Springbok Domestic Build

How we approach energy-efficient extensions

Springbok Domestic Build is operated by SPRINGBOK CONSTRUCTION LIMITED. We design and build home extensions with energy efficiency treated as a structural decision, not a finishing touch. That means we look at insulation, glazing, airtightness and ventilation together, at the drawing stage, rather than adding them later. Most of our work is rear and side extensions, garden rooms and kitchen knock-throughs for homeowners across the area.

The first thing we do is measure and assess. We look at how your existing house performs, where the cold bridges sit, which walls face the weather, and how you actually use the rooms you want to extend. From there we put together a specification that sets out the wall build-up, roof insulation values, window performance and heating approach. Nothing is priced until that specification is agreed, so there are no hidden assumptions in the quote.

On site, we manage the whole build rather than handing you between trades. Groundworks, foundations, structure, insulation, glazing and the final internal finish all sit with us. We keep a running programme so you know which week is which, and we tell you early if a delivery or a survey shifts the sequence. While we are working, the existing house stays weathertight and usable as far as the build allows.

Energy efficiency is where domestic extensions most often fall short. A new rear extension with underfloor heating but poor wall insulation will cost more to run than the room it replaced. So we build to a fabric-first standard: high-performance insulation, triple or high-spec double glazing, controlled ventilation and draught-proof junctions between old and new. Where it suits the project, we also fit air source heat pumps and solar-ready wiring.

We are a small, directly employed team. The people who quote your job are the people who run it, which keeps the detail from being lost between office and site. We work to Building Regulations and provide the certificates you need at completion. We are happy to talk through a project at any stage, including before you have drawings.

If you want to ask about a specific detail, use the enquiries page. We will give you a straight answer about what is realistic for your house and your budget.

Answers we give

Insulation, planning, costs and build times

Do I need planning permission for an energy-efficient extension?

Many rear and side extensions fall under permitted development, so no full application is needed. We check the limits for your property and tell you clearly if a householder application is required.

How much does a home extension cost per square metre?

Costs vary with ground conditions, glazing area and specification. We price from a written specification rather than a flat rate, so the figure you receive reflects your actual build.

What insulation and glazing do you use for energy efficiency?

We use high-performance insulation in walls, floors and roofs, with triple or high-spec double glazing and insulated cavity closers. The exact values are set out in your specification before work starts.

Can you build an extension without moving us out?

In most cases, yes. We keep the existing house weathertight, work in phases and protect floors and routes. Full temporary relocation is only needed where the kitchen or bathroom is out of use.

Will a new extension make my heating bills higher?

Not if it is built to current standards. Well-insulated walls and roofs, good glazing and controlled ventilation mean the new space adds little to your running costs, and often improves the performance of the house overall.

How long does an extension take from start to finish?

A typical single-storey rear extension takes twelve to eighteen weeks on site, with design and approval beforehand. We give you a week-by-week programme once the specification is agreed.