Exterior Finishing

How to choose

One of the most important decisions when specifying a garden room is the choice of exterior finish.  Fortunately, we love talking about wood, wood finishes and how to choose the perfect options for your garden room.  

On this page we will try to give you an overview of the choices available.  During your design consultation we will ask:

  • Do you want to maintain the finish or would you prefer a maintenance free solution?
  • Do you plan to paint or oil the building?
  • Do you prefer the natural look of wood that fades to a grey colour over time?
  • Which sides of the building are visible?  Should we choose a lower cost option for the sides you won’t see?
  • Would you prefer horizontal boards rather than the vertical orientation we use as standard?

All our wood is FSC certified, meaning that it is sourced from well-managed sustainable forests.

Scandanavian redwood

Our standard exterior finish is vertical exterior tongue & groove boards made from Scandanavian redwood.  It is fully tanalised under pressure to provide long lasting protection.  It arrives with a green tint from this process that will fade over time to the wood’s natuaral brown colour.  If left untreated the wood will fade to a natural grey colour.  We recommend that redwood is treated with exterior grade wood oils or paint to provide long-term protection.  The Osmo and Sikkens range of oils are our favourites.

Scandanavian redwood is our most cost effective finishing solution and is also the perfect choice if you want to add your own stain or paint finish.

thermowood cladding


Thermowood, also known as heat treated timber, is a beautiful, sustainable timber material produced using chemical-free heat treatment of redwood.

Thermowood has superior resistance to rot and fungi than tanalised redwood.  The heating process breaks down hemicellulose so that the wood doesn’t contain the appropriate nutrients to allow rot and fungi to grow and develop.  This heat treatment significantly increases its life span and is a technique originally discovered by the vikings!

As Thermowood is expected to have a prolonged life, it doesn’t necessarily need a surface treatment applied to it. Some people choose to add a finish, stain or paint to their timber to enrich its colour, but if it’s left untreated, the wood will naturally change to a silvery grey colour.


Larch is a very popular timber exterior choice for its appearance. It provides a beautiful colouring and texture and the shapes and patterns of the growth rings are very aesthetically pleasing.  Larch will often start life as pale yellow/golden brown in colour but weathers to striking silvery grey colours, although treatment and staining can change this.

Sourced from sustainable plantations in northern Europe, the chemical make-up of larch creates a high resistance to decay and rot.  This natural durability means that no treatment of the timber is required and any coatings applied are for aesthetic purposes or to slow the onset of the greying process.  

larch cladding
western red cedar cladding

Western Red Cedar

Western Red Cedar is the ideal natural material for the exterior of garden rooms and outdoor buildings due to the natural preservatives contained within the wood, making it resistant to rot and decay with no additional chemicals or preservatives needed. 

Many consider this to be the most beautiful exterior option available due to the attractive grain and texture of the wood and its warm reddish colouring.  It will fade to an attractive silvery grey over time but this process may be slowed if treated with a UV inhibiting clear oil.

Composite materials

Composite exterior panels are the ideal low maintenance, rot free alternative to traditional timber finishing and siding. It is made using a combination of FSC certified timber and recycled high density polyethylene plastics.  This makes wood plastic composite siding one of the most environmentally friendly building products on the market. 

The material is available with the textured look and feel of real wood and is also available in a wide variety of colours including black and grey colours that can provide a striking look to your garden room.

composite cladding

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