Shlomi

Hi guys, hope someones got some good grasp of the building regs and permitted development and how they may apply to my scenario. Just had a company to lay a 7x3 meter concrete slab at the rear of my garden bordering two neighbours.I'm planning to build my woodwork workshop on top of the slab and need to figure out how to maximise the size I can build on top of this pad, and how to get the maximum internal head height while sticking to the regulations. The slab is 20cm thick, 10cm below the garden lowest point and 10cm above the lowest point. However, it was obvious from the start that our garden level is very uneven, and that in some parts the slab is actually below the surrounding soil level especially around the fences where the neighbours garden begins at least 20cm above the pad level. For that reason I'm thinking to build a retaining wall to keep the soil at bay. I'm attaching some photos to help assess my first question which is, what would be a viable point to measure the 2.5m external roof height as per permitted development within 1m boundary of the fence? Do I take the lowest part of the garden as a reference, the highest point or possibly measure it from the slab itself? Is it a matter of being sensible or is there a hard and fast rule to go about this? In an ideal world I would like to be left with 2.4m internal height, after deducting the wooden base and cold roof insulation which will probably amount to 30-40cm. But if my ground level is the lowest point and my slab is 10cm above that, then I'll be left with 2m head height. If I measure from the slab then I might get 2.1m and if go from the highest points I might be able to gain myself another 20-30cm. That of course will increase the chances of neighbour complaints as the outbuilding will go well above the fence and that even might lead to an inspection ,a position which I really don't want to find myself in. Any thoughts, advice, or similar experiences to share will be most appreciated. Shlumaan

Hey ProDave thanks for the answer. Should I double check that indeed the upper slab is leveled with my neighbour's garden? Also, the first step-up from my garden is a very uneven platform, so how do you go about leveling the two platforms?

Hi there, we've just purchased a new property in enfield, north London. The garden has ample space but there seems to be the perfect spot at the back right by the corner fences to build a 15 sqm room out of timber, 2.5m high for my woodwork hobby. However, there's currently two levels of concrete, raised above the garden level, see pictures. There's an old shed on top of the lower part of the elevation but the second elevation must have had another structure which had been remove before. To get my maximum head height I will need to go down to the ground level below the concrete slabs. I am wondering why they made those two platforms elevated above the garden. My worry is that I may find something underneath which might stop me from executing my plans.. Also if I go down back to the garden level will it require rebuilding of the fence/s with my neighbours? I'm reluctant to do that. What are people thoughts?