Windows and doors

Home maintenance windows and doors hero

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 surfaces, 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 won’t 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 (top of the frame) is sagging, you need to deal with the cause before fixing it. Get professional advice on this.

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 or stainless steel ones. Speak to a window specialist if you’re unsure.

Water damage: Water damage around windows can be caused by condensation or leaks. Try to reduce the amount of condensation in your home. See our article on moisture in the home.

Check that window drain holes are clear. Keep windows well painted and remove moisture as it appears.

Insulating Glazing Units (IGUs – or Double Glazing): If there’s misting or clouding inside the IGUs then it is likely that water has got in between the panes. IGUs don’t like getting wet feet, and need to maintain clear drainage paths. They should never by puttied or sealed into rebates. They should sit on two 6mm thick setting blocks.

Aluminium windows or doors

Pitting: If you don’t clean your windows and frames, you’re 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.

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.

If the sash is twisted, you’re likely to break the glass trying to straighten it. Contact a window professional to remedy this.

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

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

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 or replaced. Speak to a window specialist.

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

Timber windows or doors

With general deterioration, sand back the paint and repaint 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 painted 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 2 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.

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

You may need to have the cords or counterweights replaced.

Sash windows can also stick because of paint or varnish build-up or moisture getting into the wood. If paint or varnish build-up is the cause, strip back to bare wood before repainting or 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 or 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 or thermal expansion
  • handles or locks needing adjustment or replacement
  • paint build-up
  • 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’s 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 (uPVC) 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.

Poor closing: uPVC windows are often stiffened with steel or aluminium sections inside hollow frame profiles. This means that the uPVC profiles may move around on the metal bracing when they are operated. Speak to the supplier if this prevents the sashes or door panels from closing properly.

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 2 weeks before painting. Ensure the paint covers 2mm of the glass 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.

To improve safety at the entryway of your home:

  • add lighting
  • alter the entry to provide better access
  • install slip resistant tapes to the steps or paths. Alternatively, replace steps with ramps
  • add a handrail
  • replace the glass in doors with safety glass
  • build a small deck to enlarge the area if it is too small to allow people to gather under shelter.

Money savers

Fixing draughts

  • check seals around aluminium joinery and putty in timber or steel sashes
  • 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, or you have a view you don't want to curtain off at night. There are now many options to further improve the thermal performance of IGUs, such as low emissivity coated glass types. Speak to your glazing supplier about these.

This page was put together with the help of BRANZ.

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Member comments

Get access to comment

Bryan S.
06 Nov 2019
Stacker doors

I have just built a new house and we have been in the house for about sixteen months From the time we moved in the stacker doors have leaked when cleaned with a garden hose
Our supplier has fixed all but one (which he has attempted to fix)
He tells me that he won’t fix it unless it leaks under rain conditions
Am I expecting to much that they should not leak under washing with a garden hose
Bernadette Smith

Denise W.
09 Dec 2015

I tried to find an up to date Consumer article on magnetic screens for aluminium windows but was unable to. Do you have one or can you please do one soon given that mosquitoes are prevalent at this time of the year

Previous member
09 Dec 2015

Hi Denise,

We don't have a lot of experience with magnetic screens for aluminium windows. Generally these are either DIY kits, where you make up your own plastic frame (with magnetic surfaces that adhere to the plastic) to which you attach the fly screen material, or pre-made kits, where the installer constructs and supplies a frame for your windows. Pre-made kits will be more expensive but are likely to last longer, and you'll be able to get a wider range of colours to suit your home.

My advice would be to ensure the screen's frame is good and thick, and can easily be bent back a fair way (so you can open and shut your window) without breaking or deforming. For DIY kits, make sure the magnetic strips are easy to attach to the frame and won't come unstuck, and that the screen material itself is easy to attach to the frame.

Kind regards,

Consumer NZ staff