How Complete Do Your Drawings Need to Be Before You Bid?

Two bids on an early drawing set aren't really prices. They're two builders' guesses about a house that hasn't been fully decided yet, with a number on each.

That's not a knock on early bids. Sometimes you want one. But the completeness of the drawings sets a ceiling on how firm any bid can be. A builder can only price what's drawn and written down, and everything else turns into an allowance or an assumption. Knowing what each stage of drawings actually shows tells you how much of a bid is price and how much is placeholder.

The design phases, in plain terms

Most architects work through three phases. The names vary a little, but the idea is the same.

Schematic design. The basic layout: rooms, rough sizes, how the house sits on the site, the general shape and look. Floor plans and a few elevations. Very little about how it's built or what it's finished with.

Design development. The house gets more specific. Window sizes and locations, wall and roof assemblies, a first pass at structure, ceiling heights, more detailed elevations. Systems start to show up, though often only as notes.

Construction documents. The set the house gets permitted and built from. Dimensions, details, sections, structural drawings, schedules for doors and windows, and ideally a finish schedule. This is the set a builder can price most firmly.

What a builder can price at each stage

Here's roughly how the split between firm price and placeholder shifts as drawings fill in. Treat this as a way of thinking, not a rule.

Stage	Priced from the drawings	Usually allowance or assumption
Schematic	Overall size and shape, rough foundation and framing	Structure, windows, systems, nearly every finish
Design development	Framing, roof, window package, much of the exterior	Mechanical, electrical, plumbing, interior finishes
Construction documents	Most of the shell and structure, doors and windows, drawn details	Whatever the set still leaves open, often finishes and fixtures

Notice that even a finished construction set can leave finishes open. Some sets say outright that fixtures and finishes are shown for location only. When that's the case, every finish in the house lives in an allowance, no matter how complete the rest of the set is. More on that in When your drawings are core and shell only.

The pieces people forget

A drawing set can look complete and still be missing things that move the price.

Structural drawings. Foundations, beams, posts, and connections from the engineer. Without them, a builder is guessing at steel and engineered lumber. A house with a big window wall or long open spans can carry real money here.

Mechanical, electrical, and plumbing design. On many custom homes these are designed by the trade subcontractors rather than drawn in the set. That's normal. It also means the heating, ventilation, and plumbing numbers in a bid are the sub's idea of your system, not yours.

A finish schedule. What tile, what flooring, what trim, what cabinets. If it doesn't exist, the bid's allowances are carrying all of it. See the gap between what you picture and what was priced.

A civil or site plan. Grading, drainage, driveway, utilities, retaining walls. On a sloped lot this is where surprises live, and a set without one leaves the builder to assume.

When bidding early still makes sense

Early pricing isn't a mistake. It's just a different tool.

A budget check at schematic design can tell you whether the house you're drawing fits the money you have, before you've paid for two more phases of design. That's worth a lot. See Check the budget at every design phase.

Early pricing is also how you pick a builder to bring on during design, if you go that route. In that case the number is less important than how the builder thinks about your house. See Bid or negotiate?

What doesn't make sense is treating a bid on schematic drawings as a firm price and signing a fixed price contract on it. That's a contract where most of the number is placeholders. See Fixed price, GMP, or cost plus.

Reading a bid from an incomplete set

If the drawings aren't finished, a good bid says so. It names the set and date it priced from, lists the assumptions it made, and puts dollar amounts on the allowances that cover the gaps. That's honest, and it's useful, because it shows you exactly which numbers are going to move as the drawings fill in.

A bid that doesn't say what it assumed is harder to use. You can't tell whether the window package is priced from a schedule or a guess. Ask.

Questions worth asking

• Which drawing set and date is this priced from?
• What did you have to assume because the drawings didn't show it?
• Which numbers in this bid will change most as the drawings are finished?
• Are structural, mechanical, and site costs priced from drawings, or from allowances and assumptions?
• What would you need from us to turn the biggest allowances into firm prices?