Insulating a shed or summer house: possibilities, tips and costs

Thomas Bott

Insulation is very important in modern buildings. Depending on its purpose, the same applies to a shed or summer house. However, the requirements and procedure are somewhat different. In general, you can carry out the work yourself. You will find the necessary information here.

View of a small summer house in the garden during the fall.
© Getty Images / Timefreezer

In this article

Insulating a shed or summer house: why it makes sense

Whether or not you need insulation for your shed or summer house depends primarily on its purpose. If you simply want to store equipment and tools in it, in most cases you can save yourself the work. However, if you want to use it as additional living space, insulation is absolutely vital. This is especially true if you also have a heating system installed. Thanks to insulation, the heat generated can be kept inside the room instead of escaping outside.

In addition, cold and heat won’t penetrate the shed or summer house as quickly. Another advantage is that thermal insulation helps against the moisture contained in air, which can otherwise settle in warm rooms, preferably in the coldest places. This often occurs on walls in uninsulated houses – especially in the winter. The difference in temperature causes condensation, which can quickly lead to mold.

A person is sitting in a shed or summer house working on an iMac.

If you want to use your shed or summer house as additional living space or, as is the case here, as an office, special regulations must be observed.

Building permit: an issue for your shed or summer house too

If you are planning to build a new shed or summer house, or want to change the use of an existing outbuilding, you must clarify the permit situation with the relevant building authority. In many Swiss cantons, individual regulations apply. If you fail to observe them, you risk having your shed or summer house demolished. You should also find out about any regulations regarding insulation and heating of the building. This is also true of fire protection, for instance.

Insulation: from the floor to the roof

Insulating a building with thermal insulation is most effective when it is as complete as possible. More specifically, this means that you should take action in four key areas:

  • the floor
  • the roof
  • the walls
  • the doors and windows

The following section explains what needs to be considered and which materials are suitable.

Floor insulation: protecting against the cold from below

When insulating a shed or summer house, you should work from the ground up. Even if the building is not placed directly on the ground, but on a concrete foundation, a lot of cold can come up through the floor.

This is especially the case in the cold season when there is frost on the ground. There are foundation beams under the floor of a wooden shed or summer house. These beams sit on the concrete. If you want to insulate the floor, you should place the insulation material between the beams. Mineral wool such as rock or glass wool is particularly suitable for this purpose. Panels made of polystyrene (Styropor) or a similar insulating material are a possible alternative. Environmentally friendly options include insulation materials made of pressed wood wool, hemp fibers or straw.

These insulation tiles should not be placed directly on the concrete floor. Narrow wooden beams that are a few centimeters high will raise them off the ground. To avoid thermal bridges, seal the joints between the insulation boards with silicone. It is advisable to place a so-called vapor barrier above the tiles. This special film prevents moist indoor air from being drawn into the insulation materials and stops condensation from collecting between the room and the exterior wall. Both can lead to the formation of mold. The actual insulation comes next. Ideally, a second vapor barrier should be placed on top of this layer of insulation, with the floor you will actually walk on above.

View of unfinished floor insulation. The vapor barrier and some of the insulation material have already been installed.

Nobody wants to have cold feet, even in a shed or summer house. That’s why you should insulate the floor well.

Roof insulation: catch rising heat

The next step is to insulate the roof of the shed or summer house. The insulation method is similar to that of a residential building. More precisely, rafter-to-rafter insulation is usually the best choice. The insulation material is placed between the rafters which support the outer roof construction. To do this, first apply a vapor barrier to the entire inner roof surface. Now position the insulation material, ideally rock or glass wool, between the rafters. Finally, attach another vapor barrier and clad the construction.

If you prefer to maintain the natural wood look inside, exterior insulation can also be an option. In this case, first line the rafters or the existing roof with a vapor barrier, then mount the insulation on top. Polystyrene or polyurethane panels are particularly good insulating materials. They are followed by a further vapor barrier and counter battens. These are the wooden slats on which you can attach tiles or wooden boards to form the external roof.

Wall insulation: insulating the largest area of all

In principle, there are two ways to insulate walls: insulation of the outer wall and insulation of the inner wall. To insulate an inner wall, proceed as you would to fit insulation between the rafters of a roof. In other words, install a vapor barrier and line the areas between the wooden strips with insulating material. Mineral wool is extremely suitable here too. Add another vapor barrier to enclose the insulation, and finally cover the whole structure.

External insulation, on the other hand, is similar to rafter-mounted insulation on a roof. The different layers are thevapor barrier, insulation material in the form of panels, second vapor barrier, counter battens and final cladding. If you want to optimize your wall insulation, simply use both types of insulation at the same time.

A small shed or summer house under construction. Preparations are being made for insulation. A vapor barrier is being installed before the actual insulation.

It is particularly easy to insulate walls during construction work, although this can also be done later on.

Doors and windows: good insulation is important here too

Complete insulation is of no use unless the doors and windows are well insulated. Otherwise they represent a weak point where heat can still escape. You should therefore opt for double-glazed windows. This allows less heat to escape through the glass. The frames of doors and windows are just as much of a problem. You should seal them well with foam sealing tape or rubber so that drafts are no longer able to get through.

There is a specific point to watch out for when insulating doors. Depending on the fitting, drafts can enter the room from underneath. You can prevent this by installing a brush seal. Another alternative is a bottom seal that can be lowered. However, this type of system is usually slightly more expensive than a simple brush seal.

Costs: here’s how much thorough insulation costs

You will have to pay a lot of money if you want to insulate your shed or summer house. The actual cost depends on the individual case. We provide a rough estimate per square meter of surface or component below. The costs for work, plaster, paint and accessories are already included.

  • Insulation
  • Costs
  • Floor insulation
  • around 60 francs per m²
  • Roof insulation
  • around 120 francs per m²
  • Wall insulation
  • around 70 francs per m²
  • Insulation for windows and doors
  • around 30 francs per unit

Conclusion: complete insulation pays off

If you want to use your shed or summer house as additional living space, good insulation is always worthwhile. Even without heating, this will make it much more pleasant inside, partly because moisture cannot penetrate so easily. However, if you have a heating system as well, you will save money in the long run, even counting the cost of insulation. After all, you will need to heat the building much less to maintain a nice warm temperature inside.

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