Open plan means one space where there were two or more rooms, so the walls that go may be carrying floor loads above. The layout you want is checked structurally before it is drawn. GS Renovation appoints the structural engineer, installs the beams and supports to the calculations, and coordinates building control. A full knock-through, including the wall removal, the engineer's fee and making good, runs from £2,500 to £6,500 and above (indicative London ranges, MyBuilder and Checkatrade, 2026).
The consent route and the inspection
Where a building notice is used, Hertfordshire Building Control states the work can commence within 48 hours of the council receiving the notice. That sets the start date, not the design date. Calculations, beam sizes and bearing details are settled before the notice is of any use.
Hertfordshire Building Control names structural beams and openings as one of the items its inspectors examine on site. Across a whole floor that can mean more than one beam and more than one set of bearings, so the visit is planned for the point when all of it is still visible.
The houses being opened up
Terraced houses were the largest accommodation type in Welwyn Hatfield at the 2021 census, at 14,814 households or 32.1 per cent. A terrace gives you two party walls and a limited run of internal walls, and that is what decides where a beam is able to bear.
Hatfield was designated a new town on 20 May 1948 under the New Towns Act 1946, so the town's housing spans the older core and everything built after designation. What is carrying load is established by survey and by opening up, not assumed from the address or the street.
Flats, maisonettes and listed homes
Welwyn Hatfield Borough Council states that permitted development rights apply to houses and do not apply to flats, maisonettes, mobile homes, caravans or other buildings. An open plan conversion inside a flat therefore starts from a different position, and the lease sets its own requirements on top.
Listed status is not confined to the historic core. Numbers 23 to 41 The Ryde in Hatfield were listed at Grade II on 22 December 1998 under entry 1246830. Internal alterations to a listed home need listed building consent, which is applied for separately from planning permission.
- Openings formed in stages to keep the home usable
- Utility and boot room space carved out of the new layout
- Knock-throughs between front and rear reception rooms
- Flush beam detailing where a downstand would look wrong
- Open-plan kitchen-diner conversions
Trusted Open-Plan Conversions in Hatfield
An open plan floor is a sequence, not a single event. Temporary support goes in, the walls come out, the beams land on the bearings the engineer specified, then services, floors and finishes follow in order. Get that order wrong and the work is undone and redone. We run the sequence as one contractor with one point of contact, appoint the engineer, and coordinate the building control application and inspections. We are fully insured and quotations are free.
- One point of contact on the phone, not a call centre
- Building control applications and inspections coordinated for you
- Our own trades on site rather than a chain of subcontractors
- The house kept usable while the opening is formed in stages
- Heating and radiator positions reworked for the new layout
- Structure and finishes delivered by one team on one programme