Troubleshooting Spray Foam Insulation Issues

Troubleshooting Spray Foam Insulation Issues

We all hope for the best.

All spray foam contractors like to think that no issues will arise while spraying foam on the job.

We all hope that our hose heat will always perform at optimal levels, our foam barrels will never run out, and the foam we spray will always be beautiful.

But some days.

Some days will be much more interesting than perfect.

And those days? Those days will require innovation and persistence.

Many things can (and might) go wrong while you’re spraying foam.

Let’s explore the causes of common spray foam issues together!


Spraying good foam starts before ever setting foot on the job site.

Good spray foam starts with clean, well-maintained equipment and proper spray foam storage.

We recommend that you clean your spray foam gun after every use.

Every. Single. One.

We know that might sound over-the-top, considering a spray foam gun is not the simplest thing to take apart and reassemble every night - that’s why we created the BOSS Shot!

With our BOSS Shot, you can quickly clean your spray foam gun without taking it completely apart after every day on the job.  

We know. It’s a dream come true.

There is nothing worse than getting everything warmed up and ready to spray and immediately getting a clog in your gun because you forgot to clean it. And there’s no need for that headache!

Get your BOSS Shot here, and start your day off right!

Your spray foam gun is an essential piece of equipment, but it is far from the ONLY piece of spray foam equipment that needs maintaining!

Regularly check your spray gun, spray hose, pressure gauges, hose heat, and preheaters to ensure great spray foam and equipment performance on the job.

Another vital factor in spraying beautiful foam is storing your materials properly.

Outside is not a good place for foam storage.

Closed-cell foam, in particular, needs to be in a climate-controlled environment to make sure that the chemicals remain in solution.

Storing foam at temperatures above ~80° F risks chemical separation and can cause bulging in foam barrels. For more specific temperature tolerance information, refer to your foam’s product data-sheet.

If you find your barrels have bulged due to heat exposure, use caution when opening them! Spray foam that has been exposed to heat in this manner may no longer be sprayable.  

To avoid loss of product, store your foam materials in a climate-controlled environment.

As explained in our 5 Tips & Tricks for Spraying Better Foam Insulation blog, we recommend flushing your A-side lines before spraying each day, no matter what type of foam you are spraying. 

If you are spraying open-cell foam, we also recommend making a habit of mixing the B-side of your foam before you begin your day on the job. Stirring the open-cell B-side with an air-driven stir tool for ~10 minutes each morning will create better foam.  

Do not stir closed-cell B-side, however. Agitation will increase the loss of blowing agents in closed-cell foam, so skip this step for closed-cell insulation jobs.

One more thing. 

Always know where your trusty 5/16” nut driver is while on a spray foam job!

We named our 5/16” nut driver George. Yes, he is important enough to have a name! (Feel free, name yours after ours. George would be honored.)

For more tips on preparing your equipment, check out our 5 Tips & Tricks for Spraying Better Foam Insulation blog post!

Let’s dig into the common issues we see on the job.


When you see good spray foam, you know it’s good spray foam. There’s no doubt.

Good spray foam insulation sprays on as a light yellowish tan color in a nice, continuous, round pattern. It sprays on smoothly and foams up well.

Pay attention to the color and expansion you see on the substrate as you spray.

If you see a significant change in spray foam color or expansion, STOP SPRAYING IMMEDIATELY.

Stopping immediately when you notice an issue with your spray foam can be the difference between fixing the issue quickly and needing a whole day to solve the problem you ignored.

As much as we would like them to, spray foam insulation issues do not fix themselves.

BOSS spray foam machines are awesome - but they are still manually operated.

They require a human to work.  

A human who is paying attention and stops spraying when they notice an issue with their foam!

After you’ve stopped, it’s time to diagnose the problem! Put on your doctor hat, and take a step back.

What was it about your spray foam that made you stop, exactly?

The likeliest issues are caused by either pressure or temperature imbalances.

Pressure imbalances tend to create changes in spray foam color and texture. Temperature imbalances drastically affect spray foam adherence and expansion. 

Let’s explore the options together. 


Pressure differentials of greater than 500 psi between the A- and B-sides of spray foam indicate either a supply or discharge problem with the system.

Think of the pressure gauges on your BOSS spray foam machine as guides.  

If a gauge reads low, there might be an issue with the supply on that side.  

On the other hand, a plug on the high-reading side would cause a backup of material, an increase in the pressure on that side of the system, and, therefore, a high reading on the pressure gauge.

A low B-side pressure reading with a high A-side reading indicates either a supply issue on the B-side or a plug on the A-Side.

A low A-side reading and a high B-side reading indicates either a problem with the A-side supply or a plug on the B-side.

Use the foam you have sprayed to help you diagnose your spray foam issue. What color is the foam spraying? What does its texture look like?


Often, color is the first suggestion that something is amiss with your spray foam.

Brown foam suggests problems with the B-side of your foam.  

The amber color of the A-side will deepen the color of the foam you spray when there is too much (or only) A-side in the mixture. If you find that your foam is spraying brown, check the B-side supply.  

Full barrel and clean B-side wye screen? It might be time to clean your spray foam gun.

A white or abnormally light-colored foam suggests issues with your A-side.  

B-side is a light color and will dull or neutralize the amber color of the A-side if the A-side is not spraying correctly. Check the A-side supply and clean your spray foam gun if necessary. Make sure to use George - your 5/16” nut driver - to close the fluid valves in your hose before removing your spray foam gun for cleaning!

Another way to determine what is wrong with your spray foam is by analyzing its texture.


Abnormal texture is also indicative of spray foam issues.

If the foam does not set up, staying as a sticky, light-colored mass on the wall, B-side is dominating the foam mixture in your gun and suggests a problem with your A-side.

A crackly texture - similar to pork rinds - on the wall indicates a mixture dominated by A-side. This texture suggests there is something wrong with the B-side of your spray foam.

After noticing an issue with your foam, stopping, and diagnosing the problem as an A-side or B-side issue, it’s time to investigate whether the problem lies with the material supply or a plug in the lines or spray gun.


If your spray foam gun is clean and you know you have flushed the A-Side of your materials, as we suggest in the 5 Tips & Tricks for Spraying Better Foam Insulation blog post, the pressure imbalance you have diagnosed is likely caused by a supply issue.

Your pressure imbalance can be caused by something as simple as your material running out. Just need to move your barrel pump to a new barrel. Well, that’s an easy fix! Phew!

Did you forget to turn your barrel pump on? This is especially noticeable when there is already a pressure differentiation indicated on your BOSS Proportioner’s pressure gauges before you even put your spray gun on your spray hose. Again, easy fix. Woot!

If your barrels are full, check the wye screen on the correct material side of your BOSS spray foam machine. This mesh screen can get plugged up and cause a pressure imbalance in the system.

Is your supply looking good? Your spray foam issue might lie in the spray foam gun.


Everything looks good on the supply end of the system, but you still have a pressure imbalance?

There is likely a plug in your spray foam gun.

We know - it’s annoying!

But it’s time to whip out George, your handy-dandy 5/16” nut driver, turn off foam supply valves, and get to cleaning.  

You should be back up and running in no time - especially if you use our BOSS Shot to clean your spray foam gun!  

Are your pressure gauges reading perfectly? If your spray foam color and texture seem right, but something is off with the expansion, you might have a problem with the temperature of your foam or substrate.


Temperature imbalances can often be identified by abnormal foam expansion. 

Heat management is a crucial ingredient in optimal foam performance.


If your foam expands too quickly, over-expands, or shrinks and peels away from the substrate after setting, your foam is too hot.

Separation of the normally round, continuous spray pattern into strips on the substrate or a stream of finger-like tendrils from your spray foam gun also indicates that your foam is too hot.


Check your hose heat and preheat if any of these issues occur. 

Simply lower the temperature of the system if, as expected, everything reads too hot.

Ensure that your spray hose’s TSU-wire is snuggled into place if your hose heat readings seem incorrect.  

For more information about hose heat troubleshooting, check out our 2-part blog post on the subject! Find Part 1 here and Part 2 here.


If your foam is expanding too slowly or not enough, and the foam seems otherwise well-balanced, the substrate or foam is probably too cold.

Increase preheat and hose heat, and ensure that the substrate is warm enough before continuing.

You can read about proper heat management in Part 1 and Part 2 of our hose heat troubleshooting blog.


We know how difficult it is to troubleshoot spray foam issues on your own - but you don’t have to!

Spray Foam Equipment & Manufacturing is here for you.

Everything we do is to put the power back into your capable, spray-foam-contracting hands!

Reach out to us with any questions you may have regarding your spray foam insulation performance. We will be happy to help you!

Until we meet again, SPRAY ON!

- The Team at BOSS

Leave a comment

  • Please note, comments must be approved before they are published

$1 Days
$2 Hours
$3 Minutes
$4 Seconds
\nSchedule Sales Consult\n","column_width":"automatic"},"menus":[]},{"id":"tmenu-menu-202114","setting":{"item_layout":"maps","title":"Maps","map_center":"51.507194, -0.083065","map_zoom":"12","map_height":"350","map_iframe":"
"},"menus":[]}],"hide_submenu":false}],"orientation":"horizontal","navigator_selector":"#AccessibleNav","mobile_navigator_selector":"#cdz-mobile-nav .cdz-menu","menu_background":"#e27125","root_color":"#FFFFFF"},"status":1,"created_at":"2024-01-31 15:57:46","updated_at":"2024-04-12 13:57:35"}; _SM.subscription = {"name":"tmenu-premium","kind":"subscription"}; _SM.translation = {};