help required with foundations

[Suki]

Thanks for taking the time to answer this. I am planning on building an outbuilding at the end of the garden within the 2.5m height restriction. 

It’ll rough be 4.7m x 2m. I’ll have trench filled concrete footings possibly 450mm wide x 600mm deep (these are the dimensions of the concrete), above that will have around a further 200 - 300 mm deep footings the exterior isn't level (it has a slight drop decline)

The original plan was to build out of the trench with Yorkshire stone work (single akin at 140mm on the bed). Would recommend this or would it be better to bring out to dpc level in blockwork (around 150mm above the exterior ground (at the highest point and then render this (on the outside) with sand and cement. Then lay the Yorkshire stonework on top of these 7n blocks with the dpc and dpm tucked into the bit between the block work and Yorkshire stonework? The inside will have a 100 - 150mm concrete slab dropped in.  The other option would be to bring to ground level with 7m blocks then Yorkshire stone to DPC, tuck in the DPC and DPM and continue with the Yorkshire stone work till I get to the wall plate? 

Dependent on which builder I ask they completely contradict each other. Looking online there’s a plethora of info but nothing that says this is a better option Over the other? 

By the way it will have a wall plate and a flat roof using 6 x 2 rafters and firings under a 
Fibreglass roof. 

Any advice from you would be greatly appreciated.

 

Read more: https://www.diynot.com/diy/threads/foundations-to-dpc-help.573526/#ixzz6yvyr0pDf

[Mr Punter]

Build up from the footings in blockwork, then swap to York Stone as soon as it will be visible (if it is suitable for below DPC).  I think it will look better.

 

Lap the floor DPM up and onto the DPC.

 

 

[Temp]

+1

 

Just check the 7N blocks are recommended for below DPC. Most but not all are.