The guide
Step
24
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Construction drawings

Selections and specifications

Tapware, tiles, floors, joinery, finishes, appliances. A lot of choices, and much better made now than on site.

This is the stage where the house starts to have a feel. Two terms come at you early, so here's prime cost vs provisional sum, explained plainly. A prime cost item is an allowance for something you haven't chosen yet; a provisional sum is an allowance for work that can't be priced exactly yet.

Every selection you haven't made becomes one of those allowances in the builder's contract. An allowance gets adjusted when the real cost is known, and it's adjusted upward more often than down — so a quote full of allowances is a quote that hasn't been finished.

Choosing now turns an estimate into a price you can hold someone to — and it means you get to choose properly, with time, against the design, from a field already narrowed to things that will work.

An allowance isn't a price. Choosing now is how an estimate becomes a number you can actually hold someone to.

Why decisions made now cost less than decisions made on site

The practical case

Every unmade selection becomes a prime cost item or a provisional sum — an allowance that gets adjusted later, almost always upward. Choosing now turns an estimate into a price the builder can work from.

What it does for you

The enjoyable part, done properly. There are a lot of choices here and they arrive close together — so you make them in batches, in an order that makes sense, from a field I've already narrowed to things that will work.

Choosing as you go, and choosing before you start

Without an architect

Selections can be left to the builder, and on the low-consequence items that's a reasonable call. What you'd be carrying is the coherence — hundreds of small choices made separately read as unrelated decisions rather than one house.

With an architect

Selections take more hours than anyone expects, mine as well as yours, so I'll tell you plainly at the outset what guidance sits inside the stage fee and what sits outside it — better that than either of us discovering the boundary halfway through, standing in a tile shop. What I won't do is hand you a supplier list and wish you luck. We work through it in batches, longest lead times first, with the palette and the logic already set so each choice narrows the next one rather than reopening it. It's genuinely one of my favourite parts of a project.

What people ask about prime cost and provisional sums

What's the difference between a prime cost item and a provisional sum?

A prime cost item is an allowance for a thing you haven't chosen yet — tapware, tiles, appliances. The supply cost is estimated and adjusted once you choose. A provisional sum is an allowance for work that can't be priced exactly yet — underpinning, unknown ground conditions, repairs behind a wall nobody has opened. In both cases the contract sets out how the difference is settled.

What happens if I go over the prime cost allowance?

You pay the difference, and under most standard contracts the builder adds their margin to it as well. Worth knowing what that margin is before you sign — and worth asking the reverse: if you come in under an allowance, do you get the full saving back. I'll walk you through both, and it's worth a conversation with your solicitor too.

How do I know if the allowances in my quote are realistic?

That's a question to put to me rather than one to carry yourself. I'll take the largest allowances and test them against what the products you're likely to choose actually cost here in Brisbane. A quote with realistic allowances can look dearer than one that's quietly optimistic, and be cheaper by the end.

How many decisions are there in a renovation?

Hundreds, genuinely. Tapware, basins, baths, tiles and their layout and grout colour, floor finishes, skirtings, door and window hardware, paint colours, joinery layouts, handles, benchtops, splashbacks, lighting positions and fittings, power point locations, appliances, cladding, roofing, gutters, the letterbox. Made one at a time they contradict each other. Made in batches, against rules we set at the start, they hold together.

Can I just let the builder choose?

On the low-consequence items, yes — nobody needs to agonise over a gutter bracket, and a good builder will make a sensible call. The ones worth your attention are the things you touch every day and the things that are expensive to change later: tapware, tiles, floors, joinery, the light in the rooms you use at night.

How to get through the selections without stalling

  • Start a folder of rooms and finishes you're drawn to.
  • Tell me which items you care about most and which you'd rather delegate.
  • Batch your showroom visits together rather than spreading them out.
  • Ask me for the list of long-lead items.
Still at the start?

If you would rather start small, the First Sketch Session is two hours at your place. You keep the sketches, and there is no obligation afterwards.