Trust Builders Construction
Trust Builders second-storey extension under construction in greater Wellington

ALTERATIONS & EXTENSIONS

Adding Space to Your Wellington Home — Extensions Built to Last.

Sleepouts, granny flats, basement dig-outs, garage conversions and full second-storey additions — integrated with the existing house, consented properly, finished cleanly.

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About alterations

How we run an alteration.

Adding to an existing home is harder than building new. The wall isn't plumb, the framing isn't straight, the floor steps where it shouldn't. We account for that early and detail the join between old and new so it reads as one house.

Council consents, structural engineering, neighbours, scaffold, live services — we coordinate the lot. You see one programme and one site supervisor, end to end.

Why choose us

Built for the existing home.

Experience

Three decades of additions to Porirua and Wellington homes — every era of NZ housing, every flavour of awkward.

Craftsmanship

Joins between old and new framing, cladding and roof done so they line through and weather correctly.

Design

We bring designers in early — or work with yours — so the result fits the house, the section and the council rules.

Granny flat / minor dwelling extension by Trust Builders, Wellington region — framing stage

GRANNY FLATS & SLEEPOUTS

A second small home, separate but connected.

Teenage retreat, parent moving in, occasional guest, rental income — the brief shifts but the build is similar. Sleepouts, granny flats and minor dwellings all sit on the same spectrum. We'll tell you whether the size and use can be permitted under the Building Act schedule (granny flats up to 70m² may be exempt under the 2024 reforms) or whether it needs full consent, then run the services connection back to the main house.

  • Permitted vs consented — clear advice up front
  • Power, water, wastewater and data connected to the main house
  • Insulated and double-glazed for year-round comfort
Basement dig-out by Trust Builders — drained cavity waterproofing on a Wellington hill home

BASEMENT ALTERATIONS & DIG-OUTS

Usable rooms below an existing footprint.

Many Porirua and Wellington homes sit on a slope with under-house space that's currently storage and cobwebs. We can dig out, retain, waterproof, line and finish it as a self-contained flat, an office, or extra bedrooms — without adding to the building footprint.
  • Structural input from engineers we've worked with for years
  • Drained-cavity waterproofing, not just paint
  • Daylight options through light wells and window cuts
Garage conversion structural work by Trust Builders, Wellington

GARAGE CONVERSIONS

Converting the garage into something you'll actually use.

Home office, gym, teenager's room, extra living. The garage is already there — we insulate, line, double-glaze, fit a separate entry, sort the heating and the network, and it stops being where the bikes live.

  • Council requirements assessed up front
  • Insulation, lining, flooring, double glazing, heating
  • Separate entry detailed to match the rest of the house
Two-storey extension framing by Trust Builders, coastal Wellington site

SINGLE & DOUBLE-STOREY EXTENSIONS

Going out, or going up.

Single-storey adds room without changing the roof. Going up keeps the section and the garden but means structural work below, scaffold, and a roofline that has to land back on the existing house cleanly. We'll talk you through which fits the home and the budget.
  • Roofline and cladding matched to the existing house
  • Engineered framing and tie-ins for double-storey
  • Programmed so the family can stay in most of the home

FAQ

Questions about alterations.

Thinking about adding on?

Send a sketch, a photo of the house and roughly what you want. We'll come on site, measure up, and write a proper quote.

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