Insulation of a camper and cottage

What is the purpose of isolation?

Insulation serves three important functions:

• thermal insulation,
• vapor barrier,
• acoustic insulation.

The most important aspect when designing a campervan or motorhome is proper vapor barrier. It is responsible for preventing water from condensing on metal elements and thus preventing corrosion. Thermal insulation is also important because it prevents our car from heating up in the summer and loses heat more slowly on cold days. Acoustic insulation, commonly known as sound insulation or dampening, is most important during the ride itself, as it significantly reduces air noise and sounds coming from the road, thereby positively affecting driving comfort.

First of all, you should think about insulation at the very beginning, when we are just starting to work with the car and have already completely disassembled it. Access to each place is necessary to prevent the formation of so-called “cold bridges” - uninsulated places through which a lot of heat escapes.

The next stage is thorough cleaning and degreasing of the surface. Bitmat materials intended for automotive insulation are in most cases self-adhesive, and in order for them to serve us for many years, it is necessary to provide them with sufficient adhesion. Building materials most often do not have a self-adhesive layer, which additionally requires the use of adhesives, which often emit harmful fumes for many months after application.

You should also choose the right materials, preferably meeting automotive standards, to avoid unpleasant situations such as peeling, unpleasant odors or lack of water resistance. Some people still try to use building materials, but what works for buildings often doesn't work for vehicles and doesn't live up to expectations. Wrong materials can lead to subsequent problems and, of course, reduced efficiency. Some try to use cheap non-crosslinked polyethylene, which, firstly, has significantly lower efficiency and durability compared to rubber-based products, and secondly, is most often equipped with metallized foil, which from the outside can look like real aluminum. outside, but ultimately does not provide adequate thermal insulation.

The last step before proceeding further is to collect all the necessary accessories. We will need, among other things: sharp knives and a butyl mat roller. Having prepared this set of accessories, you can begin installing the insulation.

Based on Bitmat's many years of experience, 2mm thick butyl mat and 3mm thick polystyrene foam with an aluminum layer should be used for the floor. We then create a wooden frame (called a truss) and fill it with, for example, polystyrene foam/XPS foam or PIR boards. We start the assembly with butyl rubber with aluminum (called butylmate), which is a good insulator of low-frequency sounds and vibrations, and will also protect the floor from water accumulation and act as sound insulation and a noise barrier. We need to cut the rug into appropriate pieces, glue it to the floor, and then roll it out with a roller.

As the next layer we recommend self-adhesive aluminum foam Bitmat K3s ALU with a thickness of 3 mm. It is worth noting that this product has a layer of real aluminum, while competitors' products often have metallized plastic foil, which significantly affects the quality of thermal insulation. Foam joints must be sealed with self-adhesive aluminum tape to eliminate cold bridges.

We lay wooden scaffolding (trusses) on the prepared layer, on which we lay a material, for example, XPS Styrodur - it will provide rigidity and complete the entire insulation. When the floor is ready, we can start working on the walls of our car.

Wall insulation is the most individual element, because it all depends on how many kilograms we have at our disposal to fit into the permissible total weight of the car, including passengers and luggage. With smaller vehicles we have more room to maneuver and can afford to cover entire walls with butyl matting. However, in the case of larger vehicles, it is usually necessary to discard the extra weight and cover the surfaces with smaller pieces of butyl mat (25x50 cm or 50x50 cm sections).

We cut the aluminum-butyl mat into smaller pieces and glue them onto large, flat surfaces of sheet metal so that they fill the space by 40-50%. This is intended to reduce vibration in the sheet metal, stiffen it and provide a good initial insulating layer.

The next layer is thermal insulating self-adhesive foam rubber without aluminum. Between the spans (reinforcement) we lay foam plastic with a thickness of 19 mm and higher to densely fill the spaces. The foam is elastic and allows it to precisely take the shape of sheets and reliefs, which will have a positive effect on the thermal insulation of the camper.

After gluing the aluminum-free foam, you should tightly seal the gaps with 3 mm thick aluminum foam, which we have already used on the floor - K3s ALU. We glue 3 mm thick foam plastic to the entire wall, covering the previous layers and the reinforcement of the structure, and seal the foam joints with aluminum tape. This protects against heat loss; aluminum has the properties to reflect thermal radiation, and also acts as a barrier against water vapor and its condensation on metal elements. Closed profiles (reinforcements) should not be filled with polyurethane foam or similar materials, since their role is to remove moisture from the bottom of the profiles. Profiles should be protected with anti-corrosion agents based on beeswax.

Don't forget about spaces like doors. We recommend covering the inner door leaf with butyl mat, tightly sealing the technological holes with it, and sticking 6 mm thick foam rubber on the inside of the plastic upholstery. Doors - side, rear and front - have many holes and, if they are not taken into account when insulating the camper, they negatively affect the final result of our work.

We finish the roof in the same way as the walls - we apply a butyl mat to 50-70% of the surface between the spans, fill this space with K19s foam and cover it all with K3s ALU foam, gluing the joints with aluminum tape. 

Cabin insulation is important primarily for driving acoustics reasons, but it also keeps the vehicle insulated. The following body elements need to be insulated: floor, headliner, wheel arches, doors and, optionally, partition. In general, we treat the interior the same way as we treat the sound insulation of any other car. Here we will mainly use two materials - butyl mat and polystyrene foam. We glue a butyl mat on all surfaces, roll it out, and then cover everything with 6 mm thick foam.

Many people are rightfully concerned about the weight of their car when reading about these many layers, especially since the word "rubber" is usually associated with something quite heavy. Fortunately, if you take a closer look at the problem, it turns out that with complete isolation, weight gain is not that great. As an example, let's look at the weight of sound insulation for the popular size L2H2 (for example, the popular Fiat Ducato or Ford Transit), insulated with Bitmat products in accordance with the recommendations above.

Living space:

• butyl mat 2 mm (12 m2) – 39,6 kg
• foam rubber 19 mm (19 m2) – 22,8 kg
• Aluminum foam rubber 3 mm thick (26 m2) – 9,6 kg.

Driver's cabin: 

• butyl mat 2 mm (6 m2) – 19,8 kg
• foam rubber 6 mm (5 m2) – 2,25 kg

In total, this gives us approximately 70 kilograms for the living space (i.e. the same as a gas tank or an adult passenger) and 22 kilograms for the cabin, which in general is not such a big result if you take into account the fact that we We provide ourselves with very good thermal insulation and noise protection during travel at a very high level.

If you have any doubts, want to make sure or choose materials individually, Bitmat technical consultants are at your service. Just call 507 465 105 or write to [e-mail].

We also recommend that you visit the website www.bitmat.pl, where you will find insulating materials, as well as a tips section where you will find many useful tips.