Dartford · Rated 4.7 on Google
Double storeyextensionsin Dartford
Adding a bedroom above a new ground-floor room is often the most cost-effective way to grow a Dartford family home. We handle the structural design, the planning route and the build.
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
4.7 starsrated 4.7 from 14 Google reviews
One point of contactdesign, planning, procurement, build and supervision managed in-house
Building in Dartford
We work in Dartford, and we know its houses
Dartford is comfortably within our working area, reached from our office at Onega House, 112 Main Road, Sidcup, DA14 6NE. Surveys and site visits are arranged Monday to Friday, 8am to 5pm.
The town mixes Victorian and Edwardian terraces near the centre with large inter-war and post-war suburban estates and a significant amount of newer development. Family houses on the estates typically have the plot width and garden depth for a two-storey extension, which is why more of our Dartford enquiries are for double-storey work than in the tighter areas closer to London.
The older stock near the centre is a different job entirely: solid or early cavity walls, original roofs, and terraced access constraints that dictate how materials and steel arrive. We survey and design each property individually rather than assuming the postcode tells us what we are working with.
The requests we get most are double-storey extensions adding a bedroom and bathroom, single-storey rear extensions to open up kitchens, loft conversions, structural openings on the ground floor, and whole-house refurbishment after a purchase.
Two-storey work almost always needs a full planning application and careful structural design where it ties into the existing roof and foundations. All of that is detailed in-house before we price the build.
Every Dartford project runs through the same five stages: design, planning and preparation, procurement, construction and project supervision, all managed in-house 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 Dartford
Send us the details and we'll be in touch during working hours, Mon–Fri, 8am–5pm.
Services in Dartford
What we build in Dartford
Home Extensions
Single-storey, double-storey and wraparound extensions designed, drawn and built by one team.
Home extensions in Dartford
Loft Conversions
Turn unused roof space into a bedroom, en-suite or office, structurally sound and building-control signed off.
Loft conversions in Dartford
New Build Homes
Individual new build homes delivered from design package through to completion.
New build homes in Dartford
Full Refurbishments & Renovations
Whole-house refurbishment, kitchens, bathrooms and period property renovation, managed end to end.
Refurbishments & renovations in Dartford
Internal Alterations
Knock-throughs, new openings, reconfigured layouts and structural steels installed safely.
Internal alterations in Dartford
Outbuildings & Garden Rooms
Insulated garden rooms, home offices, gyms and garages built to last all year.
Outbuildings in Dartford
Architectural Drawings & Design Packages
Survey, concept, planning and construction drawings produced in-house, ready to build from.
Drawings & design in Dartford
Structural Works
Steels, foundations, load-bearing alterations and structural repairs.
Structural works in Dartford
Carpentry & Joinery
First and second fix carpentry, roof structures, staircases and fitted joinery.
Carpentry in Dartford
Brickwork
Extensions, garden walls, repointing and matched brickwork on period properties.
Brickwork in Dartford
Roofing
Pitched and flat roofing, dormers, leadwork and roof coverings on new and existing homes.
Roofing in Dartford
Electrical, Plumbing & Gas
Coordinated through vetted, accredited subcontractors: NICEIC/NAPIT registered electricians and Gas Safe engineers.
Electrical & plumbing in DartfordWhy Ashcroft
Why homeowners in Dartford choose us
Structural design in-house
Two-storey work is detailed in-house by principals who are members of the Chartered Association of Building Engineers, before the build is priced.
Planning route confirmed early
Double-storey extensions almost always need a full application. We tell you which route applies at survey stage rather than after design fees are spent.
30 years of experience
30 years of construction experience across the team, on residential extension, loft and refurbishment projects.
Rated 4.7 on Google
4.7 stars from 14 Google reviews, from clients citing clear communication and high standards.
Turn-key delivery
Design, planning and preparation, procurement, construction and project supervision are all managed by one team.
Accredited electrics and gas
NICEIC or NAPIT registered electricians and Gas Safe registered engineers carry out and certify that work.
Local property issues
What we typically find on Dartford properties
Existing foundations under new load
Building a storey above an existing ground floor or garage puts new load onto old footings. Those foundations have to be exposed and assessed before any design is committed.
Roof tie-ins that leak
The junction where a two-storey extension meets the existing roof is the highest-risk detail on the build. Valleys, flashings and abutment upstands decide whether it stays dry.
Ground conditions and mature trees
Shrinkable ground and mature trees on the suburban estates around Dartford affect foundation depth. This is set from the survey rather than a standard detail.
Party wall matters on semis
Two-storey work on a semi-detached house almost always engages the party wall, so notices and procedures are identified at the start of the project.
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 Dartford is in the estimate rather than in a mid-build conversation about extra cost.
How it works
Five stages, all managed in-house
- 01
Design
We take your brief, survey the property and produce the drawings and design package in-house, no separate architect to appoint.
- 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.
Dartford questions
Frequently asked questions
Do you cover Dartford?
Yes. Dartford is within our regular working area, served from our office at Onega House, 112 Main Road, Sidcup, DA14 6NE.
How quickly can you get to Dartford?
Site visits and surveys are arranged during working hours, Monday to Friday, 8am to 5pm, from our Sidcup base.
What does a double-storey extension cost in Dartford?
It depends on footprint, the condition and depth of existing foundations, structural steel, roof tie-in and internal specification. We survey and issue a written estimate with the scope itemised.
Do I need planning permission for a two-storey extension?
Almost always, yes. We assess your property at survey stage, confirm the route, and prepare and coordinate the application.
Can you build above an existing garage?
Sometimes: it depends entirely on the existing foundations and walls, which we expose and assess before designing anything.
How long does the work take?
Design and planning come first, then construction. A written programme for your specific project comes with the estimate.
Do you do emergency work in Dartford?
No. We deliver planned design-and-build projects rather than emergency repairs.
Which nearby areas do you cover?
Crayford, Bexley, Bexleyheath, Sidcup, Welling, Blackfen and the wider Kent area.
Rated 4.7 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.”
“Adam and Rob's team did an amazing job on our extension, from start to finish they made the process straightforward and painless.”
“Professional, friendly and did a wonderful job creating a new opening between rooms in our Victorian home. Adam communicated clearly throughout. Highly recommend.”
Coverage
Areas near Dartford we also serve
Alongside Dartford we work across Crayford, Bexley, Sidcup, Kent 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 Dartford?
Tell us about the property and what you want to achieve, or call 07834 989360.