Foundations poured too high - HELP

[SPJG1997]

Hello,

First time post. I have put my questions in bold as appreciate this is a beefy post.

I convinced myself and everyone else that I could dig and pour footings on a rear single story extension. (I work in an office). Long story short, when the brick layer said “fill her up, I had the footings poured to just below FFH.

The DPC/Skirt is therefore 150mm above the internal finished floor height. BC haven’t commented so I am trying to fix matters before I ask them to inspect the build up

 

I am installing a lapping DPM under the slab and folding it up behind the DPM skirt on the perimeter walls. Is this going to cause me any damp issues? Will I have to no nails the skirting board to prevent piercing the DPM?  I will also have a thinner DPM above the slab.

Secondly, this has therefore caused me a big problem with the back doors. At the moment we are going to have a 6inch step out the back door. Which is going to look sh*te.

Is there any way I can lower the footing in the back door opening and build it back up with 150mm course of bricks. I have looked at stepped foundations used for a sloping surface, based on diagrams it looks like the DPC is staggered. I appreciate this will be cutting into the footing but technically there is nothing above it but fresh air?

I have been bo*locked enough by my old man and my Mrs so any help to get me out of this would be appreciated.

Cheers, Sam

[Russell griffiths]

I’m more concerned with that pier supporting the steel sitting on top of that tiny lintel. 
Is that drain pipe permanent or just temporary. 

[SPJG1997]

I was extremely concerned lifting up the lap and seeing that. The pier was a retro fit and the steel is sitting on the inside skin of block work. I have since back filled it with concrete going a meter down and tied in with bar and resin either side. I don’t think it’s going anywhere 

Edited March 28 by SPJG1997

[Russell griffiths]

What about that pipe work, is it temporary. 

[SPJG1997]

No that’s the new foul waste that ends at a sub stack. It’s serves a downstairs bathroom, utility room and kitchen sink. It’s just been signed off by BC last week.

Edited March 28 by SPJG1997

[Russell griffiths]

You need a cross section drawing showing what you have and the problems you think it’s going to cause. 
 

it’s to hard to try and figure out what’s going on in the pictures. 

[SPJG1997]

At the moment the foundation is sitting at FFH. 

This means the 150mm DPC is 2-3 courses of brick above FFH causing a 6 inch step at the back door.

I am wondering if I can cut/drop the foundation in the back door opening and step the DPC down.

I would then have the followed to deal with any damp/ingress

1. drip sill on the opening

2. weather shield on the back door

3. ACO drain between the patio and the back door leading into a soak away.

 

Rough sketch attached of the stepped DPC.

[BadgerBodger]

Looks like a job for tanking… although… even with the sketch I’m a little confused. It would be helpful if you could show the brickwork. If it’s a cavity wall, do you have a cavity tray or just a DPC on both leaves? FYI look on NHBC website info is your friend for simple details and general “good” practice.

 

In your scenario it just looks like the DPM that would normally form your internal DPC and dress down under the slab will be partially exposed. In itself I wouldn’t say this is a major issue but it IS more likely to accidentally be punctured torn or otherwise breached in its exposed position. 
 

certainly not best practice. 

 

Edited March 30 by BadgerBodger
Lack of clarity