Self-Build Eco-Home in Newbury | Case Study

The brief

Great Missenden Build Co. was appointed as the main contractor for an ambitious self-build eco-home on the rural edge of Newbury, Berkshire. The clients were a young professional family who had spent two years searching for a suitable plot before securing a sloping site with outline planning permission for a four-bedroom detached house. They wanted a home that would perform well beyond Building Regulations, with a timber-frame structure, traditional brick cladding to respect the local vernacular, and a planted sedum roof over part of the ground floor that would soften the building's profile against the surrounding countryside.

The architectural design placed fabric efficiency at its heart. The specification called for 300mm of wall insulation, triple-glazed aluminium-wood composite windows, a mechanical ventilation with heat recovery system, an air-source heat pump, and airtightness targeting less than 3 m³/(h·m²) at 50Pa. The living spaces were arranged around a central kitchen-diner with a south-facing glazed gable, while the bedrooms sat under a pitched roof clad in clay tiles. Because the house was being built to a demanding energy target, every layer of the structural envelope had to be installed with care and continuity, from the ground-bearing slab to the ridge line.

The clients were financing the project through a self-build mortgage with staged drawdowns, which meant they needed a fixed monthly spend cap rather than a single large upfront material invoice. The plot was also tight, with no room for a long-term material compound and limited stacking space beside the foundations. Great Missenden approached us before the groundworks started and asked us to price the full structural pack. We worked through the architect's bill of quantities, the engineer's foundation design and the timber-frame supplier's cutting list, and produced a single schedule split across twelve staged drops. The clients knew the material cost of each month before the first spade went in the ground, and they appreciated the transparency when comparing quotes.

• Client: Great Missenden Build Co.
• Location: Newbury, Berkshire (RG14, RG18)
• Project: Self-build eco-home
• Duration: 10 months
• Star Hawk material cost: £22,000

The challenge

Self-builds on rural edge-of-town plots always bring a unique set of pressures, and this Newbury project was no exception. We had to manage access, weather, sequencing, cash flow and specialist coordination all at the same time, while keeping the build programme on track for a fixed handover date.

Access. The plot was down a narrow lane with a working farm at the far end. There was no passing place for large vehicles and no room for a long-term material compound. We used 7.5-tonne tippers for the bulk aggregate drops and a flatbed for bricks, blocks and timber. For the larger concrete and aggregate deliveries we pre-staged materials in a nearby farmyard and shuttled them to site in smaller loads. Every delivery had to be coordinated with farm movements, school-run traffic and the weather.

Weather. The foundation excavation opened in February, just as the Berkshire clay was at its wettest. A reserve of MOT Type 1 and ballast was kept at our yard, allowing any water in the trenches to be backfilled and re-excavated on the same day. The site manager also kept sand and cement under cover so mortar work could continue between showers.

Fabric-first detailing. Because the house was aiming for a high fabric performance, the insulation had to be continuous and the timber frame had to be protected from moisture during construction. We scheduled the OSB, plywood and PIR deliveries to arrive just before the frame was weathered, so the boards were never left exposed for long. The cavity insulation slabs had to be cut carefully around openings and cavity ties to avoid thermal bridging.

Cash-flow staging. The clients wanted the material spend spread evenly across the ten-month programme. We split the order into monthly drops that matched the build programme, and we invoiced each drop separately so the clients could reconcile their monthly budget against their mortgage drawdown limits.

Coordination with the timber-frame supplier. The frame was manufactured off site and craned in over two days. We made sure the C24 timber, battens and sheet materials that we were supplying for the internal work and roof deck were on site before the frame arrived, because once the crane was booked there was no slack. Any missing timber would have delayed the roof deck and left the frame exposed to the elements.

Brick cladding detailing. The outer leaf was built in brick rather than render, which meant every course had to be straight and the cavity ties had to be clean. We sourced 7,916 Hampton Rural Blend Bricks and delivered them in three staged drops. Each drop was checked for colour consistency before it left the yard, and the bricklayer laid sample panels at dpc level before the main walls rose.

Same-day contact. A single named scheduler at Star Hawk handled every order for this build. When the foundation trenches were deeper than expected because of a buried hedge line, the site manager called at 7.30am and an extra 4 tonnes of ballast and 40 bags of cement were on site before lunch. That single point of contact was critical to keeping the programme moving.

Materials we supplied

Great Missenden sent us the architect's and engineer's schedules and we priced the full structural envelope for the Newbury eco-home. The materials we supplied were:

• Sub-base and concrete: 21 tonnes of MOT Type 1 Aggregate, 11 tonnes of 20mm Ballast Aggregate, 17 tonnes of Building Sand and 208 bags of General Purpose Cement for the strip foundations, floor slab, mortar and bedding.
• Masonry: 1,197 Aircrete Blocks for the inner leaf, partition walls and the insulated plinth, and 7,916 Hampton Rural Blend Bricks for the outer leaf and feature chimney breast.
• Timber and sheet: 2.5 cubic metres of C24 Timber, 171 linear metres of BS Treated Battens, 24 sheets of 18mm OSB3 Board and 4 sheets of Premium Hardwood Plywood for the roof deck, internal linings and details.
• Insulation: 66 sheets of Cavity Insulation Slab and 42 sheets of PIR Insulation Board for the walls, roof and ground-floor junctions.
• Openings: 12 Standard 100mm Cavity Lintels for windows, doors and the feature rear opening.
• Fixings: 9 boxes of Galvanized Nails and 9 boxes of High Performance Wood Screws for the battens, sheet materials and joinery.

The timber frame itself, the windows, the MVHR unit, the heat pump, the sedum roof system and the kitchen were supplied by specialist partners. We supplied the structural shell and the insulation that would be concealed behind the finished surfaces. Great Missenden managed these specialist packages, but all structural materials flowed through Star Hawk, which meant one delivery schedule, one invoice trail and one phone number for any queries.

Delivery and logistics

Self-builds live or die by logistics, and the Newbury programme needed a rolling four-week forecast from day one. We structured the drops so that materials arrived just ahead of each trade, minimising site storage while never leaving the gang waiting.

Month one — footings. The foundation materials — MOT Type 1, ballast, sand and cement — were delivered in three drops as the trenches were excavated and the concrete was cast. Because the ground was wet, we delivered slightly more than the calculated volume and held the surplus at the yard until it was needed. The 208 bags of General Purpose Cement were delivered on a pallet so they could be moved under cover quickly.

Month two — ground floor and blockwork. Blocks, sand and cement arrived shortly before the ground-floor slab pour and the rise of the inner leaf. The block order was delivered in two phases because a full load would not fit on site. The blocks were protected from rain under a tarpaulin between deliveries.

Month three — facing brickwork. The bricks arrived in three staged drops while the outer leaf was rising. We sized each drop to what the bricklayer could lay, so the bricks never sat in the mud for long. The 12 Standard 100mm Cavity Lintels were delivered just before the openings were formed.

Month four — timber, sheet and insulation. The C24 timber, battens, OSB, plywood and insulation were delivered the week before the timber frame was due. We covered the sheet materials with breathable tarps and stored them on pallets to keep them off the wet ground.

Months five to ten — follow-on drops. As the roof was closed in and the first-fix trades started, we supplied the remaining insulation and fixings in smaller, just-in-time drops. A Friday call between the site manager and our scheduler locked in the following week's deliveries. By this stage the deliveries were often only a few sheets of insulation or a box of screws, but the same single point of contact handled every request.

All deliveries were timed to avoid the farm traffic in the lane. We never sent an 18-tonne wagon down the single-track road without first confirming that the farm was not moving livestock. For the brick deliveries we used a flatbed that could reverse into the site entrance without blocking the lane.

The build

The build ran for 40 weeks across ten months, with a clear weekly rhythm that kept every trade moving.

Weeks 1–4: Groundworks and foundations. The site was stripped of topsoil, the strip trenches were dug and the foundations were poured. A suspended insulated ground floor was built over a void to minimise thermal bridging and protect the timber frame from ground moisture. Drainage for the heat pump and rainwater harvesting was laid at the same time.

Weeks 5–8: Ground floor slab and blockwork. The insulated ground floor slab was poured and the inner leaf of aircrete blockwork rose to plate level. Cavity insulation started at dpc level as the walls went up.

Weeks 9–12: Timber frame and weathering. The prefabricated timber frame arrived on two lorries and was craned into position over two days. The frame was wrapped in a breathable membrane and braced temporarily until the brickwork and roof deck provided permanent stability.

Weeks 13–16: Brickwork and roof deck. The outer brick leaf was built, the cavity insulation was installed and the OSB roof deck was fixed. The house became weather-tight, allowing the internal trades to start regardless of the weather.

Weeks 17–20: Windows and airtightness. The triple-glazed windows were installed and the airtightness membrane was taped at every junction. The first air-test was carried out and the result was well within the target of 3 m³/(h·m²).

Weeks 21–28: First fix and services. The MVHR ducting, electrics, plumbing and heat pump pipework were run through the frame. PIR insulation was cut and fitted around ducts and pipes, and the airtightness tape was checked at every penetration.

Weeks 29–36: Boarding and plastering. Plasterboard was fixed and skimmed. The kitchen and bathrooms started to take shape, and the sedum roof substrate was laid over the flat roof section.

Weeks 37–40: Finishing and handover. The sedum roof was planted, the heat pump was commissioned, the snag list was signed off and the family moved in. The final handover happened two days ahead of the original date.

The programme held firm throughout. The only significant delay was three days of snow in March that stopped the brickwork, but the internal trades kept going because the materials were already on site. The monthly delivery plan meant the bricklayer had enough bricks to resume immediately once the weather cleared.

The result

The finished house is a four-bedroom, highly insulated family home with a brick-and-timber appearance, a sedum roof and energy bills that are roughly half those of a typical new house of the same size. The MVHR system provides fresh filtered air without losing heat, and the sedum roof is visible from the master bedroom. The open-plan kitchen-diner catches the morning sun through the glazed gable, while the bedrooms at the rear look out across fields.

Great Missenden billed the clients £385,000 for the build. The Star Hawk structural and insulation pack came to £22,000.

For a material spend of £22,000, the value was in the coordination. Because we priced the whole envelope from the outset and split it into monthly drops, the clients could manage their cash flow without worrying about supply gaps. The young family later told Great Missenden that the predictable monthly invoices made it easier to stay within their mortgage drawdown limits, and that the consistent material supply was one of the least stressful parts of the whole project.

What we don't supply on a self-build

On an eco-home self-build such as this, we do not supply the following:

• Structural timber frame kits, engineered joists and trusses — supplied by the frame manufacturer.
• All glazing: windows, doors, rooflights, skylights and glazed gables.
• MVHR units, air-source heat pumps, radiators, underfloor heating and plumbing systems.
• Electrical systems, solar panels, batteries, smart-home equipment and lighting.
• Fitted kitchens, worktops, appliances, bathrooms, sanitaryware and tiles.
• Sedum roofing systems, green-roof substrates and specialist membranes.
• Scaffolding, security fencing, temporary power and welfare accommodation.
• Skip hire, waste disposal and final cleaning.

The remainder — the sub-base, cement, aggregates, blocks, bricks, lintels, timber, insulation and fixings — stays on a single Star Hawk account.

Cost transparency

The materials Star Hawk supplied came to £22,000 and broke down as follows:

Category	Materials supplied	Cost
Bricks	7,916 Hampton Rural Blend bricks	£5,080
Aggregates & sub-base	21 tonnes MOT Type 1, 17 tonnes sand, 11 tonnes ballast	£3,100
Blocks	1,197 aircrete blocks	£2,400
Insulation	66 sheets cavity insulation, 42 sheets PIR insulation	£3,500
Cement & mortar	208 bags cement	£1,660
Timber & sheet materials	2.5 cubic m C24 timber, 171m battens, 24 sheets OSB, 4 sheets plywood	£2,600
Lintels & steel	12 cavity lintels	£1,080
Fixings & hardware	9 boxes nails, 9 boxes screws	£1,580
Sundries	DPM, straps and bracing	£1,000

The remaining £363,000 covered the timber frame, glazing, MVHR, heat pump, sedum roof, kitchens, bathrooms, electrics, plumbing, decoration and labour supplied by other partners on the same site.

Why Newbury self-builders choose Star Hawk

We are 18 minutes from the RG14 postcode district and our round covers Newbury, including Thatcham, Greenham, Wash Common and Highclere. We also deliver to Reading, Basingstoke, Hungerford and Marlborough on the same day.

Most of our Newbury self-build customers are owner-occupiers building one-off homes who need a supplier that understands staged payments, rural access and fabric-first construction. If you are planning a self-build in Newbury, send your bill of quantities through the quote builder and we will come back the same working day.