FAQ Wood

No. We do not recommend application in direct sunligt. If you apply wood protection in direct sunlight, you may see stripes, because the wood protection settles too fast, and there is not enough time for it to flow together. Note that this only applies to opaque and translucent wood protection and not for wood oils.

No (and yes). If you apply a regular water based wood protection, while it rains, this will ’rain off’, as the product is water soluble. Furthermore, the humidity becomes higher, and then the drying time is prolonged. The final result of the application may be a matted surface with spots and uneven texture. If you apply a solvent based  product, when it rains, it will not ’rain off’, but you may see a matt and spotted surface as a result. New products are being developed, and in the Bondex range, there is a rain proof product available, which offers a ‘rain proof’ surface only 30 minutes after application.

In general, water based products are more sensitive than solvent based products, when there is a variation in the temperature. This is caused by the different drying processes. Water based products dry, because the water evaporates. If it is very hot, the product will dry too quickly and there will be visible brush marks on the surface. Solvent based products dry via a chemical process - the higher the temperature, the quicker the drying and vice versa. Normally we recommend a temperature between +10 - (+) 25°C during application and drying.

Yes. When the wood has been exposed to UV rays, for as little as 2 weeks, you should - in theory - sand before applying wood protection. The reason being that the binder in the wood (lignin), is degraded by UV-rays. You can typically see this when wood changes colour (greying/lighter colour).

It is extremely difficult to apply transparent wood protection with a spray, because the distance to the surface must be kept at a constant, or there will be a distinctive colour difference or overlapping of coats depending on product/drying. If spray application is carried out, the product must be diluted 20%. Normally you will need a finer

This depends on the product. Normally, solvent based products have a longer open-time, meaning that you can work with the product for a long time, before it starts to dry. On the other hand, water based products have a shorter open-time, so you cannot work with these products for very long, before they begin to dry. Also see under colours.

Yes. You can apply opaque wood protection with a roller. However, note that the roller will leave a roller structure on the surface - especially on planed wood and previously treated surfaces.

Normally, wide brushes are preferable on large surfaces, but round brushes are best suited, when you apply a solvent based product on e.g. windows.

The surface may crack, because the two coats act against each other during the drying period because of variations in the tension of the layers.

In order to obtain good adhesion or penetration, it is vital that the surface is clean, solid and free from loose wood fibres.

When the varnish has hardened completely. Normally 3 weeeks after application.

If you treat a surface, which has not been cleaned, there is a risk that the wood protection will not adhere properly to the surface and in turn it will peel off rather quickly. It is not enough just to brush the surface, before applying wood protection, removing the obvious problems such as cobwebs, dust etc. You need to clean the surface thoroughly and remove any kind of incrustations, so you are absolutely sure that the surface is completely clean. This also applies to new wood, which might have e.g. beginning fungal attacks after a long, cold winter in storage in an uninsulated room or even outdoors at the timber yard.

In general, you can say that a water based product obtains adhesion by attachment to the surface. Therefore, these products are more sensitive in terms of how clean the surface is. Alkyd based products have a better moistening/penetration ability. This means that solvent based products can adhere more easily to slightly dirty surfaces.

When using a transparent product, you can see the wood veining and structure underneath. As wood is a natural material, a wooden surface will never be uniform, and there will always be visible differences in the colour. Another reason could be overlapping, which can happen, when you return to apply on areas, which have already  been treated. The faster a product dries, the less surface you can treat at a time, if you you want to avoid overlapping.

This can be caused by a very dry and worn down surface. In this case you will normally use more product for the first coating, as the wood will be more absorbent.

Solvent based products dry by means of a chemical process, and the air humidity has no effect on the drying  time. However, the drying time will be affected by changes in the temperature. The higher the temperature - the quicker the drying. Note that if solvent based coatings dry too quickly, the result may be a spotted and uneven result on the treated surface. Water based products dry because of water evaporation. The higher the temperature - the quicker the drying. The ambient humidity has a crucial impact on the drying. The higher the humidity, the more difficult it is for the water to evaporate. This will normally cause an imperfect film and surface.

The risk is that the moisture may become trapped inside the wood. The wood protection will not be able to penetrate properly into the wood, but will remain on top of the surface. In the end this may lead to degradation of the wood and it may rot. The wood protection you applied will peel off.

This depends on the chosen product. The less film and pigment on the surface, the shorter the durability. As a rule, opaque products have the longest durability. The wood construction also plays a vital part for the durability, and rain water must be able to escape rather than settle on a surface.

Many factors play a part in the durability of wood protection: Weather, application, quality of the wood. Wood is an organic material with many variations in both structure and appearance. In general, the majority of the problems are related to the construction.

If there are too long intervals between treatments, and the wood protection has started to peel off, your wood is completely open and unprotected. This means that the wood is much more exposed to wind and elements and it will degrade much more quickly. Moisture will penetrate into cracks, creating perfect conditions for rot and mould. If there is moisture in the cracks, and the temperature is below 0°C, the wood fibres will be destroyed, and wood will suffer even further decay.

Preferably not. The product is film forming. When a horizontal surface is treated with a film forming product, moisture cannot escape from the wood underneath , and in the end the pressure becomes too big and the surface will peel and crack. In addition, most Bondex wood stains contain fungicides, which are not recommended near e.g. food and drink on a table in the garden.

Yes. Always. If it is a new deck, you can prevent mould attacks. If the deck has been treated before, it must be cleaned before applying a new layer of decking oil. If you don’t, the oil will not penetrate sufficiently deep into the surface.

Yes. Chlorine will discolour the wood and you will need to clean regularly.

Yes, there is no problem in applying wood protection without a pretreatment. Of course the wood will not be protected against rot, termites, wood destroying worms or blue stain, unless the wood is pressure impregnated, vacuum impregnated or Thermowood®

It depends on whether the deck is new or old... If it is new - no. If it is old - yes. On an old wooden deck, there will be dead wooden fibres on the surface, so it is a good idea to sand it down, until the wood again appears clean, uniform and solid.

Yes. There are two reasons for sanding the surface: 1) To get a better adhesion of the layers of varnish. 2) To remove any dust from a previously varnished surface.

Normally grit 80-120.

If you do not sand thoroughly, you may see that the wood protection does not have good adhesion with the surface. When you sand, you scratch the surface slightly, which improves the adhesion of the wood protection you apply. You also remove dead wood fibres from the surface, so you obtain a smooth and clean surface for applying wood protection. Remember - do not use too fine grit, i.e. sandpaper with grit over 220 is not useful for our products.

Yes. However, it is extremely important that the old layers are completely dry. If they are not, the layers can work against each other and result in a cracking surface.

The Slow Release technology is active only during high humidity and counteracts the growth of mould. This means that the active ingredients are only taking effect, when it is needed. When wood is attacked by mould growth, the humidity in the wood increases considerably.

When using water based products, you have a tendency to increase the coverage too much and thereby reduce the durability. You simply spread the product on a larger area than intended (more m/liter). Therefore it is important that you try to apply rich layers according to the on-can instructions and instructions stated in the Technical Data Sheet. Normally, you will not experience these problems with solvent based products, as the friction is higher than for water based products.

When you use a transparent product, the rays from the sun will be reflected from the base of the wood and the pigments, because the wood protection is transparent. When you use an opaque product, the sun’s light will only be reflected from the pigments. The more pigments, the better protection.

Clear/colourless wood protection products are available, but the durability is significantly lower compared to products, which contain (colour) pigments. In order to compensate for the ’missing’ pigments, anti-UV agents are used (as in sunscreen), but these are far less effective and also very expensive. If you use colourless wood protection, you need to apply min. 3 coats.

PPG does not recommend the use of products containing fungicides for indoor use unless there are special circumstances.

Wood preservative products are made of active ingredients, additives and solvents. Active ingredients have fungicide and/or insecticide properties. They are fixed to the wood through fixatives. Both penetrate the interior of the wood through the solvent, which acts as a vehicle. Their main properties include: effective action against degrading agents, product stays in the wood and protective action continues for a certain time. The preservative is often neglected in wood protection systems. However, if you use a preservative you will ensure: improved adhesion of the top coat, reduction of moisture absorption and biological protection of the wood. Normally, you will only need to apply a preservative on softwood (spruce, pine, fir) and not on hardwood (mahogany, teak etc.).

Preservatives on new wood
New, untreated wood should not be left for too long without treatment. The natural degradation of wood starts on the first day the wood is outside. New wood may be infected by mould, which is not visible to the naked eye. If you are in doubt, clean the wood with a suitable detergent before applying treatment.

Preservatives on previously treated wood
If the wood protection looks worn down and has started peeling off, it is time to give the wood a new treatment. Check the wood before treating it:

• Rotten wood must be renewed
• Water traps must be mended by leading water away from the wood
• Mould and incrustations must be removed with a cleaner

Preservatives on wood attacked by insects and/or wood worm
Remove all the previous finishes such as paint, coatings and varnish. Strip the surface or brush off any decayed parts. Treat all wood surfaces two times or submerge the wood in the preservative for a couple of minutes.  Treat all wood, which is in contact with other wood, their respective joints and parts embedded in walls. Replace any parts, which are excessively affected and thereby weakened.

Depending on taste and climate: water based, hybrids and solvent based products. Each have their advantages and downsides.

In general you can say that the more pigments there are in the product, the better the protection is. A transparent product/material will reflect the sun’s rays both from the wood underneath and from the pigments, because the coating is transparent. When you have applied an opaque product, the light is only reflected in the pigments in the product. The purpose of a transparent product is to leave the wood grain visible.

When you try to assess, if the treatment applied is water based or solvent based, you can rub a little white spirit on the surface. If the coating dissolves, the surface has been treated with a water based product. If the coating does not dissolve, it is likely that the surface has been treated with a solvent based product.

If the colour of the filler is lighter than the colour of the top coat, remember to sand after you have applied the filler.

No. If you apply wood protection on a surface, which has previously been treated with linseed oil, the new top coat will bubble. Linseed oil does not work with modern wood protection - this applies to both water based and solvent based wood protection products. If you want to apply wood protection on a surface, which has  previously been treated with linseed oil, you need to remove the layer of linseed oil first plus an extra milimeter. This is extremely important in order to get a good result. Linseed oil can be removed with a special lava- or (dry ice rinse), or it can be sanded down. However, if the linseed oil has burned off (it does that rather quickly), the best solution is a thin solvent based product - no cleaning needed.

Wood preservatives contain a fungicide and an insecticide for maximum protection. The main characteristic of the wood preservative is that it penetrates deep into the wood to prevent both fungal and insect attacks. Wood preservatives not only have preventive properties, but can also cure already infested areas.

Wood protection products can be divided into two categories: translucent and opaque. The translucent, pigmented stains are translucent coatings, to which insoluble pigments are added. They form a translucent film with a coloured tint, through which the underlying wood grain is visible. Opaque wood protection is covering coatings - the entire colour film is pigmented and the underlying wood is no longer visible. The majority of the PPG wood protection products contain fungicides, which offer surface protection against fungi and mould.

A varnish is a clear, transparent, hard coating or film. It is not a stain... Varnish is primarily used as a wood finish, where - stained or not - the distinctive tones and grains in the wood are intended to be visible. Varnish finishes are naturally glossy, but satin/semi-gloss and flat sheens are available.

Oils are normally used for wooden decks and garden furniture. The difference between oils and wood protection

The PPG outdoor products contain fungicide for optimum protection of the outdoor wood against mould and fungi. As these ingredients are of a chemical origin, we do not recommend indoor use

When the wood protection peels off ’before time’, it is often because of humidity in the construction or inadequate preparation. If you use a film forming product on wood with a raised moisture level, the moisture will create a pressure from within the wood, and push off the wood protection. Typically this will appear more quickly, if you have applied wood protection on wood, where you have not cleaned the wood, so that there were still dead wood fibres on the surface.

The tape test can be used for two different purposes:

1) Check wood for dead wood fibres.

2) Check if the existing coating adheres to the wood.

Use a transparent tape with good adhesion. Press the tape firmly onto the surface and rip it off. Assess the back of the tape. If there are visible wood fibres, the surface was not cleaned sufficiently before applying wood protection.

Applying wood protection on horizontal surfaces, is probably one of the biggest challenges. This is du to the heavy impacts that horizontal surfaces are exposed to. 

Especially two conditions are vital: 

1. the weather 
2. the mechanical impact from the foot traffic on e.g. a wooden deck. A horizontal surface is 100% exposed, when it rains, snows, freezes or melts several times during the day, or when the sun is shining (UV-rays).

Depending on which side of the equator you live, the direction towards the sun’s orbit will always be more exposed. In the Norhtern hemisphere, south and west facing wood is highly exposed. It is also a well known fact that the closer you are to a sandy beach, the more quickly the wood protection will degrade. This is caused by the wind carrying sandgrains through the air and thus acting like sanding paper.

All types of wood are exposed to risks resulting from UV-rays. UV-rays expose the wood for degradation and drying.

Heat treated (Thermowood®) wood provides a protective effect without the use of chemicals. The wood is heated in industrial plants to temperatures around 200°C (in the entire cross section of the wood). Wood mainly consists of three chemical agenst: lignin, cellulose and hemicellulose, where the latter is the one that absorbs the most moisture. When using heat treatment, a degradation and transformation takes place - mainly of the hemicellulose, which makes the wood less moisture absorbant. The wood becomes more stable and more resistant to fungal attacks. The heat treatment causes the wood to change to a darker shade. Heat treated wood only needs treatment with a preservative, if there is a risk of termite attacks.

If untreated wood is left outside, it will very quickly be attacked by bacteria and micro fungi, which are a part of the wood’s natural degradation process. In the beginning it is not visible, but the wood becomes more porous and absorbes more water. This creates excellent conditions for more fungal growth. Over time the attack becomes more and more visible in the shape of dark discolouration of the entire wooden surface or black incrustations on the surface, which resemble normal dirt. If you have an outdoor wooden surface, which has been left untreated for a longer period of time, it will be wise to disinfect the surface, before applying wood protection.

In general this can be caused by 2 things:

1. During application of a water based product, the humidity has been high, and this will prolong the drying time.
2. The second - and more complicated factor - is the wood species.

Some wood species contain a ”resin”, which has a chemical reaction with the wood protection. This process can prolong the drying time.This applies to e.g. Teak, Iroko, Western Red Cedar and Larch.

The white rings or spots are either caused by water, or that the surface has not completely hardened. Normally this takes at least 3 weeks. We recommend that you do not clean or use/spill water on the floor for the first week after application.

There is a wide range of signals that indicate wood has been damaged, including holes, sawdust, noises coming from within the wood, depressed soil, dead insects found next to windows, etc. Both the insect and the type of damage produced, or the appearance or size of larvae are useful to identify the type of treatment required.

• Large woodworms leave oval, 5 to 10 mm (diameter) flight holes. A dull noise heard when knocking on wood can be a sign of attack. If larvae are inside, it is possible to hear the noise they make while feeding. Their tunnels are near the surface. Adult larvae are 13 to 30 mm long and of light colour.
• Fine woodworms make many round, 1,1 to 3 mm (diameter) flight holes. Their tunnels have an irregular shape and contain dust and excrements. Adult larvae are white and 4 to 6 mm long.
• Moths make holes similar to those made by fine woodworms (diameter of approx. 1.6 mm). Their tunnels mainly follow the grain. Larvae are white and 4 to 6 mm long.
• Termites attack (coniferous and nonconiferous) wood and other materials, such as textiles, paper and even plastics.Termites open interior galleries leaving an outer, 1 to 2 mm thick shell intact. They make no noise when feeding on the wood. Termites are 4 to 6 mm long.

Remove grease, dirt etc. with a suitable detergent. Lime- and soap residues can be removed with 32 % acetic acid diluted 1:3 with water. Rinse with clean water. Sand the surface matt with fine sandpaper (grit 120-180) and remove the sanding dust. The surface should now be clean, dry and solid. Floors with old, worn down varnish, polished and waxed floors, must be sanded down to clean wood surface. Plane and vacuum.

When mounting hardwood, you need to pre-drill screw holes and countersink the screws.This is particularly important, when using corrosion resistant screws, which are easily screwed in too hard resulting in the heads of the screws falling off. We recommend to place the screws at least 50 mm from end grain to avoid cracks and splits.

• Depending on the degree of wood degradation after stripping, in addition to sanding, it may be necessary to rough-grind damaged parts and to replace them with healthy wood.
• The dosage applicable to curative treatments is always higher (always follow instructions given on the container label).
• For beams and joists larger than 10x10 cm, bore holes (diameter: 8-10 mm; depth: 2/3 of timber width) from top to bottom. Inject treatment product until saturation. Product can also be injected in the insects’ flight holes (1 every 3 cm).
• Once treatment is finished, fill holes and cracks using putty.

Some wood species contain water soluble elements or tannins, which can cause discolouration of the surface, when impacted by water. If e.g. you treat teak or oak with a waterbased, opaque white wood protection, the water from the wood protection will dissolve the pigments in the wood and cause discolouration on the surface.

We recommend to clean your wooden cladding once a year with a suitable cleaning agent. If wood protection is peeling or cracking (see item 2.3 Tape Test), you will need to sand the peeling surface, clean and then apply a maintenance coat.

If you have used wax on a surface, you can only apply wax on top of wax - no other top coats can be used.

No. Teak and some other hardwoods contain natural, protective ingredients against rot and fungi in the wood itself, and it is not necessary to treat with a wood preservative.

Softwood is characterized by normally being a light colour. It can expand considerably. Softwood normally requires pretreatment with a preservative. Some hardwoods only require preservative treatment, if there is a risk of termite attacks. The durability of hardwood is much longer than softwood, and the prices of the wood species

Accoya® is a tradename for the fast-growing Monterey Fir (Pinus Radiata). Accoya® is unique, because it has undergone a non-toxic treatment, which improves its characteristics substantially. The treatment is called aceylation. The principle is to add another agent, in order to block the water-binding alcohol groups in the wood. The added agent is typically acetic acid, which is added at 100-200°C. The scientific explanation is rather complicated, so the simplest way of explaining it is that the softwood is subjected to a vinegar, which turns it into hardwood by preventing the cells in the wood from being able to absorb water. In reality the ’vinegar’ is is acetic anhydride and it attaches itself to the wood’s hydroxyl groups, where otherwise the water would have been absorbed.. Preservative treatment of Accoya® is only necessary, when there is a risk of termite attacks. After the treatment the density of the wood is increased by 8%. According to the manufacturer, the wood has become as resistant to fungal attacks as teak, and as dimensionally stable, so that you now have a completely stable material. The wood has a guaranteed durability of 50 years above ground and 25 years in the ground. Accoya® should be treated as ordinary spruce.

Composite comes from latin: »componere«. Composite materials are created, when two or more materials are combined. Composite boards may consist of 60% wood, 30% plastic and 10% binding agent. You can use both water- and solvent based products on composite. Do not use preservatives. Depending on the quality, Composite has a tendency to bend or twist, and treatment with a PPG product cannot solve this problem.

Yes. But only if recommended for this purpose. Examples of this use are Robinie, pressure impregnated wood NTR-A. None of our products are recommended for use on wood in contact with the ground.

Bamboo has a very hard surface. This means that the products have difficulty in penetrating the surface and thereby obtain adhesion. After carrying out several tests, we recommend a thin product.

No, because there is a risk that the moisture content of the wood is too high, and that you will encase the moisture. This can result in peeling and cracking, and in the worst case rot in the wood. When spring comes you should clean the wooden surface, remove any decayed wood and wood fibres, sot you are left with fresh wood. The you should prime against rot and fungi, and apply 2-3 coats of wood protection.

It is very difficult to remove wood protection stains from flagstones or masonry, if they are dry. If the stain is discovered right away, you can probably remove most of it with white spirit, depending on the colour and posity of the surface. If the stain is dry, you can apply soft soap, which will soften the wood protection. Clean the surface the next day with a high-pressure cleaner. On cars you can remove fresh wood protection stains with white spirit. If the stains are dry, it will be necessary to polish the car with a polishing product with light sanding properties. On windows you can remove stains with a razor blade.

It depends on which type of wood protection you choose, and which impacts from the climate your wood surface is exposed to. There are several different types of wood protection products for surface treatment. They can be oil or water based, translucent or opaque.

Translucent wood protection:  has pigments, but does not hid the wood structure completely. The veining is still visible. The growth of mould is inhibited. If you choose translucent wood protection, you need to maintain relatively often - typically with 1-4 years interval.

Opaque wood protection:  contains more pigment than translucent wood protection. More "surface" is formed on the wood, which is therefore protected for a longer period of time - typically up to 10 years depending on product and climate. The wood veins are hidden, but the wood structure itself is preserved. Also in this case growth of mould on the surface is inhibited. Regardless of choice of wood protection type, you must always check your woodwork thoroughly once a year and remove dirt, algae and mould as well as mend any damage(s).

We recommend using Bondex Decking Oil, Bondex Extreme Decking Oil or Bondex Matt, as these products will enhance the warm, reddish glow of the wood. Using a wood preserver is not necessary. Treat the wood 2 times with a one or two-day interval.

Worms are the larvae from the woodworm. You can tell if the attack is active, if you can see very fine sawdust. Bondex Preserve is a product for outdoor use only, which is both preventive and curative against insects, woodworm, termites, fungi, rot and blue stain. As products curing the above problem need to be approved by registration in the various countries by local authorities, please enquire if such a product is available in your market.

Yes, but it is not the optimum treatment. However, your wood will be reasonably protected until spring, where you can finish the treatment.

Whether you choose oil based or water based wood protection is a matter of taste, but there are a couple of things to consider:

The water based wood protection products demand a very careful preparation in order to achieve a good result. In return the maintenance intervals will be longer than for oil based wood protection. If the construction and preparation is not good enough, you risk moisture absorption under a seemingly intact surface. Oil based wood protection is normally degraded over time by erosion. Therefore maintenance is easy, because the preparations are not so extensive.

All things being equal, you get the longest durability with water based, opaque wood protection, while the shortest maintenance intervals are seen with translucent, oil based products. However, please note that water based wood protection is not recommended for horizontal surfaces, where the water cannot be led away! In addition it is very important that the construction is correct.

Therefore: If the construction of the woodwork is correct, the syestems will be equally good. On areas in which the construction is lacking, we recommend an oil based system, which will tell you if there is a problem by peeling off.

Yes, you should prime larch against rot and fungi like any other coniferous wood.

When you apply wood protection the average day and night temperature must be above 5oC during the night. Furthermore the wood must be dry - wood moisture should not exceed 15%. It can be difficult to assess, if the wood is dry enough. But in many DIY stores and paint shops, you can rent a moisture meter, in case you are not sure. The relative humidity must be below 80%. As a guideline you can say that it must have been sunny or windy for at least a couple of days before the wood is dry enough.

Pressure impregnated wood can be treated, when the wood is dry - max. 18% moisture content in the wood. You can rent a moisture meter in most DIY stores.

A colourless product does not contain any pigments. The colour pigments in the surface product protect the wood against the sun's UV-rays. If you use a colourless wood protection as end treatment, the surface will quickly degrade and turn grey, and be left without protection. Colourless wood protection is therefore mainly used for thinning 1:1 with other translucent colours, if you do not want to give a lot of colour to your wood. We do, however, have a colourless product for exterior use (Bondex Long Life UV), but you need to ensure that you apply at least 75 microns in layer thickness (= at least 3 coats).

Some wood species contain large amounts of water - especially softwood (incl. Western Red Cedar), and we always recommend corrosion resistant nails and screws.

You can use both, but they should be corrosion resistant in order to avoid corrosion and metal discolouration. Some wood species - e.g. Western Red Cedar - contain corosive agents, so in this case corrosion resistant nails, screws and fittings are preferable.