Oak sleepers are probably the most popular item that we sell here at Sussex Oak, but we still see lots of people requesting or using softwood or reclaimed alternatives.
In this post I will lay out the reasons for and against using oak sleepers for your garden project.
At the end of the article you may still wish to go down an alternative route, but at least you will have all the information to make an informed decision!
In my view this is the single most compelling reason to choose oak sleepers over softwood alternatives. A pressure treated softwood sleeper will have a maximum useable lifespan of 10 years, and in many cases – and particularly in exposed coastal locations – this can be as low as two years.
Compare this to an oak sleeper and the difference is staggering. They would have a 30 year lifespan in the same conditions, and have been known to go up to 80 years.
The difference is even greater on the larger sizes of oak sleepers – our 10″ x 5″ sleepers could last up to 150 years in the right conditions(!), whereas a softwood version is still unlikely to last beyond 10-12 years.
Reclaimed sleepers will of course match or exceed the lifespan of an oak sleeper due to the creosote content, but there are other disadvantages to these.
Up until around four years ago there was a dramatic difference in cost between softwood and oak sleepers.
At one point, a softwood 200×100 sleeper was around half the price of the oak version. This gap has now closed to the point where on an order of 30 250×125 sleepers it would be cheaper to buy oak versions than it would to buy softwood.
We won’t go into the reasons behind the massive increase in the cost of softwood here, but it clearly removes one of the major arguments in favour of using softwood sleepers!
All of our oak sleepers are completely untreated, as the natural tannins in the oak are a more effective preservative than any man-made alternative. This gives them a major advantage over reclaimed sleepers which are treated with creosote.
Creosote was banned by the EU in 2006 as it is carcinogenic, and this ruling means there are limits on what these sleepers can be used for.
This is obviously a limiting factor, and when coupled with the problems caused by the leaking of creosote it means that these sleepers should only be used in areas where they’re unlikely to come into contact with people’s skin.
Softwood sleepers do not have the same problems as reclaimed ones, but the current treatments are the main reason for the short lifespan. Any attempts to increase this by using additional treatments could cause problems.
Depending on how you look at it, this can be either a positive or a negative for both softwood and oak sleepers.
An oak 200x100x2600 sleeper will weigh about 60kg when freshly sawn, whereas a softwood sleeper of the same size will weigh around 30 kg.
However, the added weight of the oak sleeper means that it requires less fixings as the weight aids keeping it in place.
Of course, if you’ve a long journey to make with the sleepers, or need to drag them to the top of the back garden, this extra weight creates a considerably bigger work for you.
On balance we believe the extra weight is an advantage, but you can draw your own conclusions.
Although oak does have a strength advantage for the same sectional size this is not particularly relevant.
It’s a common misconception that a project will need larger sizes of oak sleepers are needed due to their increased strength.
In reality, even our smallest sleeper – the 220x50x2600 – would take over 50 tons of pressure on it to fail when supported at both ends. This means that in practise any sleeper, be it softwood or oak, is more than sufficient for any retaining situation. The larger sizes are simply used for increased aesthetic quality.
Although this is a matter of personal choice I’ve always liked the subtle silver colour that oak sleepers develop over time.
In my opinion this is another, albeit minor reason to choose oak sleepers. Whilst reclaimed and softwood sleepers stay more or less the same, the pale tones of oak can be used to enhance the look of your garden.
I hope that this post has given you a little more insight into the differences between softwood, reclaimed and oak sleepers and you can now make a decision on which type is right for your application with all the facts to hand.
If you have any questions, or would like some advice then please don’t hesitate to contact us.