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Joinery – windows and doors

Doors serve as a connecting link between internal rooms in the home as well as with the outside world, whilst windows allow for the entry of natural light and also serve to cross ventilate the home.

Due to the high frequency of use associated with doors and the exposure of windows to outdoor elements as well as condensation, both these building components (especially timber units) can suffer from a variety of consequential damage when they are not adequately maintained and cared for over prolonged periods of time.

Cracking to door jambs and window reveals

Much of the mitre separation and cracking to jambs and reveals observed in the home can be explained by natural timber movement over time (via thermal expansion and contraction). The effect of this movement can also lead to sealant failure around the joints. This can result in possible moisture damage to the surrounding areas if seals are not regularly maintained.

For more information, visit:
BRANZ – Windows(external link)

Sagging lintels

Sagging of lintels can sometimes be caused by the lintel being the incorrect size for the window or door.

A good start for investigating this issue would be to check with your local council and see if the opening in question is consented and has an appropriate design in place to suit the existing span. Wet timber lintels will sag under loading unless they are propped until dry.

For more information, visit:
BRANZ – Windows – sagging lintel(external link)

Sticking doors and windows

Sticking doors and windows are one of the most common issues to affect homes, especially older homes. The causes can be many; with some of the most likely being issues with the hinges (i.e. lubrication or replacement may be required, or adjustments needed to suit heavier units which have been fitted). Glue or joint failure of the timber door frame and wall framing can also result in poor operation. Sticking is often caused by natural ground settlement resulting in pile movement and loss of support around door/window openings. The door/window frames then settle and cause the units to bind or stick when opened. This is a quite common occurrence throughout New Zealand, particularly in pre-1960’s homes.

For more information, visit:
BRANZ – Door is difficult to open or close(external link)

Glazing cracks

Stresses caused to glazing by swelling of timber joinery members can lead to glass cracking.

The effect of temperature variables (hot to cold) on glass surfaces can often result in cracking. Glass can expand in the heat and shrink in the cold resulting in a crack.

Different glass products have different tolerances, and some products are far more likely to crack due to temperature stresses than others. It’s important to assess the likelihood of temperature stress when selecting glass types for use in the home.

For more information, visit:
BRANZ – Moisture in sealed insulating glass units(external link)