Stone Extension & Whole‑house Upgrade, Castlethorpe

The Brief

A young stone-built home (c. five years old) needed more space, better flow and lower running costs. The client asked for an extra bedroom, a high-quality kitchen–diner with a “wow” factor, underfloor heating, and a full renewables package (ASHP, solar PV and battery storage). Usability outdoors mattered too: hot tub area, seating and planting to suit family life.

What We Built

Stone extensions (two)
Side lean-to for a utility room, built in matching stone. We kept the original external stone wall exposed inside for character. Small rear single-storey to complete the open-corner bifold arrangement.
First-floor addition
Compact two-storey element to create one extra bedroom (4-bed → 5-bed).
Kitchen–diner
Open-plan layout with tiled floor and wet underfloor heating throughout the ground floor.
“Missing corner” glazing
Corner bifold doors that stack away to remove the corner visually; required a concealed steel solution to support loads and maintain clean lines.
Renewables & services
Air-source heat pump, solar PV and battery storage (future-proofed for EV charging).
Landscaping
Stone garden walls, a main Indian sandstone terrace, plus a circular patio with pergola at the rear for seating—and a second pergola at the house corner to shelter the hot tub.

Planning & Compliance

Householder planning on a relatively new development brought neighbour and massing constraints. We won consent by pulling back the first-floor extent and allocating a parking space, striking a balance between amenity and the client’s brief.

Delivery Notes

Cognitive handled planning, design, structural engineering and Building Control sign-off. Early design locked the bifold corner structure and openings so renewables, glazing and UFH could be sequenced without delay. Typical lead-time risks (windows/doors, heat pump kit) were managed through early orders and site checks.

Outcome

A lighter, warmer and more flexible family home: the kitchen–diner opens wide to the garden, the exposed stone adds texture, and outdoor spaces now work year-round with sheltered hot-tub and pergola seating. Running-cost resilience improves with the ASHP + PV + battery stack, while the layout gain upstairs delivers the fifth bedroom without overpowering the street scene.