Windows and doors

Windows and doors need regular cleaning and maintenance to keep them weatherproof and in good working order.

If they’re not maintained, problems can occur such as sticking, rot or corrosion. Some maintenance tasks are common to all windows and doors. Others depend on the material the window is made from.

Cleaning and general maintenance

Frequent washing will extend the life of your windows and doors.

Follow the manufacturer’s instructions for cleaning if you have them.

Regular cleaning also gives you chance to inspect the windows. Signs that you need to increase the frequency of cleaning are chalking surface, condensation, mould growth, corroded fixings and blocked drain outlets.

For severe stains, a mild abrasive cleaner may be necessary – trial it first to make sure it is not going to scratch. Take special care not to damage the coating when cleaning coated or specialised glass – follow the manufacturer’s instructions. 

Doors sticking or jamming: This could be due to dirt, lack of lubrication or misalignment. Clean the locks and lubricate with graphite powder. If the lock is misaligned it will jam. If necessary, re-align the door. If sliding doors won’t shut properly, rain and cold air can get in. Clean and lubricate the rollers and repair or replace damaged rollers. You will need to remove the door to do this. The rollers may need height adjustment.

If the lintel is sagging, you need to deal with the cause before fixing it. Get professional advice on this.

Loose glazing rubber

Loose glazing rubber: Age and exposure to sunlight will shrink glazing rubber causing it to pull out at the corners or shrink back leaving gaps. Either reinsert the rubber or replace it with the correct size.

Corroded hinges: This is caused by salt spray, lack of cleaning, or the wrong type of metal being used. Clean and oil the hinges. Replace corroded fixings. Painting will reduce the risk of further corrosion.

If the wrong metal was used, replace the hinges with brass ones. Speak to a window specialist if you are unsure, look under “Window Repairs” in the Yellow Pages.

Rusty hinges on fanlight

Water damage: Water damage around windows can be caused by condensation or leaks. Try to reduce the amount of condensation in your home. See Combating dampness.

Check that window drains are clear. Keep windows well painted and remove moisture as it occurs.

Aluminium windows or doors

Pitting: If you don’t clean your windows and frames, you are inviting corrosion of the aluminium which leads to pitting on anodised aluminium. This will shorten the product life.

You can repair the pitting by cleaning, sanding and repainting according to the paint manufacturer’s instructions.

Powder coat chalking: This is due to age.  To help keep powder coat finishes looking good for longer, apply a vinyl restoring solution or light oil after cleaning. This will also reduce the effect of chalking.

Sashes won’t open freely: This happens if the sash is twisted, the friction stays are too tight, or the building has settled or the sash frame has swelled.

Friction stay

If the sash is twisted, you are likely to break the glass trying to straighten it. Contact a window professional to remedy this. Look under Window Repairs in the Yellow Pages.

If the stays are too tight, adjust them or replace them.

If the problem is due to building settlement, consider having re-piling and/or leveling done, then adjust the window.

Sashes won’t stay open: This is caused by worn or inadequate friction stays. Replace the stays using the correct stay for the window size and wind area. You could also fit a casement stay to hold the window open, although this is not easily done with aluminium.

You may need a professional to replace the stays. Look under Window Repairs in the Yellow Pages.

Blocked outlets: This will cause condensation to build up. Clear out the dirt and obstructions from the outlets.

Seals to the frame joints deteriorating: This is due to thermal expansion or age. It could allow moisture to get in. If the window has removable exterior glazing beads, remove the rubbers and beads and clean. Apply a bead sealant before putting the bead and rubber back on.

You may need to have older windows remade. Speak to a window specialist. Look under “Window Repairs” in the Yellow Pages.

Scratching or surface damage: This should not affect the performance and is an aesthetic issue. Buff the surface before applying a vinyl restorative or light oil.

Timber windows or doors

This is caused by moisture getting into the door or window through unpainted edges, or by general ageing. It could also be due to windows being assembled without the joints being primed.

Where edges have not been painted, allow the window or door to dry out before re-painting.

If general deterioration is the cause, sand back the paint and re-paint the door or window. For an external door or window, check that the fixture is suitable for the level of exposure to the elements. Also check that the top and bottom of the door or window is sealed to prevent moisture being absorbed.

Cracked or damaged putty: This can cause draughts, leaks and rattling windows.
Dig out the old putty, and clean and re-prime the rebates before installing new putty. Leave the putty for two weeks before painting. Ensure the paint covers 2mm of glass to create a seal.

Rotting timber: This is caused by moisture getting into the timber or because the timber is old. Find out what is causing the water to get into the timber. It could be due to a lack of priming of the joints, putty not being sealed to the glass with paint, or severe condensation.

The window may need to be removed and dismantled to remedy this problem. Contact a window specialist. Look under “Window Repairs” in the Yellow Pages.

Double hung sash windows sticking: Stiff sashes are inconvenient and make it harder to ventilate your home.

You may need to replace the cords or counterweights. If you don’t know how, contact a window specialist. Look under “Window Repairs” in the Yellow Pages.

Sash windows can also stick because of paint or varnish buildup or moisture getting into the wood. If paint or varnish buildup is the cause, strip back to bare wood before repainting/staining. If necessary, plane the wood back before painting or varnishing.

If the sticking is seasonal (during warm, wet weather but not in dry weather) the wood is absorbing moisture causing it to expand. Remove the fixture during dry weather. Find the place where water is getting in and re-paint/varnish it.

Loose catches and handles: If the catches and handles are coming loose it will prevent the window from sealing properly. Tighten or remove and reseat if possible.

Damaged door sills: These could be a trip hazard. Cut out the damaged section and replace it.

Windows painted shut: To break the paint seal, insert the end of a screw driver or chisel into the gap between the window and frame and tap it sharply with a hammer, then slide the screw driver or chisel into the gap between window and frame to trim any paint lumps.

Doors stick because of:

• Moisture absorption.
• Handles/locks needing adjustment or replacement.
• Paint buildup.Dry or corroded hinges.
• Movement of the door frame due to settlement of the house.

Allow the door to dry. If it still sticks, plane the side it is sticking on and re-hang.

Check the hinges for corrosion and replace if necessary. If the hinge screws are loose the door will stick on the handle side. Tighten or replace the hinge screws. You may need to replace them with longer screws or plug the old holes with dowel.

Check hinge pins and replace if missing or worn. Lubricate with a penetrating oil or graphite powder.

Plastic (PVC) windows or doors

Staining: This is due to corroded internal steel reinforcing or runoff from glazing beads. If the window is new, speak to the supplier. Otherwise, replace the glazing beads and clean the window more often.

Chalking or fading: This is due to weathering.  If the unit is new, speak to the manufacturer or supplier. Otherwise, wash the window more frequently to reduce the visual impact of the chalking.

Steel windows or doors

Putty deteriorating: This happens when the putty is getting old or when it isn’t painted over.

Scrape out the putty and treat any corrosion by sanding back and priming with a zinc-rich primer, metal primer and finish coat. Leave the new putty for two weeks before painting. Ensure the paint covers 2mm of the window to create a seal.

Paint bubbling and blistering: This is caused by moisture getting under the paint or poorly applied primer.

Remove the paint and treat the corrosion. Prime with a zinc-rich primer, metal primer and finish coat.

Corrosion: This is caused by a loss of protective coating due to trapped moisture. If the corrosion is severe, replace the window or sash. Otherwise a professional window repairer may be able to strip and repaint the window.

Money savers

Fixing draughts

• Check rubber seals around aluminium joinery.
• Ensure all sashes fit snugly into the frame.
• Tighten catches and latch sets to ensure doors and windows are pulled in tight to the frame.
• Use a strip of tissue paper or a lighted candle to trace the draughts. Also look for curtain movement.
• Seal around openable wooden windows and exterior doors with self-adhesive PVC foam draught strip (available from hardware stores). Clean the paint surface or the strip won't stick.
• Block open fireplaces with a loose-fitting removable panel when not in use. The loose fit allows any rain that gets in to evaporate away.
• On extractor fans and rangehoods, check shutters are working properly.
• Check your ceiling hatch is correctly fitted to reduce draughts.

Double glazing: About half the heat lost from a well-insulated home with single glazing goes out through the windows. Double glazing will halve this heat loss. It can also reduce condensation and may reduce noise.  It's worth investigating, especially if you're renovating or building a new house, and you have a view you don't want to curtain off at night.

More information

See www.consumer.org.nz for more information on double glazing and sanders.

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