Painting the inside walls of a summerhouse or log cabin can protect the timber and also transform the interior design. Let’s take a look at the different wood treatments available and where they should be used.
Taking delivery of a new summerhouse or log cabin is an exciting day, and one of the first tasks on any new owners mind is getting the building painted. The biggest concern with any garden room is the exterior timber, which needs treating for weather resistance and protection from dampness. We recommend treating a new building as soon as possible to provide maximum protection and longevity.
Painting the interior is also an important step, but most of the information online is focused on exterior wood treatment. It’s true that painting the interior is less about protecting the wood and more about improving the design, but it’s still a big decision to get the end result of a stylish and contemporary garden building.
The type of wood treatment to use for interior walls will depend on the structure of the wood and whether there is any separation between the interior and exterior wood. Painting can be carried out by yourself and easily be completed over a weekend. When it comes to garden paints, it’s always worth paying a little extra for a high-quality product. The increased weather protection provided will reduce the maintenance required in the long term.
Why paint the inside of a summerhouse or log cabin
It is possible to leave a summerhouse or log cabin untreated inside. The result can be natural timber on display and a somewhat authentic cabin feel. But with most summerhouses, we find it feels closer to sitting in a shed and so always recommend interior paint.
Colour can make a big difference inside a garden building and bring the interior to life. With summerhouses increasingly being used as an extension to our homes, creating a bright and homely environment is important. Take a garden office, a lighter design creates a welcoming atmosphere to spend hours working from every day. We painted our garden workshop white to create a contemporary design that feels spacious and matches wonderfully with a white desk and light grey flooring.
Interior paint also provides protection for the wood. Where UV shines through windows, the exposed woodwork can appear grey over time. The treatment provides a seal to protect wood against moisture and water. Timber is like a sponge that likes to reach the same moisture content as the surrounding air. Unfortunately for us, wood expands when it absorbs more water and constant expansion & contraction of wood can lead to a building that does not fit together as well. Sealing the wood with a treatment reduces any potential moisture absorption. The wood is also easier to wipe clean from any spillages.
Which paint to use inside a summerhouse:
Making the correct choice of interior paint for a summerhouse is going to depend on the type of structure and whether it has been sealed and insulated.
For summerhouses where the interior and exterior wall are made from the same single piece of wood, we recommend using outdoor garden building paint. This could be the same paint used on the exterior or another colour. Most pre-built summerhouses will fall into this category if you have not carried out any additional work such as insulation.
We recommend exterior paint as the wood is still effectively exposed to the outdoors and could experience moisture working its way through during the winter. Exterior paint provides increased weather resistance and protection from damp, mould and fungal growth.
If you are on a tight budget, most exterior shed paints are going to offer more than adequate protection for the interior of a summerhouse. While we would advise an expensive wood treatment from OSMO or Protek on the exterior, Cuprinol garden shades make an excellent choice for interior walls. A huge choice of colours are available and the paint is easy to apply, with several coats recommended.
What if my summerhouse is insulated?
A fully insulated summerhouse gives the flexibility to use pretty much any paint on the interior. Be sure to check the insulation also contains a vapour barrier to prevent moisture from working through the exterior wood. If PIR insulation boards have been used, the foil coating and insulation tape around the edges works as an effective vapour barrier. With insulation roll, a vapour barrier is inserted inside the wall to provide the same functionality.
An insulated and vapour sealed wall can be treated the same as an interior wall inside your home. Any paint can be used which best suits the interior design. Depending on the use, you may choose to use tougher paint for extra protection. Eggshell paints offer a good level of protection, whilst leaving a low sheen modern finish. Exterior garden paints still make a good choice as they can be easily painted onto wood and offer increased water resistance.
When boarding the interior wall of a summerhouse, a number of different woods make a great option. Plywood is our favourite and offers a tough surface that can also be used for mounting stuff to the wall. Further options include tongue & groove and OSB.
Can I use emulsion inside a summerhouse?
If the summerhouse is fully insulated and sealed from moisture, emulsion paint can be used. Depending on the type of wood boarding the interior, a primer will usually be required first. When wood is painted for the first time, it will absorb a lot of the moisture and the paint will not go very far. Primer soaks into the wood to quench its thirst and provide good bonding for applying emulsion on top.
We painted our garden workshop using white emulsion and the results are fantastic. The building is insulated & sealed, and several years later we have not experienced any flaking or mould on the paintwork. For the skirting boards, we used satin paint to provide a hardwearing coat of protection against knocks and pumps.
Which paint to use inside a log cabin:
Most log cabin interiors are not insulated, which makes for a smaller selection of paints to choose from. Whereas summerhouses maintain heat from insulation, log cabins thick timber logs lock in warmth to reduce heat loss. As the other side of the log is exposed to the exterior, the interior walls should be treated with exterior paint for the best results. Only if the log cabin walls are also insulated can we use interior paint.
Any exterior garden building paint will provide plenty of protection for the interior. A wood preserver treatment is recommended first to protect the timber from mould and damp. For best results, start by painting the logs at the top and work downwards. Log cabins are known to expand and contract with differing moisture contents throughout the year. Applying wood treatment to both the interior and exterior will make it difficult for the building to take on moisture and reduce the amount of movement.
Best results on insulated walls: A 4-step process
Achieving perfect results requires extra time and effort, but results in a superior finish that won’t need any maintenance for at least several years. We followed a four-step process and our interior walls still look freshly painted several years later.
Protect against knots. New young wood, including timber, can be full of sap. Over time the sap leaks out and can mark paintwork. This is particularly noticeable if painting with a dark colour that feels warm to the touch if the sun is shining on it. During the warmer months, the sap is going to come out of the wood and through the paintwork. Applying a knot blocking treatment will seal the sap in place and reduce any marks on the wood later on.
Fill in any imperfections. Most pieces of wood are not perfect and will contain a number of imperfections such as cracks, knots and marks. There may also be gaps where wooden panels are joined together to create interior walls. Wood seal and caulk can be used to smooth out any imperfections and create a smooth surface ready for painting.
Priming the wood. Primer and undercoat play an important role in achieving a great finish. New wood is extremely thirsty and will very quickly absorb the first few layers of treatment. Primer will quench the woods thirst and create an adhesive layer for the topcoat of paint to bond onto easily.
Tip: When Plywood is painted for the first time, this causes the grain to rise as moisture is absorbed. After the primer is applied, gently sand the wood to smooth it back out before applying a topcoat.
Apply the topcoat. We can now easily apply the topcoat of our chosen paint to the interior wood. Start from the top and work downwards, following the grain of the wood. Applying several coats with a roller will create the best appearance.
Best results on exposed walls:
Treating exposed summerhouse or log cabin interior walls is similar to treating the external walls and we can even use the exact same products.
Start with a basecoat treatment such as a clear wood preserver. This important step is applied to new timber to protect against rot, damp and insect attack. We like Cuprinol Clear Wood Preserver as a good value treatment that provides long-lasting protection. All exposed timber can be treated with a clear wood preserver. As the basecoat does not contain any wax or water repellent it is not visible once dried and is also suitable for windows and doors.
After our base coat has been applied, we can apply high-quality wood paint. While you could use a wood stain, we prefer to paint for a more homely feel in the interior of a summerhouse or log cabin. The paint is best applied from the top downwards, following the grain of the wood. Once dried, the result should be a smooth finish that also offers great weather resistance.
The choice of paint inside a summerhouse or log cabin is largely going to depend on the structure of the building. For fully insulated and sealed summerhouses, interior walls are protected from moisture by a vapour barrier behind the interior boarding. So we have a much wider choice of paints to use. For buildings such as log cabins where the same piece of wood is exposed to the interior and exterior, an external garden building paint is recommended to protect the wood.
When treating any garden building, the exterior is where we recommend investing to protect the exposed wood from weather conditions. We used emulsion paint inside our garden workshop to create a welcoming and contemporary feel.