House Extension Designand Build in Lincolnand Lincolnshire

The most common project we design: a rear extension of roughly 3 to 6 metres in depth, usually forming an open-plan kitchen, dining and living space. Structure is typically a steel goalpost or flitch beam where the rear wall is removed, on trench-fill or, near mature trees, deeper piled or reinforced foundations.

Wrap-arounds add the side return and are transformative on terraced and semi-detached houses, but they need careful daylight design: the deeper the plan, the more the middle of the house depends on rooflights and internal glazing. Flat roofs with a single-ply or GRP membrane and generous rooflights usually outperform a pitched roof for light on these plans.

Two-storey extensions deliver the lowest cost per square metre because you gain two floors from one set of foundations and one roof. Planning is more sensitive: ridge and eaves heights normally need to sit below the original, first-floor windows raise overlooking issues, and a side extension is often required to be set back from the front elevation.

Internally, the gain is usually a bedroom with an en-suite over an enlarged kitchen or utility. Staircase position, first-floor structure and how the new roof ties into the existing are the details that decide whether it looks original or bolted on.

Matching brick and pantile is the safe route in most Lincolnshire villages and conservation areas. Contrasting is often the better route: dark timber cladding, render, brick slips or standing-seam zinc read as a deliberate modern addition rather than a poor match, and are frequently better received by planning officers than an approximate brick blend.

Glazing needs balance. Large sliding doors and rooflights transform a space, but Part L and Part O of the building regulations limit glazed area and require overheating to be considered. We size glazing against the thermal calculations, specify insulation build-ups for walls, floor and roof, and detail the junction where the new insulation meets the old wall, the single most common cold-bridge and damp problem in extension work and damp problem in extension work.

Foundation depth is set by soil type, trees and existing drainage. Lincolnshire has plenty of shrinkable clay and mature boundary planting, both of which push depths beyond the standard 1 metre and materially affect cost, which is why we want the site visit before quoting.

Where the extension crosses or sits within 3 metres of a public sewer, a build-over agreement with Anglian Water is required. Where excavation is within 3 metres of a neighbouring structure, or the work affects a shared wall, the Party Wall etc. Act 1996 applies and notice must be served. We identify both at design stage so they are running in the background, not blocking the start date.

Sequence matters when you are staying put. Getting the shell watertight before opening up the existing wall, keeping the kitchen running as long as possible and phasing the drainage works reduce the disruptive weeks from most of the job to a handful of them. We plan the sequence into the drawings.

For commercial extensions, office, workshop or retail, the same design method applies with additional requirements around fire escape, accessibility under Part M, and often the need to keep the business trading throughout. We handle those projects alongside our residential work across Lincolnshire.