What to look for when buying a garden shed
Updated
Most sheds look alike in a photo. What decides how long one lasts is the cladding, how the timber is treated, the frame, the roof and what it stands on. Here's what to look for in the specification.
Start with what it's for
A shed for a mower and a few tools can be small and simple. A workshop, or anywhere you'll spend time, needs more headroom, a stronger floor and weathertight walls. Decide what goes in it and what you'll do in it, then choose the size, and only then the construction. Our guide to will it fit? covers measuring your space.
Cladding: overlap, shiplap or tongue and groove
| Cladding | What it is | Good for |
|---|---|---|
| Overlap | Boards that each overlap the one below. The cheapest, with the thinnest boards, but gaps can let in draughts and damp. | Tools and garden kit you don't mind getting a little dusty. |
| Shiplap | Machined boards with a curved profile that fit into each other, so rain runs off rather than in. | Most uses. Smoother, stronger and more weathertight. |
| Tongue and groove | Boards that slot together along their full length, often in a shiplap profile. | Workshops, bikes and anything that needs to stay dry. |
Thickness matters as much as the type. Overlap boards are often 7 to 10mm; better shiplap and tongue and groove is 12mm or more. The specification should give the finished thickness.
Treatment: pressure or dip treated
Dip-treated timber has a preservative coat on the surface. Makers ask for it to be re-treated every year, and any guarantee against rot usually only stands if you do.
Pressure-treated timber has preservative forced into the wood under pressure in a sealed tank. It costs more, and makers often guarantee it against rot for ten years or more. How deep the treatment goes depends on the timber and the level of treatment, so judge it by the maker's guarantee against rot, not the label. Read the guarantee's conditions too: Waltons' 15-year anti-rot guarantee on pressure-treated buildings still asks for a waterproofing coat when it's built and every year after.
Frame
A sturdier frame keeps the panels square, and on a firm level base it stops the building twisting - which is what makes doors stick. Compare the framing size in the specification, not just the cladding.
Roof
An apex roof slopes both ways and gives more headroom in the middle. A pent roof slopes one way, suits a spot near a fence, but leave a gap behind it for air and rain (some guarantees ask for 2 feet all round). Shed makers put standard mineral felt at around five years; polyester-reinforced felt, shingles or an EPDM rubber roof last much longer.
Floor
Look for a floor that sits on pressure-treated bearers, which lift it off the ground so air can move underneath. Tongue and groove boards are the traditional shed floor and cope with damp better than sheet board.
Base
Every shed needs a firm, level base. The usual choices are:
- A concrete slab: the strongest, and the most work.
- Paving slabs on a levelled bed of sharp sand: good for most sheds.
- A plastic grid base filled with gravel: quick, and it drains well.
Size it from the floor, not the roof overhang, and follow the maker's own base rule: they don't all agree. Our guide to shed bases has the detail.
Do you need planning permission?
Usually not. Most sheds in a back garden are fine, as long as they're kept low near the fence and don't go in front of the house. Flats, listed buildings, conservation areas and the other UK nations have their own rules. Our guide to planning permission covers what to check.
A quick checklist
- Cladding type and finished thickness.
- Pressure or dip treated, and the length of any guarantee against rot.
- Framing size.
- Roof style and felt grade.
- Floor type, and whether it sits on bearers.
- External size, including the roof overhang, and the height.
- How it's delivered, and whether you need to be in.
Please note: this guide is general advice to help you choose, not professional or legal advice. Every garden and every product is different, so always follow the maker's instructions and check with your council or a qualified tradesperson if you're unsure.
Sources
- Planning Portal: Outbuildings
- Power Sheds: What is the difference between shiplap, overlap and tongue and groove cladding?; Shed felt buyer's guide; How to build a shed base
- Garden Oasis: Buying a garden shed: overlap, shiplap or tongue and groove
- Shedstore: Overlap vs shiplap vs tongue and groove cladding; Forest Beckwood 12x8 shiplap double door shed
- Garden Buildings Direct: Wooden shed cladding thickness guide; Sheds and airflow underneath; Pent and apex shed differences; Felt vs shingles; How to build a shed base
- Gillies and Mackay: Thick shed framing; How big should a shed base be?
- Wood Protection Association: Preservative treatments; Buyer's guide to preservative treated wood (PDF)
- Forest Garden: Guarantee; Project guides and top tips: sheds; Sheds, storage and summerhouses: base preparation guide (PDF); Beckwood 8x6 apex shed
- Dunster House: Pressure treatment vs dip treatment
- Buildworld: Shed felt buying guide
- Atlas Sheds: Best flooring for a garden shed
- Tiger Sheds: How to install a plastic shed base kit
- IBRAN: Plastic shed base
- Fountain Timber: Constructing a base for a shed
- Waltons: How to build a concrete shed base
See also: will it fit? and shed bases.