Insulation

Insulation: Combating damp

Wooden frames can be insulated in a variety of ways, the most common of which are foil-faced foam panels or glass/mineral wool, which are sometimes used with aluminum foil.

• All these systems prevent moisture from penetrating. They must be protected from moisture and involve the installation of vapour barriers. They also depend on the structure's cavities to function properly or to remain dry.

What works very well in a sterile environment can become a real challenge in the real world when it comes to ensuring the longevity of these layers and membranes.

Construction sites are dirty, windy and rainy environments, far from having the cleanliness of a laboratory test site. Timber frames, insulation materials and even prefabricated panels all get wet on a building site.

• So it's essential to use a method that dries wood framing quickly. Although wood fiber can absorb water, it dries quickly. Once dry, it will continue to absorb moisture from the studs until both materials reach a low, comparable moisture level.

Easy insulation cutting

When insulating between the studs, it's essential to be able to cut the insulation quickly and easily, so that it fits perfectly into the wood framing and the inner surface of the framing, whether OSB or membrane.

Wool, fiberglass, mineral, natural and synthetic fibers are the best insulators between studs because of their compressibility. You can cut them slightly larger than the gap you're filling, squash them between the studs, and they'll press firmly against the edges of the space, preventing heat from escaping.

• Rigid foam panels are very difficult to install effectively between wood studs. Because of their rigidity, it's quite difficult to cut a single piece precisely to fit between the studs, resulting in air holes.

According to a Belgian study, a 3 mm gap between the inner panel and the insulation panel results in 150% more heat loss than estimated, while a 10 mm gap results in 400% more heat loss. That's why these types of insulation are becoming increasingly common on the top of rafters and on the outside of timber frames.