Category: Uncategorised

After investing in the value of Cedar to clad your home you will want to make sure that you can maintain the appearance and integrity of the Cedar.

The most common problems that occur with Cedar cladding and timber features on your home are:

(1) Cupping of boards

Cupping occurs when the timber has been left unprotected or the timber stain or wood oil surface treatment ceases to be an effective barrier to the weather. This allows moisture to enter the timber, and as it evaporates more quickly from the surface, it causes the timber to shrink on its outer face, causing the cupping effect.

This will, in time, become unsightly, cause the boards to pull away from the nails or cause them to split. Eventually it may lead to weather-tightness issues.

The solution is to ensure that you have an adequate surface treatment, such as wood oil or timber stain, applied from new, and consistently maintain that treatment. Depending on the exposure of the cladding to the weather, most wood oils or stains will give between 3-5 years of protection. After that, you risk cupping!

(2) Discolouration due to contamination

Discoloration comes in many forms. The first, and easiest to solve, is discolouration from contamination.

It may be caused by dust and dirt build up, airborne fungal spores, salt air, pollution from vehicles and roads, construction sites or other nearby industrial or agricultural activity.

To help reduce this you simply need to regularly give the cladding a ‘soft-wash’ with water. In most cases there is no need to use chemicals or a power wash with a water blaster.

If you are a DIY person, and your house is not too high, you can do it yourself. First use a soft broom to gently lift off any cobwebs. Then using the hose with a spray nozzle attachment start from the bottom and gently and systematically hose of the cladding until you get to the top. Then give it a rinse down.

Don’t be tempted to brush or scrub the cladding while you are washing as this can damage the surface coating. Don’t use bleach products, as these will change the colour of the contamination but won’t necessarily remove it. It will also mark the Cedar cladding.

Sometimes the contamination may be dark or black spots in behind the surface treatment. If so, contact us to assess it and recommend a way to remove it.

(3) Tannin staining and silvering

A common problem with Cedar is tannin staining. Like many species of timber, Cedar wood contains tannins. When moisture enters the unprotected surface or ends of the Cedar timber the water-soluble tannins migrate to the surface of the timber causing the dark tan to black discolouration. The areas that are more exposed to the weather and rain have these tannins washed away and become dull and grey (silvering).

While silvering may have a rustic charm, unfortunately, most silvering is a sign of damage to the outer layer of the Cedar.

Silvering is caused by the fraying and loosening of the top cells of the Cedar under long-term UV exposure.  Technically this is photo-oxidation. The weather and sun not only damage the outer fibres, but they also further deplete the natural oils of the timber. Hence it loses its original colour and become silver.

When the timber is damaged in this way it is becomes defenceless against the other detrimental elements such as mildew, mould, moss, lichen, and moisture.

(4) Discolouration due to mould development

If you see brown, black, red, green, or white patches developing on your Cedar, it is likely to be mould. Generally, the mould problem will be aesthetic and not actually cause a decay to the underlying timber. However, it is unsightly and is an indication of a more serious problem, excessive moisture retention. If left too long it can cause staining, so it is best to treat it early. White moulds are some of the most stubborn to remove and may permanently mark the timber.

Most moulds can be cleaned from the timber using a chemical cleaning agent. While many recommend bleach solutions, we don’t. Bleach type cleaners may only change the colour of the mould and can cause streaking on the Cedar, which is as unsightly as the original mould problem.

The key to avoiding mould developing is the application of a surface treatment such as a timber stain or wood oil which will provide a protective coating that sheds the water from the surface of the timber. Wood oils contain anti-fungal properties which will also help inhibit the development of mould. After that it is a matter of keeping your cladding clean by means of regular light wash downs that will remove the dust and other contaminants that can harbour or trap the airborne mould spores on your Cedar.

(5) Darkening of the timber due to moisture retention.

If you notice the weatherboards on your home stay dark after the rain, it is likely that they are absorbing and retaining moisture. It is also can be the result of the timber having contact with the ground, other timber such as the deck, or being too close to the flashings. This will allow the cladding, through the process of osmosis, to absorb the moisture into the timber.

As a result of excess moisture, you will have the development of mould or fungi, increase the likelihood of cupping and timber rot, and the possibility that the moisture will migrate into the interior of your home.

To prevent this, it is important to ensure that your Cedar is protected by maintaining the surface treatment of timber stain or wood oil.  You should also ensure that the timbers are not touching the ground or garden and are not tight fitting against flashings or other timber structures.

(6) Weathering of the boards

Weathering of the boards is the result of the combined effects of the sun, rain, and wind eroding away the softer timber fibres of the cladding. This results in patches of timber with a rougher surface that reflects the light differently to the smoother sections, leaving you with a patch-work effect on your Cedar walls.

Not only are weathered boards unpleasant to look at, but they are also more likely to retain moisture and trap dirt, dust, fungal spores, and other contamination on the timber. This leads to mould or mildew growth.

Extreme weathering will eventually reduce the thickness of the timber, and particularly on profiled weatherboards, make them more prone to splitting.

Protecting your timber with a timber stain or wood oil is required to prevent weathering and will maintain its consistent appearance.

(7) Opening up of joints and corners, pulling away from the fastenings.

While Cedar is a very stable timber, it will still be affected by the constant effects of moisture and heat.

When it is left unprotected moisture will start to be absorbed into the timber. As it dries, the outer face of the timber will start to shrink.  This results in cupping of the boards and the opening up of the joints and corners.  Due to the constant movement, it may also start pulling away from the fastenings or nails.

To rectify these issues, you may need to add flashings to the joints and corners, or box-in the corners. If the boards are pulling away, you may be able to gently re-fix them with screws. However, care needs to be taken so that you don’t split the cladding. If left too long, you will be faced with replacing the Cedar.

The better solution is to ensure that you keep up the maintenance by regularly cleaning and then apply a timber stain or wood oil. This will help prevent the moisture entering the timber in the first place. It will also mean that your property looks great, and that will add to its value.

(8) Decaying or timber rot at ends of boards and corner mouldings

When the cladding or corner moulding comes into constant contact with the ground, other timber structures such as decks, the flashings, or plants that are planted too close to the wall, it will start to retain moisture.  This causes the onset of timber decay or rot which will affect not only the lower boards, but also the bottom plate and studs of the building.

To prevent this, you need to ensure than the timber is not in contact with the ground or flashings and make sure that plantings are kept well clear of your cladding. This will allow airflow and help the timber dry out.

In some cases, you may need to shorten or cut back the bottom boards so that they don’t come into contact with the ground or flashings.

(9) Development of mildew, mould, moss and lichen

Cedar wood consists of cellulose, a substance contained in the cell walls of all plant materials. Cellulose provides an ideal nutrient for many mould varieties. To exacerbate matters further, Cedar is high porosity, meaning that it can absorb and trap moisture. The combination of moisture and cellulose provides mould or mildew spores with everything they need to grow and multiply.

Moss and lichen, although from different families, will take root in moist and dirt laden cladding. While moss (like a green carpet) tends to sit on the surface, lichen (like small trees or plants) extends its roots into the timber and can’t just be washed off.

Therefore, the best way of controlling mildew, mould, moss, and lichen is to keep the exterior timber clean and dry. This is best achieved by apply a timber stain or wood oil to the cladding, and then keeping it clean by means of annual wash downs.

If you already have moss, lichen, or mould on the cladding on your property we recommend that you contact a Cedar maintenance specialist to assess and advise what is the best way to treat it and then protect the cladding from further deterioration.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what you can do to maintain the Cedar on your home by reading our articles What You Need to Know about Caring for the Cedar on Your New Home and Why Cedar Needs Special Care to Maintain Good Looks and Value.

A frequently asked question is can I paint my Cedar cladding?

Many ask because they have come to realize that a painted weatherboard will likely only need re-coating after 10-12 years, but stained or oiled Cedar weatherboards may need re-treatment every 3-5 years. So, is painting the Cedar a good option? No, not really.

The first reason why painting Cedar cladding is not a good idea is that you are covering up natural beauty of the wood’s grain and not adding value to your property. Even if the Cedar is new and can be painted without the issues mentioned below, why would you invest in Cedar cladding and then not enjoy some of the benefits it offers?

The second reason why painting Cedar is not a good idea is that it can lead to some serious maintenance and weather-tightness issues.

Cedar constantly contracts and expands with the changes in temperature and humidity levels. Weathered Cedar is likely to have small fissures, and even splits, in it is surface. Due to the constant movement, it is almost impossible to form a complete seal over these cracks, splits, or the joins in the timber.  Any moisture that gets on the boards will try to find its way in through any gaps.  That moisture can then be trapped in the weatherboard cladding and will cause them to decay and may migrate to the timber framing or internal walls of your home.

If you can successfully form a seal over the timber, you can trap the moisture in the timber. When it is exposed to the warmth of the sun that moisture will try to come out, creating blisters and then splitting the paint surface.  At that point the integrity of your paint film coating has been compromised and will now allow moisture to enter into the timber.

So, what are the recommended surface treatments for Cedar? Timber stains or wood oils. Both of these treatments are transparent coatings designed to be used for Cedar timber.  They will provide protection to the timber while allowing you to see the beauty of the natural grain and colours.

See Recommended Cedar Treatments.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what you can do to maintain the Cedar on your home by reading our article What You Need to Know about Caring for the Cedar on Your New Home.

Cedar cladding is something that can add visual appeal and value to your home. So, if you own a Cedar clad home, you will want to be aware of the main threats to your Cedar and the appearance and value of your home.

The three main enemies of Cedar timber

Cedar’s worst enemy is the sun. And here in New Zealand we have some of the harshest UV rays in the world. The UV light changes or destroys the wood’s lignin, a component of wood that hardens and strengthens the cell walls. Technically this process is called photo-oxidation, but put simply it is the surface fibres of the timber degrading or breaking down. Evidence of this happening is the ‘silvering off’ of the Cedar, and then being able to rub off the loose fibres.

Combined with Cedar‘s second enemy, rain, this sun damage allows moisture to be absorbed into the timber. As the boards dry, the moisture on the face the cladding evaporates and the timber on the outer face shrinks, causing cupping. Eventually the cupping will result in the cladding pulling away from the fastenings, splitting and popping out on the corner joints.

The breakdown of the surface fibres also creates toeholds for the third enemy of your Cedar, mildew, mould, and lichen. Once these get established the timber will look aged and dirty, with red, black, green, or white moulds, and lichen growth. If left for too long, and the timber is exposed to constant moisture, more significant damage will occur as, fungi, the precursor to wood rot, develops.

 Pamper your Cedar

Like us Cedar enjoys some pampering. Regular light wash downs will help keep the surface free from dust, dirt salt-air contamination and mould or mildew spores. Periodic retreatment with a protective timber stain or nourishing pigmented wood oil will maintain a level of UV protection and keep the cladding moisture proof. This pampering will help extend the Cedar service life and keep it looking great.

Maintenance of your Cedar is an investment in the future value of your property, so call us to find out what we can do to help you maintain the value of the Cedar on your property so that it retains its beauty and value.

See our Cedar Cladding Maintenance Program.

If you have moved into new home you no doubt expect that it is going to be low or almost no maintenance for many years.  However, all things, even those that are new, require some form of maintenance or servicing to keep the running well and looking great.  We clean and polish our new shoes, we get our new car serviced, we vacuum our new carpet.

Cedar cladding is the same; it needs to be serviced or maintained from new. And when you do that, it will look great and be serviceable for years to come.

Also bear in mind that even though you only moved into your new home a few months ago, the cladding was likely installed 3-6 months before your new home was completed.

What type of servicing or maintenance is required?

If the Cedar cladding on your home has been oiled, it will need a ‘soft’ wash and maintenance re-oil within 12-months of the initial oiling. This “top-up” coat will help replenish the Cedar’s natural oils and anti-fungal properties, help consolidate the colour tone, and ensure that all exposed surfaces have a level of protection against the elements.

After this, the retreatment times will be between 3-5 years depending on the timbers’ exposure to the elements. Areas exposed to the sun and prevailing weather will need re-treatment more often than the protected and southerly sections of cladding. The good thing is that wood oil is only applied 1 coat at a time, and this leads to a significant savings in labour costs.

A pigmented wood oil provides UV protection. Without this the timber is exposed to the sun’s harmful rays and will start to ‘silver off’ in an uneven manner.

For stained Cedar cladding you will want to start your maintenance with a “soft’ water wash soon after you move into your new home. This will remove any accumulation of dust and dirt from the construction process and give you an opportunity to inspect the cladding more closely. Then you can expect to get at least 2-5 years protection from the timber stain coating. If, however, you start to notice any fading of the colour, oxidation of the stain, or that the timber doesn’t bead water or darkens significantly after getting wet, it will require re-staining.  Normally this process requires a light chemical wash and then the application of 2 coats of timber stain.

Apart from maintaining the retreatment with wood oil or a timber stain, one of the best maintenance things you can do is give the Cedar cladding a refreshing water-only wash-down every 6-12 months using your garden hose. This will wash off the dirt and dust and help prevent mould spores settling on the timber.

This regular wash-down is particularly important if you are close to a main road, on-going construction, agricultural zone, or are in a coastal area.

Other important maintenance considerations.

It is a good idea to keep planting well away from the Cedar cladding to ensure that the plants don’t rub the surface treatment off the Cedar, or trap moisture in the timber. Also ensure that the cladding is not touching the ground or coming into direct contact with decking, etc.

It is important to avoid ‘bleach’ type cleaners, not only on the cladding but also on the windows, as they will cause streaking or staining of the Cedar. You should not use a brush or wipe oiled cladding as this will rub off the surface oil and colour pigment.

Unless you have had training in washing Cedar, it is never recommended to use a pressure-washer to clean Cedar cladding or garage doors. Even a low-pressure jet of water can remove the protective coating and damage the timber.

By maintaining the Cedar, you will not only protect the timber and ensure the integrity of the cladding, but you will also maintain the appearance of your new home and add to its value.

* Some build warranties and products may require re-coating earlier than this. So make sure you check both the build warranty and product specifications.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what care should be taken for your Cedar by reading our article Why Cedar Needs Special Care to Maintain Good Looks and Value.

When taking possession of a new Cedar clad home, you expect that it will be maintenance free for some time.  However, if it is not up-to-standard or there are defects, that maintenance free period will be shortened considerably.

What do you need to look for?

(1) Cedar cladding should be protected by a timber stain or wood oil. For that to happen the product used needs to be properly applied in the first place. Look for an even colour tone on the boards. While you want to be able to see the natural patterns and grain of the Cedar, the stain or wood oil treatment shouldn’t be patchy or faded. Make sure that the stain or oil treatment has been applied evenly and that you have protection for your Cedar on all exposed surfaces. Pay close attention to the joins and grooves in shiplap cladding.

(2) Check for marks, dust or dirt that are under the surface of the stain or oil treatment. If the Cedar hasn’t been cared for during the build, or not properly cleaned before treatment with stain or oil, these marks could become unwanted permanent features on your valuable Cedar.

(3) Ensure that the Cedar timber doesn’t come into contact with the ground, landscaping, the window and door flashings, or with the decking timber or other timber installation. If it does, it can cause moisture to be trapped and absorbed into the Cedar, and lead to early rotting of the boards.

(4) Look to see if there is any build-up of dust and dirt on the Cedar. Although new, your home has been part of a construction zone. Therefore, it may need a special “soft wash” to remove the dust and dirt that has built up.  We recommend a soft wash shortly after you take possession of your home, and then at least every year after that.

(5) Check what products have been used, and what the maintenance requirements are to ensure that your build and product warranties are valid. Some companies will require annual wash downs, and re-coating every second year. Knowing what products and colours have been used is important for warranty purposes and to ensure that the right processes and products are used to maintain the Cedar.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what you can do to maintain the Cedar on your home by reading our article What You Need to Know about Caring for the Cedar on Your New Home.

Mistake 1: Thinking that Cedar is a no maintenance building material.

While Cedar is a great cladding material that will enhance the appearance and value of your home, it does require regular maintenance.

Cedar is low maintenance, not maintenance free.

Like any organic material, once we stop it from growing, left unprotected Cedar timber will start to deteriorate.  Any timber cladding that is completely left and never maintained will over time cup, warp, or split and eventually rot away.  On your home that needs to be avoided at all costs.

Mistake 2: Thinking that wood oil and timber stain are the same thing. 

Both oiling and staining the Cedar are effective ways of protecting your Cedar and enhancing the appearance of your property, but they work very differently.

A wood oil (example above), such as Dryden WoodOil or Resene Wood-X, is absorbed into the Cedar helping to replenish the natural oils that are lost over time.  The oil sheds moisture away from the timber, thereby making it weather resistant.  Being a semi-transparent treatment allows the natural timber grains to show through. It is recommended that you use a pigmented wood oil which allows for colour choice, a more even colour palette, and adds a level of UV protection.

Timber stains (example above) are ‘film forming’ and sit on top of the timber and provide a protective barrier to the elements.  They protect the timber by forming a membrane between the timber and the elements. They are also initially semi-transparent, but depending on the product used, may become opaque after repeated applications.  Normally 2 coats of stain are required for each re-application.

See Oil Verses Stain on our website.

Mistake 3: Thinking that a wood oil treatment or timber stain will last as long as paint.

Both timber stain and wood oil are the recommended protective treatments for Cedar timber.  Both require regular re-treatment to ensure that the Cedar stays protected.  While a painted weatherboard may be protected for 10-12 years, on an average the re-treatment times for stained or oiled Cedar are between 3-5 years depending on the exposure of the cladding to the elements.

Mistake 4: Thinking that you can save money by putting off maintenance.

Unfortunately, this is not the case.  Putting off regular and timely maintenance won’t save money.  It may actually cost you more.

Left unprotected the Cedar timbers will start to silver-off as the UV rays damage the polymer bonds within the timber surface.  If not protected, the wood cells will become faded and loose, subsequently eroding the wood surface.  As moisture enters the timber and then is evaporated away, the timbers will start to cup, pull away from the fastenings, become brittle, and eventually split.  If this happens, rather than just maintenance, replacement of the cladding will be required.

Mistake 5: Getting bad or misinformed advice on how to care for the Cedar.

Those that have less experience in maintaining Cedar may tell that Cedar doesn’t require any maintenance, and that you can just let it silver-off.  Or they may recommend that you paint it to reduce the maintenance required. (See Why Painting Cedar is Not such a Good Idea) Our experience as Cedar maintenance specialists tells us that this is not true.  Your Cedar cladding will perform and look the best if it is properly maintained, and that maintenance is an investment in the future value of your property.

Good News for Cedar Homeowners

With regular maintenance your Cedar cladding can last indefinitely.  As specialists in Cedar maintenance, we can guide you through the process so that you avoid the mistakes mentioned above.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what you can do to maintain the Cedar on your home by reading our article What You Need to Know about Caring for the Cedar on Your New Home.

Wood oils and Timber stain are both used to protect your Cedar timbers from the effects of rain, sun, general weathering, mould or insects.

Both, if used with the lighter to medium colours, allow for the natural grain of the timber to show through the protective treatment.

In the past many favoured stains as they provided more colour options. But today’s pigmented oils come in a wide range of colours and can change the look of the natural timber to your preference.

So what do you need to know about timber stains and wood oils, and which is better for your property?

Wood Oils:

Oils are designed to be absorbed more deeply into the timber and provide protection through their water repellent characteristics, anti-fungal additives, and colour tone pigments. Because the oil is absorbed in the timber, oiled cedar cladding has a matt or flat finish.

The pigment provides protection from the sun’s UV rays and reduce uneven discolouration. As the timber dries the absorbed oils migrate back toward the surface continuing to provide a level of protection. Provided it is re-treated regularly (topping up the oil reserves as it were), oiled timber will remain supple and be less likely to cup, split or warp.

Another advantage of oiled cladding is that it is reasonably graffiti resistant as paints will not adhere strongly to the oiled surface.

After the initial treatment with wood oil, as in the case of a new build, or oiling a property that has been converted from being stained or has been neglected, a second “top coat” needs to be applied within 12 months to complete the treatment. After this the re-treatment schedule would be the same as with stain.

Extra care needs to be taken when cleaning oiled cladding. Bleaching and strong cleaning chemicals, water blasting, or harsh brushing or rubbing will remove or discolour the colour pigment which sits on the surface of the timber. All that is needed to keep the treatment and underlying cladding in good condition is a light water wash down each year.

See FAQ about using a clear oil.

Timber Stains:

While a stain will migrate into the timber to some extent, it is principally a film-forming surface coating. Two coats are required each time to provide adequate protection.

Re-treatment times will vary depending on conditions and exposure of the timber to the elements. Experience shows that 4 years is the average. After this the cladding will stop beading water, which means that the timber will start to absorb and retain moisture.

The constant movement from the wetting and drying of the timber will cause a breakdown in the stain’s surface coating and the eventual cupping and splitting of the timber. Dust, salt air contamination and mould spores adhere more to moist timber, and increase the incidence of mould and mildew developing.

Once the stain surface is oxidised and broken, the integrity of its protective qualities will be compromised. This allows moisture to be absorbed into the cladding. If untreated this can lead to the timber starting to cup, warp, split, and even rot.

In time, repeated applications of stain will build up, becoming less transparent and leaving a shiny surface. To retain the original wood grain look you will need to strip off the stain and start the process again.

The Cost Factor:

Oil is a more expensive product than stain. It will be generally twice the price of stain per litre. The second (“top coat”) of oil also needs to be applied within 12 months of the initial treatment. However, only one coat of oil needs to be applied for each treatment and the time to apply it is less than for stain.

Stain needs to be applied with two coats each time. Therefore, after year 5 the labour hours are at least twice that of oil for each re-treatment.

Figure 1 – Comparison of staining vs oiling times for an average size home

In this example, after 13 years and 4 re-treatments, the total labour hours for stain were 264 as opposed to oil being just 120. Therefore, even though using a wood oil means that you need to apply and second “top-coat” coat within 12 months of the initial treatment, you will very quickly get a significant cost saving in labour.

See FAQ about using a clear oil.

If you are not sure about any of these matters, contact us for some advice.

Learn more about what you can do to maintain the Cedar on your home by reading our article What You Need to Know about Caring for the Cedar on Your New Home.