Should I Install a Concrete Base or Slab Base for My Garden Building?

Crane Garden Buildings explain the benefits of a concrete slab in this guest post

Concrete slab for a garden room


When investing in a garden room, garden shed, summerhouse or other type of garden building, regardless of its value, to maximise the life of it, one of the most important decisions you have to make is what the actual building is going to stand on once it is in your garden.

There are only two viable options for the base: paving slabs or concrete.

Correctly laid, either one is a suitable option, but we recommend that paving slabs are only used on smaller, lighter buildings, up to a maximum size of 8’ x 8’ (2.4m x 2.4m). Beyond that size, we recommend a concrete base for maximum performance.

Whichever option you do opt for, you should make sure it is correctly installed, otherwise you could find that your pride and joy quickly turns into something that is no longer a joy to use.

What’s the Worst that Can Happen?

Even the smallest garden shed is relatively heavy (in excess of 150kg), and with a poorly laid or insufficient foundation and varying ground conditions, over time, it will settle unevenly and lead to premature deterioration.

Door and window frames will become misaligned and opening or closing them will be difficult. Rain coming in through gaps or cracks can damage the contents and advance damage or rotting of the wood. Misalignment will also put undue stress on other parts of the structure, leading to cracking or breaking and will cause further issues.

NB: not installing a sufficient base for your garden building is likely to invalidate any warranty that comes with it.

Size and Positioning of a Concrete Base 

When deciding where your garden building will be situated, if it’s close to a boundary or fence, you should leave enough access space around the sides to allow you to move around the building for routine maintenance/upkeep.

The base should be constructed from reinforced concrete at least 100mm thick and protrude from the ground by a minimum of 50mm.

We recommend constructing a base to the stated metric size (rather than the imperial size) otherwise, it will extend beyond the building and look unsightly.

Building A Concrete Base

Local ground conditions will affect the finished base and it is vital that it does provide sufficient support. With that in mind, we strongly recommend seeking local professional assistance when constructing a concrete base.

We offer a cost effective additional base construction service so you can be confident that your building will not deteriorate prematurely. Contact us to discuss your specific requirements.

About Crane Garden Buildings

We have been building market-leading quality garden buildings for over 40 years at our factory, near Kings Lynn in Norfolk.

Highly-skilled craftsmen hand-make every component (including doors and windows) using FSC® Certified timber and expert joinery techniques, to create exceptionally strong and robust buildings that will last year upon year.

We offer a wide range of:

Garden Rooms




For more information visit the Crane Garden Buildings website or call the team on 01760 444 229

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