A concrete slab is the dependable, permanent default for a bar shed and suits most level gardens. Ground screws go in fast with very little digging or mess, and they shine on slopes, awkward access and places where you might want to move the building later. Ground conditions and the building maker's requirements should make the final call.
The quick comparison
| Deciding factor | Ground screws | Concrete base |
|---|---|---|
| Mess and digging | Minimal | Excavation, formwork, spoil to remove |
| Time before building | Usually build straight on top | Wait for the concrete to cure |
| Slopes | Adjust to height on each screw | Needs cutting in or retaining |
| Ground conditions | Rocky or very soft ground can be a problem | Copes with most ground if properly designed |
| Permanence | Can be removed | Permanent |
| Under-floor airflow | Built in, with a timber frame | Building sits on the slab |
| Roots and services | Must avoid pipes and cables | Must avoid pipes and cables |
| Floor finish | Timber frame and deck | Slab can be the floor |
Read the garden bar base guide for slabs, paving and timber frames in more depth.
Who should choose ground screws
- Sloping gardens, where levelling for a slab would mean a lot of digging. See building on a slope.
- Gardens with poor access for concrete or a mixer.
- Renters or anyone who might move the bar.
- People building on or next to decking, where a timber frame on screws is a natural fit.
Who should choose a concrete base
- Level gardens with reasonable access.
- Heavier buildings, such as log cabins, where the maker specifies a slab.
- Bars where you want a hard floor you can tile or paint, or a built-in duct for a power cable.
The hidden work on each side
Ground screws
The screws themselves are quick, but you still need a frame or bearers on top, and the frame must be level, treated and tied down. Installers usually check the ground first, because stones, old foundations or very soft soil can stop a screw from holding. You must know where underground pipes and cables run before anything goes in. Some building makers specify particular bases, so check their warranty conditions.
Concrete base
The work is all up front: digging out, a compacted sub-base, formwork, concrete and time to cure. Spoil needs taking away. A slab that is not level or slightly too big can funnel rain under the walls, so it should finish just inside the building's footprint or be detailed to shed water. If you want power, plan a duct for the cable now. Work out the volume of concrete and sub-base from the slab size before ordering, and see delivery and assembly for what the building needs on arrival.
Ask the building's maker which bases they accept under warranty, then check your ground and where your services run before choosing.
Quick answers
Are ground screws strong enough for a log cabin?
They can be, if the installer sizes and spaces them for the load and ground. Check the cabin maker’s base requirements and warranty conditions first.
How thick should a concrete base be?
Follow the building maker’s specification. The garden bar base guide explains the layers.
Can I put a bar shed on paving slabs instead?
Often, for lighter sheds, if they are laid level on a firm sub-base. See garden bar base.
What about a garden that slopes a lot?
Ground screws or a raised timber frame usually beat cutting a big slab in. See garden bar on a slope.