and their advice is not to do it as they are concerned the kit might not accurately align with the blockwork. The groundswork company has suggested they can’t be confident in the accuracy of their kit as his foundations are normally within a few mm. 
 

I’ve gone back to the kit company and suggested we build the blockwork as designed, fit the kit then knock out the blocks back to the slab then insulate, expansion gaps, sheeting, screed and cold spots dealt with. They have said I can do it that way but they still don’t recommend if without being clear why not. Any views? 
 

 

[George]

Have you got some details or sections you could post?

 

It depends how the TF and ground floor slab interact.

[Dave Jones]

use marxox blocks under the joining walls. These shed builds never fail to amaze.

[Kelvin]

The block would be removed down to the slab. The insulation is 150mm and screed is 75mm.  
 

 

[Kelvin]

18 minutes ago, Dave Jones said:

use marxox blocks under the joining walls. These shed builds never fail to amaze.

That might work. 
 

Yep. This weeks fun has been trying to get the foundation layer overlaid on the plot in DWG format for accurate setting out. I’ve got it now but it’s like pulling teeth. If I knew then what I know now…

[Russell griffiths]

Drop a block down at doors and infill with a high density xps insulation. 

Sit doors directly onto the insulation.