Hi. I am building a masonry house pouring a subfloor first and will later in the process put in insulation and screed.

my question is do I need a strip of 25mm insulation between the sub floor concrete and the inner leaf block. That block will be a standard dense block but the block above it adjacent to the floor insulation will be a thermal block

thanks

 

6 hours ago, Moggaman said:

Hi. I am building a masonry house pouring a subfloor first and will later in the process put in insulation and screed.

my question is do I need a strip of 25mm insulation between the sub floor concrete and the inner leaf block. That block will be a standard dense block but the block above it adjacent to the floor insulation will be a thermal block

thanks

 

It's unnecessary IMO, as you'll not be putting such a thermal break in the rising masonry work. Just install a robust perimeter insulation to keep the heated screed from losing heat to the walls and you'll be fine.

Sounds to me like you are building in a thermal bridge. If you can use insulating block for the wall above the floor then why not through the floor too?

 

I would avoid aircrete above the floor, they tend to crack badly 

15 hours ago, tonyshouse said:

Sounds to me like you are building in a thermal bridge. If you can use insulating block for the wall above the floor then why not through the floor too?

 

I would avoid aircrete above the floor, they tend to crack badly 

I am using one course Of thermal block from subfloor to FFL, so the floor insulation meets the thermal block with the wall insulation tight to the inner leaf.. not quite passive but decent all the same?.

my question was mainly relation to the need to put a 25mm insulation layer between the sub floor and the inner leaf. I don’t see the benefit unless there is a need to separate the slab from the wall for structural purposes?

thanks