How is thermal insulation of roofs made?
Thermal insulation of roofs is an important part of a building’s energy efficiency and comfort: it keeps heat from escaping in winter and keeps the interior cooler in summer. Making good roof insulation means choosing suitable materials, preparing properly and installing everything carefully, including a vapor barrier.
1. Common insulation materials
The most common materials used for roof insulation are:
- Mineral wool (stone wool or glass wool): The most common insulation material. It is easy to install, offers good thermal insulation and fire safety, and can be fitted either between the roof structures or directly below the roof.
- Polyurethane foam or boards: A very effective insulator. Foam can be sprayed directly under the roof, where it forms a tight layer that prevents heat loss well, though it is usually a more expensive option.
- Cellulose insulation (e.g. Ekovilla): An ecological alternative made from recycled paper fiber. It offers good insulation and can be installed in the same way as mineral wool.
2. Preparations
Before starting, make the necessary preparations:
- Check the roof: inspect its condition and repair any leaks or damage first.
- Gather materials and tools: insulation material, vapor barrier, tape and fixings, plus a tape measure, knife, hammer and nails.
- Wear protective equipment: goggles, gloves and a respirator, especially when handling old insulation that may contain harmful substances.
3. Installing the insulation
- Cut the insulation to size so that it fits snugly between the roof structures and fills the space evenly, with no gaps.
- Fasten the insulation firmly in place, to the structures and to adjoining pieces.
- Seal the seams and joints carefully so that ventilation works correctly and moisture does not accumulate in the insulation.
- Install a vapor barrier on the warm side of the insulation: cut it to size, attach it to the roof structures with tape and staples, and make sure it is airtight with no holes or gaps. The vapor barrier keeps moisture out of the insulation and protects the structure from moisture damage.
- Finish the job by checking that everything is firmly in place, adding an extra layer of insulation if needed, and covering the insulation with a protective material such as plasterboard.
4. When to hire a professional
Making roof insulation requires skill and the right tools. If you are not confident in your own skills, or if the roof structure, ventilation or vapor barrier detailing is unclear, it is worth hiring a professional to do the installation.
