Exterior timber varnishes for doors and joinery

Note: Refer to the PDF flowchart for a visual of the steps below:

New or timber that has been stripped

1. Wash with Resene Timber and Deck Wash, rinse and allow to dry.

2. Sand using 220 grit zinc stearate to remove any surface imperfections and to arris any sharp edges. Wipe the surface with a tack rag to remove all sanding residue from the timber surface.

3. Treat using Resene TimberLock preservative. Allow 24 hours to dry.

4. Finish options:

   • Stained (Recommend)
     1. Apply Resene Waterborne Colorwood and allow 24 hours to dry.
     2. Apply 5 coats of Altex Timbercote Marine Varnish, BEFORE applying the final coat. Lightly sand to remove nibs and imperfections using 220 grit zinc stearate sandpaper. Wipe using a tack rag.
   • Natural
     1. Apply 5 coats of Altex Timbercote Marine Varnish, BEFORE applying the final coat. Lightly sand to remove nibs and imperfections using 220 grit zinc stearate sandpaper. Wipe using a tack rag.

Old, already varnished exterior timber

1. Treat any moss and mould with Resene Moss & Mould Killer.

2. Wash thoroughly to remove any contaminants.

3. Sand throughly using 220 grit zinc stearate to degloss the old varnish, if there are flaked or U.V. damaged areas. Strong consideration should be given to completely stripping back to bare timber - refer notes.

4. Apply 2 coats of Altex Timbercote Marine Varnish.

Notes - varnished (front) doors and joinery:

• Many of our customers will want to ‘varnish’ their front doors and their exterior joinery, such as French doors – however, exterior varnishes or clear finishes have a very chequered history in Australia and New Zealand.

• The problem is not the varnish or polyurethane, it is that they are not effective at preventing U.V. light from passing through the clear surface and attacking the timber beneath. Remember U.V. light attacks timber resulting in the top layer of the timber becoming weakened and greyed. Also any break or split in the film will allow moisture to get in and mould to grow.

• We recommend a first coat of Resene TimberLock is applied for a ‘natural look’ before varnishing but our preference is for Resene Waterborne Colorwood to be applied as well – The darker the colour the better, as pigments (or the colour) in Resene Waterborne Colorwood resist U.V. light. While both Resene Waterborne Colorwood and Resene TimberLock penetrate the timber they can be used together without affecting the other.

• We recommend Altex Timbercote Marine Gloss and you will need to apply at least 5 coats for a new door or if it has been stripped back to bare timber.

• If the old varnish surface has deteriorated it should be stripped back to bare wood and treated as if it were new.

• Most boaties will apply 5 to 7 coats of Marine or Spa Varnish to the brightwork (exposed timber) of their boats and sand and apply a maintenance coat annually.

• The door will require recoating every couple of summers depending on how exposed it is.

• Remember to ensure the edges of the door are well sealed.

• Any stopping should be done after the first coat of varnish, using plastic wood or coloured putty matched to the timber.

• This system is not suitable for Totara or Matai.

• Standard clear finishes can be used on wooden eaves, as they are not exposed to direct U.V. light. (Although eventually they will deteriorate as reflected U.V. light from windows etc takes its toll). Apply a coat of Resene TimberLock (for hardwoods) or Resene Waterborne Colorwood first, followed by at least 3 coats of Resene Qristal Poly-Satin or Poly-Gloss or Resene Aquaclear. For a higher performing system Altex Timbercote or Resene Uracryl Clear with U.V. blockers could be recommended.

Key accessories - essential to complete the job

• Resene Moss & Mould Killer
• Resene Timber and Deck Wash or Resene Paint Prep and Housewash
• PAL 50mm or 63mm Premier Oval brush
• Resene Paint pot (for decanting into)
• Masking tape
• Painter’s gloves
• Sandpaper – 120-220 grit zinc stearate to arris edges and prep timber and/or coatings
• Tack cloth, to remove sanding residue (important if using zinc stearate sandpaper)
• Putty and/or coloured wood filler and putty knife
• Stirrer
• Turps

Add ons - to make job easier or quicker

• Drop sheet
• Short bristle scrubbing brush
• Dusting brush
• Paint stripper and scraper if needed

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