07834 989360 Mon–Fri, 8am–5pm - AboutServicesAreasOur WorkReviewsContact07834 989360Request an Estimate Home/ - Areas we cover/ - Builders in South East London South East London · Rated 5.0 on Google # Loft conversionsand extensions acrossSouth East London We work throughout South East London on loft conversions, rear and side extensions, structural openings and whole-house refurbishments, one contract from first drawing to final finish. Request an estimate07834 989360 Written, itemised estimate after a survey, no obligation to proceed. 30 yearsof construction experience across the team CABE membersprincipals are members of the Chartered Association of Building Engineers 5.0 starsrated 5.0 from 14 Google reviews One point of contactdesign coordination, planning, procurement, build and supervision under one contract Building in South East London ## We work in South East London, and we know its houses South East London is on our doorstep. Our office at Onega House, 112 Main Road, Sidcup, DA14 6NE sits on the boundary, so the boroughs to the west and north of us, Bexley, Greenwich and their neighbours, are regular working territory. Surveys and site visits are arranged Monday to Friday, 8am to 5pm. The housing here is denser and older than in the Kent suburbs. Victorian and Edwardian terraces with side returns, semi-detached inter-war housing, converted flats and maisonettes, and post-war infill all appear within a few streets of each other. Terraced sites bring their own constraints: no side access, shared party walls on both sides, limited space for materials and skips, and neighbours very close to the work. That is exactly why the structural and access planning is done before the scaffold goes up. Steel has to be able to get in. Propping has to be designed where a party wall is involved. Party wall procedures apply where work affects a shared wall or excavates near a neighbour's foundations, and identifying that early avoids a build stopped at week three. The requests we see most often across South East London are rear dormer loft conversions for an extra bedroom and en-suite, side return and rear extensions on Victorian terraces, full-width structural openings to create a single kitchen-dining-living space, and whole-house refurbishment of a period property that has been left untouched for decades. South East London terraces and Victorian conversions often need careful structural design in tight sites with limited access. Our principals are CABE members, so the structural and building control side is resolved before the scaffold goes up. Every South East London project runs through the same five stages: design, planning and preparation, procurement, construction and project supervision, all managed under one contract by a team with 30 years of experience, with principals who are members of the Chartered Association of Building Engineers. You can request an estimate or read more about how we work. ## Get an estimate in South East London Send us the details and we'll be in touch during working hours, Mon–Fri, 8am–5pm. Services in South East London ## What we build in South East London ### Home Extensions Single-storey, double-storey and wraparound extensions, design coordinated and built by one team. Home extensions in South East London ### Loft Conversions Turn unused roof space into a bedroom, en-suite or office, structurally sound and building-control signed off. Loft conversions in South East London ### New Build Homes Individual new build homes delivered from design package through to completion. New build homes in South East London ### Full Refurbishments & Renovations Whole-house refurbishment, kitchens, bathrooms and period property renovation, managed end to end. Refurbishments & renovations in South East London ### Internal Alterations Knock-throughs, new openings, reconfigured layouts and structural steels installed safely. Internal alterations in South East London ### Outbuildings & Garden Rooms Insulated garden rooms, home offices, gyms and garages built to last all year. Outbuildings in South East London ### Architectural Drawings & Design Coordination Survey, concept, planning and construction drawings coordinated with our recommended architects, ready to build from. Drawings & design in South East London ### Structural Works Steels, foundations, load-bearing alterations and structural repairs. Structural works in South East London ### Carpentry & Joinery First and second fix carpentry, roof structures, staircases and fitted joinery. Carpentry in South East London ### Brickwork Extensions, garden walls, repointing and matched brickwork on period properties. Brickwork in South East London ### Roofing Pitched and flat roofing, dormers, leadwork and roof coverings on new and existing homes. Roofing in South East London ### Electrical, Plumbing & Gas Coordinated through vetted, accredited subcontractors: NICEIC/NAPIT registered electricians and Gas Safe engineers. Electrical & plumbing in South East London Why Ashcroft ## Why homeowners in South East London choose us ### Local to the boundary Our Sidcup office sits on the South East London and Kent border, so this is local work rather than a distant contract. ### Structural design coordinated for you Our principals are members of the Chartered Association of Building Engineers, so tight-site structural questions are resolved before work starts. ### 30 years of experience 30 years of construction experience across the team, on residential projects from single openings to complete refurbishments. ### Rated 5.0 on Google 5.0 stars from 14 Google reviews, based on clear communication and attention to detail. ### One point of contact Design, planning, procurement, construction and supervision all sit with us, which matters most on constrained sites where coordination is everything. ### Accredited services trades NICEIC or NAPIT registered electricians and Gas Safe registered engineers carry out and certify their own work. Local property issues ## What we typically find on South East London properties ### Terraced sites with no side access Every load of material and every piece of steel comes through the house or over the roof. That has to be planned into the method and the price, not discovered on the first delivery. ### Party walls on both sides Work affecting a shared wall, or excavation near a neighbour's foundations, brings party wall procedures into play. Flagged early it is process; flagged late it stops the job. ### Victorian solid walls and damp Raised external ground levels, blocked sub-floor vents, bridged air bricks and hard cement pointing cause far more damp in this stock than rising damp does. Diagnosis comes before decoration. ### Original roofs and dormer structure Terrace roofs vary in condition and in what they can carry. New floor structure for a loft conversion has to span off load-bearing walls on designed steel rather than rely on existing ceiling joists. None of this is unusual, and none of it is a reason not to build. It is the reason we survey before we design and design before we price, so what turns up in South East London is in the estimate rather than in a mid-build conversation about extra cost. How it works ## Five stages, all managed under one contract - 01 ### Design We take your brief, survey the property and coordinate the drawings and design package with our recommended architects and engineers, so you have no separate consultants to find or brief. - 02 ### Planning & preparation Applications, building control and the programme of works are prepared and coordinated before anyone lifts a tool. - 03 ### Procurement Materials and vetted trades are secured against a fixed scope, so the build starts with everything in place. - 04 ### Construction Your build is delivered by skilled tradesmen working to the agreed drawings, programme and standard. - 05 ### Project supervision A named point of contact supervises the site, handles building control and keeps you updated to completion. South East London questions ## Frequently asked questions Do you work across South East London?+Yes. We work throughout South East London from our office at Onega House, 112 Main Road, Sidcup, DA14 6NE, which sits on the border. How soon can you survey a property here?+Surveys are booked during working hours, Monday to Friday, 8am to 5pm. Give us a call and we will agree a time. What does a loft conversion cost in South East London?+It depends on the type, rooflight, rear dormer, hip-to-gable or mansard, the structural steel required, whether an en-suite is included and the finish level. We price from a survey with the scope itemised. Can you build on a terraced house with no side access?+Yes, and it is a large part of what we do here. Access, material handling and steel installation are planned into the method and the estimate from the start. Do you deal with party wall matters?+We identify where party wall procedures apply at the outset and coordinate the work around them, so it does not stop the build midway. Do you work on flats and maisonettes?+We do consider them, but lease and freeholder consents apply alongside building regulations. Send us the details and we will tell you what is involved. Is there an emergency call-out service?+No. We deliver planned design-and-build projects rather than emergency repairs. Which nearby areas do you cover?+Greenwich, Bexley, Welling, Blackfen, Sidcup, Bexleyheath and the wider Kent border. Rated 5.0 from 14 reviews ## What our clients say “Adam, Robbie and the team were fantastic delivering our kitchen extension and bathroom, great communication throughout and happy to adjust the design as we went.”Peter TingayKitchen extension & bathroom“Adam and Rob's team did an amazing job on our extension, from start to finish they made the process straightforward and painless.”Keith WeirHome extension“Professional, friendly and did a wonderful job creating a new opening between rooms in our Victorian home. Adam communicated clearly throughout. Highly recommend.”Holly MillsStructural opening Coverage ## Areas near South East London we also serve Builders in BexleyBuilders in WellingBuilders in BlackfenAll areas we cover Alongside South East London we work across Greenwich, Bexley, Welling, Blackfen and the wider Kent and South East London area from our office at Onega House, 112 Main Road, Sidcup, Kent, DA14 6NE. If you are not sure whether your postcode is covered, contact our Sidcup builders and we will tell you straight away. You can also see examples of our work or start from our home page. ## Planning work in South East London? Tell us about the property and what you want to achieve, or call 07834 989360. Request an estimate07834 989360 Extension, loft conversion and refurbishment specialists based in Sidcup, working across London, Kent and the surrounding areas. 5.0 from 14 Google reviews Facebook - Instagram ## Services Home extensions - Loft conversions - New build homes - Refurbishments & renovations - Internal alterations - Outbuildings - Drawings & design - Structural works ## Areas we cover - Bexley - Kent - South East London - Welling - Sidcup - Bexleyheath - Dartford - Crayford - Blackfen ## Get in touch - 07834 989360 - info@ashcroftconstructiongroupltd.co.uk - Onega House, 112 Main Road, Sidcup, Kent, DA14 6NEMonday8am – 5pm Tuesday8am – 5pm Wednesday8am – 5pm Thursday8am – 5pm Friday8am – 5pm SaturdayClosed SundayClosed © 2026 Ashcroft Construction Group Ltd. All rights reserved. ReviewsCookie policyPrivacy policyTerms & conditionsPrincipals are members of the Chartered Association of Building Engineers (CABE). 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