How to Measure a Spray Foam Job Site Like a Pro

Bidding a Spray Foam Job, Part 1: How to Measure a Spray Foam Job Site Like a Pro

Each spray foamer comes into the spray foam business in a different way.

Despite our differences, however, our introductions to the foam industry have one thing in common:

We started at the beginning.

It may be shocking that none of us was born knowing how to clean a spray foam gun or operate a spray foam machine…

But it’s true! 

In fact, every single spray foam contractor you’ve ever met – even the one with all that experience and money – had to learn how to spray foam.

They had to start at the beginning, too.

One step at a time, they worked to get to where they are – and we truly believe you can find success in this business, too, as long as you stick to it!

Some things in this business we learn with time and practice…

Like knowing it’s a good idea to mix open-cell B-side before spraying it, but it’s a decidedly terrible idea to mix closed-cell B-side ever

But some skills are useful to learn before others…

Like learning how to bid a spray foam job efficiently.

To calculate a spray foam job bid, you only need to know two things: 1) the material costs of the job and 2) your labor costs.

With those two pieces of information, you can use our go-to formula for calculating a spray foam bid:

Job Bid = (Material Costs x 2) + Labor Costs

This formula makes calculating a job bid look simple – and it is! – but without some insider knowledge, taking the on-site measurements necessary for calculating material costs can be intimidating.

Without help, it’s difficult to find your way in this business…but you’re not alone on your spray foam journey!

Central Urethane is here to help you navigate the ins and outs of spraying foam – including teaching you how to bid a spray foam job like the pro that you are.

Let’s learn how to take quick job-site measurements so you can approach bidding jobs without fear!

How to Take Quick Building Measurements

The goal when measuring at a spray foam job site is to obtain the total spraying area (in square feet) so you can calculate the material costs of the job. 

You will need the substrate’s square footage to calculate the job’s board footage, which you’ll use to estimate the job’s material costs.

1 Board Foot = 1 Square Foot x 1” of Foam Thickness

Foam thickness comes either from your customer or building regulations. When bidding a job, therefore, the only things you’re doing on-site are getting measurements of the structure and calculating the spraying area. 

This measuring process does not need to cause undue stress. You don’t need to climb a ladder or take more than a couple of actual measurements.  

In fact, the entire measurement process should only take a few minutes!


Well, most jobs you will spray are constructed in a series of rectangles – wall cavities, the underside of a roof, etc. – and knowing that, you can use geometry to make your life much easier when trying to put a bid together. 

To find the area of a rectangle, multiply its width by its height

In practice, this means that all you really need from a job site are ~4 measurements – two for the walls (width and height) and two for the roof deck or underside of the roof (width and height).

There are a few rules of thumb for getting these measurements quickly, all of which are based on building science and common sense.

Because lop-sided houses are only acceptable when they are constructed for Willy Wonka.

Since most people aren’t Willy Wonka, in most cases, measurements in a house will be uniform.

And that makes your life a LOT easier!

Okay – let’s start with learning how to measure walls easily.

Measuring Walls

Height Measurement

The height measurement of a home is often the simplest measurement you’ll take, since it is typically uniform throughout.

To find the height of the building, therefore, measure the height of a wall in feet, and you can likely use that single measurement for every room of the house.

Simple, right!?

Next, you need to find the width/length measurement of the house.

Width Measurement

To find the width/length measurement of a house, you typically only need to know the distance between studs.

Fun fact: most houses use a stud width of 16” (~1.33’).

(Unsure of the stud width? Measure it once, in feet, and then you can still follow the procedure outlined below, using the appropriate number of feet for your job.)

Knowing this, all you need to do to find a width/length measurement of a house is count the number of wall cavities (or spaces between the studs) that you will spray in the house and multiply that number by 1.33 ft

Easy peasy!

Important tip: Since you want your area calculation to be in square feet, ensure you use stud width measured in feet and a wall height measurement in feet, not in inches. 

Once you’ve gotten the height and width measurements for the spray foam job, multiply the height measurement (in feet) by the width measurement (in feet) to find the spray area (in square feet) for the spray foam job.

Great work! And you didn’t need to climb a ladder!

Next, it’s time to estimate the roof measurements.

Measuring the Roof Deck

Intimidated by measuring the roof deck for your spray foam job bid? Don’t fret! You don’t need to climb a ladder to estimate the area of the roof you’re going to spray. You can get all the measurements you need from the ground!

Here’s how.

Height Measurement

The height of the roof deck can be estimated by counting the seams of plywood it is made of. 

A standard piece of roof deck plywood is 8 ft x 4 ft.

With this information, you can multiply the number of seams you see on one side of the roof deck (from the top of the wall to the roof ridge) by the appropriate number of feet, and you have your height estimate!

No ladder necessary.

Now, for the roof width!

Width Measurement

Here’s the critical bit of information when estimating roof deck width:

Homes are typically built using 2’ rafters.

Knowing that, you can simply count the rafters you see (including the ends) and multiply that number by 2 feet to get the estimated length/width of the roof deck.

Quick and simple. Pretty great, right!?

To find the area of the roof deck, multiply its height by its width. This will give you the square footage of one side of the roof. Double the number to find the measurement for the whole roof.

Feeling overwhelmed by all of this measuring? Don’t fret!

Remember: a job bid is an estimate. (That’s why we have you double your material costs in your bid!) It doesn’t need to be perfect, just accurate enough that you won’t overcharge your customers or sacrifice your profit for the work you complete.

With the techniques described above, you can be confident that your measurements are accurate enough to serve you and your customers effectively.


Central Urethane is here to help you succeed in your spray foam contracting business – because when you win, we all win!

If you need reliable, consistent foam material that has fantastic coverage for your money, check out our X-PRESS Seal products!

And if you have any questions about bidding a spray foam job or how our foam material can help you succeed in your business, feel free to call or text us at 260-205-8882!

We’d love to help you in any way we can!

Next time, we’ll discuss using your on-site measurements to calculate material costs for a spray foam job.

Until then, we wish you the best!

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