Should I make a footing, despite a masonry foundation wall?

[tobbew]

Hello

I feel like I am spamming this section, but I hope that I will calm down soon. Now I will try to tie things together a bit. I am attaching a picture so you can see how it all looks.

We are casting a slab for a conservatory. The long side extends in depth in the picture (right side) and this consists of a roughly 3-meter high masonry wall, which is buried and filled in from both sides.

On this wall, there will be a 10m long glass wall with four pillars that support the brick exterior roof of the house.
As an edge beam for the casting and to somewhat break the thermal bridge, there is a 10cm stone as the last layer, so we cast within this and then cut the stone after casting, as it is about twice as high as needed.

The wall is, in any case, built with 20cm-leca. On this wall, the pillars, which are 14 cm deep, will stand entirely on the wall. However, the slab in the upper centimeters will be 10 cm wider because it is a narrower stone in the top layer, so the slab will just take the pressure there.

I am then wondering, should I still make a footing of 20 cm along this long side? I was thinking of taking out so that there is 10cm xps300-insulation, and then there will be a footing that is 20 cm deep and 20 cm wide, with longitudinal reinforcement in two layers. Why? Well, I think, even if the pillars are entirely above the wall, there might be significant pressure a few cm inside as well?

There is no engineer involved in this stage, but we know roughly the weights that will come from the roof and so on.

I have heard from various builders that a footing is probably completely unnecessary, but that it feels safe to do, and there are no direct extra costs. Then the pillars can also be moved in a few centimeters so that they are not on the outer edge of the leca stone, which might reduce the outward pressure.

What would you do? Thanks!

 

[tobbew]

I decided to make a footing anyway. I have removed the S100 insulation and placed a 300 with a 20cm width along the entire wall. Whether it's necessary or not, we may never know, but it will then be a substantial edge with a 20cm wall + 20cm footing.

If we also pull the pillars a few cm from the outer edge so that the outward pressure might decrease a bit, it would probably be great! Let's hope for that anyway.