Structural alterations, new openings and steel support in Sidcup. Trusted, professional, 30+ years' hands-on experience.
From new openings to replacement joists and supported openings, GS Renovation carries out structural alterations throughout Sidcup's interwar suburban houses. Backed by 30+ years across Bexley and its DA15 streets, we design each change with a structural engineer and see it through building control, so your 1930s home stays sound as it opens up.

The 1930s and interwar houses around Sidcup were built on generous plots, which is why so many owners want to reconfigure rather than move: forming a wide opening between kitchen and dining room, cutting a new doorway through a solid wall, or adding a supported opening for bifold doors at the rear. Each of these changes the way loads travel through the house, so a structural engineer designs the beam or lintel and specifies the padstones before any brick is touched.
We also see plenty of tired original timber in these interwar homes, from bouncing floor joists to notched, over-drilled sections weakened by decades of pipework and cabling. Where joists have sagged or been cut about, we replace or double them up to the engineer's spec, restoring a floor that feels solid underfoot rather than one that flexes every time you cross the room.
Some DA15 alterations reach down to the foundations. The clay subsoils across parts of Bexley can shrink and heave, and a few of these interwar houses show historic settlement, so where an engineer's investigation calls for it we underpin in carefully sequenced bays to deepen and strengthen the footings before new loads go on. We never rush this; each bay is dug, poured and cured in turn so the house is never left undermined.
Every structural alteration here is notifiable under the Building Regulations, and Bexley Council's building control inspects the propping, the steel or new joists, the padstone bearings and any underpinning before sign-off. This is a Building Regulations process, not a planning one, unless you are altering the exterior of a listed building or a home within a conservation area. We book the inspections and provide your certification.
Homeowners across Sidcup trust GS Renovation because we treat every alteration as an engineered job, not a guess. One team handles the engineer's calculations, temporary support, replacement joists or underpinning, padstone bearings and Bexley building control sign-off, with tidy working in your occupied DA15 home and 30+ years of interwar experience behind it.
I had a bathroom refit which I was very pleased with and I then went on to get my kitchen refitted as I was so happy with the way he worked. Even…
George always kept to commitments and arrived on time. He offered helpful suggestions during his initial visit and promptly provided a reasonably…
Excellent service. George's knowledge and skills are the best in the market. He knows what he is doing, does really high quality work, gives good…
FAQ
Any change is costed and agreed in writing before it is carried out. If you add to the structural alterations scope at your DA15 property, or the interwar semi-detached structure needs more than the survey suggested, GS Renovation sets out the effect on both price and programme. Work does not continue on a Sidcup site until you have agreed it. Ring 07472 424 226 and GS Renovation will explain how variations are handled at a DA15 address. As a rough guide, structural alterations in London ranges from roughly £1,500 for a simple opening to £15,000 or more where underpinning or major works are involved (indicative London ranges, MyBuilder and Checkatrade, 2026). Your figure depends on the size, specification and condition of the property, which is why we survey before quoting.
Set by scope and by approvals, in that order. A straightforward structural alterations job at a DA15 address moves quickly once the structural stage is signed off, while an interwar semi-detached Sidcup property usually needs longer for making good. GS Renovation allows for both in the programme it issues. Nothing is committed until the Bexley survey has established which one you have. Ring 07472 424 226 and we will describe the stages for a DA15 home in Sidcup.
That is the engineer's work, not ours. We are a contractor: for a structural alterations job at a Sidcup address GS Renovation arranges the engineer, the temporary works and the Bexley Council approval, then constructs exactly to the issued design. You receive the calculations for the DA15 property as part of the record. It is the document a buyer's solicitor will want. Ask on 07472 424 226 about Bexley projects. That separation is what protects a Bexley homeowner legally.
Yes, building regulations approval and an engineer's design, and it is notifiable under the Party Wall Act where it falls within three metres of a neighbouring structure. Underpinning at a DA15 address is carried out in controlled bays to keep the existing building stable throughout.
Structure, services and previous work, in that order. On a structural alterations job in an interwar semi-detached Sidcup home the unauthorised alteration by a previous owner is the commonest find at DA15, and it has to be resolved before Bexley Council will sign anything off. GS Renovation deals with that as part of the job. You are told as soon as we find it. GS Renovation will explain how structural alterations handles an unauthorised DA15 alteration found on site.
Yes. Bouncing floors in interwar DA15 homes usually come from undersized, sagged or over-notched joists cut about for old pipework. As part of a structural alteration we have an engineer specify the correct joist size, then replace or double up the timbers and tie them in properly. Bexley building control inspects the work, and the floor ends up solid rather than springy.
We take those enquiries regularly. A property sitting just outside Sidcup is often closer to a current Bexley site than one at DA15, so structural alterations there is sometimes easier rather than harder. GS Renovation charges nothing for the survey. Call 07472 424 226 and we will check the next available slot. Building control is coordinated with Bexley Council wherever the address sits. Nothing at all is owed for the DA15 visit or the written quotation.
Every Service, One Team
The same trusted team, 30+ years' hands-on experience and free, no-obligation quotes apply to every GS Renovation service in Sidcup. Explore what else we do locally:
Same Service, Nearby Areas
We carry out structural alterations across Sidcup and the surrounding areas. Explore a nearby location:
Free, no-obligation quote for structural alterations in Sidcup. Rated 4.9 from 31 reviews on MyBuilder, fully insured, and building control handled for you.