planning on building a new shed in the next few months as a bike store/general workshop. it’ll be my 3rd shed i’ve built but the biggest, so i’ve drawn some rough plans up for a partitioned 6ft x 14ft layout as that’s all the space i have to play with. i want to have a solid concrete floor like in a garage or brick shed, and build the structure out of timber

has anyone on here built a shed to this sort of spec? i want the concrete floor for fixing ground anchors/tool boxes/heavy duty work bench down and be as durable as possible. previous shed’s i’ve built have all been raised wooden floors on timber bearers but i’ve only used them for storage. also i want to maintain as low an overall height as possible to not cut out too much light to our patio area/kitchen window – 2m pent roof is the thought for now. what i’m concerned about is what to do where the timber meets the concrete base – should i try to provide an overhang so any rainwater on the shed cladding doesn’t pool on the concrete base and seep underneath and rot the frame/pond inside? or should it sit on top and be sealed somehow? any other ideas/solutions/details? i will be putting a filter drain next to the shed as the garden falls towards it, so water from run off off the garden shouldn’t be a problem. all advice appreciated! cheers

1 layer of concrete blocks on the base and then build the shed up overlapping the concrete blocks by half and the timber frame attached to said concrete blocks?

Or make a stepped (top hat) concrete base with shuttering when you pour and have the shed overlap down the sides of the step a touch. If you leave a small gap around the edge you could then hose down inside the shed and brush the water out if needed.

cheers – i did think of building a 1-2 brick high wall first with the frame to sit on top but forgot to type that… i will have loads from demolition of a coal bunker. how does the dpm fit in with all that? just under the main concrete slab and tidied up around the edges be ok maybe?

Then water would still get in surely?

I’d create a DPM’d tray with the DPM deep enough so that your ground anchor bolts don’t go through it.

I built a log cabin on a concrete base, dimensions wee slightly out so the bearers did not overlap the base in one direction. Painted the bearers with bitumen paint then put flashband on-top of the bearer and concrete base. Made sure the cabin overhang the bearer to give a good drip path.

4 years in, no water anywhere.