Foundations too high - Help

[cdbe]

The inside doesn't seem to much of an issue, what's going on outside?

 

[Notch7]

The insulation will sit on top of the slab and the underfloor heating will be covered by a liquid screed.

Just to clarify, your drawing shows 125mm reinforced slab on top of the concrete, I guess you are doing that so the underfloor heating clips to the slab, then you can have relatively thin layer of liquid screed on the slab so a bonded screed.

Your idea for the doors sounds OK, are you having the patio flush to the doors etc, so no door call, if so you need a threshold ACO drain. If you are having bifols doors make sure the bottom weather seal works well

 

[Spjg1997]

Just to clarify, your drawing shows 125mm reinforced slab on top of the concrete, I guess you are doing that so the underfloor heating clips to the slab, then you can have relatively thin layer of liquid screed on the slab so a bonded screed.

Your idea for the doors sounds OK, are you having the patio flush to the doors etc, so no door call, if so you need a threshold ACO drain. If you are having bifols doors make sure the bottom weather seal works well

I am thinking about the build up order. To me it makes more sense to layers it

50mm liquid screed
100mm insulation with UFH
Thin DPM
100mm slab
Thick DPM
50mm blinding sand
150mm compacted hardcore

Planning on using top of speed fit insulation so that the UFH is mainly heating up the screed as opposed to allowing heat leakage down into the slab.

I have asked to SE if we can skip the mesh as it’s only a 8mx4m kitchen - reinforcing it seems a bit overkill?

I’m getting more comfortable with dropping the foundation and using a weather seal. Im not sure if we will have a flush floor onto the patio but understanding the options and implementation more and more.

Starting to feel more positive about this!

 

[Spjg1997]

The inside doesn't seem to much of an issue, what's going on outside?

No plans yet - at the moment it’s the old cobbled garden. Depending on how the door threshold works out then I am planning an aco drain running into a soak away followed by a small resin patio

 

[robinbanks]

the underfloor heating will be covered by a liquid screed.

120mm of liquid screed is crazy. That little 20mm finger of it near the edge is liable to break off. Strive for an angle when you're stihl slicing and chipping your founds

is there a reason you have you put the insulation at the bottom?

That's where it goes when you want to have effective UFH

I didn’t think I could fit a back door directly onto the footings?

What's the notional difference between eg a footing 200mm below ground level, plus a 200mm wall, and a footing at ground level, shaped as though it has a 200mm wall? (But if it makes it easier to think about, cut all the footings away and build the wall back.. I was just pointing out that notionally you've already built the wall out of concrete, you just need to cut the excess away to reveal it)

How come your building inspector didn't say anything?

 

[Spjg1997]

120mm of liquid screed is crazy. That little 20mm finger of it near the edge is liable to break off. Strive for an angle when you're stihl slicing and chipping your founds

Ah! It was an incorrect model, he sent me an updated one - my bad. You can see it’s a 50mm screed etc. in the updated attachment. When you say Stihl - are you referring to a concrete chainsaw?

That's where it goes when you want to have effective UFH

I was of the impression that it would be more efficient for the heat to only have to travel through a 50mm screed bouncing back off an insulation board as opposed to 150mm (slab and screed).

I wanted to avoid the whole rebar and tie thing as I’m doing it myself but looking at the other posts it looks like this is the most thermally efficient way of doing it. Is it a massive ball ache and do you have to be particularly skilled?

What's the notional difference between eg a footing 200mm below ground level, plus a 200mm wall, and a footing at ground level, shaped as though it has a 200mm wall? (But if it makes it easier to think about, cut all the footings away and build the wall back.. I was just pointing out that notionally you've already built the wall out of concrete, you just need to cut the excess away to reveal it)

I can see what your saying now, thank you.

I considered this but I wasn’t sure if the footing would hold the same values as engineering brick (strength and water resistance) - but on reflection I guess it’s all underground and serves the same purpose. If the cut is not clean as a whistle I am worried about its structural integrity.

How come your building inspector didn't say

Tricky to say, I was a bit of a headless chicken when she came round the first time. But she never has a tape measure and is very led by the builder/me. Not the best.

Is it worth fessing up to her about it before I do it -
Or should I just do it and hope it’s not notices once the doors are in and the return is concealed.

We strategically placed mess around the room when the drainage was signed off whilst we decide what to do about the footings