#1 Why the choice of the right wood is essential

26 February 2018| News|

Once a week we give important tips about building a summerhouse in our new series: “What makes a quality summerhouse”. Our architects and wood professionals explain which details are important when you want a summerhouse to last as long as possible. From material choice to final assembly, everything will be dealt with. In this way, you can become an expert on wooden summerhouses yourself!

With a summerhouse you create a cosy and inviting environment in every garden. It is a lovely place to relax or have fun moments with family and friends. The real wellness ambiance arises when the summerhouse is made of wood. Because of the warm appearance of wood, a relaxing place arises which can be easily integrated in every garden.

Naturally, a summerhouse is meant to last for eternity. However, everyone knows wood will eventually start to decay when exposed to rain and moist.

But: With the right wood choice, nothing stands in the way of a durable summerhouse!

What details should you pay attention to when choosing the right kind of wood? We would love to explain this to you, so you can pick a summerhouse which will still look as good as new after several years.

Hardwood, softwood, pine or spruce?

The first step when choosing wood is the question whether hardwood or softwood is the best option. Hardwood has a big advantage: it is durable and lasts long, but it is quite expensive and difficult to process.

For this reason, softwood is more suitable for building a summerhouse. It is easier to process, and one will have an accurate result. Spruce is often chosen as material for a summerhouse. In general, spruce and pine are suitable as materials. The difference is that pine has bigger knots than spruce. Wood is a natural product, which means the knots will shrink during the drying process. Big knots increase the chance of cracks arising, which makes it possible for water to leak inside. That is why spruce is more suitable than pine.

Spruce – pay attention to what?

Spruce is not spruce. It depends on the quality of the chosen wood whether it is really suitable for building a summerhouse. We advise you to pay attention to the following matters:

  1. Small distance between the growth rings: It is ideal when the spruce is from the northern countries. Because of the cold climate the trees grow slowly there. This makes the growth rings be closer together, which makes the wood more stable and durable.
  2. Kiln drying: Wood works. With warm weather, the wood shrinks and when it is rainy, wood expands. A wooden plank of e.g. 15 cm in length can shrink 5 mm. Therefore, it is recommended for wood which is used as material for a summerhouse to be kiln dried to approximately 12-16% moisture content. This limits the working of the wood. Besides that, kiln dried wood is more stable.
  3. Thickness: When one wants to build a summerhouse which lasts for eternity, it is essential to not save money on the wall thickness. For smaller summerhouses with a wall length from four to five meters, a wall thickness of 28 mm is sufficient. For summerhouses with larger dimensions we advise a wall thickness of at least 44 mm. This is very important for the stability, because the roof has to be able to carry more weight, for example when snow has fallen on it. Wall thicknesses of less than 28 mm are not ideal for a summerhouse which has to last for years.
  4. Spring and groove: It is important to pay attention to the type of log cabin system. This should be a spring and groove connection system. With a log cabin interlocked system with spring and groove you will get a very stable wall construction. In addition, the corner connections will be wind- and waterproof.

Stop moist: You choose foundation beams

Every summerhouse is as strong and durable as its most vulnerable part. In this case, this is the place where the walls will be standing on the foundation. When it rains for a long time, the foundation will be wet for a long time. This means water gets into the wood deeply and encourages mould and rotting wood. That is why it is important to stop moist as much as possible.

An option to stop the moist is by using a plastic foil. This protects the house against water.

But a better solution exists: You choose foundation beams!

What is a foundation beam?

A foundation beam is located underneath the house and is the base of the construction. The walls and doors are placed on the foundation beam. In this way, the walls of the summerhouse are not placed directly on the foundation. With this system, you should pay attention to two matters:

  • Treatment: The foundation beam can be produced from Norway spruce. It is important that it has received the right treatment, so water cannot cause any damage. Pressure treatment is a suitable solution, because this treatment protects the wood optimally and the wood will be able to survive all weather conditions for a long time.
  • Position: The foundation beam should not be placed directly underneath the walls, but a bit more inside. If one looks at the summerhouse from the outside, the walls will fall a bit over and the foundation beams are a bit to the inside. In this way, not only moist is stopped, but the foundation beam also makes sure the water flows away via the outside.

Why is it so important the water flows away?

For a summerhouse it is very important where the water flows to. Rain falls down along the walls. When the walls are placed directly on the foundation, the rain water will gather there, and it will create puddles. The lower part of the walls will be standing in the water and the wood will start to decay. If the summerhouse is placed on foundation beams which are a bit to the inside, the rainwater will fall of the walls a few centimetres above the ground. This makes the walls dry faster, so the water cannot cause any damage. When the walls and foundation beams are placed in one line, the rainwater would not fall off. It would reach the lower wall planks via small cracks and the water would get into the wood. This would give the water the opportunity to still damage the lower edge of the summerhouse. On our website you can find even more practical tips about how you can protect your wooden summerhouse against rain and water.

Last details: The right treatment

The last step to a summerhouse which lasts for years is the choice of the right treatment. The house can be treated with a pressure treatment, and the foundation beams can be too. As alternative, the summerhouse can be pre-treated with a sprayed impregnation and later the (outside) walls can be stained in the colour of your preference. This also protects your summerhouse against weather influences and you can enjoy your summerhouse for years to come. At our website you can read more about the advantages of the several paint treatments.


Wood is a natural material which works. The wooden planks of a summerhouse will therefore expand and shrink. For this reason, it is wise to use as few screws as possible during the installation of a summerhouse. This is to prevent cracks from appearing between the wall planks with warm weather. Next week we will explain in our next blog how a summerhouse can be installed without screws and why this does not have a negative effect on the stability of the house.