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All About Untreated and Treated Timber with SheShed

At SheShed we supply our cabins in either treated or untreated timber (and sometimes both options) – both of which have strong characteristics of durability and stability as they are made from the versatile Nordic Spruce Wood (See blog: What is Nordic Spruce). This is a denser timber that comes from the same family as pine, fir, and cedar. But what is the difference between untreated and treated timber and how can this affect you when you are buying and maintaining your own SheShed? This all depends on your budget, what you will be using your SheShed for, and what your personal preference is for the finished look and feel of your cabin.

Untreated Timber

Untreated timber has a beautiful finish and reflects the rustic aesthetic of wood straight from nature. It is just as strong as pressure treated timber and is easy to cut, drill and glue. Many people prefer its finish on the inside of sheds and buildings, as its light and natural feel has not been altered by chemical substances. It is also an inexpensive material to use as it has not gone through the treated process. Untreated timber is great in places where it is well protected so that there will be no risk to decay – such as internal walls. However, it can also be used externally, as long as it's finished with at least one coat of good primer and two coats of paint. Click here to learn about our recommendations for painting your SheShed.

Our untreated timber is all kiln dried by 14% - 16% in drying chambers, removing much of the natural moisture and sap, which helps to stop the wood from deforming, and gives it a higher resistance to insects and fungal risks compared to regular untreated timber. The kiln drying process ensures that the timber dries to a point where it reaches an equilibrium moisture content – meaning it can be stable in an indoor environment and will not easily absorb more moisture from the atmosphere. As weather conditions naturally expand and contracts the wood, we make sure that our building systems are developed in a way to make sure that the timber has enough room to contract and expand once your SheShed is built. However, you must thoroughly paint your untreated timber shed so that you get the maximum longevity from your cabin. The painting process ensures that untreated timber is protected and sealed against the weather and remains covered by our manufacturer’s warranty. As a finished product, untreated timber takes stain and paint more easily which makes it a great choice for those who want a smart polish or varnish coated floor on the inside of their SheShed - as the wood will more easily achieve the desired finish that you're after.

Once again, to maintain untreated wood in an outside environment, products such as polyurethane, natural wood treatments, shellac and wax products can all be used to protect the timber from everyday elements, but many of these have a more limited lifespan with more regular maintenance needed, which is why only a 3-coat paint system is required for our 5-year warranty to apply. Once your SheShed is built, the first primer/sealer undercoat will need to be applied to the outside right away as any exposure of water directly on the untreated timber may cause staining, warping, or even damage to the wood itself.   

Tussock Cabin - 8.75m2 (3.5m x 2.5m) - Untreated Wood Painted, Plus Step Added By Customer

Treated Timber

Our treated timber starts with the same kiln drying process as the untreated timber, but it then goes through a computer-controlled pressure treatment process. The premanufactured Nordic spruce timber is placed in a large pressure vessel where the air is sucked out, so the wood becomes enclosed in a vacuum. The vacuum chamber is then filled with the non-toxic chemical impregnating agent, and the pressure in the vessel is gradually increased so that the wood absorbs the agent to an H3.2 treatment level. This process ultimately changes the colour of the timber to be darker than the natural wood, but it has many benefits as the treatment protects the wood against rot, decay, insects and presents better resistance to any internal mould or fungus.

Star Canopy Cabin- 9m2 (3m x 3m) + 9m2 Canopy - Treated Wood Unpainted - Darker Coloured Wood Due To Pressure Treatment

While it is more beneficial to use pressure treated timber, like any timber product it still needs care and maintenance, so we still recommend all our SheShed cabins get painted to maintain their longevity, and ensures your cabin remains under our warranty. If it does not get sealed with paint, treated timber can absorb moisture over time and is still subject to the effects of the sun drying and potentially cracking the timber. Pressure treatment is not a waterproofing solution on its own – so a quality painting system for your cabin is essential to protect your SheShed against the elements and significantly reduce its risks to damage. Our windows and doors do not go through the pressure treatment process and are instead spray-treated, but they must in the same way be regularly maintained to protect them from the sun and rain.

Overall, pressure treated wood is a very versatile product that can still be easily worked and maintained like its untreated counterpart, so the biggest benefit is simply that treated timber is more forgiving towards occasional neglect in its ongoing maintenance.

Pros & Cons for Treated vs Untreated Timber

Untreated Pros

  • Naturally chemical free.
  • Lighter colouration.
  • Less expensive.

Treated Pros

  • Non-toxic.
  • More resistant to insects like borer & termites.
  • More resistant to wood rot and decay.

Untreated Cons

  • Any cracks in exterior paint may allow water damage.
  • Less resistant to insects like borer & termites, (if they find a gap in the painting).

Treated Cons

  • More expensive.
  • Darker colouration.

In conclusion, we try to provide our customers options for both types because both untreated and treated timber have their benefits; both must be protected from the weather elements, and both make great materials for building and enjoying your SheShed for potentially decades to come. The biggest difference is simply that treated timber is more forgiving towards any occasional neglect in its ongoing maintenance, (because any potential gaps in the painting that may open over time won't have the same level of risk for insects or decay).

In the end it comes down to your personal preference, so if you take care to properly maintain your wooden shed, just like you would for a timber house – you know you will have a great and solid cabin to enjoy for many years to come.

Do you have any questions?

We would love to help answer those for you!


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