Window Installation in Wellington

Wellington asks more of a window than almost anywhere else in the country. Gusts pass 60 km/h on roughly 173 days a year, and the council splits the city into wind zones running from Low all the way to Specific Design. A window rated for a sheltered Hamilton street will leak air and water on a Brooklyn ridge. We check the zone before we order, so the unit that arrives is rated for the wind that hits it.

Wind zone decides the window before anything else does

Windows sold in New Zealand are tested to NZS 4211. That standard sets pressures for structure, air leakage and water. An Extra High rating covers a site wind speed up to 55 metres per second, and above that the joinery has to be specifically designed.

Wellington City Council publishes a wind zone map covering Low, Medium, High, Very High, Extra High and Specific Design. Plenty of the hill suburbs sit in the top two bands. That changes glass thickness, the depth of the frame section, how many fixings go in and how the flashing is detailed. We look the zone up for your address before we quote, and we tell you what it means for the price.

What thermally broken joinery really changes

Plain aluminium conducts heat straight through the frame. On a cold Wellington morning the frame gets colder than the room, moisture in the air condenses on it, and you get water on the sill even with double glazing in place. A thermally broken frame puts an insulating strip through the middle of the section so the inside face stays warmer.

It costs more per opening. Worth it on south and west facing rooms, bedrooms where condensation is already a problem, and any home where the owner is chasing warmth rather than just replacing something broken. On a sunny north facing lounge that already runs warm, standard double glazed aluminium is usually the sensible call.

The install, not just the window

Most window failures we get called to are installation failures, not product failures. Water gets in at the head because the flashing was cut short or the sealant was run instead of a proper hook and hem. Air whistles through because the gap around the frame was stuffed with offcuts instead of being sealed.

We set the unit on packers, check it square and plumb in both directions, fix it at the spacings the wind zone calls for, seal the perimeter air gap, and fit the head flashing with the right upstand. In Extra High wind zones the flashing upstands increase and sealant goes under the head flange. Then we make good the linings and clean up.

Consent, or no consent

Replacing a window like for like in an existing home is exempt work under Schedule 1 of the Building Act. No consent, no council fees, no waiting. That covers most of what we do.

You do need a consent if the opening gets bigger, if structure changes, or if the work is part of a larger consented job. New builds and additions are consented anyway, and since the 2021 H1 changes any consented residential work has to be double glazed. We will tell you at the quote which side of that line your job sits on.

Window Installation at a glance

Frame options

Aluminium, thermally broken aluminium, uPVC, timber

Glass

Double glazed IGUs, Low E, argon fill, laminated or toughened where required

Standards

NZS 4211 performance rating, NZS 4223 safety glazing

Wind zones

Low through Extra High, Specific Design referred to an engineer

Weathering

Head flashing with correct upstand, sealed perimeter air gap

Consent

Like for like replacement is exempt under Schedule 1

Typical timeframe

Two to five weeks from measure to install, depending on joinery