Wooden Decking in Durban – What Timber to Use

Wooden decks Durban

A CCA treated pine substructure and balau deck boards

Wooden decking in Durban, or any other area in South Africa is a valuable, inexpensive way of creating extra outdoor space. The climate in South Africa lends itself to outdoor living and as such a wooden deck in Durban is almost essential. There are many articles on this blog on how to build a wooden deck, what methods we use in building etc. so please feel free to browse and find what you are looking for. In this article I will mention some of the types of wood we use in building our wooden decks and provide reasons why we choose those types of wood.

Our deck substructures are made from CCA treated pine. Pine is a locally grown timber, relatively fast growing and as such inexpensive. It is used widely in the building trade as structural timber. It does however need to be CCA treated in order to prevent rot and insect infestation. CCA treatment is available in various H levels or Hazard Classifications. H3 is what is typically used in wooden decking as it is suitable to live out doors with occasional wetting. H4 is what one uses for posts or beams that are in constant contact with wet soil. If you stick to these guidelines, as set out by The South African Wood Preservers Association, then you will get a minimum of 50 years life span from your H3 timber and 30 years from your H4 timber. Pine is also relatively cheaper than balau. Balau can be used as a substructure but it is about 4 to 5

Wooden decks Durban

A balau substructure

times the price of treated pine. Balau will rot quicker than correctly treated pine in a substructure, believe it or not.

The pine that needs to be used in the substructure needs to be at least S5 which is SABS structurally approved timber. What it means is that there is no more than a certain specified amount of knots per square metre of timber. Pine is very knotty and is split up into different S categories which all carry a different price tag.

Pine is however not my fist choice for deck boards. Firstly it costs pretty much the same as balau. The reason for this is that the grooves below are machined here in South Africa and it is S7 timber so virtually knot free and it therefore carries a higher price tag then S5 pine. Added to this is that you are using almost twice as much timber because it is less dense. Typically a pine deck board would be 32mm thick whereas a balau deck board would be 19mm thick. The cubic metre rate for balau deck boards is also about half the price of the structural balau. Pine also tends to, warp and crack more easily then balau when exposed to direct sunlight because it is less dense and expands and

Wooden decks Durban

Balau deck boards

contracts a lot more than balau. This is fine for a substructure which uses thicker pieces of wood and is protected from the sun, but doesn’t work well on deck boards.

Based on all the above, it makes financial sense, and structurally it is the best option, to use H3 and H4 CCA Treated pine as a substructure and balau deck boards.

There are other options for deck boards. Massaranduba and Garappa are both very good woods which will outlast balau, but cost about 20% more per square metre. They are mostly used in the Highveld and in areas of South Africa where they experience extreme temperatures between seasons. Because they are denser, more stable and less prone to cracking

Wooden decks Durban

Balau deck boards

and warping, they can withstand minus 10 in winter and plus 30 in summer. Durban however has a more stable climate with less extremes between seasons and as such balau is the most suitable choice for hardwood decks.

For a free no obligation quote on your wooden sun deck in Durban please call us on 082 496 5444 or use the contact us form below.

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Deck Refurbishments

Deck refurbishment

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I have done quite a few deck refurbishment jobs and as mentioned in a previous article it is work I would rather stay away from. However, especially in the early days, it was necessary to do these jobs to keep paying the bills. Also it has provided me with a solid understanding of what not to do when finishing or sealing a deck. Also it has allowed me to see other construction methods of other deck builders first hand. Because these decks are relatively old one can see how a certain technique has behaved over time. But sometimes it is better to leave them alone, as I have done recently, because it can be like opening a can of worms.

The first thing to consider when sealing a new deck is to assume that you will be the one who has to refurbish it when it comes to refurbishing. This way you will probably apply the best finish to it so that future maintenance jobs are easy. The article on deck finishes covers in more detail what types of finishes are available and their pros and cons. When refurbishing one needs to first establish if there is structural timber that needs to be replaced. Sometimes it can be difficult to see if this is needed until deckboards are lifted. We did a job in La Lucia where we simply replaced deckboards and once we took the deckboards off we noticed that some of the joists had been eaten by insects and rotted. Although it is unusual for balau to be attacked by insects it can happen in the sap wood or if the tree was felled while it was still young. As a client and a contractor it is best to know exactly what state all the timber is in before the quote is accepted because no-one wants to find that once they lift the first deckboard the joists are so bad that new deckboards cannot be re-attached to them. So get underneath the deck, take a screw driver and poke around and see is there is rot or degradation.

Deck refurbishment

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Rotten deckboards themselves are quite easy to pick up as they will normally be visible from the top and they will normally start on one end where the water has been absorbed by the end grain. As mentioned in other articles, water is absorbed by wood through the end grain largely and very little is absorbed through face or side grain. As such the wood will rot from the ends first. If a rotten deckboard is found rather replace the entire length of that deckboard as chances are it will have started rotting all the way along. Be careful to know what deckboards have been used. A 19 x 68 deckboards is so close to a 21 x 72 that with the naked eye one might miss it. But looking at it carefully you will see it is both thicker and wider (and more expensive). Measure it to make sure.

Balustrades can sometimes rot too but normally only where water tends to collect. Screw holes left open and not filled with epoxy are also areas where the boards can rot more quickly. Some decks are not worth trying to repair. I’ve seen decks with posts that have rotted off and beams and joists that have rotted. It is not worth trying to patch that as eventually the whole deck will need to be replaced. The cost of this will exceed building a new deck. Pine decks tend to rot more easily especially if they have been built using H2 CCA Treated pine. A separate article will run through the different type of CCA pine and which ones are suitable for which application.

Use the search bar on the top right to search for other related articles or see below.  For a free no obligation quote on refurbishing your deck please call us on 082 496 5444 or use the form below.

Deck Maintenance and Deck Sealing

deck maintenance

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I was prompted to write an article on deck maintenance and deck sealing this week as we had a small quiet patch and as a “filler in” we sanded and sealed a picnic table, repaired a broken ball and claw foot and a leather couch and this reminded me to write this article.

Deck maintenance and deck sealing is always a question asked when quoting on new decks. Clients want to know that if they invest this kind of money in their property, will it be expensive to maintain in subsequent years. The simple answer is no, but if not correctly sealed in the beginning, then it can become an expensive and time-consuming task each time it needs to be maintained. The question is also sometimes asked when choosing between timber or composites.

There are many ways to seal a deck. “Finishing” is the correct term for it and this term also applies to all other timber products. Varnish, polyurethane, oil, sealer, paint etc. are all products used to “finish” a project. When it comes to decks there are certain products to stay well clear of. Because a deck lives outside in the hot African sun, any finish that dries on the surface of the timber will result in problems once it starts to degrade. All finishes will degrade and it is therefore very important to stay away from those that dry on the surface. It is common sense that anything that has dried on the surface will have the tendency to lift, either by cracking, flaking or peeling. When it comes time to maintain the deck, one will either have to sand it all off, or lightly sand it and re coat it with the same or similar product that was used in the beginning and live with a patchy finish. Therefore varnish is a big no-no. Polyurethane, although very durable and hard will also crack and flake and is better left for the purpose it was intended, indoor finishing on cupboard tops etc.

So that leaves us with those finishes that soak into the wood, nourishing them and when they degrade will not peel or flake because they have not dried on the surface. Simple hey? Not so. There are products which contain higher wax contents than others and although still classed a timber sealer, tend to soak in and leave a waxy film on the surface. This waxy film (or coating for want of a better word) will also tend to go blotchy once the sun does it work on it and will therefore also require some degree of sanding. Before we carry on, it is virtually impossible to sand the entire coating off. The electric sanders do not reach all corners, especially on a balustrade. The belt sander, rotex sander and any other sander will be too wide for the deckboard. Because there is a gap between boards, to allow water to drain away from the deck, the surface of the deck is not perfectly flat. So one will need to tilt the sander left and right as they sand down the length of the deckboard in order to remove the whole coating. Try it, it will cure you of varnish for outdoor products. The corners where the machines cannot reach will need to be sanded by hand and your labour bill will be more than erecting a new deck. I tried in my early days and learnt the hard way.

Oils can be used with some success. Raw linseed oil will take weeks to dry as it is raw and completely natural and therefore needs to soak in completely before you can walk on it. Also when the sun bakes down on the deck it will start to get soft and can become very hot to walk on. Boiled Linseed Oil will dry quicker as it contains additives that help the drying process but will still take a few days to dry. In the meantime the dog will run on the deck and leave muddy footprints that will dry into the surface. Again a lesson I learnt when experimenting with my own deck. Boiled Linseed Oil is not really boiled, it just means it has additives to help it dry faster than raw Linseed Oil. So for all intents and purposes it is a sealer. Danish oil will work well. I have not finished a deck in Danish Oil, but have used it quite successfully on outdoor furniture.

So now that we’ve eliminated the definite no no’s, we are left with timber preservatives or penetrating finishes. These are very viscous, almost as viscous as water. They are easy and quick to apply, no runs, no streaks and they go on quickly as they soak right into the wood. Seeing as they soak right in, they cannot flake or peel as there is no coating that has dried on the surface. We use a product manufactured by Timberlife called Satinwood 28 Base. This is a product designed for woods of low porosity. They also manufacture one for woods of high porosity. Don’t get them mixed up or the sealer will disappear right through your pine deck in a day or two or sit like a coating on your balau deck.

At least 2 coats are necessary on the first application and because the deck is new, one will need to reseal it about 3 to 4 months later. After the first year this maintenance interval will increase to every 6 months and the older the deck gets the longer the maintenance interval will become. The deck will slowly become saturated (well almost) with the sealer and it will last longer. It comes in clear and one can add a tint of your choice. They recommend that you use at least the lightest tint as the tint contains stabilisers which slow down the degradation process due to UV in the sun’s rays.

Even though it will need to be done every 3 to 4 months in the first year, the process is simple. Wash the deck and reseal. No need to call in the professionals and pay their rates. No need to sand and no paint stripper required. DIY it on a Saturday or Sunday or get your domestic helper to do it.

Timberlife also supply a product called Ultra Care Gold. This has a higher wax content as mentioned above and is not suitable for horizontal deck surfaces but works very well on the vertical posts of balustrades. They also sell Deckwash which is used to wash the deck on a monthly basis and again nourishes it and leaves it looking new for longer. It is inexpensive and well worth using. Simply mop it on and mop it off.

So in short stay away from finishes that dry on the surface. Stick with those that penetrate the timber and nourish it.  In the case of a deck that has been coated with a coating that has dried on the surface one can either lightly sand and re-seal with the same coating or if budget allows one can remove the coating, by using paint stripper and a high pressure cleaner. Stick to a maximum of 150 bar pressure otherwise the timber can be damaged. I’ve successfully removed coatings on decks with this technique. It is messy, uses a fair amount of water and a considerable amount of paint stripper. Depending on the thickness of the coating, one might need to apply the paint stripper more than once and blast it off with the high pressure cleaner.

High pressure cleaning can also be used to clean the deck before resealing it with Satin Wood 28 Base, but is often not necessary. I say not often necessary if you catch it before the balau starts to “grey”. Balau will tend to turn a grey colour if left unsealed or if the sealer that is there reaches a point where it is almost completely degraded due to the sun’s UV. If this occurs and the deck is then resealed, it will go very dark, regardless of what tint you use. The grey colour is in fact a thin layer of black algae. You will find that it is quite slippery when wet. This black algae needs to be removed first before resealing. Again Timberlife, and Woodoc, and some other manufacturers supply a product that will remove a lot of this by bleaching it. Timbrite is the one I use and it can be scrubbed on with a brush and then hosed off. It won’t take all of it away, so high pressure cleaning is a quicker way of getting rid of it. I would suggest scrubbing Timbrite on with a brush, then high pressure cleaning it off with 150 bars of pressure. This will renew the wood back to almost its original colour.

Leaving a balau deck unsealed will not necessarily speed up the rotting process. Balau is extremely durable as it contains natural resins and oils which repel water and the toxins in it discourage insects. So sealed or unsealed it will still last for years. Some prefer it unsealed to give it the natural grey look, but take note that if you then decide to seal it, clean it first as described above.

All the above also applies to outdoor furniture or any other timber that is in direct contact with the sun’s rays, especially those that are in the horizontal plane as they are getting more direct sunlight than the vertical pieces.

Timberlife are of course not the only ones who sell these products. They can be commonly found in hardware stores (Dulux, Woodoc and Plascon), but buying from the manufacturer is of course cheaper, but a bit more effort is required than popping in to your local hardware store.  All of them do pretty much the same job.

Good luck and remember that a deck is a living thing, nourish it, feed it and it will reward you.  If you’re feeling lazy, not interested in DIY or simply don’t have the time complete this form and I will submit a quote to maintain your timber deck.  Or you can reach us 082 496 5444.