Decking through the eyes of a beginner

Learn from my mistakes

I am pretty handy with the tools and had just finished full renovation of my house. It was time to tackle the exterior and first the first job on the list was the existing back deck. The bones were good but the boards were ugly and had been damaged during the reno.

As someone with no decking experience, I thought it would have been as easy as removing the old boards and screwing down some new ones. Boy was I wrong!

Buying the materials

The first step was to choose a decking board that I liked. More accurately, a board that my wife liked. I went for 136mm x 22mm spotted gum. I got some samples and tested out some stain colours. I ended up with a stain called Cutek in a colour called Rustic Gold. Not only would this give the boards a nice colour, it will protect them from the elements as well. Then came the big question… how much would I need?

Decking timber is ordered in lineal meters (lm). I knew the area of the deck in square metres so needed to convert this to lm. There is an array of decking calculators available online. All I needed to know was the length and width of the deck, the board width and board spacing.

Length and width was easy as I was just using the same sizes as the existing deck. And I know that the board width is 136mm. But board spacing?? This was something that I had not heard of and didn’t know why it was important. I asked my local timber merchant who educated me in decking spacing. Timber expands and contracts depending on the environment. When it is wet/cold, the timber absorbs moisture causing it to expand. This is where the spacing of the deck is most important. If the boards are too close together, they will push against one another and cause the boards to deform and potentially break the screw heads. Each species of timber reacts differently and I was advised to go with 4mm spacing.

With that question answered, I could use the calculator to work out how much decking I needed. It was then time to work out what screws to use.

This question was a little more difficult to answer. I went to a few different timber merchants and hardware stores to get some advice. Unfortunately, no one had asked (what I know now to be) the most important questions (more on that later). The two questions I was constantly asked were “Are you using softwood or hardwood decking boards?” and “Are you screwing into metal or timber joists?” Both questions were easy to answer and resulted in a very large number of options for screws. Thinking I knew what I needed, I then based my decision on looks and chose what screw I thought looked best. I ended up with a 12 gauge, 50mm, type 17 screw. To figure out how many screws I needed, I went online and found a generic decking screw calculator.



The pain of the stain

With the purchasing done, I ripped up the old decking boards and waited for my delivery of timber. When it arrived, the first thing that dawned on me is that I would have to stain the boards before I installed them. Because the stain also protects the deck, the boards need to be coated on all four sides. While this was not a hard job to do, it was very time consuming and I needed a lot of space to be able to stain all 288 lineal meters at one time. Good thing I hadn’t ripped up the old deck… oh wait…

With that chore out of the way, it was time to start laying the boards. But where do I start? My deck is in an alcove. This means it is surrounded on three sides by the house. The forth side has a balustrade and overlooks the backyard which is about a metre lower than the deck. The boards will go parallel to the backyard and I can either start from the house side or the backyard side. After consulting Dr Google and a few phone-a-friend’s, I found out that you should always start from an open end. In most cases when decking, to fit the last board in you will have to cut it down its length. By starting at the open end you can have a full decking board where you will see the edges and leave the cut end against the house where it will be hidden.

Starting to deck. Well at least I hope…

Okay. Now it is time to start laying the boards. I placed the first one down and realised that the end of the board didn’t line up with a joist. I thought this was a bit odd so I grabbed a few more. I then realised that no board length was the same and none lined up perfectly with the joists. This means that I will have to cut each and every board to suit my joists. And FYI, my joist spacing is standard 450mm centres. So I get the drop saw out of the shed and went to cut the board to length. New issue… my saw won’t cut all the way through the width of the board. After convincing the wife that I actually needed (not wanted) a new saw, I went out and bought a sliding compound mitre saw with a laser sight (insert the Tim “The Tool Man” Taylor grunt here).

The trouble with the wrong screw

Back to it and the first board is cut and ready to be installed. I marked out where I wanted the screws to be and attempted to drive the first screw. Then, with a puff of smoke, the board split. A bit confused at what had just happened, I tried to drive another screw through on an off cut. The same thing happened. The screw struggled to drive through the board, sending out some worrying smoke and before it was all the way through, the board had split. After a bit more research it turns out that you need to pre-drill when using hardwood decking boards. I cut the damaged part of the board away and tried again.

The screw now had no trouble getting through the decking board but then… SNAP! The head broke clean off the screw when driving through the joist. I pulled the board off the joist leaving the snapped screw in place. Luckily the screw had snapped close to the head and I was able to use a pair of vice grips to twist the screw out of the joist. Maybe I have to pre-drill the joists as well? I gave that a go and got the screw in. It turns out that the joists are also made from hardwood. If only someone had let me know when choosing the screws that I needed to pre-drill before driving the screws into hardwood. Or recommend a screw capable of driving through hardwood timber without the need of pre-drilling (something that I now know is possible).

Having got the first two screws in place, I wasn’t happy with the finish of the timber around the screws. In the driving process, some timber splinters had got stuck under the head leaving quite a poor finish. I removed the screws and countersunk the holes. After re-installing the screws, the finish was much better. Having worked out a system, I now needed to pre-drill and countersink all 1,400 screws. More time added that I was not expecting. Again something that could have been avoided by purchasing the correct “self-countersinking” screws.


Getting everything aligned

As I went to drive the next screws, I had to figure out a way to make sure that all of the screws were in a line. I knew that if I were to fix the boards in the centre of the joists, they would all be in a straight line across the width of the deck. But what about down the length of the deck? I ended up making a crude template out of some scrap aluminium I had lying around. I bent the aluminium at 90° so I could butt it up against the edge of the board. I drilled two holes for the screws and used this to mark out where the screws needed to be. This worked well most of the time. But there were some boards that were a few mm wider or narrower. This meant getting the ruler out and measuring.

I was now getting on a roll and had a good system in place. I got the first row of decking in and it looked good. To space the boards I had thought ahead (which was an achievement for me) and bought a pack of 4mm loose nails. I partially drove a nail into each joist, hard up against the first board. This gave me a consistent 4mm spacing down the full length of the deck. As the second row of decking went in, I found some boards difficult to line up because there was a bow in them. I got around this by fixing the first two screws in place, then using a clamp to squeeze the boards together on the other end. This was the easiest way that I found when working alone.

Order anxiety

Getting past the half-way point, I started to worry that I may not have enough boards or screws. I tried to put that out of my mind and keep going. But sure enough, I ran out of boards and screws. I didn’t realise the large amount of off cuts I would have. And with the screws, the calculator did not factor in joins. Each join requires 4 screws rather than 2. When the next shipment of screws and timber arrived, the finish was in sight

Some of the joists closer to the house were damaged and I had to strengthen them with some new timber. As I started to lay the boards over the new timber, I could see them peeking through the gap between the decking boards. Because the new timber was blue (due to the termite resistant treatment) they really stood out. I didn’t have this issue with the old joists as they were all very dark. I then had to paint the tops of the new timber black. This didn’t really have to be done, but I knew if I didn’t do it, it would always annoy me.

The deck in review

Finally, the last screw is in and I can sit back and enjoy my work. The deck has now been complete for 2 years and it was well worth the effort. Some of the things that I learnt from my experience, and would definitely tell to anyone about to start their decking project:

  • Buy enough materials! Make sure that you find out what lengths the boards you are going to use come in. If they are not a set length they will be random. Find out from the supplier and account for enough wastage. For the screws, use a calculator that factors in joins
  • Buy the right screws. I would have saved a lot of time if I had screws suitable for the job
  • Test both the stain and the screws on some off cuts before using on the finished product
  • Have the right tools before you start
  • Allow enough time for each step of the process
  • Paint the joists prior to starting. I have also found out that there is a black joist tape you can buy. It not only makes the joists look black, it also protects them from exposure to moisture
  • Be prepared for a lot of cutting
  • Timber is a natural product so be aware that it is not all the same. Some pieces may be slightly different sizes than others