Your summerhouse or log cabin should create an atmosphere to enjoy and spend time inside. Plenty of ventilation is essential to keeping heat and moisture under control.
To enjoy your garden building for as long as possible, we recommend installing ventilation as part of the construction to ensure the building and contents are protected from the get-go. Moisture content inside your timber garden room can be very different from inside a house. Untreated wood acts like a sponge to absorb moisture on cold and wet days. Left untreated, this can lead to expansion in the logs or cause mould to build up around doors and windows.
For any building, moisture control is an important consideration, which is why you will find an air vent in pretty much every room inside your home. The issue with buying many pre-built summerhouses is that there is no ventilation system fitted as standard. This is due to them being designed for infrequent use throughout the summer months. But if you decide to insulate and use your summerhouse throughout the year as a garden office or gym, ventilation is required.
There are several benefits to ventilating your summerhouse or log cabin at the time of installation. Firstly, it creates a comfortable place to spend time in, particularly as a garden office. Fresh air feeds in throughout the day as you are working, avoiding that stuffy and tiring feeling once you have been working for a few hours. Secondly, the contents of both the building and any items inside are protected. With a wooden building, it’s always a top priority to reduce the chances for rot & damp to take hold. Minimising this by reducing moisture content build-up can keep your interior looking new and protected from the elements.
The best way to ventilate your summerhouse or log cabin will depend on the size and how often the building is being used. Let’s take a look in further detail.
Insulation & heat retention
For use in the colder months, insulation is essential inside a garden room and we have discussed this in detail in previous guides. Good quality insulation helps to keep the temperature inside consistent throughout the changes in weather conditions outside. A warmer interior reduces the opportunity for cold & damp loving mould to grow.
For a summerhouse, any exterior facing walls, as well as the floor and roof should be insulated. In a log cabin, we do not need to worry about insulating the walls but should still insulate the floor and roof, where most of the warm air will escape. Double glazing is also great for stopping condensation building where the single glass windowpane is at a lower temperature than the air inside.
Without adequate insulation throughout the building, condensation and eventually mould is going to build-up where the warmer air from a heater is coming into contact with colder surfaces facing the outside. This is often first noticed around doors and windows where the temperature is coldest. Insulation helps retain heat, reduces running costs and creates a barrier to prevent moisture build-up on cold surfaces.
Choosing the right location
Thinking about ventilation before your log cabin or summerhouse has even been installed can give you an advantage when it comes to maximising the results. Ideally, it should be positioned somewhere to benefit from wind circulating the air. This means leaving at least a metre gap around each side of the building to allow air to flow and move around without any damp building up over time. Here, we are looking to avoid creating space behind the building where rainwater can puddle and find it difficult to escape.
At the same time, the summerhouse or log cabin should not be placed against and trees or other foliage in the garden. Plants are going to remain damp for much longer and be rubbing up against the walls of the building, not allowing it to dry out sufficiently. A concrete base using a dampproof membrane or paving with a water run-off provides the best environment for reducing damp build-up around a summerhouse.
Ensure wood is treated
The most practical step you can take to prevent your garden building from becoming damp over time is to treat the wood correctly. Once your new summerhouse is erected, we recommend applying wood treatment products as soon as possible, before any water has had the chance to get into the woodwork.
The exterior should first be treated with a wood preserver. This protects against rot, mould and insect attack. If insulating the interior, we also recommend treating the wood which will be covered while it is still easy to access. After preserver, high-quality paint should be applied to the exterior. This will provide waterproofing and stop and moisture from making its way into the wood. Many garden building suppliers will require the wood has been treated properly to maintain the warranty.
Passive Ventilation
A passive ventilation system comes in the form of vents installed on walls inside your garden room. The aim is to keep fresh air circulating through the inside while pulling moist air out and creating a comfortable environment. In the summer, ventilation helps to keep the building cool when the sun is shining on it all day. Passive ventilation does not require any electric and is the easiest way to achieve a ventilated garden room.
While one vent will make a difference, using 2 vents is often recommended. Each vent is placed high up on walls at opposite sides of the building. Two openings will allow the air to circulate more freely and create airflow throughout. We recommend wents with a mesh to reduce any bugs or insects trying to get into your summerhouse or log cabin.
Windows & doors
The simplest way to increase ventilation in your garden room is to open the windows and doors. In fact, during the summer most of us will do this and increase ventilation without even thinking about it. Leaving the window open allows air to circulate and provides a constant stream of fresh air coming in. Opening the windows and doors more often can be a quick fix if you start to see signs of damp building up.
The difficulty here is during the winter and overnight, meaning that for most of the time there is no ventilation. If your summerhouse is not being used over the winter, it could be months with no fresh air let into the building. Furthermore, even on warmer days, windows and doors are going to be locked overnight. Opening windows and doors is a quick fix to improve ventilation but should only be used to supplement other permanent solutions.
Active ventilation
Whereas passive ventilation depends on natural air currents, active ventilation uses power to provide a consistent system. Electric fans can be installed on the walls of a garden building to pull fresh air in and moist air out. If you do not have electric in your summerhouse, solar versions are available. Their use is best suited for large ventilation needs including very big summerhouses and putting a sauna inside.
For most log cabins and summerhouses, an electric fan will not be required. If you want an impressive solution, some fans integrate with smart home systems and can be controlled via smart temperature and moisture sensors.
Air source heat pump
Air conditioning systems are a versatile way to heat and cool your summerhouse in any month of the year. An air-source heat pump can provide hot air in the cooler months and cool air in the warmer months. They are an excellent way to maintain a stable and comfortable temperature and control the moisture content in the room.
Air source heat pump systems require professional installation which can be expensive. However, they are very efficient and the running costs can be lower than running an electric heater in the winter. The pump is placed outside and requires space around the building to be installed.
Our verdict
Overall, ventilation is an important consideration if your summerhouse or log cabin is going to be used throughout the year. Taking steps to reduce moisture build-up right from the construction stage will provide the best results and peace of mind. Ensuring adequate rainwater runoff and treating the exterior wood with a high-quality product will keep the outside of the building from absorbing moisture.
A passive vent is ideal to increase airflow in a summerhouse or log cabin. Vents can be easily installed to provide a quick fix to ventilation issues. While electrical systems are available, the cost and complex installation is prohibiting for most of us.
Hi, while the need for ventilation in the roof and building is usually known about by many, what about cavity ventilation? Say a cabin had 4” timbers for the wall, then 2” of ridged insulation between the timbers and 1” over the top covering the timbers. That leaves a 2” cavity in each section. Presumably the cavity will need venting, however it’s unclear if to do this just at the bottom or top or vents top and bottom to give a better airflow. I’d appreciate your thoughts on the matter. Thanks.