A garage is often the coldest part of the house. If you only park the car in it, that hardly matters. But if you use it as a workshop, hobby room, utility room or storage for things that do not like damp, it is a different story. Insulating a garage gives you a dry, pleasant space you can use all year round. In this article you will read which parts to tackle first, which materials work well and where things often go wrong in practice.
An uninsulated garage gets very cold in winter. Warm, moist air then settles on the cold walls and roof. The result is condensation, mould and rust on your tools. Insulation keeps the inside of the walls warmer, so most of that condensation disappears.
If the garage adjoins your home, you will notice the difference indoors too. The wall between the garage and the living room, or the floor of a bedroom above it, will be less cold. And if you want to do more with the space later, for example converting the garage into living space, good insulation is the first step anyway.
Most heat escapes through the roof and the walls. With a flat roof, it is best to insulate on the outside when the roofing is renewed. If that is not possible, an insulated ceiling on the inside also works. With a pitched roof, you insulate between or under the rafters.
If you only insulate the walls and leave the roof cold, the problem often moves to the ceiling, where the moisture then condenses. So ideally tackle the whole shell in one go, or make a phased plan that starts with the roof.
For the walls, a timber batten frame against the existing brickwork is the familiar approach. Mineral wool goes between the battens, a vapour barrier over it and finally boarding. This creates an insulated lining wall that you can finish, paint or have plastered.
Insulation without a proper vapour barrier can do more harm than good. Moist air then travels through the gaps in the insulation and condenses against the cold wall. You will not see it until the wool is wet or the boards start to go mouldy. That is why the membrane always belongs on the warm side, on the inside of the insulation.
It is important that the membrane is fitted airtight. Tape the overlaps with the matching tape, also around sockets and pipes, and connect it properly to the floor and ceiling.
A well insulated wall does not help much if there is a thin steel up-and-over door in it. That door is often the biggest leak. An insulated sectional door or a door with insulated panels makes a big difference. If you no longer use the garage for the car, the door can also make way for a wall with a window or door frame.
The floor is usually a concrete slab on sand. You can insulate it by laying insulation boards on top with a new screed. That does cost height, which you need to allow for at the doors. Read more about the options in insulating a floor.
In 2024 we insulated a garage in the Zwolle region with exactly this build-up. A timber batten frame went against the brick wall, with mineral wool in between. We then fitted a Taftex vapour barrier and finished with lining walls. In the garage insulation project you can see the steps in pictures.
Would you like to know whether your garage can be done the same way? Shahiro is happy to come and take a look. Send a WhatsApp message with a few photos or request a tailored quotation. If you are unsure about the budget and possible grants, also read about the ISDE grant for insulation.
Always tape the seams of the vapour barrier before the boards go on. Afterwards you can no longer reach them, and that is exactly where damp develops later.
For the walls, mineral wool between timber battens is a proven choice, combined with a vapour barrier. For a flat roof, insulation boards on the outside are often the most effective. What suits best depends on the construction and how you use the garage.
Insulating on the inside usually does not require a permit. If you change the outside, such as the facade or the garage door facing the street, that may be different. Check with your municipality or via the Omgevingsloket.
That depends on the situation. The ISDE scheme of the RVO focuses on insulating the home itself. A detached garage usually falls outside it. Always check the current conditions on rvo.nl.
For the walls of an average garage it is often a matter of a few working days. If the roof, floor or a new door are added, it takes longer. After a visit you receive a clear schedule.
Call or WhatsApp Shahiro with your question, or send a few photos. Where needed we come and take a look, free of charge.
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