Know what a building will cost while you can still change it

The decisions that set a building's cost are made early: the program, the unit mix, the number of stories, the structure and the skin, the parking. The first real number usually arrives after those decisions are made, and it often arrives as a single figure with the reasoning left out.

Preconomics is being built for the owners, developers and architects making those early calls. The aim: describe the project you have in mind, before there are drawings or alongside the first ones, and get a cost range you can reason with. That means what it is likely to cost, how wide the range is, and what is driving the width.

What it is built to give you

• A range, not a point. Every line and the project total carry a low, a likely and a high. The range is wide at concept and narrows as the design and the assumptions behind it firm up.
• Every assumption written down. Where the program or the drawings do not say, the estimate states what it assumed, such as a finish level, a parking ratio or an HVAC system. You will be able to change any of them and see what moves.
• What to settle next. The biggest, least certain lines come first, so you know which question is worth answering before the next design meeting.
• A trail behind every number. Each figure traces back to its quantity, its unit cost, where that cost came from, and the assumptions it depends on. When a number changes between versions, you will be able to see why.

How the numbers are made

Each line uses the most precise information available for it, and records which it used:

1. a bid or quote for this project;
2. local historical cost from completed projects;
3. published unit costs adjusted for location;
4. industry rules of thumb;
5. a share of project cost for a similar building.

We are adding one more, between the first two: a short opinion from a trade contractor on this project's scope (see For subcontractors).

At concept most lines sit low on that list, and the range says so. As information comes in, lines move up it and the range tightens.

Software reads drawings, drafts assumptions and writes the narrative. It does not produce the numbers. Every dollar figure comes from quantity times unit cost, calculated by ordinary code against cost data that people own and can inspect.

Starting before there are drawings

We are building a short set of program questions that will be enough for a first range: building type, unit count and mix, stories and construction type, parking, quality tier, region, and anything already decided. Questions you leave open become stated assumptions rather than silent ones. When drawings arrive, what they show will replace what was assumed, and each new version will be compared line by line with the last.

Where it stands

Preconomics is in pilot, starting with multifamily in Wisconsin. If you are an owner, developer or architect with a project at concept or schematic design, get in touch. If you are a trade contractor, see For subcontractors.