YES - All timber joinery has to be finished to seal and protect it. By 'finishing' we mean the application of either an opaque or transparent finish applied to all 6 sides to protect it from the elements. Without a finish all timber will swell or crack and will discolour. No warranty applies to unfinished joinery. To preserve your warranty as well as your joinery, a full coat of sealer must be applied to dry timber joinery within 48 hours of delivery. Generally timber joinery will require of least 4 coats of finish, two coats of primer/sealer or undercoat and two top coats to give lustre and long-lasting protection. All joinery should be checked regularly but the life of the finish will depend on its exposure. Joinery fully exposed to weather and sunlight or joinery in coastal areas will need more frequent maintenance. Look for signs of dryness, peeling, surface split or discolouration.

All six faces of the joinery are important and in some joinery units (bifolds, pivots, double-hungs) there are hard to reach places to finish. The top and bottom however, are crucial faces of the door - the stiles (or vertical edges) of the door were once part of a tree trunk and were designed to 'suck up' water. Water left sitting on the sill or on the top of the door is absorbed through the exposed end grain if not properly finished and this absorption leads to bowing, twisting and eventual rotting of the timbers.

Woodworkers recommend certain products in the SIKKENS range of finishes as being ideal for joinery. Please avoid water based acrylic finishes as they void your warranty. Sikkens is an oil based resin that has the advantages of

• Long life in exposed conditions & easy maintenance.
• Can be used internally & externally
• Easy to apply and easily re-applied over time.
• Nourishes the timber & prolongs its life.
• Easily removable from glass
• Lubricates items like double hungs and sliders thus enabling them to slide over each other more easily for smoother operation.

There are 2 products in the coating system – SIKKENS CETOL HLSe (sealer) and SIKKENS FILTER 7 PLUS (top coat) available in a range of tints as well as the pine clear 077 transparent finish.

The answer depends on your own assessment of your skills to DIY, the project and the level of perfection you want to achieve. Skilled painters are hard to find and many will baulk at using oil-based paints because of the repetitive visits required to apply each coat. Nonetheless, a good painter will either make or break the final appearance of your joinery.

Apply caution, and clarify the qualifications when using internet-based labour suppliers such as Airtasker, Taskrabbit, HiPages, Service Seeking etc as you have no idea of the competence of the people that can answer your enquiry, and we have witnessed some horrific outcomes where good joinery has been totally ruined by amateur painters targeting a budget.

What the client wanted

What the client got

Some painters prefer quick application coatings that give them a very profitable turn around but can be disastrous for the joinery and its owner. Generally speaking, if the joinery is completely internal you can use any finish, but for external items the following is a list of products you should avoid

• Polyurethane coatings, estapols and lacquers - All such finishes are too inflexible and restrain natural timber movement. They therefore crack quickly and because they retain and concentrate heat, can cause severe warping or splitting in the joinery. They also break down quickly in ultraviolet light. These finishes void your joinery warranty if used externally.
• Acrylic coatings - As explained above acrylic finishes suffocate timber. Coatings tend to 'stick' and restrict movement where, for example, sashes have to slide across each other in windows and doors. They are generally complicated to re-apply over time requiring etching and other surface keying to permit subsequent coats to bond. These finishes void your joinery warranty if used externally.
• Varnishes and Natural oil finishes - Marine varnishes do not have a long life & most modern varieties have similar disadvantages to lacquers. Natural oil finishes are good for the timber but tend to be absorbed over a fairly short time so that regular recoating is required.
• Water repellent preservatives - Contain repellent waxes, resins and usually fungicide to provide a temporary water barrier which breaks down progressively due to atmospheric oxidization. Can cause compatibility and bonding problems with subsequent finishes.

The white primer used by Woodworkers is a stabilizer and filler primer, designed to fill imperfections in the grain, and allow for sanding to a smoother finish.  The purpose of the primer coat is to adhere to surfaces and form a binding layer that is better prepared to receive subsequent paint coats. However, the primer coat is not a waterproof sealer, and if the timber gets wet prior to the top coats being applied, the tannins can run through the primer coat.  This is especially applicable to high tannin releasing timbers such as Kwila (Used on joinery sills, balustrading etc.). If you don’t intend to apply the top coats prior to the timber getting wet, we would recommend the use of a stain blocker primer. (This product is not part of Woodworkers range).

Modern external finishes are likely to be either acrylic or oil based. If you saturate a rag with methylated spirits and rub the finish, you will  see a softening of the finish and some rub off on the rag if the finish is water based acrylic. You will see no effect if the finish was oil based.

Woodworkers do not recommend or warranty external joinery painted with most acrylic (water based) paints because they have the effect of wrapping the timber in plastic so that the wood can't breathe. Just as food wrapped in a plastic bag will rot over time, non-porous acrylic paints hasten the demise of timber. Importantly, when the seal is broken in an acrylic coating water can be drawn into the moisture hungry timber and become trapped in the plastic encasing causing rot and fungal growth to occur in the waterlogged woodgrain. This is particularly likely with external fully exposed joinery such as gates. Acrylic paints also tend to cling to each other causing sliding sashes to stick. Coatings need to be microporous, allowing the timber to breathe and move and should contain organic oils to nourish the wood the way it was treated within its tree. For this reason Woodworkers recommends finished that are oil based, which are flexible to allow movement and are proven to be remarkably durable.

Woodworkers recommends that the sashes be removed to finish a double hung window and has compiled a video to show how to remove and re-tension spiral balances. If this is not done it is virtually impossible to avoid getting paint on the spiral balances which looks unsightly. It is important that acrylic paints are not used for sliding sashes as they cause sashes to stick rather than slide smoothly.

Apply the first coat of SIKKENS HLSe within 48 hours over clean raw timber. After applying the initial coat, when dry, lightly sand along the grain of the timber using a fine (preferably sponge backed) abrasive pad, 180 grit sandpaper or fine stainless steel wool. Do not fill nail holes etc until after the first coat is applied as unsightly smear marks will be trapped under the finish and will not be removed easily. Stop holes after the first coat of sealer with an oil based wood fill putty that is darker than the timber (Walnut generally has the colour of a timber knot, whereas commercially available Cedar putties are generally lighter than the timber and do not blend in successfully). Repeat the sealing and sanding process until a smooth even finish is achieved. It is important that all smoothing and preparation be done at the priming/sealing stage as you should not need to sand the top coats. SIKKENS FILTER 7 PLUS (with UV filters for added protection) is recommended for the top coats as it builds quickly to a rich satin finish. The process of finishing the frame timbers is the same, but be aware that the outside of the frame including the underside of the sill needs to be fully sealed before installation.

Generally door manufacturers will not warranty a product that has a different finish on each side as finishes can 'unbalance' the door and cause bowing or twist. This could occur if, for example, you used a polyurethane finish internally and an oil finish externally. However, if you used an oil based transparent finish internally and an opaque oil finish externally the problem should not occur. Houses built early last century, or earlier, successfully used transparent varnishes internally and oil finishes externally e.g. Newstead House, Brisbane.

For glazed items it is recommended that you run the primer coat 1 mm onto the glass to achieve a good seal between the glass and the timber. It is also important to remember to be very careful when sanding near the glass as it is easily scratched in the process (particularly items with toughened glass which is VERY prone to scratching). It is important that you check the item upon delivery as any claims of scratched glass are difficult to resolve once the item has been on site for any length of time. For more information on glass, see our FAQ #4 on timber and glass.

Woodworkers do not recommend large bats or fielded (raised) panels for external use. Where they are used they need to have extra care in sealing and maintenance especially for exposed situations. Most door designs use plywood rather than solid timber for panels because the inherent strength of plywood eliminates the chance of splitting. Where solid timber is used either for bats (e.g. Cricket bat doors) or panels (e.g. 8 panel door), special care needs to be taken to reduce the chance of splitting. Doors are constructed using the floating panel method which allows panels to move slightly within the door as they expand and contract due to moisture variations. If a finish is used which effectively cements the panel in place, pressures can build up that will crack the solid timber. This is why flexible finishes are preferable to hard urethanes or lacquers. Where you have doubts about the ability of the panels to move, it is best to cut a fine line around the junction between the door's structure and the panels with a stanley knife to ensure they can move freely. For timber bats there is no substitute for ensuring the bats are very well coated with 4 or 5 coats of finish to shield the timber against moisture intrusion even after several years service.

On some frames nails may deliberately be left protruding where there is a likelihood that the timber bead may need to be removed for painting or installation. This is traditional joinery practice and not an oversight or error. Importantly Woodworkers does not stop up nail holes as this needs to be done AFTER the first seal coat is done. lf these are puttied beforehand it usually leads to unsightly smear marks under the prime coat that cannot easily be removed.