Hill site builders in Christchurch

A home on the Port Hills can give you views no flat section can match. It can also be the hardest kind of build there is. Steep sections bring problems you don’t meet on the flat: getting trucks and materials on site, holding the ground in place, and planning the build around weather and slopes. Every one of those calls needs experience to get right, because the wrong one is expensive to undo.

On a steep section, access shapes the whole job. Before anything else is decided, we work out how concrete trucks, cranes, materials and trades will physically reach the house site, and where everything will be stored once it’s there.

At Kemp House in Lyttelton the section was an untouched, very steep hillside. Before we could start on the house, we built a 50-metre driveway and a bridge strong enough to carry a 28-tonne concrete truck. That work had to be designed, consented and built first, and it set the pace for everything after it.

Access decisions affect cost and timing more than almost anything else. They include:

• whether the driveway or a temporary track goes in first, and how strong it needs to be
• when to bring in a crane, and where it can safely set up
• whether concrete can be poured straight from the truck or needs pumping up the slope
• how materials are delivered and stored when there’s no flat ground to put them on

Engineering for the slope

Hill sites need more engineering than a flat section, and it starts before the design is finished. A geotechnical report tells us what the ground is made of and how stable it is. On parts of the Port Hills, rockfall and slope stability also need assessing. That information drives the foundations, the retaining walls and the drainage.

We work closely with the engineers from the start, so the design can actually be built on the site and the budget reflects what the ground needs. At Kemp House, designed by Common Architecture with engineering by TM Consultants, the house sits on steel portals with a timber floor and a half concrete slab over a concrete block retaining wall. That’s the kind of structure a slope demands, and every part of it has to be set out and built precisely.

Engineering on a hill site usually covers:

• foundations that suit the ground conditions and the slope
• retaining walls to hold the section and create usable space
• stormwater and drainage, so water is managed on and below the slope
• any conditions Christchurch City Council attaches to the building consent

Planning the build schedule

A hill build can’t be scheduled like a house on the flat. The order of work matters more, and some stages can only happen in the right conditions.

Earthworks, retaining and foundations need to be done in the right sequence, and ideally in drier months, because wet ground on a slope slows everything down. Crane days, concrete pours and engineer inspections all have to line up. When one of them moves, the rest of the programme moves with it. We plan this in detail before work starts and confirm the dates with you at the pre-construction meeting, so you know what to expect and when.

Why experience matters

On a hill site, most of the important decisions are made early: how to get on site, what has to be built first, and how the house meets the ground. Make the right calls and the build runs smoothly. Get them wrong and you pay for it later in time and money. We’ve built on steep sites and know the questions to ask before they become problems.

We bring the same approach to every hill build: early involvement, clear pricing that reflects what the site really needs, and regular updates so you always know where the job is at.

Where we build on the hills

We build and renovate across the Port Hills and the hill suburbs of Christchurch, including Cashmere, Cracroft, Huntsbury, Scarborough, Redcliffs and over the hill in Lyttelton. Our own home in Cracroft, on Worsleys Road, was a relocated house that we placed onto new foundations on a Port Hills section and renovated inside and out.

Talk to us before you buy or design

If you’re looking at a hill section, or you already have one, the earlier we’re involved the better. We can help you understand what the site will need before the design is locked in. If you haven’t chosen an architect yet, we’ll listen to your vision and introduce you to three or four whose work suits it, so you can find the one you gel with. If you already have one, we’re happy to work alongside them.