How to Build a Wood Deck
Article Summary: I have received a lot of requests for an article on how to build a wood deck, it seems that decks are extremely popular out in d-i-y land! Building a deck is pretty straightforward as long as you follow some basic guidelines. This article should help you make a wonderful deck that, if you look after it, will last your lifetime.
One of the first big jobs I ever attempted on my own was the building of quite a large wood deck. It was essential that this was done right because the deck owner was my future Mother-in-law! So after much deliberation about how I was going to tackle the problem, I first set out a basic plan so that she could see on paper what would replace the existing structure. Having gained her approval I then moved on to source and price materials. With a ballpark figure of how much the project was likely to cost, I started work by demolishing the existing wood deck.
Note : depending on where you live, you should always make sure that you follow the rules and regulations that are applied by your local council/authority. In some areas if you are replacing an existing structure you do not need any planning approval, but in almost all cases you will need some sort of building regulations approval. Building regulations are there to make sure that structures are safe and legal, but in all states/counties they are different, so always check first.
The wood deck I constructed was to be built on a slope – one end was about 6 inches off the ground, the other was about 4 feet over a distance of 8 meters. After demolishing the old structure I marked where the concrete support foundations were going to be. I then dug square holes about one foot square and about 18 inches deep. I filled these holes with the correct grade of concrete for a supporting foundation. If you contact your local concreter, they will tell you exactly what grade you require. I ordered my concrete to be delivered although you can always mix your own if you like hard work.
When the concrete has set, use brackets that keep the posts off the ground. This will eliminate rot which is always a problem when burying posts either into earth or concrete, neither of which is recommended. Make sure posts are in a straight line by using a string line, first to set the position of the post brackets, then to line up the posts as you fix them down. Support the posts by using wood supports nailed or screwed into the posts.
The next stage involves fixing the joists to the posts. Use bolts that go straight through the posts, do not just nail or screw these in, this is asking for trouble! You will have to use span tables to get the correct size of joist to use. If you have had drawings made for you by an architect the sizes should be given on the drawings. Always use the correct sizes as your local authority will check that you have followed the drawings to the letter.
To get straight lines always use a chalked string line. An easy way to get levels is to use a hose pipe with clear plastic tubing at each end. Fill it up with water and you will be able to get perfect levels over long distances. The main benefit of the hosepipe method is it’s cheap and yet still very accurate.
Use geometry to get perfect 90 degree corners. The 3/4/5 rule works a treat. Just in case you need reminding, Pythagoras’ theorem helps us builders get nice, square corners with the formula a2 + b2 =c2. Even if you use a simple tape measure, the 3/4/5 method is good for checking your measurements.
There are several methods for fixing the wood decking to the deck joists. You can either nail it direct, screw it direct, or for a longer lasting decking, Use special fixing that actually hold the decking off the joists. The benefit of this is that water cannot remain in contact with the wood and therefore rot is reduced substantially. Always finish your deck with a special outdoor wood protector that is UV resistant for a long lasting wood deck. A good substitute for real wood is an engineered product that will need far less maintenance than wood, the choice is yours.