What is the difference between treated and untreated timber?

Why treat timber?

Timber is usually treated to improve its durability for external use or to protect it from insect infestation. 

How effective is timber treatment?

Over recent years many of the traditional treatment chemicals have been withdrawn due to their toxicity. This has in large parts means the new treatment chemicals are less effective, than previous ones. 

What are the alternatives to traditional timber treatment?

We recommend the use of naturally durable timbers such as Douglas fir and Larch. The durability can be further improved by opting for heartwood only option. We would recommend this for cladding in particular. Both Douglas Fir and Larch are thought to last 30-40 years in most external applications. Secondary treatments such as  YakiSugi or some kind of oil based spray can be applied post installation and at regular intervals according to product recommendations ‒ typically every 3-5 years. 

Types of timber

Oak timber

Oak timber is even more durable, but is considerably more costly. This is recommended for high value projects and particularly where it is coming into contact with the ground. If the timber is planned to go into the ground, oak that has been charred would be the best option.

Painted timber

Although not always considered a timber treatment, painting has been used traditionally as a timber treatment as it will protect timber from the elements and from insects, and subsequent layers of paint can be added as required. 

Insect infestation        

If the concern is that the timber may be attacked or eaten by insects (for example in restoration projects where woodworm is known to affect the area), then we would always recommend seeking expert advice on the best treatment options to help you avoid that particular pest. 

If you are clear that you wish to have treated timber supplied, we are able to mill your timber and collaborate with fellow Pembrokeshire business Merlwood who have facilities to treat it. Get in touch if you require this service.