Timber Decking

A wooden deck in the garden can be just a beautiful feature or it can be functional or both but if you’re thinking about having one, have a read and discover some of the “Gotchas”. In my case I didn’t do the 7Ps! (Prior Preparation and Planning Prevent P*ss Poor Performance)

I have 2 wooden decks, one is very small and serves to bring a few levels together to avoid steps. The other is quite large (3M x 6M) and was a feature that added some usability to the sunniest part of the garden and it looked gorgeous 🙂 We originally had a “Patio” with concrete slabs and we wanted to extend it. My neighbour was a timber salesman / manager and he said he could do us a good deal on decking boards and framework. He said he would arrange to give the timber a 30 year “pressure*” treatment* instead of the usual 20 year. We were sold on the idea of having a timber deck.

We (wife and I) set about designing a deck and spent quite while doing some maths  (inc pythagoras and Trig). We knew the width of the boards and played about with different sized gaps to arrive at a “module”, which all the deck design would be based on. The finished result was stunning and pretty much unique.

Unfortunately, I didn’t go along with my Engineering education and decided to go along with the advice of a timber salesman ! I wanted to put concrete pads down, leveled to suit, to rest the framework on; which would ensure the framework was not in contact with the soil. Neighbour advised that the 30 year treatment would ensure the wood wouldn’t rot so I just needed to put the “landscape fabric” down and lay the deck on top. Mistake one 🙁

Mistake two was not realising (knowing) that the decking boards would need regular oiling / treatment to prevent cracking; even with the pressure / “vacuum” treatment  🙁

The deck has been down some 12 years and has been pressure washed a few times and oiled a few times. Unfortunately, the supporting  framework has not survived and has rotted in most places due to mistake one! With this in mind we have decided to remove the deck and go back to the patio and grass idea!

The rot was worse than expected and all due to mistake one 🙁

*Pressure treatment often referred to as “Tanalising”. Tanalise is a basically a trade name and refers to a “chemical treatment” where the wood is exposed to a “vacuum” (not pressure) and this allows the “chemical” to be absorbed by the wood to prevent / delay rot.. The original “Tanalising treatment” was second to none, it did prevent / reduce wood from rotting but the EC enforced a change in the “chemical” recipe. Unfortunately, this change pretty much made the Tanalising treatment to be almost a waste of time. Farmers, who use a lot of fence posts, now found that the fence posts were rotting below ground and needed replacing more often than before. It would seem that “pressure treated” timber was no longer worth the expense 🙁 The treatment does still offer some protection.

There are many reasons why you would want a timber deck but make sure you know what you are letting yourself for.

1. Timber will rot if it’s below ground, unless suitably treated.

2. Timber that doesn’t dry out will rot even if treated. (unless using creosote or similar, think telegraph poles)

3. Timber decking boards will need a regular cleaning, oiling / painting to prevent cracking and decay.

I would strongly advise looking at the “plastic wood” option. The “reclaimed plastic” wood will never rot and the decking boards will only need pressure washing once or twice per year. Unfortunately plastic wood is not very good with standard “wood screws” and there are some concerns about it being slippy. Even timber can become slippy if algae is allowed to grow, so regular cleaning is the answer.

I love wood, I love the idea of “timber” decks but in reality timber decks are “High Maintenance” and are not fit and forget. You could have a look at Cedar or Larch for the decking boards but the “plastic wood*” seems to be the best option, at least for the framework.

The main thing to really think about is the (supporting) framework. If this is likely to get wet and not dry out, it will rot! You really need to think about how you will level & support the framework to make sure it never stays wet. “Plastic wood” will never rot, even if it’s in standing water. If you need to level and support the framework, have a look at metal or plastic legs. Engineering bricks or concrete pads are also a good option, along with a DPM (damp proof membrane) between the bricks / concrete and the wood.

*Plastic wood is generally a lot more expensive than real wood

Conclusion.

A “timber deck” can be a thing of beauty and a functional feature. It is very unlikely that it will be maintenance free but if you choose the right materials and make sure that the supporting framework won’t rot, it should last many years.