Substructure on Low Level Wooden Pool Deck

 

We are busy with a new wooden pool deck build in Hillcrest, Durban and I have taken a video to show how the substructure is built before the deck boards go down.
This is a low-level wooden pool deck that we are building which is only about 200mm off the ground. Because it is 200mm off the ground we can’t simply use 38 x 38 cleats as we have done in the past which are secured to the ground. We still need to use a joist of at least 114mm wide which is supported every 1.6m with a foot or post as there will be a void beneath the joist and the paved substrate. We have aimed to get our deck flush with the floor inside the house which is about 200mm above the paved area around the pool.

We built our substructure in a number of separate frames which are then lifted up into place on the wall side and secured using sleeve anchors. The opposite ends of each frame are then also lifted up to get the top of the joists level and flat and supported using a 76 x 76mm square post which rests on top of the paving. We will also remove some paving on every other post and sink that into the ground to ensure that the deck doesn’t sink over time if the paving sinks. The separate frames are then all attached to each other.

We have left our joists long to extend over the pool and now that the side of the frame is attached to the house we can work out exactly where we want our joists to end so as to get our fascia board on the inside of the pool completely flush with the vertical of the coping of the pool. This way we can slide our fascia down to cover the coping neatly. We can now trim our joists to the correct length and install another 38 x 114 joist running at right angles to the main joists. We could not make use of a beam and joist system here because we don’t have space beneath our joists to install a beam. We would need an extra 228mm to do this. So our frame is assembled in one single plane rather than having joists sitting on top of beams.

We’ll install some truss hangers where the joists meet the side beam which is attached to the wall. All that is holding those joists to this side frame now are two 60mm screws from behind so they need to be supported with a truss hanger to stop them ever dropping if the screws fail. Those screws are screwed into ends grain which is never that strong in terms of fixing.

The trick to this type of deck is to get the fascia frame around the pool to sit completely flush with the coping of the pool so that a fascia board (two deck boards) can be installed in the vertical plane to cover the fascia. Once that is all fixed in place and can’t move then we can deck.

Balau deck boards will be secured on top of our joists and we will start our deck boards on each side of the pool and deck towards the house and towards the grassed area. When decking towards the house we need to hope that the pool is parallel to the house and if not then we need to adjust our spaces between boards to accommodate any difference. So for instance if one side, between pool and house is 20mm shorter than the other, then we will need to increase the gaps between deck boards by 1mm for 20 boards to get the deck parallel to the house. If not we will end up with a wedged shape board as the last board which will be unsightly and will fail more easily. Also we need to try to end on a full board rather than a ripped half board as that too will be unsightly and may fail prematurely. Again we will adjust the gaps as we go to ensure we end on a full board. The gaps are normally 5mm, but we can adjust them to 4mm or 6mm without being noticed. Then we will “fill” the section between each long side of the pool and again we need to ensure that we don’t end on a half board, by adjusting our gap to 4mm or 6mm. The final result will be a deck with full deck boards and no wedges.
The grassed side is easy enough in that we can protrude over the end of the paving to end on a full board and terminate our deck there. On this end we will install a screen of 1.8m high the length of the deck. So we will tie our upright posts for the screen into the posts for our deck to secure the deck into the ground with concrete to prevent any slippage, and at the same time providing an upright of 1.8m for our screen.

For a free no obligation quote on your wooden sundeck, pool deck, balustrades, screens, cladding, walkways etc. please contact us on 082 496 5444 or use the contact us form below.

Wooden Pool Deck Built in Westville, Durban

Pool deck built Westville Durban

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Balau Deck board

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50 degrees

Here was a nice size wooden sun deck, or pool deck, we built of approximately 60m². I say a nice size because at that size one can reduce the costs slightly, pass a saving on to the client, and make a little bit more money on the job.

Wooden deck with jacuzzi cladding Durban

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This wooden sun deck was built around the pool as you can see from the pics alongside. It also extended to the far end of the house and was enclosed by a balustrade on two sides with two gates leading to the garden. Access to the deck was from two bedrooms on one end in front of the pool and from the lounge on the other end. The level of the floors, in the rooms, near the pool, were not the same level as the level of the lounge floor so we were left with a choice to either step the deck or have a small step up to the lounge. We chose to create a small step up to the lounge because having a step in the middle of your wooden pool deck is only going to lead to someone tripping and hurting themselves.

In this article I want to write about the different ways of laying the boards when it comes to pool decks or any other deck where the boards can possibly run in both directions. If a deck needs to be built with deck boards all running the same way it is relatively easy to install them in that the ends do not need to match up. The problem one can have in trying to match up ends of deck boards is that if they are not cut at precisely 45° then the length of the cut ends will differ. I’ve drawn a sketch alongside to illustrate this.

It is highly unlikely that any pool will be perfectly square. When installing the wooden pool deck it may be necessary to cut one end at say 44° and the matching board that runs at right angles to it, at 46°. The two ends will not be of equal length and will therefore not match up flush with each other. The problem is compounded with each deck board that is added. Let’s assume that the one cut end is 2mm longer than the other. After installing 15 deck boards (or one metre) the boards will have shifted by 30mm (15 x 2mm). This will be unsightly. The problem is also compounded by the variance from 45° which results in the difference in lengths of cut ends being greater.
There is a way to overcome this problem and that is to install a joiner between the cut ends as the sketch alongside illustrates. The other way is to run the deck boards all in the same direction (i.e. not all parallel to the edge of all sides of the pool, but rather all parallel to each other).

Pool deck built Westville Durban

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Another advantage though of running the deck board’s parallel to all edges of the pool, with corner joins, is that you will have face grain facing the pool and not end grain. Water is absorbed largely through the end grain of wood and if this end grain is facing the pool, then it stands to reason that the deck boards on this side of the pool will be exposed to more water and will tend to rot more quickly than those with face grain facing the water. Even though we use balau for our deck boards, which is rot resistant, all wood will rot and by employing methods that will inhibit rot, makes good sense. Having said all that, it is easy and cheap to replace deck boards and if a deck board with end grain facing the pool gives you 15 years life, the cost vs. preference is not that great.

For a free no obligation quote on your pool or sun deck, or any other outdoor timber construction, please call us on 082 496 5444 or use the contact us form below.

Balau Wooden Sundeck Built in Kloof, Durban

Wooden Sun decks Durban

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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.

Wooden Sun decks Durban

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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

Wooden Sun decks Durban

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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.

Wooden Sun decks Durban

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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

Wooden Sun decks Durban

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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.

For a free no obligation quote for your wooden sundeck, pergola, walkway, screens or other timber construction please use the contact us form below or call us on 082 496 5444.

Timber Decks Durban – Umhlanga

Timber decks Durban

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This existing timber deck in Umhlanga Durban had reached a point of no return and our recommendation to the client was that we remove it and replace it. It’s never a good thing to hear that you must throw it away and buy a new one because it can’t be fixed, but often wooden decks are not built as they should be built and they therefore do not last as long as they should.

From the picture alongside you can see the damage done to the posts at ground level as a result of insects. Given another year or so and those posts would have failed and although the deck might not have come falling down, it would have become unsafe and a danger to those trying to enjoy it.  See far below for pics of the finished product.

The existing deck had been built out of pine and I can only think that the wrong H class was used. As I’ve mentioned in other articles, pine used for decking purposes needs to be CCA treated to at least an H3 level and any pieces in direct contact with the ground should be treated to H4 level. You can read up more on the H levels here http://www.sawpa.co.za. In a nutshell though, off the shelf H2 treated timber will not last. And don’t be fooled by the timber yard telling you they will “double dip” it. The pressure between H2 and H3 treated timber is different, so doubling dipping H2 will not make H3, it will make H2 + H2 and it WILL rot. On the other hand if the correct H level is used the suppliers will offer up to a 50 years guarantee on this timber against rot and insect infestation. Who’s building a deck that will still be around in 50 years?

We first removed the existing deck boards so that the joists were exposed. We removed all joists but left the main beam on the front edge so that we could use it as our guide to installing the new beam. We used the existing posts as temporary posts to build our substructure, then installed our new beam and dropped posts to ground from there. We then removed the old beam and old posts and were left with a new timber deck substructure in pretty much the same place as the old one. It made our life easier and took a lot less time.

There was a gate we built and installed along the one side. We used stainless steel hinges on it. I’ve found that stainless steel hinges with bearings in the spine are not that costly. In fact a lot less expensive than brass and, in my opinion, a lot more durable. The solid brass can sometimes be a bit soft whereas stainless steel is a lot harder. This is especially the case when talking about screws. Brass screws tend to sheer of quite easily under pressure.

Timber decks Durban

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It was a nice job to kick the year off with as it was relatively simple. The only hurdle was trying to build 3m in the air on a very steep slope. We used extension ladders but still it makes it difficult and a bit slower because someone has to hold the ladder and keep moving it when screwing down pickets on the balustrade which is time consuming.

For a free, no obligation quote on your timber decking and other outdoor timber construction needs in Durban please call us on 082 496 5444 or use the contact form below.

Timber decks Durban

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Timber decks Durban

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Timber decks Durban

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