Estimating basics

What is a cost book in construction estimating, and whose prices are in it

A cost book is the list of unit prices an estimate is built from. The question that actually matters is whose unit prices, because the answer decides whether your estimate describes your business or somebody's national average.

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The short answer

A cost book is a structured list of unit prices. One line per thing you install or do, each with a unit, a labor figure and a material figure. Hang and finish drywall, per square foot. Set wall tile, per square foot. Swap a tub for a shower pan, each. An estimate is then quantities multiplied by those lines, totalled, with your overhead and profit applied.

That is the whole mechanic and it has not changed in a century. Walker's Building Estimator's Reference Book is in its thirty third edition doing exactly this. What has changed is where the numbers come from, and that is the part page one skips.

Two different things go by this name

	A published cost book	Your own cost book
Where the numbers come from	Survey data averaged across a region or the country	What you actually paid and how long your crew actually took
Who it describes	A typical contractor who does not exist	Your shop, your subs, your suppliers
How it gets updated	A new edition or a quarterly data release	You, after a job comes in wrong
What it is genuinely good for	Sanity checking, unfamiliar scopes, insurance and claims work	Pricing the work you do every week
Where it hurts you	It averages away the reason you are cheaper or dearer than the next guy	It is only as honest as the last time you updated it

Most estimating software ships with the first kind and calls it a cost database. That is a selling point for somebody starting out and a problem for a shop that already knows its own numbers.

What one line in your own book holds

A unit you can count

Square foot, linear foot, each, or hour. The unit has to be something that falls out of a measurement, or the line is useless on a real job. If you cannot count it off a room, it belongs in overhead and not in the book.

Labor at your crew's actual pace

Not a published productivity figure. How long your tile setter takes on a normal bathroom, loaded with your burden. This is the number that makes your book yours, and it is the one most shops have never written down.

Material at what you pay

Your supplier, your account, your discount, with your waste factor already in it. Published books use list or regional average. The gap between that and your counter price is margin you either keep or give away without noticing.

How a shop builds one

Start with the twenty lines you actually sell

Not four hundred. Most remodeling shops do the same twenty or thirty operations over and over. Write those down with a unit each and leave the rest for later.

Fill them from jobs you have already closed

Your own invoices and timesheets are better data than any survey. Take three finished bathrooms and work backwards to what each line really cost you.

Price one past job with it

Run a job you already know through the book. If the total comes out well under what you charged, your labor lines are optimistic, which is the normal failure.

Correct it when a job comes in wrong

A cost book is maintained, not finished. The discipline is going back after a job that lost money and fixing the line that caused it, which is twenty minutes nobody ever has and everybody should take.

Where a published book still earns its place

This is not an argument that published cost books are useless. They are good at the thing your own book is worst at, which is pricing work you have never done.

Asked to quote something outside your normal run, a reference book gives you a defensible starting figure and a scope checklist you would not have thought of. Insurance and restoration work often requires a recognised source, so the published figure is the one that gets paid. And a new estimator with no history behind him has to start somewhere.

The mistake is staying there. A published figure is a borrowed opinion about an average job. Once you have twenty jobs of your own on the books, your own numbers beat it every time on the work you do all the time.

Use the published book for scopes you do not know
Use your own lines for everything you do weekly
Keep the two separate so you always know which one made the number
Write down the date you last touched a line

Questions contractors ask

Is a cost book the same as a cost database?

In practice yes, and the words get used for both kinds. A cost database usually means a software vendor's preloaded set of regional prices. A cost book can mean that, a printed reference like Walker's, or the list of unit prices you built yourself. It is worth asking which one somebody means before you buy anything.

How many lines do I need to start?

Twenty to thirty covers most remodeling shops, because most of what you sell repeats. A book of four hundred lines you did not build and do not trust is worse than twenty you did.

How often should I update it?

Whenever a job comes in wrong, plus a pass through material prices when your supplier moves them. Calendar reminders do not work for this. A job that lost money does.

Does your software use its own prices or mine?

Yours. We price the scope against your own cost book, line by line, with every quantity traceable back to where it came from. We do not ship a national average and we do not let a model decide your number.

Where do the quantities come from?

From the capture. On a recent iPhone Pro the room is measured with LiDAR, so the quantities come off a sensor. On any other phone it falls back to photographs plus room sizes typed in, which is weaker and gets treated that way.

What does it cost to try?

Two scans free with no card. Solo is 79 dollars a month for one user and 20 scans, Crew is 149 for five users and 60, Shop is 349 for unlimited users and 200. A job your own crew captures on site is not metered on any plan.