Open-plan extensions in Nottingham
An open-plan extension adds space at the back of the house and takes out the walls between the kitchen, dining room and living area so they work as one room. The extension is often the easier half. This page covers the harder parts: the structure, the layout and making a large room comfortable to live in.
We coordinate the structural engineer, building control and the build, from the first survey to the final decoration.
- Steel beams designed by a structural engineer
- Open-plan and broken-plan layouts
- Building regulations, including fire safety
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What an open-plan extension involves
Most open-plan projects combine a single-storey rear extension with removing one or more walls: typically the wall between the kitchen and the back reception room, plus the old rear wall of the house. Some homes only need the knock-through. Others need the new floor space as well.
Open plan suits households that spend most of their time in the kitchen and want to see the garden, and each other, from the hob. It suits less well if someone needs a quiet room for work or television, or if cooking smells and noise would bother people. Broken plan, covered below, is often the answer to that.
Best for
Family homes where the kitchen is the busiest room, and older houses with small, closed-off rooms at the back.
Typical timescale
Around 10 to 16 weeks on site as an indicative guide, depending on size and how many walls are removed.
Removing walls: steels and structural calculations
The first question for every wall is whether it’s load-bearing. Rear walls almost always are. Internal walls often carry floor joists or a wall above, and it isn’t always obvious from below, so the floor above and the roof are checked too.
A structural engineer then designs each beam: its size, where each end bears, and whether it sits on padstones, new brick piers or steel posts down to new foundations. The calculations and drawings go to building control with the building regulations application.
On site, the structure above is held on temporary props while the opening is formed and the beam goes in. Building control inspects the steel before it’s covered, and it then needs fire protection, usually plasterboard boxing or intumescent paint, as specified.
A downstand beam hangs below the ceiling and is the simpler option. A flush beam sits up within the ceiling for a clean line but costs more and involves more work to the floor above. Ground-floor chimney breasts can also come out, but the masonry above has to be properly supported, and on semis and terraces the stack may be shared with the neighbour. Where a beam bears on a party wall, a Party Wall Act notice is usually needed.
Questions the engineer answers
- Is the wall load-bearing?
- What size of steel is needed?
- Downstand or flush beam?
- Where do the ends bear, and do they need new foundations?
- What fire protection does the steel need?
Broken-plan layouts and zoning
Broken plan keeps the light and the sense of one space, but gives each activity its own area. It’s often more comfortable to live in than a completely open room.
Kitchen zone
An island or peninsula separates the person cooking from the seating area while keeping them part of the room. Keep the hob away from the main walkway to the garden.
Dining zone
The table usually works best near the garden doors, with a pendant light or roof lantern marking the spot.
Living or snug zone
A partly enclosed area using a glazed screen, pocket or sliding doors, a change in floor level or a run of shelving, so the television and conversation don’t compete with the kitchen.
Utility off the kitchen
A small separate room for the washing machine, dryer and coats keeps the noisiest appliances out of the open space.
Floors, lighting and beams
A change of flooring, separate lighting circuits for each zone and even the line of a downstand beam can mark where one area ends and the next begins.
Heating, noise and cooking smells
Heating
A large room with a lot of glazing loses heat faster than the small rooms it replaces. A heat loss calculation shows what’s needed and whether the boiler or heat pump can cope. Underfloor heating suits big open rooms but has to be decided before the floor screed.
Acoustics
Tiles, glass and plaster make a big room echo and let kitchen noise travel. Rugs, soft furnishings, acoustic panels, a quieter extractor and dishwasher, and partial screening all help.
Extraction
Building regulations require extract ventilation in a kitchen, and in an open room it matters more. An extractor ducted to outside clears smells and steam far better than a recirculating one.
Daylight
A deep open room can be dark in the middle, away from the garden doors. Rooflights or a lantern over the kitchen or dining zone bring light where it’s needed.
Building regulations, fire safety and planning
Removing a load-bearing wall needs building regulations approval, whether or not you’re extending. So does the extension itself.
Fire safety is the part people don’t expect. In a typical two-storey house, the hallway and stairs are the escape route. If the kitchen is opened up to the hall and stairs, or a room can only be reached by going through the open-plan space, the design needs to show a safe way out, often through escape windows or doors, and building control will usually expect mains-powered, interlinked smoke alarms. In a house with a floor more than 4.5m above ground, such as one with a loft conversion or three storeys, an open stair is more restricted and usually needs extra measures such as a sprinkler system and fire-resisting separation. Building control agrees the approach for your house.
Taking out internal walls doesn’t need planning permission, except in a listed building, where listed building consent is needed for internal changes too. The extension part may fall under permitted development, depending on the property and any restrictions. Our rear extensions guide explains the size limits.
We coordinate
Structural calculations, the building regulations application, party wall matters and any planning application needed for your project.
How we build an open-plan extension
Free survey
We measure up, look at the walls you want removed and talk through how the space should work.
Design and steels
Layout drawings, then the structural engineer specifies the beams and supports.
Approvals
Building regulations, including fire safety, plus any planning application and party wall notices.
Groundwork and shell
Foundations, including pads for any new posts, then the extension shell is built and made weathertight.
Structural opening
Temporary props go in, the steels are installed and inspected, and the walls come out.
First and second fix
Heating, electrics, plastering, flooring and the kitchen are fitted.
Handover
Final building control inspection, a walk-through with you and handover of the certificates.
Open-plan extension costs
| Project type | Indicative guide range |
|---|---|
| Wall removal and single steel beam only | £3,500 – £7,000 |
| Small rear extension with open plan layout | £35,000 – £50,000 |
| Medium kitchen-diner extension, one wall removed | £50,000 – £75,000 |
| Large open plan extension with bi-folds and lantern | £75,000 – £100,000+ |
These are indicative guide ranges, not quotes. The amount of structural work makes the biggest difference: how many walls come out, the size and type of steel, and whether new posts and foundations are needed. You receive a written, itemised quotation after a free site survey.
Open-plan extensions across the area
Not sure if we cover your street? Give us a call and we will let you know.
See the work before you decide
Photos of our extension work are in the project gallery, and customer feedback is on our reviews page, where reviews are published once they’ve been matched to a real job. At your survey, ask us for a past customer you can speak to about a similar open-plan project.
Open-plan extension questions
Most walls can come out, but a load-bearing wall needs a steel beam, or another structural support, to carry the weight above. A structural engineer checks each wall and designs the support, and the calculations go to building control before work starts.
Taking out internal walls doesn’t need planning permission unless the house is listed. The extension part may fall under permitted development, depending on its size and any restrictions on your property. Building regulations approval is needed for both the wall removal and the extension.
It can. If the kitchen opens onto the hallway and stairs, or a room can only be reached through the open-plan space, the design needs a safe escape route and suitable smoke alarms. Houses with a loft conversion or three storeys face stricter rules. Building control agrees the approach before work starts.
Broken plan keeps one connected space but gives the kitchen, dining and living areas some separation, using islands, glazed screens, sliding doors, changes in floor level or shelving. It keeps the light while reducing noise and smells in the seating area.
Not if it’s designed for it. The new structure is insulated to current building regulations, and a heat loss calculation shows what heating the room needs. Underfloor heating is a common choice for large kitchen-diners, but it has to be decided before the floor is laid.
As an indicative guide, removing a wall with a single steel beam is around £3,500 to £7,000 on its own. Open-plan extensions that combine new floor space with wall removal typically range from about £35,000 to £100,000 or more. You receive a written, itemised quotation after a free survey.
Most open-plan extensions take around 10 to 16 weeks on site, depending on size and how many walls are removed. It’s an indicative figure rather than a guarantee, and design, structural calculations and approvals come first.
Find out which walls can come out
Book a free site survey. We’ll look at the structure, talk through open-plan and broken-plan options and follow up with a written, itemised quotation.