Maintenance and Care of Painted Timber Products

 

It is the responsibility of the homeowner to ensure that annual maintenance is carried out. Maintenance should be carried out every 12 months. In some cases, this may be required more regularly e.g. sea spray.

Maintenance Checklist

Wash all exterior surfaces using a low pressure wash system to remove dust, dirt and other contaminants.

  •  Do not use a high pressure washing system e.g. water blaster
  • If the washing does not remove stubborn areas of mold or dirt use a soft brush or broom and an appropriate cleaning agent to remove these deposits. Check with the paint manufacturer and read the directions on the product to apply the cleaning agent.

Once the building is clean and the surfaces have been inspected for damage, wear and tear and paint coating degrade then repairs and must be undertaken immediately.

  • If the paint surface has been damaged, then:
  • Remove all damaged paint, sand back if required
  • Apply a quality oil based primer on any bare timber
  • Once the primer has dried apply 2 top coats of a quality top coat paint.

It is a general rule that timber weatherboard homes should be repainted every 10 years if the initial coating product used was of high quality, delivering a good quality coating finish. In some cases, repainting may be required earlier depending on condition and exposure to harsher elements.

 

Maintenance and Care of Stained Timber Products 

Using and Maintaining a Stain Finish on Exterior Timber Products (Radiata Pine)

As a rule, water or solvent based stains provide less weather protection to timber than high quality paint systems. Nonetheless, stain can be used on exposed timber when the timber has been treated to H3.2, H4 and H5 standard but extra care must be taken at installation with regular maintenance of the timber being undertaken.

Stain must not be used as a protective coating in exterior applications where the timber is treated to H3.1 (LOSP) or H1.2 ( Boron).

As with paint, do not use dark colours as these tend to absorb more heat and accelerate damage to the stain or paint.

Use a reputable brand and follow the manufacturer’s instructions including coating the stain on all sides and exposed edges on the first coat. This includes staining the ends of boards, which are particularly susceptible to absorbing moisture. Follow up with at least three further coatings once the product is installed. Generally the harsher the environment, the more coatings needed.

Generally, there are two types of stain; one that is a film forming best for smooth surfaces and one which is penetrating which is best for rough and bandsawn timber surfaces. Seek expert painting and staining advice on what is best for your situation!

 

Maintenance Including Recoating:

Check the condition of the stain every few months (more if in harsh environments). If in or near salt spray zone, regularly wash the exterior timber with clean water to dilute the salt. Other air pollutants can be harsh on paint/stain systems including vehicle fumes, geothermal and dust/grit. Do not use high pressure systems such as water blasters as they can damage existing coatings and the timber. Edges and corners of timber are more susceptible as less stain protection is often applied (more difficult). Make sure such areas are liberally coated.

A regular programme of washing the timber and recoating is best. Recoat before the stain breaks down (flaking or cracking) as this will expose the raw timber to the weather and the likelihood of absorbing excess moisture.

 

Use of Nails and Fittings when staining:

Galvanised wood nails and fittings cannot be used with stain for exterior purposes.

NZ Standard 3604 advise that galvanised nails and fittings must not be used on non painted timbers using H3.2, H4 and H5 CCA and ACQ treatment regimes. Stainless steel nails or fittings or equivalent product must be used (refer to the building code, local council requirements and BRANZ for guidance).

 

BRANZ Good Practice Guide