Most garden bar problems that look like carpentry problems start underneath. A door that sticks by July, a floor that bounces, a damp corner behind the fridge: all of them can trace back to a base that was rushed so the fun part could start.
Read the maker's base requirement first
If you are buying a bar shed, summerhouse or log cabin, the supplier will publish what the building should sit on and how level it must be. That instruction matters more than any general advice, including ours. Some guarantees depend on it. Save a copy with the order paperwork.
For a freestanding counter, the base question is simpler but still real: the counter needs firm, level, free-draining ground, and its feet or bearers should not sit in standing water.
The four common routes
Concrete slab
A cast slab is durable and suits heavier buildings. It is also the most permanent choice and the hardest to undo. It needs proper preparation, a sensible finished level relative to the surrounding ground and a plan for where rainwater goes. Many people bring in a groundworker for this stage, and that is often money well spent.
Paving slabs on a prepared bed
A slab base works for many lighter buildings when it is laid on a compacted, level bed. The weak point is usually the preparation, not the slabs. Uneven settlement shows up later as racking doors and windows.
Timber frame or bearers
A treated timber frame can bridge uneven or sloping ground and keeps the building off the soil. It needs ventilation underneath and timber rated for ground contact where it touches the earth. Check the frame for rot periodically, because it is the part you will never otherwise see.
Ground screws
Screwed steel foundations are installed with little digging and can suit awkward access or tree roots. Their suitability depends on the ground and the load, so the installer should assess the site rather than quote blind.
Drainage decides how long it lasts
Whatever you choose, think about water first. The base should not create a pond at the door. Leave a gap between cladding and soil, keep downpipes and gutters pointed somewhere useful, and avoid banking up soil or bark chippings against the walls.
Plan the cable route before the base is finished
If the bar will have a permanent electrical supply, talk to the electrician before the slab is poured or the frame is boarded. A duct laid in at the right moment is far easier than breaking out a finished base later. Our power guide covers what to decide before that conversation.
Check the base against the rules too
The base can affect height. Planning limits for outbuildings in England are measured from ground level, so a raised base on a sloping plot can push a building over a limit it looked well within on the product page. Read the planning starting point before choosing a tall frame.
Work out the quantities
Once you know the base type and the thicknesses your instructions call for, the base calculator gives you the area, edge length, concrete and sub-base volumes or slab count, drawn to scale. Still choosing? Read ground screws vs concrete.
Before you order anything, mark the footprint with string lines, add the overhang of the roof, and stand where the door will open. If the base would sit in the wettest part of the garden, move it now while it is still only string.
Sources
Primary guidance checked 10 November 2026.