#1 Why the choice of the right wood is essential
26 February 2018| News| Andrea Wuestman
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 the most important details when you want a summerhouse to last as long as possible. From material choice to final assembly, we’ll be covering everything. So by following our posts you can become an expert on wooden summerhouses too!
With a summerhouse, you create a cosy and inviting environment in every garden. It makes a lovely place to relax or create memorable moments with family and friends. You get the most benefit when the summerhouse is made of wood. Because of the warm appearance of wood, this creates a relaxing place which can easily be integrated in every garden.
Of course it would be nice if a summerhouse could last for eternity. However, everyone knows wood will eventually start to decay when exposed to rain and moisture.
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’d 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 of whether hardwood or softwood is the best option. Hardwood has a big advantage: it’s durable and lasts a long time, but it’s quite expensive and difficult to process.
For this reason, softwood is more suitable for building a summerhouse. It is easier to process, and you get 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. This is why spruce is more suitable than pine.
Spruce – what are the most important factors?
Not all spruce is equal. The quality of the chosen wood affects whether it is really suitable for building a summerhouse. We advise you to pay attention to the following characteristics:
- Small distance between the growth rings: the spruce should ideally be from northern countries. Because of the cold climate the trees grow slowly there. This makes the growth rings closer together, so the wood is more stable and durable.
- Kiln drying: Wood works. With warm weather, the wood shrinks, while in wet weather, wood expands. For example, a wooden plank 15 cm in length can shrink 5 mm. So it is recommended that wood used as material for a summerhouse should be kiln dried to approximately 12-16% moisture content. This limits the working of the wood. In addition, kiln dried wood is more stable.
- Thickness: When you want to build a summerhouse which lasts for eternity, it’s essential not to skimp on the wall thickness. For smaller summerhouses with a wall length from four to five metres, 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 stability, because the roof has to be able to carry more weight, for example when snow has fallen. Wall thicknesses of less than 28 mm are not ideal for a summerhouse which has to last for years.
- Tongue and groove: It’s important to pay attention to the type of log cabin system. This should be a tongue and groove connection system. With a log cabin interlocked system with tongue and groove, you get a very stable wall construction. In addition, the corner connections will be wind and waterproof.
Preventing moisture: You choose foundation beams
Every summerhouse is as strong and durable as its most vulnerable part. This is the point at which 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 that water gets into the wood deeply and encourages mould and rot. That’s why it is important to stop moisture as much as possible.
One option for doing this is by using plastic foil. This protects the building against water.
But a better solution exists: You choose foundation beams!
What is a foundation beam?
A foundation beam is located underneath the building and forms the base of the construction. The walls and doors are placed on the foundation beam. In this way, the walls of the summerhouse aren’t placed directly on the foundation. With this system, you should pay attention to two aspects:
- Treatment: The foundation beam can be produced from Norway spruce. It’s important that this has received the right treatment, so water can’t cause any damage. Pressure treatment is a suitable solution, because this protects the wood optimally so that it can survive any weather conditions for a long time.
- Position: The foundation beam should not be placed directly underneath the walls, but a little inside. If you look at the summerhouse from the outside, the walls will overlap a little and the foundation beams will be slightly inside. In this way, not only is moisture prevented from entering, the foundation beam also makes sure the water flows away to the outside.
Why is it so important that the water flows away?
For a summerhouse it’s 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, which 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 set slightly inside, the rainwater will fall off the walls a few centimetres above the ground. This makes the walls dry faster, so the water can’t cause any damage. When the walls and foundation beams are placed in a single line, the rainwater would be unable to drip 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 cause damage to 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.
The final details: The right treatment
The final step to a summerhouse which lasts for years is the choice of the right treatment. The building can be given a pressure treatment, including the foundation beams. As an alternative, the summerhouse can be pre-treated with a sprayed impregnation and later the (outside) walls can be stained the colour of your preference. This also protects your summerhouse against the weather and you can enjoy your summerhouse for years to come. On our website, you can read more about the advantages of the various paint treatments.
Wood is a natural material which works. So the wooden planks of a summerhouse will expand and shrink. This means it’s wise to use as few screws as possible during the installation of a summerhouse. This prevents cracks from appearing between the wall planks in warm weather. Next week we will explain how a summerhouse can be installed without screws and why this doesn’t have a negative effect on the stability of the building.
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