Shed building

A shed is a floor, four framed walls, a roof and a way for water to leave. The carpentry is genuinely straightforward — square, level, plumb, and nothing structurally clever — which is why so many people build one as their first real project and why so many of those end up damp, racked or, occasionally, unlawful.

What actually decides the outcome is three things settled before any cutting. The planning position, because permitted development has exact limits on height, boundary distance and how much garden you may cover, and they are stricter on designated land and absolute within the curtilage of a listed building. The base, because a building on ground that moves will stop closing and no amount of good framing prevents it. Water, meaning roof covering, overhang, ventilation and getting the timber up off the ground.

The other thing worth settling early is what you are actually building. A shed stores things and needs no insulation. A workshop is used in winter and needs insulation, power and light. A garden room is occupied, which changes the specification substantially and can change the regulatory position too. Building the first and wanting the third is the commonest regret.

Materials, basic store

£600–£1,200

Materials, insulated workshop

£2,500–£5,000

Decide before cutting

Planning, base, water

The overspend that pays

The roof covering

1. 1

   Step 1: Decide what it is for, honestly

   Store, workshop or occupied room. Insulation, power, window area and floor construction all follow from it, and none of them is cheap to add afterwards.

   You will know it worked when: A specification rather than a size.

2. 2

   Step 2: Check the planning position against the actual numbers

   Height, distance to the real boundary, proportion of garden already built on, and whether you are on designated land or in a listed curtilage. Ring the planning authority if anything is close; a lawful development certificate is worth having if you ever sell.

   You will know it worked when: You know it is permitted, rather than assuming.

3. 3

   Step 3: Build the base and let it settle

   Level, drained, and big enough that the walls sit inboard of the edge so water runs off rather than in. Do not rush this to get to the interesting part.

   You will know it worked when: A flat, firm, free-draining platform.

4. 4

   Step 4: Frame the floor and get it dead level

   Everything above inherits this. Ten minutes with a long level here saves an afternoon of packing later, and a floor that is out shows up in every door and window.

   You will know it worked when: A level deck you can stand on.

5. 5

   Step 5: Frame the walls — on the deck or in place

   Building panels flat and standing them up is faster with help; framing in place stick by stick needs no lifting at all. Both are correct, and the second is the accessible route almost nobody writes down.

   You will know it worked when: Four square, plumb walls.

6. 6

   Step 6: Get the roof on and watertight before anything else

   The moment the structure is up, water is the enemy. Sheath, cover and flash it properly, with the overhangs you designed in, before you think about cladding or doors.

   You will know it worked when: A dry inside.

7. 7

   Step 7: Clad, hang the door, and leave it a season before fitting out

   Timber moves. Living with the building through a wet spell before you line it, insulate it or fill it tells you where water and condensation actually go.

   You will know it worked when: A building you have watched behave.

• A base that will not move — Concrete pad, or bearers on properly laid and compacted paving. This is the £300–£900 nobody budgets and the one that determines whether the door still shuts in five years. Everything else is built on it, literally.
• Treated timber for anything near the ground — Use-class treated stock for bearers, floor joists and the bottom of the frame. Untreated softwood in contact with damp ground has a short and disappointing life.
• A roof covering worth the money — Mineral felt is £60 and buys a few years. EPDM rubber or a shingle system is £250–£600 and buys decades. Re-roofing a full shed is the worst job on this page and the one entirely avoided at the start.
• Generous overhangs — Free at design time and the single most effective thing for keeping walls dry. Most kits have almost none, which is why kit sheds rot at the cladding bottoms.
• A circular saw, a drill driver and a long level — The whole tool requirement for a basic build, £150–£350 for decent ones, and all three outlast the shed. A track saw or a mitre saw makes it faster, not possible.
• Clamps, more than you own — The substitute for a second pair of hands, and what makes solo framing realistic.
• Insulation and a vapour control layer, if it is a workshop — Only if you will use it in winter — and if you will, decide now, because retrofitting insulation into a finished shed means taking the lining off again.
• What can wait — Guttering, a water butt, shelving, a bench, and any of the interior. All are better fitted once you know how you actually use the building.

The first stage is one small building done properly: a log store, a bin store, something open-sided where a mistake costs a weekend rather than a season. It teaches square, level and plumb, which is nearly the whole craft, without the weatherproofing problem on top.

The second is a full shed, and the learning is planning and water rather than carpentry. Knowing the permitted development limits, building a base that stays put, designing overhangs that keep walls dry, and understanding condensation well enough not to make it worse. Somebody who has done that can build almost any small garden structure.

After that it goes two ways. Up in specification — insulation, power, a garden room, and eventually the regulatory territory of habitable space. Or into the craft — timber framing, real joinery, and structures that stand on their joints rather than their fixings. Plenty of people also stop, entirely reasonably, with a good workshop and no further ambitions about buildings, and then spend the next decade using it for something else in this catalogue.

The neighbouring rules people meet next:

• Electricity is its own regime — A supply to an outbuilding is a fixed electrical installation and falls under Part P, with a competent-person or building-control route. Running an extension lead across the lawn indefinitely is the alternative nobody should choose.
• Boundaries are not where you think — Measure to the actual legal boundary rather than to the fence, which is frequently not the same line. The 2-metre rule is measured to the boundary, not to somebody’s panels.
• Trees can be protected independently — A tree preservation order or a conservation area constrains what you may cut or dig near, and roots are a base problem as well as a legal one.
• Covenants sit outside planning entirely — A restrictive covenant on the deeds can forbid outbuildings even where planning permits them. Rare, and worth thirty seconds of checking.

• Garden workshop — The same shell with insulation, power, light and a floor you can stand on all day. The commonest upgrade and the one to decide at the start.
• Garden office or room — Occupied space, which raises the specification substantially and can bring building regulations into play. A different project wearing similar cladding.
• Log store and open-sided structures — Much simpler, no weatherproofing problem to speak of, and the ideal first build to learn framing on before committing to a full shed.
• Greenhouse and potting shed — Glazing changes everything about the structure and the ventilation, and puts the project next to the growing side of the catalogue.
• Sauna and hot tub buildings — A shed with a heat source in it, which is a substantially different set of regulations and hazards — covered separately for exactly that reason.
• Timber framing proper — Where this leads if the framing is the part you enjoyed: real joinery, pegged joints and structures that do not rely on nails.