Kitchen Extensions Borehamwood

A kitchen extension in Borehamwood is built onto a house stock where 38% of homes are terraced houses and 23% are semi-detached or detached. On a terrace that means a single storey rear addition; on a semi, a rear or wraparound kitchen. 36% of homes are flats, and a flat has no householder permitted development rights, so a ground floor flat needs planning permission for any kitchen extension. We build the groundworks, drainage, steel, roof and glazing, then fit the kitchen in the same programme.

For Borehamwood, on London-derived ranges a rear kitchen extension of about 30 square metres typically costs £45,000 to £97,500 excluding VAT, or £60,000 to £100,000 for a side return; Hertfordshire work generally runs below that. GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Borehamwood: the structural engineer we appoint designs the foundations and steel, we build the room and fit the kitchen, and a registered electrician certifies the electrics.

Sizing a Borehamwood kitchen extension to Hertsmere's Part E limits

Size the extension to Part E before the kitchen layout is fixed, because the depth decides where the island, sink and table can go. Hertsmere's Planning and Design Guide Part E says the council is likely to refuse a rear extension that breaches the 45 degree line or runs more than 3.35 metres beyond the original rear building line. On a Borehamwood terrace that depth sets the room: take the existing back room, add what the line allows, and plan the units around the result. Part E applies when the extension needs planning permission; one built under permitted development follows the national limits instead. The original rear building line is the house as first built, so check whether an earlier lean-to already uses some of that depth.

Height matters in a kitchen because of roof lights, extract ducting and pendant lighting over an island. Part E says a single storey extension should not be higher than 3 metres with a flat roof or 4 metres with a pitched roof, measured from ground level. It also limits any parapet wall to 0.3 metres above the main flat roof. Inside a flat roof, the joists, insulation and falls take their share, so the finished ceiling sits lower than the outside figure. We set out the roof build-up with the structural engineer we appoint before roof lights are ordered, so the ceiling height in your Borehamwood kitchen is known at drawing stage.

Housing in Borehamwood

Count the homes in Borehamwood and you get about 15,090: 90% built since 1945, 8% between the wars and 2% before 1919, with flats at 36% and houses at 63%. 38% of homes here are terraced; a terrace kitchen extension in Borehamwood starts in a narrow side return.

Side and wraparound kitchens on Borehamwood semis

A semi gives you the side passage as well as the garden, which is what makes a wraparound kitchen possible. Part E says single storey side extensions should sit at least 1 metre from the side boundary where there is significant separation between buildings. On a Borehamwood semi with a wide gap to the neighbour, that metre comes off the width of the side element, so a galley run of units along that wall may be the realistic layout. Where the houses already sit close together, the drawings should show the separation as it exists, so the planning officer can judge the side element against it.

Roof shape is the other constraint on a wraparound. Hertsmere states it will normally resist extensions that result in crown roofs, because they add bulk that is out of keeping with the street scene. A wraparound that meets at the corner can drift into that shape if the side and rear roofs are drawn as one flat top with pitched edges. We raise this with your designer early, because a corner valley or two separate roofs changes the steel at the corner, the gutter route and where the rainwater pipes come down past the new kitchen window.

Drainage, flood maps and steel for a Borehamwood kitchen

A kitchen at the back of the house moves the sink, dishwasher and washing machine away from the existing drain run, so the drainage is designed before the foundations are dug. British Geological Survey mapping records London Clay Formation beneath Borehamwood, described as clay, silt and sand. Clay moves with its moisture content, which is why the foundation depth and any drain passing under the new slab are set by the structural engineer we appoint and inspected on site. Where a manhole or drain sits inside the new footprint, it is relocated, or built over with the water company's agreement if the sewer is public, before the slab goes down.

The national planning data register records Environment Agency Flood Zone 3 land and Flood Zone 2 land inside the Borehamwood built up area boundary. If your garden falls within either, any planning application has to address flood risk, and the kitchen floor level and door thresholds are best settled at that point rather than on site. Check the flood map for your own address before the drawings are finished. The steel that opens the old back wall into the new kitchen goes in once the new walls and roof are up, so the house stays weathertight while the opening is formed and propped.

Designations and the garden left behind in Borehamwood

None of Hertsmere's 15 conservation areas is in Borehamwood, and the only Article 4 direction it lists under Borehamwood on its conservation Article 4 page is Land at Theobald Street. For a kitchen extension here, designation is therefore rarely the hurdle; depth, height and the garden you keep are. If your house is on or beside Theobald Street, check the extent of that direction with Hertsmere before assuming permitted development applies, because a direction can remove rights that a neighbouring street still has.

For a two or three bedroom house, Hertsmere's guide looks for 60 square metres of rear garden left once the build is done; for four bedrooms the figure is 80. On a narrow Borehamwood terrace plot that can cap the kitchen depth before the 3.35 metre limit does. Measure from the back of the proposed extension to the rear boundary, multiply by the plot width, and take off any shed or outbuilding you plan to keep. If the result is tight, a shallower extension with a wider opening into the existing room can give a more usable kitchen than a deep, narrow one.

• Building control inspections from footings to completion
• Drain diversions and build over agreements with the water company
• Boiler relocation and flue changes on the enclosed rear wall

VOA Council Tax stock of properties, March 2025, for Borehamwood Cowley Hill, Borehamwood Brookmeadow, Borehamwood Kenilworth and Borehamwood Hillside. Counts rounded by the VOA.

Alongside kitchen extensions in Borehamwood, the pages that usually help next are kitchen renovation in Borehamwood, kitchen extensions in Radlett, fitting the kitchen itself, the Party Wall Act on a boundary build, our London kitchen extensions page and Planning a Kitchen Island.

Why Borehamwood Homeowners Choose GS Renovation

GS Renovation builds the whole kitchen extension in Borehamwood as one job: groundworks, drainage, walls, steel, roof and glazing, then the units, worktops, tiling and decoration. The structural engineer we appoint designs the steel and foundations, and we build to their calculations. You or your designer hold the planning consent; we build to it and give you the drawings and programme for building control. One point of contact runs the sequence, so the kitchen fitters arrive to a dry, plastered room with plumbing and electrical first fix already in.

• Paperwork and certificates handed over for when you sell
• New floor level matched to the existing house, with no step at the opening
• Drains surveyed by camera before the footprint is fixed

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.