07834 989360 Mon–Fri, 8am–5pm - AboutServicesAreasOur WorkReviewsContact07834 989360Request an Estimate Rated 5.0 on Google · Sidcup, London & Kent # Extension & Renovation Specialists in Sidcup & South East London Covering Bexley, Dartford, Kent & the surrounding areas From first sketch to final coat of paint, one team manages your entire project – no separate architect to find, no separate engineer to chase, no gaps to fall through. 30 years’ experience across London and Kent. Request an estimate07834 989360 Design, planning and build under one contract - CABE-member principals - Rated 5.0 from 14 Google reviews - One named contact from survey to handoverSpeak to us Mon–Fri, 8am–5pm · Onega House, Main Road, Sidcup ## Get a price for your extension or loft conversion Send us the outline of your project and we’ll come back with the next step, a survey, drawings, or straight to pricing. 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 What we build ## One team for the whole project, from first drawing to final finish Extensions, loft conversions, refurbishments and new builds: plus the structural, carpentry, brickwork and roofing trades that deliver them. ### Home Extensions Single-storey, double-storey and wraparound extensions, design coordinated and built by one team. View home extensions service ### Loft Conversions Turn unused roof space into a bedroom, en-suite or office, structurally sound and building-control signed off. View loft conversions service ### New Build Homes Individual new build homes delivered from design package through to completion. View new build homes service ### Full Refurbishments & Renovations Whole-house refurbishment, kitchens, bathrooms and period property renovation, managed end to end. View refurbishments & renovations service ### Internal Alterations Knock-throughs, new openings, reconfigured layouts and structural steels installed safely. View internal alterations service ### Outbuildings & Garden Rooms Insulated garden rooms, home offices, gyms and garages built to last all year. View outbuildings service ### Architectural Drawings & Design Coordination Survey, concept, planning and construction drawings coordinated with our recommended architects, ready to build from. View drawings & design service ### Structural Works Steels, foundations, load-bearing alterations and structural repairs. View structural works service ### Carpentry & Joinery First and second fix carpentry, roof structures, staircases and fitted joinery. View carpentry service ### Brickwork Extensions, garden walls, repointing and matched brickwork on period properties. View brickwork service ### Roofing Pitched and flat roofing, dormers, leadwork and roof coverings on new and existing homes. View roofing service ### Electrical, Plumbing & Gas Coordinated through vetted, accredited subcontractors: NICEIC/NAPIT registered electricians and Gas Safe engineers. View electrical & plumbing service All construction services we offer Project photography ## Real extensions, lofts and refurbishments we've completed Every photograph is our own work across Sidcup, Bexley, Dartford and South East London. Why homeowners choose us ## Fewer appointments, fewer delays, one standard of finish Most extension projects go wrong in the gaps between consultants. Removing those gaps is the whole point of a turn-key contract. - ### Designed by the people who build it We coordinate the drawings with our recommended architects and engineers and feed in buildability and cost from day one, so the design works on site as well as on paper. - ### CABE-member principals Our principals are members of the Chartered Association of Building Engineers and work to its codes of practice and ethical standards. - ### Supervised, not left to trades A named point of contact supervises the site, coordinates accredited subcontractors and handles building control on your behalf. 30 years of construction experience across the team CABE members principals are members of the Chartered Association of Building Engineers 5.0 stars rated 5.0 from 14 Google reviews One point of contact design coordination, planning, procurement, build and supervision under one contract How it works ## Five stages, all managed under one contract The same five stages run on every project, from a single structural opening to a complete new build home. - 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. Recent work ## Projects delivered across London and Kent A selection of extension, loft and refurbishment work completed by our team. Single-storey extension ### Open-plan kitchen extension Rear extension opened into the existing kitchen and dining space, with rooflights bringing daylight deep into the plan. Single-storey rear extension ### Rear extension in Catford Rear extension in facing brickwork with black-framed glazing, finished internally with panelling and tiled flooring. Loft conversion ### Loft conversion with new rooflights Unused roof space converted into habitable rooms, including new stairs, structural steels, insulation and rooflights. See our completed extensions and loft conversions Rated 5.0 from 14 Google reviews ## What our clients say Communication, attention to detail and projects delivered on time are the themes that come up again and again. “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“A major renovation in Greenwich: new en-suite, master bathroom, wraparound extension, new kitchen and more. Thorough and detailed.”Sam HallMajor renovation, Greenwich“Work done to a high standard within a tight timeframe. They handled most of the communication with building control, which we appreciated. Friendly and helpful team.”Victoria CovilRefurbishment“Renovation of our upstairs bathroom into a bedroom plus a brand new bathroom and boiler. Professional, reliable and highly skilled, with clear communication from Robbie throughout.”Emma WheelerInternal alterations Read our Google reviews Request an estimate ## Tell us what you're planning Send us the outline of your project using the form at the top of the page, or call the team: we'll come back with the next step, whether that's a survey, design or straight to pricing. 07834 989360 ### Areas we cover Based at Onega House in Sidcup, working across Bexley, Kent, South East London and the surrounding areas. - Builders in Bexley - Builders in Kent - Builders in South East London - Builders in Welling - Builders in Sidcup - Builders in Bexleyheath - Builders in Dartford - Builders in Crayford - Builders in Blackfen ## A turn-key builder for London and Kent homeowners Ashcroft Construction Group Ltd is an extension and home improvement specialist based in Sidcup, serving London, Kent and the surrounding areas. We are run by construction professionals with 30 years of experience across the team, and we deliver a complete, turn-key solution for residential, and some commercial - projects, managing every stage from design coordination and planning through procurement, construction and project supervision. That one-stop approach removes the need for you to separately appoint an architect, a structural engineer or other specialists. We coordinate all of it under one roof, which saves both time and cost, and it means there is nobody to point at when a detail needs resolving. If you value quality workmanship, professionalism and the certainty that your project will be completed to the highest standard, that is the service we are built around. Our principals are members of the Chartered Association of Building Engineers (CABE) and follow its codes of practice and ethical standards. Where specialist trades are required, electrical work, plumbing, heating and gas, we appoint vetted subcontractors who hold the relevant accreditations themselves, NICEIC or NAPIT for electrical work and Gas Safe for gas, and we coordinate them into the build programme so certification arrives with completion rather than weeks after it. ### Extensions that suit the house they join Most of our work is residential extension and loft conversion projects: single-storey rear extensions that open a kitchen into the garden, wraparound extensions that square off a tired ground floor, double-storey extensions that add a bedroom above new living space, and loft conversions that turn wasted roof space into a proper room with an en-suite. The design decisions that matter are rarely the obvious ones, glazing lines, roof form, where light lands at four in the afternoon, and how the new brickwork ties into the old. We survey the property before designing anything, then set out the planning route, whether that is permitted development or a full application. You see layout options and understand the structural approach before money is committed to a build. Where the work involves removing load-bearing walls, forming new openings or strengthening floors, the structural detailing is coordinated with our engineers and inspected by building control as the work proceeds. ### Clear communication is the service Read our Google reviews and the same words keep appearing: communication, detail, on time. Clients tell us the difference is knowing what is happening next week rather than just this week, and having one number to call when a question comes up. That is why project supervision is a formal stage of our process rather than something we do if there is time. We also handle the parts homeowners least enjoy. Building control liaison, inspection bookings, scheduling of accredited trades and the sequencing that stops a plasterer arriving before an electrician has finished, those are our problem, not yours. Our attention to detail, clear communication and commitment to delivering projects on time and to a high standard are why so many of our clients continue to trust and recommend us. ### Where we work From our Sidcup base we work throughout Bexley, Bexleyheath, Welling, Blackfen, Crayford, Dartford, South East London and the wider Kent area. Being local matters on a build: we can get to site quickly, our trades know the housing stock, and we stand behind work in the area we live in. If you are looking for solid workmanship delivered by highly skilled tradesmen with a professional service from start to finish, we would love to hear from you. ### Straight to the point? Call and speak to the team during working hours. If it is easier, send your details and we will call you back. 07834 989360Monday8am – 5pm Tuesday8am – 5pm Wednesday8am – 5pm Thursday8am – 5pm Friday8am – 5pm SaturdayClosed SundayClosed Common questions ## Before you get in touch Do you handle the drawings and planning as well as the building work?+Yes. We coordinate the drawings and planning with our recommended architects and structural engineers, then build the project ourselves. The drawings are not produced in-house, but you deal with us throughout: you do not have to find, brief or chase separate consultants. Which areas do you cover?+We are based in Sidcup and work across Bexley, Kent, South East London and the surrounding areas including Welling, Bexleyheath, Dartford, Crayford and Blackfen. Are you accredited?+Our principals are members of the Chartered Association of Building Engineers (CABE) and work to its codes of practice and ethical standards. Electrical and gas work is carried out by vetted subcontractors who hold the relevant accreditations themselves: NICEIC/NAPIT for electrics and Gas Safe for gas. How do we get started?+Send us your details and a short description of the project. We will arrange a survey, discuss the design options and set out the route through planning and building control before anything is committed. Do you take on commercial work?+Our focus is residential construction and home improvement, and we do take on some commercial projects. Get in touch with the details and we will tell you honestly whether it suits us. ## Ready to price your project properly? Send us your details and we'll set out the next step, no obligation, no pressure. 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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