CD50 Timber Protection Oil

CD50 is the timber protection oil originally developed for cedar weatherboards and all species of dry timber. CD50 controls a wide range of mould, fungi and bacteria, and is the oil of choice for:

  • Weatherboards and timbers up to 50mm depth
  • Situations when better weather protection is needed at the surface

Directions for Use

All Situations: 

The CD50 Products work by penetrating deep into the timber, therefore, before application: Ensure there are no sealants, barriers or any other products that could affect the penetration of CD50. (LOSP treated timber must have a wax level of less than 2%). 

If any coating has been used, it must be thoroughly removed by sanding or stripping before applying CD50.

LOSP treated timbers must have had sufficient time for the treatment to dry or evaporate off – do not apply if an odour is still present. 

The retained moisture content of the timber should be no more than 17% 

Do not dilute, add thinners or alter in any way

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Test for Stains Paints and other Film Formers

Take a cup of cold water - go to a protected part of the house where there has been little weathering e.g. the south side or under the eaves - dip your fingers in the water - flick the water at the timber. If it soaks in, the timber is probably not treated with a surface coating. If the water beads, it probably has a surface treatment


Coloured CD50

To retain or enhance the colour of the timber, Colourtones are used. The Colourtone is added to the CD50 before use. 
A sample of the Colourtone should be tried on a sample of the actual timber as different timbers affect the appearance of the colour. 
Allow for some lightening to take place over the first 3-8 months as weathering occurs. The final colour is obtained after 2 coats of coloured CD50.   
Colour retention is more durable on rough sawn timber, and dressed timber that has been lightly sanded.    
New timber is milled smooth and often has a mill glaze which will greatly restrict the initial colour build. 

Use the correct size Colourtone for the pail or can of CD50. Shake & stir the Colourtone to ensure it is evenly dispersed before adding to the CD50. Add all of the Colourtone to the appropriate size pail or can. Stir thoroughly before use and frequently during use. 

New Timber 

Coat all four sides of the timber, and apply a second coat between 2 weeks and 6 months after the first coat.
During construction apply the second coat after completion of all dusty earthworks (timber may require a light wash first) Avoid contact with plants and waterways. 


When used on some plywoods, CD50 may accentuate characteristics in the underlying layers. The use of Colourtones will tend to camouflage this. CD50 may penetrate only to the glue line. Do not use on veneers

Old, Dirty or Weathered Timber 

If no film forming product is present, wash with SARAClean to remove dirt, mould and silvered fibres. Use DEEPClean to remove tough stains such as watermarks, grease and resin stains. When completely dry, apply CD50 as for new timber. 

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Existing or Failed Coatings 

Timber with film forming products (conventional stains, paint, polyurethane, varnish and oils) must be removed before applying CD50. CD50 products cannot be applied over another coating, as they must be free to penetrate inside the timber. 

Old failed coatings can be removed to restore timber back to its original timber character and colour. This is achieved using a process involving specially formulated chemicals and controlled water washing. It is recommended that highly skilled and trained operators carry out the restoration process. The restoration process is followed by the application of CD50 as for new timber.
Timbers that are warped and cupped can often be returned to near original profile and flatness. The dimensional stability and natural appearance of the timber will be maintained for many years with maintenance applications of CD50. Contact Churton Pacific Ltd for restoration advice. 

Maintenance for New and Restored Timber 

Reapply CD50 as necessary to retain the appearance of the timber. Reapplication time is from 2 to 6 years – this depends on the timber type, porosity and exposure to weather and sunlight. Where UV exposure is extreme e.g. coastal and fully exposed conditions, reapplication times may be reduced accordingly. 
Coloured horizontal exterior surfaces exposed to full sunlight such as decks and handrails may require annual maintenance. 
Reapplication involves a simple wash with SARAClean, and when dry, reapplying one coat of CD50. Between applications, keep surfaces clean – wash off any accumulated dirt, salt or pollen.


Apply CD50 with brush, speed brush, roller or spray – avoid excess drips and runs. Timber should be only slightly oily after application. 
Allow to dry before reapplying, or allowing foot traffic, if on a deck. 
Wash up in detergent or turps. 

Other Points

Penetration takes longer on new hardwood timber. 
For thicker timbers such as posts, beams and logs - use CD50 Extreme.


These figures represent typical averages for common cladding timbers: Cedar, Pine, Douglas Fir, Macrocarpa etc.,

New timber dressed 
12 to 15 square metres per litre 

New timber rusticated or bandsawn, old restored timber dressed
7 - 9 square metres per litre 

Old restored timber rusticated 
4 - 7 square metres per litre    

Shingles and Shakes
2 -5 square metres per litre 

Mould and Fungus    

Clean looking timbers may be contaminated with mould spores, which are invisible to the naked eye. If timber in this condition is coated with CD50 it is possible that dark staining may occur. If such staining appears, contact Churton Pacific Ltd or your local supplier for DEEPClean Heavy Duty Timber Cleaner. See SARAClean, and DEEPClean for removal of stains, mould, and fungus.

Weather and Temperature    

Cold temperatures will affect the viscosity of CD50 and will tend to slow down the rate of diffusion. Storing containers in a warm place immediately prior to application will help alleviate this problem. Timbers to be coated with CD50 must be clean and dry, with residual moisture content of no higher than 17%. 
Do not apply CD50 to exterior timbers if it is likely to rain within 6-8 hours of application.

For full Technical and Safety Information - See CD50 Technical Data Sheet