Structural Alterations Old Street
Structural alterations, new openings, underpinning and floor structures in Old Street, designed by the engineer we appoint and inspected at every stage.
- Rated 4.9 from 31 reviews on MyBuilder
- London guide: from £1,500
- Free site survey, itemised quote
GS Renovation carries out structural alterations throughout Old Street and EC1, from new openings in the brick and concrete of the post-war blocks around St Luke's to alterations in the newer apartments by the roundabout and the area's few converted warehouses. Our founder's 30+ years on the tools has taught us that these post-war, converted and new-build homes hide surprises behind their finishes, so every alteration begins with proper engineering rather than guesswork.
In Old Street, a simple new opening starts from £1,500, and underpinning a single elevation typically costs £6,000 to £21,000 (indicative London ranges, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Old Street.
Price guide
| Work | Indicative London 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. Prices checked September 2026. Full breakdown: RSJ & Load-Bearing Walls.
How the job runs
- Free site survey at your Old Street address and an itemised quote.
- The engineer we appoint designs the work, and it is registered with Islington Council 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.
Openings and beams in Old Street apartments
Forming a new opening in an Old Street flat means understanding what sits above it. In a converted warehouse that might be a thick masonry wall or a section of the original industrial frame; in a post-war or new-build block it could be a blockwork or concrete element tied into the whole structure. We have an engineer calculate the loads and specify a steel beam that bears onto padstones and transfers weight safely into the remaining structure.
Replacement joists, supported openings and localised underpinning all follow the same disciplined method. We install temporary propping, expose the structure, carry out the work in controlled stages, and only remove props once the new steel or timber is fully bearing. Working inside an occupied EC1 apartment, we protect floors and shared communal routes, keep dust contained, and keep disturbance to the flats around yours to a minimum while the alteration is made.
Housing in Old Street
Count the homes in Old Street and you get about 6,800: 76% built since 1945, 5% between the wars and 16% before 1919, with flats at 99% and houses at 1%. Where most homes are flats, structural repair to a block in Old Street usually falls to the freeholder.
Basement work under an Old Street building is tightly limited
Going below ground in Old Street comes up in the older buildings and warehouse conversions that have a cellar. Islington Council says planning permission is usually required for the construction of a basement. Its Basement Development SPD, adopted January 2016, says basements should generally not exceed 1 storey in depth and not exceed 3m floor to ceiling height. So in a building that already has a storey below the street, the realistic scope is deepening or improving what is there within those limits, not digging a second level.
A basement application in Islington needs a Structural Method Statement in accordance with Policy DH4 and Section 6 and Appendix B of the Basement Development SPD. It must be signed by a Chartered Civil Engineer (MICE) or Chartered Structural Engineer (MIStruct.E) appointed by the applicant, and we make that appointment in your name. For an Old Street building with neighbours pressed close on both sides, that statement sets how each section of wall is supported during the dig, and our site sequence follows it exactly.
Consents and sign-off in EC1
Structural alterations in an Old Street leasehold flat need the freeholder's licence to alter, and your managing agent will want to see the engineer's drawings, method and insurance before granting it. We assemble that package and coordinate the approvals, then work within building-management rules covering working hours, protection of common parts and use of the lift, so consent is not held up on our side.
These works fall under the Building Regulations, so Islington Council's building control inspects the beams, padstones or underpinning and issues the completion certificate. Internal structural work does not need planning permission. External changes may, and to a flat they almost always do, because flats have no permitted development rights; a listed building also needs listed building consent for internal alterations. Where an alteration touches a wall or floor shared with an adjoining flat, the Party Wall Act applies and you serve the notice as building owner, using the drawings we supply.
- Load paths carried down to foundations on new piers and pads
- Temporary works, propping and needling
- Underpinning and foundation strengthening in sequenced bays
VOA Council Tax stock of properties, March 2025, for Old Street & St Luke's. Counts rounded by the VOA.
Trusted Structural Alterations in Old Street
Old Street clients choose GS Renovation because structural alterations demand one team that owns the whole job. We install steel designed by the engineer we appoint, help you obtain the freeholder's licence to alter, coordinate the managing agent, and see Islington building control through to certification. Safe propping, staged demolition, tidy protected working and our founder's 30+ years of experience give you a result you can trust.
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…
George always kept to commitments and arrived on time. He offered helpful suggestions during his initial visit and promptly provided a reasonably…
FAQ
Frequently Asked Questions about Structural Alterations Old Street
What is the going rate for structural alterations around Old Street?
Structural alterations around Old Street typically costs £1,500 to £21,000 or more, from a simple opening to underpinning one elevation (indicative), but scope varies more than the market does. Two Old Street jobs of the same size can be different work, because what each wall and floor carries decides the design. GS Renovation surveys and prices each on its merits at EC1, with the Islington Council building control fee shown separately.
Do I need planning permission for structural alterations in my EC1 flat?
Not for internal structural work. New openings, replacement joists and underpinning are controlled under the Building Regulations, and Islington Council's building control signs them off. Planning permission is not involved. You will, however, need the freeholder's licence to alter for a leasehold Old Street flat. External changes to a flat usually do need planning permission, since flats have no permitted development rights, and a listed building needs listed building consent for internal work too.
Can a mezzanine be added in a high-ceilinged Old Street flat?
Where headroom allows both levels, yes, but it is a structural alteration first and joinery second. The new deck puts load into walls, piers or columns that were never sized for it, so the engineer checks each bearing point. Building control approves the design and the escape route from the upper level, and the lease almost always needs the freeholder's written consent before anything is fixed.
Why does the engineer want the original drawings for an Old Street block?
Because some concrete floors cannot be drilled or cut blind. Modern slabs can carry reinforcement or tensioned cables at depths only the drawings reveal, and hitting one is a serious structural problem, not a snag. The managing agent or freeholder usually holds the structural set. Without it, the engineer may specify a scan of the slab before any core hole for pipes or fixings.
Is it possible to cut a new doorway through a brick wall in an Old Street conversion?
Usually, with a lintel sized for what that wall carries and needles holding the brickwork above while the hole is formed. Original warehouse walls are thick, so two or three lintels may sit side by side to cover the full depth. A wall separating your flat from a neighbour's is not normally a candidate, so the engineer confirms which walls are internal before drawing anything.
Will the floor of my Old Street flat carry a stone island or a heavy bath?
It depends on what the floor is. In a warehouse conversion it may be timber boards on joists or on original steel beams; in a new-build it is typically a concrete slab. Concentrated weight, such as a stone island or a filled cast-iron bath, is checked by the engineer against that construction. Timber floors sometimes need extra joists; slabs rarely do, but their depth limits pipe runs.
Can a basement take up the whole yard behind an Old Street building?
No. Islington's Basement Development SPD says a basement and other structures should cumulatively occupy less than 50% of the original garden and be smaller in area than the original footprint of the dwelling. Behind a tightly built Old Street property the original open area may be small, and any later structure there already counts. We work out what the original yard was from historic plans or the title first.
How is Islington building control charged for underpinning in Old Street?
Against the length of wall. Islington's Table 1 domestic charges include domestic underpinning up to 10 m in length, so the foundation plan from the engineer decides which line applies. Where underpinning runs along a party wall and a rear wall together, that length adds up quickly. We measure it from the drawings before applying and book an inspection for each sequence of pins before it is concreted.
Is Islington's pre-application site visit worth it for structural work below an Old Street home?
For anything that counts as basement work, it can prevent a refused application. Islington offers householder pre-application written advice with a site visit, and follow-up advice afterwards. An officer who stands in the existing cellar sees its depth, the light and the yard, which is what the basement limits are measured against. We bring the engineer's outline section so the advice is about a real proposal.
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