Structural Alterations Borehamwood
Structural alterations, new openings, underpinning and floor structures in Borehamwood, designed by the engineer we appoint and inspected at every stage.
- Rated 4.9 from 31 reviews on MyBuilder
- Guide from £1,500 (London-derived)
- Free site survey, itemised quote
Structural alterations covers new openings, replacement joists, beams and support to retained masonry. GS Renovation is a contractor: we appoint the structural engineer and build to their calculations, and we never produce those calculations ourselves. In Borehamwood that means one organisation for design policy and a different one for building control.
For Borehamwood, on London-derived ranges a simple new opening starts from £1,500, and underpinning a single elevation typically costs £6,000 to £21,000; Hertfordshire work generally runs below that. GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Borehamwood.
Price guide
| Work | Indicative range |
|---|---|
| Simple new opening | from £1,500 |
| Underpinning, single elevation | £6,000 to £21,000 |
| Major structural works | from £15,000 |
Indicative London ranges (MyBuilder and Checkatrade, 2026), not a quotation. Hertfordshire work generally runs below the London figures; your price follows a site visit. Prices checked September 2026. Full breakdown: RSJ & Load-Bearing Walls.
How the job runs
- Free site survey at your Borehamwood address and an itemised quote.
- The engineer we appoint designs the work, and it is registered with Hertfordshire Building Control or an approved inspector. On a shared wall you serve the party wall notice as building owner; we supply the drawings.
- Props and any trial holes first, then the opening, joists or underpinning in the engineer's sequence.
- Building control inspects each stage before it is covered, then issues the completion certificate.
What the geological survey shows under Borehamwood
A clean sheet, on the published mapping. BGS 1:50,000 mapping returns no superficial deposits at ten points sampled across Borehamwood, from Shenley Road to Cowley Hill, Theobald Street, Elstree Way and Barnet Lane. The same ten points show no artificial ground, so no made ground or infill appears on the published map. No mass movement deposits are recorded there either, so no landslip is shown. The sheet covering the town is EW256, North London.
That is a starting point, not a ground investigation. Mapping at 1:50,000 will not show a filled garden pond, an old soakaway or a shallow drain run under the wall you want opened up. Where an alteration reaches foundations, the engineer decides whether trial holes are needed. What the mapping does give you is the absence of the large scale surprises, which is worth knowing before anyone prices the work.
Housing in Borehamwood
About 15,090 homes are listed for Borehamwood, and the mix is 63% houses to 36% flats, with 90% built after 1945, 8% in 1919 to 1939 and 2% earlier. Terraced houses make up 38% of homes here, and underpinning the party wall of a terrace in Borehamwood needs a notice to the neighbour.
Roof alterations Hertsmere pushes back on
Three in particular. Hertsmere states it will normally refuse the conversion of a sloped hip end roof into a flat gable end roof. It states it will normally resist extensions that result in crown roofs, because they add bulk that is out of keeping with the street scene. It expects dormers to sit within the rear roof slope, and normally resists a dormer in the front roof unless one is already established in the street scene.
On size, Hertsmere states that in most cases a dormer should take up no more than 60 per cent of the roof slope. These are design positions rather than structural ones, but they decide what may be built, which in turn decides what steel and what timber the engineer has to design. Establishing the position with Hertsmere before drawings are finalised saves paying twice for the same set.
Two organisations, not one
Hertsmere Borough Council does not run its own building control service and directs building control enquiries to Hertfordshire Building Control. So design and policy questions go to the council, while inspection of the structure goes elsewhere. Hertfordshire Building Control is registered in England under company number 09990656, and describes itself as a not for profit organisation that returns all profit to Hertfordshire local councils and their residents.
For you the effect is two sets of paperwork on two timetables. A planning decision and a building control sign off are not the same thing, and holding one does not imply the other. We coordinate the building control application and the inspections, and we tell you plainly which parts of a scheme need a Hertsmere decision and which do not.
Locally listed buildings in Borehamwood
Hertsmere's local list appendix for Elstree and Borehamwood, dated June 2016, contains 26 entries with Borehamwood addresses. Hertsmere states that being on the local list does not affect a building's permitted development rights. It also states that local listing gives it an additional basis to require extensions and external alterations to be sympathetic to the original building. The rights stay; the design scrutiny goes up.
Hertsmere's only Special Character Area, covered by Policy SADM31, is the Bushey Heath Ministry of Defence housing area, and there is no equivalent designation in Borehamwood. Internal structural work remains a Building Regulations matter in any case. Where an alteration changes the outside of a locally listed building, the design conversation with Hertsmere comes first and the steel is designed around the answer.
- Trial holes to confirm foundation depth and ground conditions
- Load paths carried down to foundations on new piers and pads
- Wall plate, joist hanger and restraint strap installation
VOA Council Tax stock of properties, March 2025, for Borehamwood Cowley Hill, Borehamwood Brookmeadow, Borehamwood Kenilworth and Borehamwood Hillside. Counts rounded by the VOA.
Why Borehamwood Homeowners Choose GS Renovation
Hertsmere sets the design policy and a separate body inspects the structure, so a Borehamwood alteration has two authorities to satisfy on two timetables. We handle both threads: engineer appointed and briefed, drawings coordinated with your designer, building control application and inspections coordinated. GS Renovation is registered in England, company number 14611254, fully insured, and rated 4.9 from 31 reviews on MyBuilder.
We loved working with George and Ibrahim and would highly recommend them. They have done splendid job on our new kitchen refurb which including new…
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
The kitchen has been fitted to the high standard. Saaid was polite, professional, tidy, he pays attention to a little details that make huge…
FAQ
Frequently Asked Questions about Structural Alterations Borehamwood
How do you price structural alterations in Borehamwood?
The method for pricing structural alterations in Borehamwood is deliberately dull: measure, scope, itemise, then compare with £1,500 to £21,000 or more, from a simple opening to underpinning one elevation (London-derived). Nothing is quoted over the phone, because a blind figure changes later. GS Renovation allows for the post-war suburban construction at WD6 and prices Hertfordshire Building Control sign-off of the permanent support before concealment as its own line.
Can a commercial building on Elstree Way be converted to flats without planning permission?
No. Hertsmere's employment area Article 4 directions took effect on 25 May 2023 and remove the Class MA right to convert commercial premises to homes at the Elstree Way and Stirling Way employment areas in Borehamwood. The Class ZA right to demolish a vacant commercial building and replace it with homes is removed at those two areas as well. Borehamwood Enterprise Centre and Theobald Court are named as locally significant employment sites covered by the Class MA direction.
Which Hertsmere policy is an external alteration judged against?
Policy SADM30 of the Site Allocations and Development Management Policies Plan, which sets the design principles. That plan was adopted by Full Council on 23 November 2016, and it states that extensions to buildings will be assessed stringently in respect of their visual effect. The design decision therefore leads and the structural design follows it. We establish the position with Hertsmere before the engineer is asked to size steel for a scheme that could still change.
Is Hertsmere's design guide still the current standard, given its age?
Part E remains the adopted guidance for residential extensions. It was adopted in 2006, and a clarification note was published in April 2010. Part B, which covered permitted development, was withdrawn in 2010 because of continuing changes to the General Permitted Development Order, so Hertsmere publishes no local document setting out your permitted development rights. Those come from the national order, and we confirm the current position rather than working from withdrawn guidance.
How do you check whether a tree beside the work is protected?
Ask Hertsmere directly, because the national planning data register returns no tree preservation order records for the borough. Hertsmere publishes its own orders instead, so searching the national register alone tells you nothing either way. This matters where an alteration reaches foundations near a tree, since the engineer may want the root protection area settled before any excavation. We raise it at survey stage rather than once a trench is open.
What has to be submitted with a Hertsmere planning application?
Whatever the National Validation Requirements ask for, because Hertsmere publishes no separate local list of validation requirements. It also requires application plans to be drawn to a recognised metric scale, to include a scale bar and to be supplied in PDF format. That sounds like a formality until an application is returned invalid and the determination period starts again. We check that the drawings your designer prepares meet that standard before they go in.
Every Service, One Team
More GS Renovation Services in Borehamwood
One team for every GS Renovation service in Borehamwood:
Same Service, Nearby Areas
Structural Alterations Near Borehamwood
We carry out structural alterations across Borehamwood and the surrounding areas. Explore a nearby location:
Ready to Start Your Borehamwood Project?
Free, no-obligation quote for structural alterations in Borehamwood.