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Hi, I am installing a new "green" solid redgum post and rail fence at my property. I want to oil the fence, initially anyway, to preserve some colour before it goes a dark grey. I have 2 questions.
1 How long to I leave the green timber before I oil, or do I oil as soon as its installed?
2. What would be the best oil to use, I intend to spray it on.


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We suggest leaving the timber for a week or two so it is at least surface dry, to improve penetration of the oil. With a dense timber such as red gum penetration will be limited, but if you leave it too long it will start to turn grey which is what you are trying to avoid. Among commercial products anything marketed as decking oil or outdoor furniture oil would do, preferably with a light pigment to increase its life span. In earlier times old sump oil was a popular and economical treatment, but it turned the wood quite dark. 

I was just wondering if you know anyone who can test board such as mdf for formaldehyde levels and other specifications? I want to test a board to ensure that it complies with specifications. Any help would be appreciated.

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We normally recommend AMCOSH since they have a NATA-accredited laboratory and have previously worked on particleboard. They are located at Werribee in Victoria, phone 1300 622 494, website

is there any copper,chromium,arsenic,creosote contain in tanalith ti h2f pine

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Tanalith Ti does not contain copper, chromium, arsenic or creosote. It is an envelope treatment applied to timber house framing and is suitable for use south of the Tropic of Capricorn. The active ingredient is described in Tanalith literature as follows: 

Imidacloprid is a synthetic neonicotinoid preservative that is used in both agricultural and veterinary products such as flea treatments for dogs and cats. It is non-toxic to humans and other mammals. A safe, organic based preservative, it greatly enhances the durability and the lifetime that the preservation process confers to the treated timber products.
Further information is contained in the Tanalith Ti data sheet available here:

Melunak as used in internal stairs. Is it Naturally termite resistant, and where is that data available?

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Melunak is classed as a light hardwood in 100 Malaysian Timbers published by the Malaysian Timber Industry Board, and rated "Moderately Durable". According to their rating system this implies a life of 2 to 5 years in the ground. The testing is conducted under severe tropical conditions and the timber would last longer in a temperate climate. However, the "Moderately Durable" rating suggests that melunak is unlikely to have a high termite resistance. In any case it would seem irrelevant for an internal staircase where no doubt some kind of barrier system is in place to protect the house. 

I am quoting some free standing merbau privacy screens and want to concrete the merbau posts in the ground. How suitable is merbau for this?

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Merbau is rated Durability Class 3 in the ground according to Australian Standard 5604, Timber - Natural durability ratings. This means it has a probable in-ground life expectancy of 5 to 15 years. The reason for this rather broad range is that local climate varies around Australia and so does the immediate environment. For example, in-ground posts will have a shorter life if they are adjacent to a discharging downpipe, or placed in a heavily watered garden bed, ie. in a damp location. Concrete doesn't necessarily offer much protection and may actually hold moisture. If the posts are in a relatively dry location they should comfortably achieve the upper end of the range. You might want to treat the in-ground portion of the posts with a supplementary preservative such as Preschem boron sticks or CN Timber Protective Emulsion to maximise their life.

Hi, I'm looking for some information on appropriate specification of timber product and preservative treatment for an above ground, residential floor application that is subject to flood event. The nominated finish floor level is the minimum design level so all structural timber is below this. Your help is much appreciated.


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We wouldn't be too concerned about the need for a preservative on your floor timbers assuming the sub-floor space is properly ventilated. In the event of flooding the timber will become saturated but a flood is a relatively short-term event and when the floodwaters recede the timber will dry out again. A more hazardous situation for timber is when it is damp for long periods rather than saturated, for example in an outdoor structure such as a deck or pergola in a damp climate. However, if your site has the potential to be flooded we suggest you avoid lightweight structural members such as timber I-beams which are fine in dry situations but not as robust as solid timber when saturated.

I am using Big River Timbers product, Armourpanel, as flooring. Can a wax/oil product be used as a coating? I am concerned that polyurethane coating will need to be sanded back in the years to come and with only a 4mm veneer this is not an option.

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Our understanding is that Armourpanel flooring comes pre-coated and is warranted for 20 years under normal residential conditions. The website includes this statement:


The veneer has a highly protective UV cured coating, which means the floor will remain fresh in appearance and should not need to be sanded back for many years. Additionally Big River’s pre-finished engineered flooring comes with a 20 year limited warranty against wear-through under normal residential usage, leaving it well prepared to survive day to day family living.


If the floor eventually needs sanding and re-coating it is possible to sand the 4mm face veneer. Sanding normally removes only 0.5 to 1mm of timber. However, if you wish to apply wax to help to prolong the life of the factory-applied coating, that is possible but it will need buffing to maintain a shine. In our opinion it would be better to leave it alone and take advantage of the fact that it is pre-coated with a finish that needs no maintenance. Wear can be prevented or reduced by placing rugs or mats in high traffic areas and avoiding placing chairs and other furniture directly on the wood.

I am useing Merbau posts for the house entrance what is the best way to preserve them. If I use an oil it will stain the tiles after rain thanks Bill

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If the posts are exposed to rain, tannin is likely to leach out and leave a brown stain on the tiles. An oil finish will not necessarily stop this as it doesn't form an impermeable barrier against rain. A paint coating will stop water from leaching out the tannin, but if you prefer a natural oiled finish some pre-treatment of the timber would be advisable. For example, manufacturers of deck cleaning products claim that a preliminary scrub of timbers with a high tannin content (such as merbau) will remove much of the tannin and thus reduce the risk of leaching.

I am using Merbau posts for the house entrance what is the best way to preserve them. If I use an oil it will stain the tiles after rain thanks Bill

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If the posts are exposed to rain, tannin is likely to leach out and leave a brown stain on the tiles. An oil finish will not necessarily stop this as it doesn't form an impermeable barrier against rain. A paint coating will stop water from leaching out the tannin, but if you prefer a natural oiled finish some pre-treatment of the timber would be advisable. For example, manufacturers of deck cleaning products claim that a preliminary scrub of timbers with a high tannin content (such as merbau) will remove much of the tannin and thus reduce the risk of leaching.

I have a new FSC EUCALYPTUS outdoor setting from Stratco. How do I go about staining and or oiling it?

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There are various outdoor furniture oils on the market, eg. Cabot's Garden Furniture Oil, Feast Watson Outdoor Furniture Oil, etc. Cabot's claim on their website that their oil "lasts twice as long as traditional garden furniture oils" but it's not clear how they tested their product or what they mean by "traditional garden furniture oils". However, any of the major brands should give satisfactory results as long as they are well maintained - it's important not to wait until the oil has weathered off and the timber has started to turn grey before you re-coat.

I have several sections of Norfolk Island Pine (approximately 30 - 34 inches in diameter) that have exposed to the weather since February 2015 (Cyclone Marcia damage).

I'd like to use some rounds from this log to make into small table tops but am concerned about future shrinkage and subsequent cracking.

Is there something I can treat the disc with that will seal it and prevent this happening (while still showing the grain etc)?

Many thanks,


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As they dry, round discs commonly develop a shrinkage crack running back to the pith. This can be prevented by a prolonged soak in polyethylene glycol (PEG). A detailed explanation of the process is available on the net at this location: PEG is available from chemical supply companies.


Is there a product available that will preserve an outdoor timber table, primarily from the sun. After application, will not change the colour of the wood and will leave it looking natural, meaning I do not want a gloss finish.
Thanks for your help

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There are various clear finishes on the market that give reasonably good service if they contain ultra violet absorbers, eg. Sikkens, Intergrain Ultraclear Exterior, etc. However, if not maintained they generally fail by peeling which creates difficulty when re-coating since the perished coating has to be removed before re-coating. If you are prepared to keep up the maintenance, these coatings will keep your table looking great. Otherwise a finish such as decking oil will give you a matt natural finish, and may be easier to maintain.


timber preservation and finishes

We have designed footing for a house near the coast in South Australia. The owner has contact us regarding the external timber. The builder has used H2S LVLs for a number of exposed timber beams. He has also cut a number of LVLs in half (horizontally to halve their depth) and used these for fascias. We are trying to come up with a reasonable solution to ensure the durability of these timbers. Is there any coating that can be applied to seal the exposed timber beams? Is there a painted finish that would adequately increase the durability of the beams, and if so what process is recommended eg primer or sealer and then paint? The owner would really like to have the beams exposed for architectural reasons. If there is no way we can adequately seal the beams in place, do you know if there is a way and material which we could use to box the timbers, that would protect them but still give the owners an exposed timber look?

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As you are probably aware, H2S treatment only protects timber against insect attack, not wood rot. If the fascias are far enough back under the eaves so they will not be wet by rain, or gutters overflowing, then a paint coating would be adequate. It’s water that’s the issue, not moist air. If the fascias are likely to get wet regularly it’s a different story and we would be cautious about the effectiveness of a site-applied preservative in place of the recommended pressure treatment.

I am currently writing our waste management procedure, and would like to know if there is any treated timber that does not come under the classification of "Timber that has been treated with preservatives" under "Schedule 2 Materials that must not be burnt so as to discharge visible smoke into the environment" in the Environmental Protection (Unauthorised Discharges) Regulations 2004. We are looking at what off-cuts of timber can be burned as energy recovery as part of our waste minimisation programme. Many thanks

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The answer to your question turns on what the regulations mean by ‘preservatives’ and what they aim to achieve. There doesn’t appear to be a definition of a ‘preservative’ in the regulations, so a strict interpretation might prohibit the burning of any treated timber. On the other hand the aim of the regulations seems to be to prevent visible smoke in the environment, which suggests that if treated timber can be burned without discharging visible smoke into the environment, then that would be acceptable. It’s not recommended to burn timber treated with arsenic-based preservatives unless it’s done under controlled conditions, because arsenic is given off in the smoke and left behind in the ash. However, the regulations don’t seem concerned with this potential problem. But timber treated with creosote would clearly be prohibited since it gives off a black oily smoke. Then again ‘Blue Pine’ (house framing treated against insect attack) is only treated with a low-level chemical such as permethrin, as used in Mortein, which would not leave a dangerous residue nor produce any more smoke than untreated timber. We feel you really need to get a ruling from the WA Environmental Protection Authority, taking into account the kind of treated timber you propose to burn.

treated timber, burning, waste disposal, waste management, smoke, emissions

My question is in reference to the various wood preservatives used in construction currently.
I live in Sydney and most houses being built are timber framed with an exterior brick cladding. Most of the structural timber I see used is treated in some way (green, blue, red, etc.).
I understand that these treatments are used to minimize the possibility of insect attack; however,the plywood used for bracing is usually untreated.
Is plywood less prone to insect attack or is there another reason?
Furthermore, most old houses used untreated timbers and rudimentary termite protection, yet they are still standing solid.
Are treated timbers re-usable in future generations?
I thank you in advance for generously sharing your expertise.

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Many timber-framed houses now being built use some kind of treated timber for protection against insect attack (termites and borers). Treated wall bracing is available, but perhaps some builders are unaware of this. Untreated plywood is no less susceptible to insect attack than solid timber, so if the bracing is untreated then only the frame will be protected. Having said that, most builders also provide termite barriers, so treated timber is essentially a second line of defence in the event that insects (particularly termites) breach the barriers. Regarding the fact that old houses used untreated timber, but are still standing, many of them would have experienced termite attack during their life-span. Termite damage is usually detected and acted upon before it causes serious structural damage. The point about using treated timber is to stop termite attack occurring in the first place, thus avoiding the disruption and expense of in situ treatment, and possibly repairs and replacement of damaged timber. As to whether treated timbers are re-usable, treated house framing could certainly be re-used although it would not carry the warranty that applied to its original use. Timber treated for outdoor use (generally treated with copper-based preservative and therefore greenish in colour) could be re-used for a similar purpose.

What are alternative timbers to Turpentine for wharf fendering, and what strength grade and preservative treatments would be required for these grades to match properties of Turpentine?

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The reason why turpentine is a preferred timber for marine structures is because it has a proven resistance to many types of marine borers (but not all). Marine borer resistance is not closely related to the hardness of the timber but is attributed to its silica content. Turpentine is often used without preservative treatment, although if used in the round the sapwood is able to be treated, providing a protective envelope. However, you mention the timber in this case is to be used for wharf fendering which suggests it could be above the water-line, rather than in the water. If so, any Class 1 Durability hardwood would be suitable, eg. ironbark, tallowwood, etc. If the fendering is in the water an alternative to turpentine is preservative treated hardwood, preferably in the round so adequate penetration of preservative can be achieved. Koppers specialise in 'double treatment' of marine piles - for further information click on this link:

We need to replace the paling fences on each side of our property (Brunswick VIC), and although one neighbor and I are happy to use a standard treated pine paling fence, our other neighbour has said that they will only use a 'non-treated and sustainable' timber. I am stuggling to find information on what a suitable non-treated timber option would be? My main priority would be for a fence that is resistant to termites and rot/fungus, as well as matching the pine paling fence that will be installed on the other side. Can you use non-treated wood for standard fencing, if so, what it is, and who would do this, as the fencing companies that I have called have all questioned why I would possibly be looking for a non-treated wood for fencing? Alternatively,what is the most ecofriendly timber for fencing that I can suggest?

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The most practical option is probably cypress pine. Most fencing contractors use treated pine as a standard item, but many use cypress pine for posts and rails as it has a natural resistance to wood rot and insect attack, without the need for preservative treatment. It is also used for garden sleepers. Companies that stock these products may be prepared to saw palings for you, or to order cypress palings from their suppliers.

We are building a hall for a school with poles encased in concrete footings 2m deep in the ground, the poles are red ironbark narrow leaf. Can you pl. advise of alternate method of protection other than chemical for termite protection?

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Red narrow-leaved ironbark is a highly durable timber, and is rated Class 1 Durability for in-ground contact according to Australian Standard 5604-2005, Timber - Natural durability ratings. It therefore has a high natural resistance to wood rot and insect attack without any treatment.

Encasing timber in concrete may or may not have a beneficial effect, depending on whether the concrete is porous and retains moisture, or is dense and excludes moisture.

A non-chemical method of termite protection is a stainless steel "sock" fitted to the in-ground portion of the poles. Alternatively, inserting boron sticks into the base of the poles will provide added protection against decay and insect attack. Although not strictly "non-chemical", boron has very low toxicity and by this method is retained inside the pole. The technique is used by utilities to maintain their service poles.

For more information about the design with respect to durability, download the free WoodSolutions guide Timber service life design – design guide for durability.

Red narrow-leaved ironbark, Termite resistant, Chemical free, Boron

Is there a way to reliably use wide (eg 200mm) strips of solid timber in the top of a bathroom cabinet, to give the appearance of a single piece of timber whilst avoiding problems with "cupping"? What is the recommended approach for bathroom tops?

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Wide planks can be edge-glued to make up benchtops, but unless you are a skilled handyman it might be best to have the work done by a joinery shop. If you intend to do it yourself, make sure the timber is properly dried to a moisture content of 10-12% and use a water-resistant glue.

It is also very important to install and seal the top correctly. The sealer must be applied to all surfaces, including edges, forming a complete envelope.

For more information about timber in internal design, download the free WoodSolutions guide Timber in Internal Design.

Bathroom cabinet, Cupping, Bathroom Tops, Joinery, bench tops, benchtop

We're planning on building a new home, and would like to have natural (unpainted) timber window frames. We're happy to use preservatives and oils, but not paint or urethane. Some of the frames would receive direct sun and weather. We're not in a high fire risk area. We'd prefer FSC/responsibly sourced. I'm concerned about durability and cost. I've found a local supplier who uses rosewood which is class 1 durability, but it's on the expensive side. Western red cedar is class 2 durability, but a bit soft. Do you have recommendations for other types of timber to look into? We live in Melbourne.

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Western red cedar is fairly soft but generally performs well if it's out of range of knocks and bumps. Hardwoods suitable for window joinery are in the higher price range because they are selected to be of high quality, free of knots and other blemishes.

You could consider jarrah from Western Australia (as distinct from "Pacific jarrah" which is usually vitex, a South American timber). Jarrah windows are durable and hard-wearing.

If you are planning to oil them, be aware that the windows under full weather exposure will need oiling several times a year to look their best.

We also recommend that the glass is installed with wooden glazing beads bedded in silicone, rather than putty, since putty needs the protection of paint to prevent it drying out and cracking in the long term.

For more information about the design, construction and maintenance of timber windows and doors, download the free WoodSolutions guide Timber windows and doors.

window, windows, oil, western red cedar, jarrah

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