Large garden room/summer house on part paved base

[britishboy7]

We currently have a 3m x 3m concrete base at the bottom of the garden when an old summer house stood when we moved in. We would like to build a more modern style, larger garden room/summer house (self build, styled with the cedar cladding on the outside and bifold doors to the front), but would like it to be 6m wide x 3m deep. Half of it would be built onto top of an old patio, would this be suitable?

was thinking a 6m x 3m concrete base (4" deep) right across the current base and patio?

Any tips or pointers greatly appreciated

 

[ivixor]

You can do a concrete base, although that's an expensive way to do it compared with a timber base. Are you going to be keeping within permitted development limits on height, or submitting a planning application?

 

[britishboy7]

You can do a concrete base, although that's an expensive way to do it compared with a timber base. Are you going to be keeping within permitted development limits on height, or submitting a planning application?

Thanks ivixor, going to stay within permitted development so under 2.5m high. Could i do a timber base straight on top of the current half concrete slab/half paved area? Would the timber base go straight on top, or anything inbetween with a DPM/sheet?

 

[ivixor]

You need to have the timber base elevated so there is ventilation underneath, i'd say 10cm is a good target for the space. For mine I just placed the timber on concrete blocks, with a DPC between them. Where the building exceeds the concrete slab, I'd pour a footing of concrete for the block to rest on. For 6x3m you'd probably end up with 8 blocks around the edges, though this depends on timber size.

 

[big-all]

remember the 2.5 is from the natural ground level not the top off the concrete

 

[britishboy7]

Thanks guys

big-all, the whole lower garden area is patio (and the part concrete base thats flush with the patio), do i take that as my ground level? If not, how would i know the natural ground level?

At present, from patio level up i have about 6" of concrete gravel board, then standard 6ft fence panels

 

[big-all]

is there anything within the footprint off the new structure to suggest a natural ground level
planning portals
interactive house
https://interactive.planningportal.co.uk/detached-house/outside
sheds
https://interactive.planningportal.co.uk/detached-house/outside/sheds
planning permission
https://www.planningportal.co.uk/info/200130/common_projects/43/outbuildings