Before the Slab Goes Down: A Pre-Build Checklist for the Shed You Will Actually Use
Before building a shed, review this pre-build checklist covering site prep, foundation, layout, storage, utilities, permits, and long-term use.
Picture the shed you meant to build. Soft light through a window, a bench running along one wall, a door you can swing open on a Sunday morning, and a space that finally belongs to the thing you love doing.
Now picture the shed most of us end up with about eight months later. Camping gear. A treadmill nobody uses. Four boxes that were never unpacked from the last move.
The building is rarely at fault. What went missing was a decision, and it went missing early. Most people buy a shed and then work out what to do with it, when the order that actually works runs the other way. Deciding the purpose first costs nothing while the design is still on paper, and it quietly shapes almost every choice that follows.
Start With the Verb, Not the Square Metres
Ask anyone what they want and the answer arrives in numbers. Six by nine. Something about that size. Numbers feel like progress, but floor area tells you very little about what the building has to do.
Try starting with a verb instead. Throwing pots. Restoring furniture. Lifting weights. Packing orders for a small online shop. Every one of those verbs brings its own quiet list of demands. A potter needs a water supply, a floor that can be hosed out and somewhere for a kiln to vent. A woodworker needs dust extraction and enough circuits to run two machines at once. A home gym needs ceiling height for an overhead press, a floor that forgives a dropped barbell, and far more airflow than anyone expects.
Sizing against the garden and the budget is the habit almost everywhere. Take Perth in Western Australia, where summers run long and dry and a steel structure is the default choice at the back of a block. The sheds Perth homeowners commission are typically measured against the space beside the house rather than the task going on inside, and the result is a building with nothing wrong with it and nothing much to do. The dimensions were right. Nobody ever gave it a job.
What You Do In There Decides Which Way It Faces
Once the verb is settled, orientation stops being a matter of taste and becomes a matter of timing. The wall that catches late afternoon sun will hold that warmth long after sunset, particularly if it is steel or darkly clad. If you plan to be in there after dinner, that matters enormously. If you are a Saturday morning person, far less.
It is worth learning the prevailing afternoon breeze on your site too, because an opening placed to catch it is the cheapest cooling you will ever install. Whichever hemisphere you are in, the principle holds: name your hours first, then choose the aspect that suits them.
Orientation is also the one decision you cannot revisit later. Which way the building faces is settled the day the slab is poured.
Which Way It Faces Decides Where the Openings Go
With the aspect chosen, the doors and windows almost place themselves. The wall facing away from the equator, south of the equator that means the southern wall and north of it the northern one, gives soft, even light all day with very little heat gain. That is the studio wall, the one for colour work and fine detail. The wall facing the equator brings welcome warmth in winter and can be shaded through summer by a modest eave. Generous glazing on the hot afternoon wall needs a very good reason.
Access deserves the same thought. A roller door wide enough for a car is not the same as one wide enough for a car plus room to open its doors. A separate personnel door sounds like an indulgence until the first wet winter, when you stop lifting a full roller door to fetch a single tool.
Openings also decide whether air can move at all. Ventilation needs an inlet and an outlet on opposite sides of the building. Two windows on the same wall will move almost nothing.
Where the Openings Go Decides How You Handle Heat and Damp
This is the point where retrofits turn expensive, because insulation and ventilation are cheapest when they are specified alongside the frame. A blanket laid under the roof sheeting during construction costs a fraction of lining a finished ceiling later, and it also helps with condensation.
Condensation is the quiet spoiler. On a cold morning, warm air inside meets a cold roof and the moisture drops back onto whatever sits below. Tools freckle with rust, cardboard softens, and the cause stays invisible unless you happen to be standing there at six in the morning. A vapour barrier under the slab, insulation under the roof and vented air at the ridge solve it between them. None of the three does much alone.
The Ten Point Pre-Build Checklist
Run through these before you sign anything.
Name the activity, not the room. "Studio" and "workshop" are labels. "Throwing and glazing pottery two evenings a week" is a brief.
Count the people and the hours. A space used alone at weekends and one used by three people on weekday evenings need different lighting, airflow and circulation.
Map the services early. Power, water, drainage and data are all far cheaper to trench once, before the slab is poured and the planting goes in.
Match the floor to the load. Machinery, a vehicle hoist, dropped weights and a kiln all carry requirements a standard domestic slab does not automatically meet.
Fix the orientation on paper. Mark where the sun sits mid afternoon at the height of summer and where the breeze comes from, then place the building against both.
Decide the doors before the walls. Door type, width and position drive the framing, and they are the hardest element to change once the structure is standing.
Plan the light in layers. Daylight for the hours you have it, task lighting over benches, and general lighting that does not leave you working in your own shadow.
Treat insulation and ventilation as one system. Roof insulation, wall insulation, ridge or rotary venting and eave intake are a single decision, not four separate ones.
Check the local rules before you settle on a size. Setbacks, boundary clearances, wall height and total outbuilding coverage vary from one council or municipality to the next, and they tend to bite at exactly the size people want.
Allow for the version of you in five years. Most of us underestimate depth rather than width. An extra metre now is far cheaper than an extension later.
Why the Checklist Costs Less Than the Retrofit
The advertised figure for a shed is usually the kit alone. The built cost takes in site levelling, the slab, approvals, door upgrades, insulation, electrical work and often a concrete apron so you are not walking mud inside. Comparing published shed prices against a finished budget is the most common way people end up caught short, and it is why late decisions feel so painful. By then the contingency has gone.
Every point on the checklist above is close to free while the design still lives on a screen, and genuinely costly once the building is up.
See It Before You Buy It
Plans are hard to read if you do not read plans for a living, and proportion is the first thing to get lost. A roller door that looks generous on a drawing can read as the entire front wall in reality, and a roof pitch chosen from a list means very little until you see it sitting against the house behind it.
Modelling it first helps enormously. A shed builder tool that lets you set dimensions, roof style, door positions and colours before you commit will catch the proportion problems a dimensioned drawing hides, and it makes the conversation with a supplier far more specific. It is also the cheapest way to test whether the finished structure will read as part of your garden or as an object dropped into it.
When the Plan Outgrows the Garden
Sometimes the checklist produces an answer the garden simply cannot hold. If the activity involves stock, regular deliveries, staff or vehicles larger than a family car, residential setbacks and outbuilding limits will stop the project long before the design does.
That is not a failure of planning. It is the planning working. In Perth, businesses that reach this point tend to move out to light industrial pockets such as Wangara, Malaga and Bibra Lake, and the commercial sheds Perth operators put up there are specified around clearance height, floor loading and truck access rather than around what fits beside the house. Recognising that threshold early spares you from building a compromise at home and outgrowing it within two years.
The Shed You Will Actually Use
The difference between a shed that becomes a studio and one that becomes storage is rarely money, and it is almost never the quality of the building. It comes down to whether anyone decided, before the slab went down, exactly what was going to happen inside.
Answer that first and every other choice falls into place. Answer it last and you spend the next few years working around decisions you never knew you were making.
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