Frequently Asked Questions
Everything you need to know before starting a building project.
Planning & Permissions
Many single-storey rear extensions can be built under Permitted Development (PD) rights without a formal planning application. The limits depend on your house type: detached houses can extend up to 8m under the Prior Approval process (or 4m without), while semi-detached and terraced houses can extend up to 6m (or 3m without). There are also restrictions on height, proximity to boundaries, and materials. If your property is in a conservation area — parts of Addiscombe, South Norwood, Upper Norwood, and Sanderstead are — PD rights are more restricted. We check all of this at the survey stage and advise you on the best route before you commit to anything.
A Lawful Development Certificate (LDC) is a document from Croydon Council confirming that your proposed work falls within Permitted Development and doesn’t require planning permission. It’s not legally required, but we strongly recommend getting one. It costs around £120 and takes 6–8 weeks. The reason it matters: when you come to sell the property, your buyer’s solicitor will ask for evidence that any extensions were done legally. Without an LDC, you may need to pay for an indemnity insurance policy or, in the worst case, face delays in the sale. It’s cheap insurance.
The Party Wall etc. Act 1996 applies if you’re building on or near a shared boundary with a neighbour. Specifically: if you’re building a new wall on the boundary line, carrying out work on an existing party wall (including inserting steel beams), or excavating within 3–6 metres of a neighbour’s property (depending on depth). You need to serve a formal Party Wall Notice at least two months before work starts. Your neighbour can consent (in which case no further action is needed) or dissent (in which case party wall surveyors are appointed to produce a Party Wall Award). Most neighbours in our experience consent without issue, especially when we explain the process and show them the plans. We manage the entire process and include the cost in our quotation.
Croydon has around 30 conservation areas including parts of Addiscombe, South Norwood, Upper Norwood, Crystal Palace, Sanderstead, and the town centre. If your property is in a conservation area, Permitted Development rights are more limited: for example, you generally can’t add a dormer to a front-facing roof slope, and extensions visible from the street may need full planning permission. You can check whether your property is in a conservation area on Croydon Council’s interactive planning map, or we can check for you during our initial site visit.
Yes — they’re separate things. Planning permission controls what you can build (size, appearance, position). Building Regulations control how you build it (structural safety, fire safety, energy efficiency, drainage). Almost all extensions, loft conversions, and structural alterations need Building Regulations approval even if they don’t need planning permission. We submit the Building Control application on your behalf and coordinate all the required inspections throughout the build. At the end, you receive a Completion Certificate — an important document for future property sales.
Costs & Payment
As a guide for 2024 South London prices: a single-storey rear extension typically costs £40,000–£55,000 for a straightforward 3–4m build. Side-return infills usually fall between £35,000 and £60,000. Wrap-around extensions (rear plus side) range from £70,000 to £120,000+. Double-storey extensions start at around £70,000 and can exceed £130,000 depending on size and specification. These figures include foundations, structure, roofing, windows, electrics, plumbing, plastering, and decoration. Kitchen units, bespoke joinery, and landscaping are typically quoted separately. Every project is different, so we provide a detailed, itemised quote after the site survey.
Our quotes include all building work: foundations, structural steelwork, brickwork or blockwork, roofing, windows and doors, first and second fix electrics, first and second fix plumbing, plastering, decoration, and all Building Control fees. We also include scaffolding, skip hire, and Party Wall notice costs where applicable. What’s typically excluded: kitchen units and appliances (we install them, but you buy from your chosen supplier), bespoke joinery, specialist items like underfloor heating (quoted as an optional extra), and any work outside the agreed scope. We lay all of this out clearly in the quote so there are no grey areas.
We use a stage payment schedule tied to milestones, not dates. A typical schedule might be: 10% on signing the contract, 20% on completion of foundations, 20% on completion of roof/weathertight stage, 20% on completion of first fix, 20% on completion of second fix and decoration, and a final 10% retention held for 30 days after completion and snagging. This means you only pay for work that’s been done, and we carry the cost of materials and labour between stages. We never ask for large upfront deposits.
Yes, always. We recommend setting aside 10–15% of the project cost as a contingency. For new-build extensions this is more of a precaution, but for renovations — especially on older properties — it’s genuinely important. Old houses have surprises: hidden damp, rotten timbers, outdated plumbing that doesn’t meet current standards, previous alterations that weren’t done properly. We try to identify as much as possible during the survey, but some issues only become apparent once walls are opened up. If a contingency item arises, we photograph it, explain the issue, provide options and costs, and get your approval before proceeding.
Timeline & Process
The total timeline from first meeting to completion is typically 5–8 months. That breaks down into two phases: pre-construction (design, planning applications if needed, structural engineering, Building Control submission, and Party Wall notices) usually takes 8–12 weeks. Construction then takes 10–16 weeks for a single-storey extension, or 14–22 weeks for larger or more complex builds. We provide a detailed programme at the start of every project so you know what to expect and can plan around it.
One of us (usually James or David) visits your property, takes measurements, has a look at the structure, checks for anything that might complicate the build (drains, trees near boundaries, party walls, conservation area restrictions), and talks through what you want to achieve. There’s no hard sell — the purpose is to understand your project, give you a realistic idea of cost and timescale, and flag anything you should know about before going further. The visit is free and there’s no obligation. If you want to proceed, the next step is a detailed design and quotation.
Croydon Council aims to determine householder planning applications within 8 weeks, though it can sometimes take longer if they request additional information or if there are objections from neighbours. A Lawful Development Certificate (for Permitted Development work) also takes around 8 weeks. A Prior Approval application for a larger rear extension takes 42 days. We submit all applications on your behalf and chase them up if they’re running behind.
We can carry out design work, structural engineering, and preparation during the planning application period, so you’re ready to start on site as soon as approval comes through. What we can’t do is start any physical construction work before planning permission (or a Lawful Development Certificate) is granted. Starting work without the correct approvals is a criminal offence and could result in Croydon Council issuing an enforcement notice requiring you to demolish the work.
During the Build
For extensions and loft conversions, yes — the vast majority of our clients stay in their homes throughout. There will be noise, dust, and some disruption to your routine, but we take steps to minimise it: dust sheets and temporary partitions, materials stored neatly, site cleaned at the end of each day. For full house renovations, it depends on the scope. If we’re stripping out and rebuilding room by room, you can sometimes stay in the unaffected areas, but for a whole-house strip-out, you’ll need to move out temporarily. We’ll be honest about what’s realistic.
Our standard working hours are 8:00am to 5:00pm, Monday to Friday. We don’t work weekends unless it’s been specifically agreed (for example, to make up time after bad weather). Croydon Council’s noise restrictions for construction work are 8am–6pm Monday to Friday and 8am–1pm on Saturdays, so we operate well within those limits. We ask our team not to use loud power tools or carry out demolition before 8:30am out of courtesy to your neighbours.
Every project has a named site manager who oversees the work day to day. For larger projects, we also assign a project manager who handles scheduling, materials ordering, and client communication. You’ll have their direct phone number and email. Our project manager sends a weekly progress update with photos and a note on the coming week’s work. If anything comes up that needs a decision, we’ll call you — we don’t make assumptions or proceed without your input on anything that affects the design, cost, or programme.
Construction work creates dust — there’s no way around it. What we do is contain it as much as possible. We hang heavy-duty dust sheets and zip-up temporary doorways to isolate the work area from the rest of your house. We vacuum and sweep at the end of each day. For particularly dusty work (chasing walls, cutting bricks, sanding), we use extraction equipment. Your house won’t be spotless during the build, but we won’t leave it looking like a bomb site either.
After Completion
All our building work carries a 12-month defects liability period. If anything we’ve built develops a fault within the first year — a crack, a leak, a sticking door, anything — we come back and fix it at no charge. Beyond that, many elements carry longer manufacturer warranties: windows (typically 10–20 years), boilers (5–10 years), roofing membranes (15–25 years). We hand over all warranty documentation at completion. For structural work, you’ll also have a Building Control Completion Certificate, which provides independent confirmation that the work meets current regulations.
Snagging is the process of identifying and fixing minor imperfections after the main build is complete. Things like a paint touch-up needed on a window frame, a door that doesn’t quite close flush, a tile with a slight lippage. We carry out our own internal snag before handing over, then walk through the property with you to compile your snag list. Everything on it gets resolved within two weeks. Some items (like minor plaster cracks from the building drying out) may take a few months to appear — these are covered under our 12-month defects period and we’ll come back to address them.
At completion, we hand over: a Building Control Completion Certificate, electrical installation certificates (Part P), gas safety certificates (if applicable), any manufacturer warranties for windows, boilers, and other products, a copy of the Party Wall Award (if one was made), and copies of all planning approvals or Lawful Development Certificates. Keep all of these safe — your solicitor will need them when you eventually sell the property. We also provide digital copies for your records.
In most cases in Croydon, a well-executed extension or loft conversion adds more value than it costs. A loft conversion adding a bedroom and en-suite can add £40,000–£70,000 to a property’s value in South London, against a build cost of £45,000–£70,000. A rear extension creating open-plan living typically adds £30,000–£60,000. The key factors are quality of finish, how well the new space integrates with the existing house, and whether it has a proper Completion Certificate from Building Control. Unfinished or uncertified work can actually reduce a property’s value, which is why getting it done properly matters.
Still have questions?
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