Here’s a balau wooden sundeck we’ve just built on Kloof, just inland of Durban.
We used a 19 x 90 balau deck board on this wooden sun deck at the client’s request. We normally use a 19 x 68 balau deck board as they are considerably less expensive per square metre than the 19 x 90 balau deck boards and we can pass that saving on to our clients. Granted it is quicker to install a deck board that is wider as you need less boards per square meter (in this instance 15 boards per square metre using a 68mm wide board and 11 using a 90mm board), but not by that much that it warrants paying 35% more for it. 90mm boards are about 35% more expensive per square metre than 68 mm boards.
When screwing down a 19 x 90 deck board I put two screws, per board, in each joist line, one in each shoulder. I have seen other deck builders putting one in
every alternate shoulder. It does work, but if you do get a board that is particularly prone to warping it will warp where the one screw has been left out. It is not a huge cost or effort to put a second screw on the opposite shoulder of each board at each joist line. Obviously the wider the board the more prone it will be to warping. Why they are more expensive I haven’t yet worked out because good balau is good balau is good balau. If the wider boards we taken from a different part of the tree, the heartwood vs. the sapwood, then I would understand the price difference, but they aren’t. It is a preference, at a price, that’s all.
We ran the deck boards all in the same direction on this wooden deck. With this deck we ran the deck boards parallel to the edge of the pool meeting each other at a 45° angle on the corners. It is far easier to run them all in the same direction as you will never get a problem of matching the cut ends. If one board is cut at 46° and one therefore at 44°, they will be of different lengths and will not match up. In this instance you need to install a barrier between then (one deck board’s width) to hide any difference in length between cut ends. But I’ll write another article about that later. Running them all the same way on both sides of the deck eliminates this problem.
You need to be careful though to start installing your deck boards in the middle of the deck and not on one end. If you start on one end, you may very well reach the 90° corner and find that you have to rip a deck board in half to cover your space. This is unsightly and will result in that deck board failing more quickly than the rest. So start in the middle and move outwards to both ends and end with a full deck board.
There was also some other work on this wooden deck build in that the client wanted a planter stand built so he could place potted plants in it and he wanted his Jacuzzi walls clad. We battled a bit with the Jacuzzi cladding as the original brick structure that was there was skew and we had to try to mitigate this by building up
our substructure to bring it back to square.
The cladded vertical posts you see in the pics alongside are 19 x 90 boards (x 3 of) around a 76mm steel awning post. We needed to build the steel awning post up to get to our 290mm and then attach it to the post. Although it looks very nice to have such bulky wooden posts, it does block the view slightly when sitting at the pool. Why 290mm when each board is 90mm (90mm x 3 = 270mm)? Because we set each corner chasing the other surface. And let’s just forget about the 5mm gap we had in between each board.
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