Structural Alterations Woolwich
Structural alterations, new openings, underpinning and floor structures in Woolwich, 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 Woolwich, in the post-war blocks and new riverside apartments that make up most of SE18, and in the Victorian and Edwardian terraces with their rear closet wings and side returns. Our founder's 30+ years on the tools means we build new openings, replacement joists, underpinning and supported openings correctly, to the engineer's design.
In Woolwich, 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 Woolwich.
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 Woolwich address and an itemised quote.
- The engineer we appoint designs the work, and it is registered with the Royal Borough of Greenwich 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 in Woolwich terraces
The Victorian and Edwardian terraces around Woolwich were rarely built for the way people live now, so structural alterations range from forming a wide opening into the rear closet wing to replacing tired or overspanned floor joists and creating supported openings between rooms. Each of these changes the loads in the building, so a structural engineer designs the work before anyone lifts a tool.
New openings in solid masonry are formed with a steel beam or lintel bearing onto padstones, propped temporarily and built in stages. Where old joists have sagged or been notched, the engineer specifies correctly sized replacements at the right centres and we fit them. Where foundations are shallow, as they often are in older SE18 stock, the engineer may design underpinning to deepen and strengthen them, which we then build.
Housing in Woolwich
Count the homes in Woolwich and you get about 21,990: 75% built since 1945, 2% between the wars and 24% before 1919, with flats at 74% and houses at 26%. Where most homes are flats, structural repair to a block in Woolwich usually falls to the freeholder.
Outside structural changes in the Woolwich Conservation Area since 2019
The Woolwich Conservation Area was designated in May 2019, so a house bought before then may have come with no mention of it in the purchase searches. Its appraisal says alterations and extensions to heritage assets will only be supported where they sustain and enhance their heritage significance. Where structural work that shows outside needs planning permission, such as a rebuilt bay or a new opening in a flat, which has no householder permitted development rights, that is the standard the proposal is measured against. Check the boundary for the address before any structural design starts.
That moves the elevation into the design brief. In Woolwich 24% of homes were built before 1919, and on a house of that age the detail that carries significance can be the brickwork, the arches over openings and the proportion of the windows. A new opening designed to reuse the brick, match the arch and keep the proportion has an answer to the appraisal; one drawn only for the steel does not. Ask the structural engineer we appoint to work with whoever draws the elevation, so the beam and the face of the wall are decided together.
Engineered and signed off across SE18
Every structural alteration in Woolwich is notifiable under the Building Regulations, so the Royal Borough of Greenwich building control department inspects the work and issues the completion certificate you will need when you sell. Planning permission is a separate matter: internal beams, joists and underpinning need none, even in a conservation area. A listed building is the exception, where listed building consent is needed for internal structural work as well as external changes.
Because the flank and dividing walls of a Woolwich terrace are usually shared, forming openings, taking bearings or underpinning close to that boundary is notifiable under the Party Wall Act, and you serve the required notices on the neighbour as building owner, or your surveyor does. We give you the drawings the notices need, coordinate the engineer and the inspections, and build to any award, so the alteration is properly designed, built and signed off.
- Temporary works, propping and needling
- New door and window openings in solid masonry
- Crack repair, helical bar stitching and masonry restraint
VOA Council Tax stock of properties, March 2025, for all 6 statistical areas in Woolwich. Counts rounded by the VOA.
Why Choose GS Renovation in Woolwich
Homeowners across SE18 choose GS Renovation for structural alterations because we bring the whole chain together: the engineer we appoint designs the openings, joists or underpinning, we build them and work to any party wall award with neighbouring terraces, and Greenwich building control signs off the result. Add careful staged propping, tidy working and our founder's 30+ years of experience, and you have one accountable team.
Reviewed jobs near Woolwich
1 MyBuilder review from Woolwich, with each customer's own job title:
- Replace kitchen extractor hob, Woolwich, 27 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…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
FAQ
Frequently Asked Questions about Structural Alterations Woolwich
Can you quote structural alterations for an SE18 property over the phone?
GS Renovation will not give a real quotation for structural alterations in Woolwich over the phone, only the range, £1,500 to £21,000 or more, from a simple opening to underpinning one elevation (indicative). On 07472 424 226 we can explain what moves the cost and whether the job needs building regulations approval of the engineer's design, but the SE18 property has to be seen first. Builders who quote blind across Greenwich revise the figure once the floor or walls are opened.
What kinds of building are altered in Woolwich?
Period terraces, post war housing and a substantial amount of newer apartment development. Around Woolwich that range means the same request produces very different work: a Victorian terrace is altered with beams into brick walls, while a recent block is a designed frame where internal walls may carry nothing at all. The construction is established before any structural proposal is made.
Can a new opening be formed in a solid wall in a Woolwich house?
Usually, with the masonry above supported while the work proceeds. In an older Woolwich property the wall is solid brick with no cavity, so the full thickness is cut. The load above is carried on needles and props to the engineer's design until the new beam or lintel is in place and pinned up. The bearings each side are formed in sound brickwork.
Can a flat in a Woolwich block be altered internally?
It depends on the construction and the lease. Some blocks around Woolwich are framed, with partitions that carry nothing and can often be moved with consent, while others are of panel construction where the walls are structural. The lease reserves structural alteration to the freeholder in either case. Both are checked before design work begins, because in some buildings the answer is no.
What does a structural engineer's report on a Woolwich property contain?
What was inspected, what the structure is doing, what is causing any defect and what should be done about it. For your Woolwich property that usually includes the load paths relevant to the proposed work, the condition of what was seen, and calculations where new members are required. We appoint the engineer and build to that report, and do not produce structural assessments ourselves.
What if a Woolwich flat sits under a shared roof?
The roof is almost always the freeholder's responsibility rather than the leaseholder's. In your Woolwich block or converted house, the structure and covering above the top floor are usually retained by the landlord. A leak or a repair is theirs to deal with, even where the damage appears inside one flat. Establishing that from the lease before commissioning work avoids paying for somebody else's obligation.
Does taking down a rear addition in a Woolwich conservation area need planning permission?
It can. In Royal Greenwich conservation areas planning permission is always needed for total or large demolition of a building measuring more than 115 cubic metres. A house is well over that size, so for a rear addition the question is whether taking it down counts as a large demolition of the house. A detached workshop or garage is measured on its own. Work out the volume from measured drawings, and if it is close, raise it with Royal Greenwich first, since a demolition cannot be put back.
Can underpinning a Woolwich house go in on a building notice?
The route exists, since Royal Greenwich lists mass concrete underpinning among its building notice charges. Drainage is the exception. Royal Greenwich requires a full plans application to build over or within three metres of a public sewer, and in a Woolwich terrace the sewer connection can run close to the wall being underpinned. Have the drains traced before the application goes in, so the route is chosen once and the underpinning bases are designed around the pipe.
What does Royal Greenwich ask for when a Woolwich cellar becomes a room?
Where the scheme needs planning permission and the house adjoins other homes, a Basement Impact Assessment, because Royal Greenwich counts cellar conversions into habitable accommodation as basement work. The Structural Method Statement supporting it must be signed off by a Chartered Civil Engineer or Chartered Structural Engineer, so the structural engineer appointed for the scheme must hold one of those titles. Royal Greenwich supports only single-storey basement extensions, so lowering the floor further means staying within one storey below ground.
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