John Gardener's Answer
Wed 6 Apr 2016 17:38pm
Th type is depending on the size of shed & the usage. The 1st thing to consider is location! Ideally the shed should be accessible from all sides to enable you to maintain it, i.e. treat it once a year with fence or wood care treatment.
As standard 6x8 or 8 x 12 wooded shed, usage (garden tools, bikes etc) you have 2 options:
1: concrete slab base
This is the lowest cost option. You will need to dig out a base roughly 1 slab width wider than the size of the shed & about 1 1/2 the depth of a slab. Ensure the space is level, then I would lay a weed membrane, then cover with a dry soft sand/cement to the depth of 1/2 a slab or just over ensuring the sand is compacted to give a stable base. Lay your slabs down in line, ensuring again that they are level & true using a rubber mallet to tap them into the sand so that they lay flat without pivoting. Allowing a gap of about 5-10mm between each to fit into your space. Then once all your slabs are laid, I would brush extra sand over the slabs to fill the joints, then begin to erect your shed.
2. Hard concrete base
Mark out your base area again allowing at least 50mm surround, dig down at least 150mm. Build a timber frame for the outer area of your base using 6 x 1 timber. In fill 80 - 100mm of hardcore, thump this down to create a hard level base, then cover with sand, again level. Finally mix your concrete mix, not too sloppy, fill in to just level or above the top of the 6x1 timber frame. Using a long piece of 3x2 or similar drag it across the concrete to ensure you fill every area of the base & it is level.