Pressure Treatment vs Dip Treatment

Created by Andy Hobson on Friday, 25th of January, 2013. Updated on Friday, 11th of July, 2014.

Pressure Treated wooden Garden Sheds

If you’re buying a product which is made from wood and it’s going to go outside, whether it’s fencing, a garden shed or an arbour then you need to know about timber treatment.

The two main types of treatment that timber products made from softwoods like Arbours, Garden Buildings and Fencing experience are either Dip Treatment or Pressure Treatment.

Treatment is very important as over time timber will become susceptible to rot and insect attack which can severely damage it.

Dip Treatment

Dip treated products are generally cheaper and this is because the process of dip treating takes less time to do, leading to lower labour and storage costs.

If a product is dip treated the treatment will thin and fade over time and most manufacturers will require treatment annually to comply with their guarantee conditions. They will also advise that you isolate it from the ground using a pressure treated gravel board for example with fencing.

Although they are cheaper to buy, you need to weigh up what is important to you, whether you want to save money initially or to spend more time and money treating the product annually.

Pressure Treatment

The process of Pressure Treating or Vacuum Pressure Impregnation as it is officially know involves a longer process. Firstly the wood is dried naturally using air flow or a kiln, this removes moisture from the wood so it is ready to be treated.

Next the wood is placed into a pressure treatment tank, and air is removed via a vacuum. Then the tank will be flooded with preservative liquid, then the excess fluid is extracted using a vacuum again.

The low pressure of the wood draws the preservative deep into the grain of the wood making for a fully treated piece of timber.

Pressure treated products can usually be identified by their green tinge finish when new, but this will fade to a honey brown colour over time, naturally blending into your garden.

Weathering will not affect pressure treatment, so it will last much longer. Although if you do saw/cut a piece of pressure treated timber manufacturers will always advise to treat the newly exposed part.

Further Information

View all the Pressure Treated Sheds for sale on GardenSite with a 15 year anti-rot guarantee.

Please let us know what you think by leaving a comment below...


Posted by Ian Claydon on Friday 30 May 2014
very helpful i will now buy pressure treated thanks
Posted by Mike C on Monday 26 August 2013
Excellent article. Just the right amount of information to inform me to buy pressure treated
Posted by Geoff Dawson on Tuesday 29 January 2013
A very helpful article
Posted by Frank Archer on Friday 25 January 2013
Great article! Thanks for this, I now know I want a pressure treated shed not dip treated