To make a long story short: I'm renovating an old SKånelänga and have just poured a new slab in half the house. Now I will build thin LECA walls inside the exterior walls to create a smooth surface to plaster against and to get some insulation without enclosing the interior of the exterior wall with cold and moisture. Now to my dilemma: The house is built with timber framing and brick in all the framing compartments. Inside this, a brick wall is built up, with a few centimeters of air gap against the exterior wall, but in one corner of the house, this inner-exterior brick wall is missing. The inner-exterior wall of LECA I am planning to build will use 70mm LECA blocks to avoid taking up too much floor space, with an air gap of 30-40mm. However, in the part of the house where there is only a timber-framed wall, i.e. no brick wall, the air gap will be 30-40mm PLUS the 150mm missing as a brick wall, which is too large an air gap for my liking. The solution is to use wider LECA blocks in this part so that they align with the section that has a brick wall where I will use 70mm wide LECA blocks.
The problem itself is visible in the picture below. In the section where I will have wide LECA blocks, the foundation stones protrude 150-180mm (about 100-150mm high) because I chose to cast the slab slightly lower than the timber frame's base (to prevent all the concrete from running out through the doors...). This means I can't lay the first course with a 30mm air gap against the exterior wall. The question is how I should solve this. One idea is to lay the first course with 70mm blocks right up to the projecting foundation ledge, then build up the ledge to the height of the LECA blocks (i.e. 190mm) so that I can lay the second course on top, which will be of the wider type blocks (250mm or whatever it turns out to be, I haven't measured exactly yet). What do you think about that? Do you think that the construction of building/pouring the foundation ledge to the height of the 70mm blocks and then laying the subsequent courses with wider blocks, supported half by the 70mm block and half by the built-up ledge, will be sturdy enough for the pressure of the LECA wall?
The problem itself is visible in the picture below. In the section where I will have wide LECA blocks, the foundation stones protrude 150-180mm (about 100-150mm high) because I chose to cast the slab slightly lower than the timber frame's base (to prevent all the concrete from running out through the doors...). This means I can't lay the first course with a 30mm air gap against the exterior wall. The question is how I should solve this. One idea is to lay the first course with 70mm blocks right up to the projecting foundation ledge, then build up the ledge to the height of the LECA blocks (i.e. 190mm) so that I can lay the second course on top, which will be of the wider type blocks (250mm or whatever it turns out to be, I haven't measured exactly yet). What do you think about that? Do you think that the construction of building/pouring the foundation ledge to the height of the 70mm blocks and then laying the subsequent courses with wider blocks, supported half by the 70mm block and half by the built-up ledge, will be sturdy enough for the pressure of the LECA wall?
Unfortunately, I don't have an answer to your question, but I'm in a similar situation as you. I have an old half-timbered house where I plan to tear out the insulation and replace it with something that breathes.
How did you come to decide on using Leca-block? I've also considered that solution but haven't decided anything yet. Did you have other materials in mind, and if so, what made you choose Leca?
How did you come to decide on using Leca-block? I've also considered that solution but haven't decided anything yet. Did you have other materials in mind, and if so, what made you choose Leca?