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Before you can start using DIY spray foam insulation kits, there are several things that need to be taken into consideration and planned for. A safely and correctly applied foam job requires a bit more than just spraying foam onto wall cavities.

Prepare the Area to Be Insulated

The Surface

how-to-spray-foamMake sure that the areas that are being sprayed are clean or wiped down properly and dry. There should be no water, dirt or debris on the surface you’re spraying, or you will not get a good seal.

Before starting, make sure that all electric boxes or other connections are covered and tied up in plastic bags. Foam can expand and enter sensitive areas if they are not properly sealed away. Wiring, pipes, and other fixtures can be sprayed over, but anything you need to work on later shouldn’t be covered. Cutting into the foam later will ruin the seal and reduce its effectiveness.

Watch the Temperature

The temperature of the surface you are spraying also needs to be checked, and preferably the temperature of the room you are spraying in. Adhesion and the expansion of the foam are reduced by low temperatures.

Try to keep your chemical temperature between 75-85 degrees F and your surface/room temperature between 80-100 degrees F. Using a ColorWise™ Temperature Warning Nozzle will help ensure that you are spraying foam at the optimal temperature every time.

Safety First!

Always wear the appropriate safety gear when using spray foam. Eye protection, proper respiration gear, and protective clothing should always be used when spraying foam. Make sure to only use in a well-ventilated area.

Setting up the Kit

Putting the Kit Together

There are different types of spray foam kits available, and they all have their own set of instructions. Make sure that you read and follow the instructions included with whichever kit you have purchased and make sure you read all safety information before using.

Some kits will have hoses already attached to the cylinders of chemical, others will require that you put these on yourself. Some have the gun already attached to the hoses, so require that you set this up yourself.

For the Handi-Foam 205 E-84 Kit, the set up runs something like this:

  • Shake cylinders well before use.
  • Open both valves completely.
  • Use petroleum jelly to lubricate the open nozzle of the gun.
  • Attach nozzle as per kit instructions.
  • Spray a test shot into a disposable container to ensure mixing is correct.

Nozzle Usage and Testing

Testing your nozzle ensures that the foam is flowing properly and mixing as required. Once your test shot cures, you should be able to rip a piece out and see that the inside is properly set and dry. The outside of the foam should be solid and not tacky.

If you stop spraying for longer than 30 seconds you must replace your nozzle. Not replacing the nozzle can lead to kit damage and accidents. Keep the trigger safely on when not spraying, as this will keep the gun from discharging when not in use.


How to Spray

Once your kit has been set up and tested, you are ready to spray. Most kits do not require you to pull the trigger completely open, and this allows for more control over the spray volume you use. Spraying close to your surface will cover a smaller area with more foam, while spraying further away from your surface will cover more of an area with less foam. Using a combination of nozzles (Fan or Cone shaped) will also give you a different spray spread.

Try and cover your surface area with as few passes as possible, as spraying onto wet foam can become messy and create an inconsistent surface. If you need to spray more than one layer, wait until your first layer of foam has cured.

What to Cover

You can cover just about anything in foam, as long as you’re not planning on accessing it regularly. Handi-Foam should not harm your wiring, piping, or plastics, and covering as much area as possible will ensure a good seal.

How Much Foam to Apply

You may not necessarily have to fill in whole wall cavities, but it is best to check on what standards are required before starting your job. Obviously, the more foam that is used will increase how effective a barrier you create, but always check the building codes for your area in regards to vapor barrier requirements.


When you have finished your spraying, you can scrape away any cured foam that has covered the front of your wall studs. Doing so shouldn’t compromise your seal and it will make putting on any finishing materials a lot easier.

Storage and Re-Use

Properly Storing your Leftover Spray Foam

If you find that you have foam left over, you can store and reuse your tanks. If you intend on doing this, there are a few things you need to make sure you do.

  • Turn off the valves and leave the used nozzle on the gun, with the safety on.
  • Never unhook your hoses.
  • Every three days, replace the nozzle and spray a small amount of foam.
  • Use the foam within 30 days of first spray.

How to Reuse your Foam

Before using your foam again, make sure you that remove the used nozzle before removing the trigger safety. Open up both valves and make sure the face of the gun is clean and clear of any debris and apply jelly, just as you did the first time you used the kit. The kit can now be used again but make sure you stop using it when the foam starts to sputter and not spray correctly.

Using the kit when the foam is starting to run out will mean that you are spraying foam that has not been mixed correctly and results will not be optimal.


Always make sure that you dispose of your tanks according to the federal, state, and local regulations in your area. Your local waste disposal service should be able to help you if you do not already know these. Never incinerate tanks.

Your kit comes with instructions on how to unhook your hoses and vent your tanks after use. Make sure you are wearing your protective clothing as contents will still be under pressure.