How do you spray foam a trailer?

In today’s blog post, we will answer the following question: How do you spray foam a trailer? We will explain what spray foam is and why you may want to use it for your trailer. We will also reveal the pros and cons of spray foaming a trailer. 

How do you spray foam a trailer?

To spray foam a trailer, follow these steps: 

  1. Prepare the trailer:
  • Degrease and dust the area to be spray foamed;
  • Lightly moisten the substrate to improve adhesion.
  1. Apply the spray foam:
  •  Warning: check the packaging first. Before applying some types of spray foam, you should hold the spray bottle upside down.
  • Shake the spray bottle vigorously for 30 seconds and screw the nozzle supplied with it onto the bottle.
  • Now apply the foam in the hole to be sealed over an area of ​​approximately two-thirds of the area to be sealed. This is because spray foam swells as it hardens.
  • For proper operation, be sure to shake the spray bottle regularly.
  • If you are applying multiple coats, it is usually helpful to moisten between coats (see the packaging for this).
  • If you are applying the spray foam to a special substrate (plastic, lacquered steel, etc.), first check whether the adhesion is good.

Please note: above all, do not apply too much spray foam on your trailer, as it can swell enormously, which can have particularly harmful consequences if you, for example, apply the foam as insulation in a cavity wall. The expansive force of the foam causes the wall to be compressed outwardly. If you are using spray foam only for its sticky function, you can commercially look for “low expansion” on the packaging. This type of spray foam swells less.

  1. Remove the excess spray foam:
  • Once hardened, remove excess spray foam immediately. Use a box cutter.
  • If you cannot remove everything, you can buy a special spray foam remover from the store. Apply this product to excess spray foam using a brush. 
  • As soon as the product has worked, you can remove the excess by rubbing it with a dry cloth.

What are the benefits of spray foaming your trailer?

Unlike mineral wools which eventually settle over time, foam insulation is more stable and that is just one of its many benefits.

Exceptional insulating capacitiesInsulating foam owes its performance to its micro air bubbles which prevent the cold from entering the RV. Conversely, these micro air bubbles help keep the heat inside. 
Thus, the insulating foam provides an optimized performance depending on the space to be heated.
100% airtight insulationAs it develops a liquid texture from the beginning, foam insulation can fill even the smallest cracks in a space that makes itself completely airtight. Since all the interstices are sealed, no heat loss is possible.
Environmentally friendly insulationUnlike other insulators, the foam does not contain VOCs or other toxic elements. It is also odourless. In addition, it does not generate microparticles in suspension.
Very resistant insulationAs a foam, this insulation is soft and malleable. Once hardened, it turns into a firm and unbreakable block. In this form, the foam cannot settle. It is also rot-proof. 
A very light insulationInsulating foam is 99% air. It is therefore the lightest solution for insulation. 
Insulation that lets the RV breatheThe spray foam is permeable to water vapour. Thus, there is no need to install a vapour barrier on the RV. The latter will be able to breathe properly.
Easy-to-apply insulationAs has been mentioned several times, foam insulation can go in anywhere. It is the perfect solution for hard to reach places. By eliminating all thermal bridges, the insulating foam guarantees optimal thermal insulation.
An ecological insulationDon’t be fooled by the industrial character of insulating foam. It is completely ecological. Moreover, the products that are offered on the market have received environmental quality labels.

Some rules for spray foaming your trailer

In order to ensure the best result, there are certain rules for good use of the expanding foam in a trailer:

  1. Before spray foaming your trailer:
  • Wear protective goggles to protect yourself from splashing liquid foam.
  • Moisten the surfaces to which the foam will be applied to speed up the chemical reaction and for the foam to harden faster.
  • Check that the temperature is between 10 and 30 ° C.
  • Shake the bomb about twenty times to heat the foam and homogenize it.
  1. During the process of spray foaming your trailer:
  • Place the end of the valve at the entrance to the cavity to be filled.
  • Gently squeeze the valve control tip with the canister upside down.
  • Good to know: multiposition bombs, as their name suggests, can be used in all positions.
  • Fill the cavity halfway, as the foam triples in volume during expansion.
  • Operate in small quantities and add more products as needed later.
  • Important: too large a dose of the product causes too much expansion. This can deform wood and some materials.
  1. After spray foaming a trailer:
  • Allow the foam to spread and seep into inaccessible places.
  • The foam dries on the surface in 15 minutes, but through drying takes about 12 hours, depending on the thickness, temperature and humidity.
  • When the foam is dry, cut off the excess with a cutter.
  • It can be coated or painted for a nice finish.
  • Clean the valve with acetone.

If you are spray foaming a trailer to insulate it from the cold

Most trailer owners use spray foam to prevent water lines or outdoor faucets from freezing in winter. Here’s how you can do it too:

  1. Cut off the top of a plastic bottle.
  2. Insert the bottle on the faucet.
  3. Inject the foam into the bottle to wrap around the faucet.
  4. Protect pipes exposed to cold
  5. Cover the pipes with foam.
  6. Lightly fill each wave.
  7. Let it dry and cut off the excess with a craft knife.

Note: if you want to insulate a window surround (between the frame and the wall) only use the expanding foam if you are sure that the water and airtightness are ensured. The foam is only made to provide additional thermal insulation.

If you are spray foaming a trailer to fix a hole

  1. Plug a pipe passage through a wall by injecting foam into the hole.
  2. Fill in a space between two sections of walls with small touches.
  3. Fill in a hollow under a shower tray in the same way.
  4. Fill the gaps in the electrical ducts using foam instead of plaster. It will fill the cavities and block the ducts.

Final thoughts

Insulating foam is used for the insulation of surfaces that come into contact with the outside, namely: walls, floors, ceilings and the roof. Moreover, the foam itself can be covered with concrete which will serve as a support for the tiling.

Thanks to its consistency, the foam insulation can be applied to wood, plaster, stone and concrete. The application of the foam is done by means of pneumatic and hydraulic machines, which is why only professionals are authorized to carry out this kind of project. The insulating foam is compatible with heated floors.

Spray foam is a material that is often used in construction to seal. It can be useful to fill the beams with this material due to its easy placement. However, it must be taken into account that it is a very porous material and that it can create humidity very easily. 

In addition, unlike rock wool, once inserted between the beams it is very difficult to remove it in case we need it, since it adheres to the floor of the RV, so it is better to avoid it. Although if you want to use it, it can be a good alternative!

Please feel free to share your thoughts and comments on the content. 

FAQ on ​​How do you spray foam a trailer?

Can I spray foam my RV?

Yes, you can spray foam your Rv if the intention is to insulate the underbelly of the vehicle. Spray foam is a common thermal insulator used mainly for floors. The advantage of spray foam is that it is airtight and easy to apply.

How to insulate a trailer floor?

Foam insulation is the most used product for insulating a trailer roof and it is found everywhere on the market.

How to insulate a trailer for winter?

A little extra insulation, such as curtains and rugs, makes you more comfortable in winter. So, take out the thick bedding or invest in an electric blanket, it will help. Park your trailer so that the windows face the sun during the day.

Is spray foam toxic?

Unlike other insulators, the foam does not contain VOCs or other toxic elements. It is also odourless. In addition, it does not generate microparticles in suspension.

Is spray foam easy to apply?

Yes, spray foam is very easy to apply. It is the perfect solution for hard to reach places. By eliminating all thermal bridges, the insulating foam guarantees optimal thermal insulation.