Give old window frames new life
Window frames have to withstand environmental conditions such as rain, wind and exposure to ultraviolet light, which eventually take their toll
By Aarifah Nosarka
Cast iron, wrought iron and mild steel window frames have been around for centuries and are common in many South African homes. In newer homes, cast metal frames have made way for PVC and aluminium, which require very little maintenance. Timber window frames are also popular because they are timeless, add character to a home’s architecture and are considered more environmentally friendly. If properly taken care of, wooden and steel frames will last as long as the building to which they are fitted.
Signs that a frame should be restored
Timber
When the level of sheen starts to fade, edges show wear and there are indications of water exposure to raw timber, a revamp is needed.
Steel
Rust is an indication that a frame needs to be restored. It can cause glass to crack and masonry to crumble at the fixing points.
How to restore wooden window frames
Step 1: Gently remove the old putty using a hammer and wood chisel. Be careful not to damage or break the glass.
Step 2: Clear out the debris and clean the working area thoroughly. Remove any rotten areas.
Step 3: Clean the area and treat affected spots with wood filler, which acts as an adhesive and filler.
Step 4: Once the filler has dried, sand the area, apply a finishing layer of filler, allow it to dry then sand smooth.
Step 5: Apply your choice of finish to the window frame.
Restoring steel frames
Step 1: Gently remove the old putty using a hammer and wood chisel. Be careful not to damage or break the glass.
Step 2: Scrape down the paint with a scraper and remove layered paint using paint stripper.
Step 3: Sand the surface until smooth
and wipe away the sanding dust with a damp cloth.
Step 4: Treat rusted areas with a rust treatment product or rust converter, and prime the metal surface with metal primer.
Step 5: Glaze with putty designed for use on metal sashes. Knead the putty in your hands to make it soft and pliable. Be
careful when pressing the putty in around the edges.
Step 6: Apply a topcoat using a good quality exterior paint. Allow it to dry for a naturally good seal.
Tips for working with putty
• Do not prepare more putty than you can use.
• Place unused putty back in the liner and fold to seal.
• For optimum performance, ensure that unused putty is not kept for more than 40 minutes.
• Add linseed oil for better workability.
• Mineral turpentine can also be used to help smooth the putty.
Three main sealing finishes for wood
Varnish
When varnish is exposed to the sun, it becomes brittle and hard over time. This prevents the varnish from moving with the substrate, causing the coating to tear and crack. Eventually, this leads to water entering behind the skin, which results in peeling and flaking.
Cobus Lourens from Swartland says removing and recoating wood that has been sealed can be hard work. However, you do not have to sand the entire window. Close the window to see which parts are exposed. Sand down the exposed areas. Sometimes normal sanding does not remove all the varnish. Use sugar soap or paint stripper to remove varnish in tough spots. When the varnish is removed, wash off the residue with water and allow the wood to dry before recoating. Internal surfaces only need to be roughened slightly with sandpaper in order to give the new coating something to grab onto.
Sealers
According to Cobus, sealants are a better option for sealing frames. They are easier to apply and maintain. They are durable, with a lifespan ranging from one to five years on exposed surfaces. Cobus says that once the coating has dried out, sand the timber and wipe it down with a cloth that has been soaked in mineral turpentine. Allow the surface to dry before recoating with a fresh sealer.
Oil
This is an old method of sealing and has a short lifespan. Cobus says that if the oil finish is not thinned down, build-up will occur, which makes the surface tacky. To remove and recoat, scrape off the tacky bits and wash with mineral turpentine. Let it dry before resealing with another product.
Cobus recommends using water-based coatings to seal wood. “They are the easiest to apply and maintain, and boast a wide range of other benefits like quick drying times and easy clean-up.”
Varnish versus sealants
Woodoc’s Frikkie Greeff explains the differences between an ordinary varnish and sealers:
• Varnish is a pure surface coating. Little or no penetration of the product takes place into the wood. Dilution does not help as the diluent will penetrate, but the resin will remain on the surface. This is why a varnish peels off wood once
deterioration starts.
• A sealer is a formulation of resins and oils or waxes that penetrates into the wood on first application. If the first coat is applied as per instructions, the wood is saturated and the second and subsequent coats build up on the surface. As the second and third coats bind with the first coat, which is part of the wood, no peeling or flaking will occur and therefore no deep sanding is required when applying maintenance coats in the years to come.
Frikkie says that a tinted sealer will always outlast a clear one as the transparent iron oxides in the pigment will give extra UV protection.
General tips
• Depending on the product used, applying more thin coats is better than fewer thick coats.
• Leave sufficient drying or curing times between coats. Drying time with solvent-based coatings should be no less than a day.
• Lubricate moving parts such as rollers, locks and hinges with a silicone-based spray before applying a sealant.
• Do not paint in direct sunlight, very cold or humid conditions.
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