ᐅ Interior Insulation of Load-Bearing Sand-Lime Brick Walls: Is It Feasible or Advisable?

Hello,

Although I have already tried to read a lot about wall insulation and found some information in forums, I have not yet found a clear “yes” or “no” regarding my current insulation idea. I hope this will change in this forum :-)

We plan to completely renovate an older farmhouse (from the 1950s) and are initially faced with the question of the right wall insulation or extension. The house is built with a cavity wall made of bricks (with an air gap between the two walls). Since the current interior layout of the living area and the barn section does not suit us at all, all interior walls and an existing wooden ceiling will be removed. To install a new floor structure in this fairly wide house, corresponding new load-bearing (interior) walls will be necessary.

Now to the important question: Is it possible to build an additional sand-lime brick wall on the inside of the house—set inward from the cavity brick wall—on which the floor structure can rest (along with load-bearing interior walls made of sand-lime bricks)? And if this is possible, would it also make sense from an energy efficiency point of view to use this as insulation, or could this lead to any problems?

In addition to this insulation, we are also considering whether it would be useful to insulate the cavity between the two brick walls with blown-in insulation.

I look forward to any opinions, ideas, and comments.

Thank you very much and best regards,
Paul

Sand-lime brick is very heavy, and constructing load-bearing walls from it requires your foundation slab to be able to support this weight, as well as ensuring a proper connection.
Your roof frame must also be able to handle the removal of the floor slab and interior walls.
What does the structural engineer say about your plan?!

It will probably be more cost-effective to demolish and rebuild.

Thank you for the quick response!

The roof can be disregarded in this solution, as it is fully decoupled and supported by its own timber frame structure.

I haven’t really given any thought to the foundation slab yet. I simply assumed it would be strong enough to handle the load. What practical (material) alternatives could there be for the outlined concept?

The appointment with the structural engineer will unfortunately only take place at the end of August due to the holiday period. Until then, I would like to clarify my ideas.

Hello everyone,

Based on my latest findings, I have a small addition regarding load transfer and the concrete slab.

I only just realized that under the varying floor heights in the house, there are separate concrete slabs in different areas. In other places, there is only clay soil. Similarly, the brick wall (exterior wall) rests on a clay foundation.

For this reason, I would like to remove the existing individual concrete slabs and pour a new concrete slab, on which the new load-bearing sand-lime brick interior walls could then be built. Of course, the slab would be designed according to the loads it needs to carry.

However, I would prefer not to touch the foundation of the brick exterior wall (i.e., not to underpin it). It has stood firmly for 60 years, and interfering might cause more harm than good. The new slab would need to be separated from (or suitably connected to) the brick wall to ensure no damage occurs to the wall if the concrete slab moves.

The question is whether this is a sensible approach or if there might be a better way to do it.

Thanks for any advice and opinions!

Best regards,
Paul