Last Updated on August 24, 2026 by
Everyone planning a house asks the same question first: what does it cost per square metre? The honest answer is that the question is missing its own inputs. A rate describes a building whose shape, height and layout have already been settled, yet at the point most people ask this question, none of that has actually been decided. A number cannot answer a question about a house that isn’t detailed enough to be priced.
Right now you’re probably holding something closer to a sketch than a plan. Several decisions inside it are already made, whether you meant to make them or not, and each one is quietly setting what the finished plan will cost. Change them now and it costs nothing more than an eraser; once drawings exist, that eraser is gone.
Read a rough sketch the way a designer does and five of those early design decisions are already sitting inside it: the finish level you’re briefing to, a simple footprint or a cut-up one, one storey or two, how far the structure spans, and whether wet rooms sit together or are scattered. By the end you’ll read your own sketch the same way.
The Early Design Decisions That Set Your Budget
When a concept sketch lands on my desk, the first thing I look at is the outline, not the room labels, because the outline is what starts setting the cost before anything inside it has been decided. A rate per square metre sounds like a fact, but every one of the early design decisions behind it is a choice, made by somebody. If you don’t make each one deliberately, your sketch makes it for you.
Order matters here because all five are effectively locked by the time a sketch becomes a set of drawings. The earliest, cheapest moment to get any of them right is also the moment most people spend no time on at all.
Take the clearest example first: the level of finish you brief a designer to work to. Published rates for entry-level building in one South African city sit at around R5,000 to R8,000 per square metre in 2026, standard mid-range work runs R8,000 to R12,000, and premium, bespoke-finish work reaches R12,000 to R20,000. Those figures are useful here only as a comparison against each other, never as a number your own build should expect to land near; read together they describe three different houses rather than three prices for one house.
That asymmetry is worth naming once, plainly. Two of these five decisions, finish level and storey count, have published price bands behind them. The other three don’t.
Footprint shape, span length and wet-area grouping have to be argued from how a building actually goes together, not read off a table, and that’s exactly what the next three sections do.
A Simple Footprint Versus a Cut-Up Plan
Set a simple rectangle against a plan broken into wings, returns, pop-outs and a courtyard, holding the floor area identical between the two, and one of the early design decisions is already visible before a single wall goes up. I count corners before I count rooms when a footprint like that lands in front of me, because every corner you add increases the external wall wrapped around each square metre of floor, and external wall is one of the more expensive things a house owns per metre it covers.
More external wall for every square metre of floor means more footing to dig and pour, more wall structure to build, more cladding or brickwork to fix, and more junctions where two planes meet and have to be detailed and weatherproofed properly. A more complicated roof usually follows a more complicated plan, and roofs are the least forgiving part of a house about a junction that got rushed.
None of that lands as one big line on a quote. It’s spread thinly across footings, framing, cladding, flashing and roofing, which is why a cut-up plan rarely looks expensive on paper, and why the difference is almost impossible to negotiate away once the drawings are done because there’s no single line to cut, only dozens of small ones hiding inside other trades.
That doesn’t make a simple rectangle the automatic right answer. A wing that turns a corner buys light into a room that would otherwise sit dark, a return can buy privacy between two parts of the house, and a courtyard can buy an outdoor room a plain box never gets. The decision is whether you are buying that extra wall on purpose, or picking it up by accident because the sketch looked interesting.
One Storey Versus Two
Put the same floor area on one level against two, and two effects pull in opposite directions: go up a storey and the footprint halves, so the footing and roof cover less ground per square metre of floor. But a suspended floor, a stair, taller walls and harder access fill the gap, none of it free.
Figures published by a South African cost reference for put single-storey work at R5,000 to R20,000 per square metre and double-storey work at R10,000 to R20,000 — published as estimated ranges rather than fixed prices, for that same city in 2026. That pair of bands is one of these early design decisions with a real published number behind it, and the shape of the two ranges matters more than either figure alone.
Look closer and the bottom of the two bands is where the real difference sits: both top out at R20,000, so going up a level doesn’t raise the published ceiling. The floor moves from R5,000 to R10,000, though, and on this published rate set, the entry end of the double-storey market thins out once a second level is added. Read that way, going up a storey lifts the floor of what the work can cost far more than it lifts the ceiling.
Everything that made the cheap end of the market cheap – a slab on ground, no stair, easy access for every trade, disappears the moment the house goes up, while the top never moved. The published double-storey floor also sits above the entry tier from earlier: the cheapest double-storey rate starts above where entry-level work has already finished.
The storey decision is usually forced by the block, the setbacks or a view worth capturing, long before cost enters it. Price the version your land actually needs, not the one that looks cheaper on paper. A rate is not a total, and a compact double-storey footprint on a narrow block can land differently from a sprawling single-level house on a wide one.
Wet Areas Clustered Versus Scattered, and Standard Spans Versus Long
Wet areas – rooms with plumbed water and drainage: bathrooms, ensuites, laundries and the kitchen, behave differently depending on where they sit on the plan. Clustered back to back or stacked floor to floor, they share one short run of pipework, one waste stack and a single zone to waterproof. Scattered to opposite corners for privacy or outlook, every run multiplies, and the falls drainage needs start dictating where the pipework can go.
I look at bathroom and laundry positions before almost anything else on a plan, because this is probably the decision made most often by accident… by-product of where the bedrooms landed. Put the bathroom at one end of the house and the laundry at the other because that’s where they fit, and the plumbing bill has just been set by a choice nobody thought of as a plumbing choice.
And then we have the span…
A span is the clear distance a floor or roof member crosses without support. Push it out – a wide open-plan living area, a big opening onto a deck, a garage door with a room above it — and whatever carries it gets deeper and heavier, while whatever sits below must grow stronger. Internal walls that line up floor to floor give the structure somewhere to land instead – free to draw at sketch stage, costly to add later.
Every one of these decisions is eventually tested against a country’s own building code, which sets the minimum standard any design has to meet. In Australia, for example, that’s , and a designer is working to it from the first sketch, whether or not the client ever reads it themselves.
The One Test to Run Before You Pay for Drawings
Before you pay anyone to turn a sketch into drawings, run one test on it. Trace the outside wall line with your finger and notice how much of it there is for the floor area it encloses. Mark every tap and drain on the plan and see how far apart they sit. Then check which walls, if any, line up directly above one another. A sketch where any of those three answers surprises you is worth changing now, while it still costs nothing to change.
None of this replaces a designer, and none of it replaces a properly priced quote. What it does is decide what you brief them to draw. Work through these five early design decisions before that first meeting, and the quote that comes back will describe the house you actually meant to build, not the one your sketch chose for you by accident.
Frequently Asked Questions
1. How early should I start thinking about construction costs?
Ideally, before you commission detailed plans. Decisions about the size, shape, number of storeys, structural spans, plumbing layout and finish level can substantially affect the eventual build cost. At the sketch stage these things are relatively easy to change. Once engineering, documentation and approvals are underway, redesigning can become expensive.
2. Is building a simple rectangular house really cheaper?
Usually, all else being equal. A simple footprint generally requires less external wall, fewer foundations, fewer roof junctions and less complicated flashing and weatherproofing than a house of the same floor area with numerous wings, corners and projections. That doesn’t mean every house should be a rectangle, but complicated shapes should ideally provide a worthwhile benefit in return for their additional cost. ()
3. Is a two-storey house always more expensive than a single-storey house?
No. A two-storey home introduces additional costs such as stairs, suspended floors, taller structural elements and more difficult construction access. However, it can also substantially reduce the size of the foundations and roof required for the same total floor area. Site size, slope, setbacks and local construction costs can therefore make either option more economical. ()
4. How much money can I save by putting bathrooms, the kitchen and laundry close together?
There isn’t a reliable universal dollar figure because plumbing and labour costs vary enormously by location and project. However, grouping wet areas can reduce pipe runs, drainage runs, penetrations and the complexity of installation. In a two-storey home, stacking bathrooms or other wet areas above one another can provide similar efficiencies. The important principle is to consider plumbing while developing the floor plan rather than after it has effectively been locked in. ()
5. What should I give my designer or architect to help keep the project within budget?
Give them more than a total budget figure. Explain your desired finish level, which features are essential, where you’re prepared to compromise and which architectural features matter enough to justify additional expense. Ask them specifically to consider footprint complexity, structural spans, storey configuration and wet-area locations during concept design. A clear cost-conscious brief gives the designer a much better chance of producing a house you can actually afford to build. ()
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