Structural Alterations Catford
Structural alterations, new openings, underpinning and floor structures in Catford, 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 Catford, from new openings to replacement joists and underpinning across SE6. Our founder's 30+ years on the tools means we understand how SE6's Victorian and Edwardian houses are built and how to alter them safely, with engineer's calculations and Lewisham building control behind every job.
In Catford, 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 Catford.
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 Catford address and an itemised quote.
- The engineer we appoint designs the work, and it is registered with Lewisham 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.
Structural alterations for Catford homes
Period terraces in Catford often need more than a single wall removed. Widening the opening into a rear closet wing, forming a supported opening for bi-fold doors onto the garden, or replacing tired Victorian floor joists that have sagged over a century all count as structural work. Each is designed by a structural engineer so the new steelwork or timber is sized for the actual loads it will carry.
Where a bay front has dropped or a rear wall has cracked, the cause is often shallow Victorian foundations on London clay. We investigate before we specify anything, and where underpinning is the right answer we pour it in sequenced bays so the wall is never undermined all at once.
Housing in Catford
Of the 7,650 homes the valuation list records in Catford, 61% were built before 1919, 4% between the wars and 33% since 1945; 66% are flats and 34% are houses. Structural repair to a block in Catford usually falls to the freeholder under the lease, so it is agreed with them before anything is opened up, which matters here because most homes are flats.
Structural work near the shared drains behind Catford terraces
28% of Catford homes are terraced houses, and behind a terrace the drains from several houses often join before reaching the sewer. That matters for structural work as well as extensions. Lewisham uses a full plans application for any new proposal to build above or within 3 metres of a drain or sewer. Rebuilding a failed rear wall, underpinning a back addition or putting in new foundations close to that run can therefore fall under the full plans route. In Catford we lift the inspection chamber covers at the first visit, before anyone assumes the quicker route is open.
The second consequence is a separate consent. Lewisham's guidance says a build over agreement must be applied for before doing any works if a home is within 3 metres of a public drain or 1 metre of a public lateral drain. A shared run serving more than one Catford house is likely to be public, so the agreement can apply to structural work at the back of a terrace, not only to new building. We have the run traced by camera where it is unclear, so the structural engineer we appoint can place new foundations to suit it.
Engineering and consents in SE6
Every steel we install bears onto padstones, is propped with Acrows while we cut the opening in stages, and is bolted or pinned exactly as the engineer's drawing specifies. New lintels over widened openings, replacement joists and underpinning are all detailed on the engineer's calculations, which we submit to building control so there is a clear paper trail from design through to completion.
Structural alterations inside your home need Building Regulations approval rather than planning permission, and Lewisham Council's building control inspects the key stages and issues the completion certificate. Where the work touches the party wall shared with the house next door, you serve the required Party Wall Act notices as building owner before any tools come out, using the drawings we give you.
- Chimney breast removal and support to the stack above
- Building control applications, inspections and the completion certificate
- Trial holes to confirm foundation depth and ground conditions
VOA Council Tax stock of properties, March 2025, for Catford East & Mountsfield Park and Catford Bridge. Counts rounded by the VOA.
Trusted Structural Alterations in Catford
GS Renovation handles Catford structural alterations as a single accountable package: engineer's design, building control inspections and the build itself, all under one roof. You deal with one experienced team rather than chasing trades, we work tidily around your family, and everything is signed off by building control, drawing on our founder's 30+ years on the tools.
Reviewed jobs near Catford
1 MyBuilder review from Crofton Park, with each customer's own job title:
- Replace small section of wooden worktop, sink, tap and gas hob, Crofton Park, 17 Apr 2024 (5 out of 5)
Read all 31 on our reviews page.
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 was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
FAQ
Frequently Asked Questions about Structural Alterations Catford
Can you quote structural alterations for an SE6 property over the phone?
A rough steer on structural alterations in Catford is possible by phone; a quotation is not. The steer is £1,500 to £21,000 or more, from a simple opening to underpinning one elevation (indicative), and the figure waits until the SE6 property has been seen, because Victorian or Edwardian construction rarely matches the assumption. The call also covers the approvals: building regulations approval of the engineer's design. Ring 07472 424 226 or email info@gsrenovationltd.co.uk.
What structure is involved in adding a bathroom upstairs in Catford?
The floor, more than the walls. Fitting a bathroom into your Catford house means running waste pipes across or through joists, and the depth and position of any notch or hole is limited. A bath or a large shower tray also concentrates weight. Where the layout requires more than the floor allows, joists are strengthened or a new support is designed rather than the timbers being cut to suit the pipework.
How is a bay supported during work at a Catford property?
On temporary works designed for it, because a bay is more fragile than it looks. The bay of your Catford house stands on slender piers and carries the wall above, sometimes with a second bay on top. Work below or beside it, or repair of a failed lintel within it, needs the load taken on props positioned by the engineer. Bays are among the easier structures to damage during building work.
What is done about tree roots affecting a Catford house?
The cause is established before anything is cut down or underpinned. Where a tree near a Catford property is drawing moisture from clay ground, removing it can cause the ground to swell and lift the foundations, which is a different kind of damage. Root barriers, managed pruning or a designed foundation repair may all be options. The engineer and an arboriculturist decide between them rather than the owner.
Is the garden retaining wall at a Catford property structural?
It is holding back ground, which makes it a structure with a design life. Where a Catford garden is terraced or higher than the neighbouring plot, the wall retaining it carries lateral pressure that increases when the ground is saturated. Bulging, leaning or cracking means it is failing. Rebuilding one properly involves drainage behind it and a foundation, not simply relaying the bricks.
What does making good actually include at a Catford property?
Returning the affected areas to a decorated finish, and the extent is written down before work starts. On a Catford job that normally covers plastering, floor repairs, skirting and architrave, and preparing surfaces for decoration. Whether full redecoration of the room is included is stated explicitly rather than assumed either way, because it is the most common source of disagreement at the end of a job.
Can the cellar under a Catford house be dug out to make a room?
Possibly, but expect it to count as basement development. Lewisham Local Plan Policy QD9 requires a Basement Impact Assessment, and the plan says it must be carried out by a suitably qualified and recognised independent assessor and paid for by the applicant. The dig must not harm the stability of the house, its neighbours or the public realm, taking into account local geology. For a Catford house the assessment goes in with the planning application, and the underpinning design follows from it.
Is there a way to ask Lewisham planners about a new opening before designing it?
Yes. Lewisham's Duty Planner Standard Service gives written advice from a planning officer on simple homeowner projects. It covers simple householder extensions and alterations not within a conservation area. For a Catford house outside a conservation area where a new side window or a wider rear opening changes the outside, that advice settles the principle before the structural engineer details the steel. It is cheaper to change a sketch than a set of approved calculations.
Why does Lewisham ask for part of the fee before approving Catford structural drawings?
Lewisham splits full plans application fees into two payments, with plan checking fees paid upfront when the council receives the application. The first part pays for checking the structural engineer's design. The second covers the inspections once work starts. For a Catford owner this means the plan checking money is spent even if the scheme is later changed, so the drawings are worth settling before the application goes in.
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