Most people know that insulating their house is both environmentally responsible and cost effective, but many still don’t think to apply this to their garage. An integral garage that adjoins the house is often effectively the largest single “interior” space. It shares interior walls and possibly also ceilings and can thus undermine the rest of your household insulation if it’s not playing its part.

The reasons for insulating a garage are little different to those that apply to insulating the main house. It helps maintain a warm, dry atmosphere and a stable temperature all year round. Insulating the garage doors also specifically increases security quite considerably, adds additional soundproofing and helps keep out dust, vermin, leaves and rain.

Also, some people actually use their garages as more than a point of access to the house. But even if you’re not thinking of using the garage for say a gym or a workshop, it’s common to find refrigerators, washing machines and such, and there may also be water pipes to protect.

Essentially, any insulation is only as good as its weakest point. There’s no point, for example, fitting double glazed windows then neglecting to insulate the void above the ceiling, or indeed vice versa. Wherever there is a weak spot then warm and cold air will leak through, bypass all the other defenses and rendering them next to useless.

So to summarize thus far, effective insulation saves money, is environmentally friendly and helps keep your home at a comfortable temperature. But insulation is only effective if it is applied across the board, and for many folk their integral garage represents a sizable chink in their insulation armor.

So how do you insulate a garage properly?

The typical modern garage has features in common with a typical modern house, such as a floor (which is typically concrete), walls and a roof space (or ceiling void, depending on what’s above). It also has something somewhat unique – a huge great door (or several).

Insulating the floor, ceiling and walls is a little different to the procedure adopted in the main dwelling areas. For example, walls can have standard insulation batts inserted in the cavity (access permitting), or fiber glass blown in, or if necessary simply affixing foam board to the interior.

Where the garage doors are concerned, things can get a little more specialized. There are two obvious weak spots: the gaps around the panel and the door panel itself. The gaps are not that difficult – a simple bubble seal fitted to the bottom of the door panel and weather strips on the sides will make a huge difference. But the garage door insulation itself depends on what it’s made of.

Metal door panels are a fairly thin skin of (usually) steel and provide just about zero insulation (metal is instead a very effective conductor of heat). However being both light in weight and essentially “hollow” (there is a front and sides but no back) it is very easy to fit very good insulating panels in the void on the inside of the door.

Solid wooden garage door panels have much superior natural insulating properties but still not close to what’s really needed. Unfortunately, unless you buy modern insulated wooden garage doors (which cleverly conceal internal insulation) your options with solid door panels are limited to applying reflective foil.