Everything you
need to know

Fellner Construction is a residential construction company specialising in high-end house extensions, full renovations, bathroom and kitchen installations, and bespoke projects. The company is led by a professional with more than 20 years of hands-on experience across every level of UK residential construction — from site carpenter through to project manager for established London firms.

We work with a deliberately select number of clients each year. This is a conscious choice that ensures every project receives our complete and undivided attention — from first conversation to final handover. Our services cover South London and its residential neighbourhoods.

Our services cover South London and its residential neighbourhoods. If you are outside this area and have a project you'd like to discuss, please get in touch — we consider each enquiry individually.

Our leadership holds an NVQ Level 6 Diploma in Construction Contracting Operations Management — the highest vocational qualification in the sector. This is supported by more than two decades of hands-on site experience, spanning carpentry, site supervision, site management, and full project management.

All members of our team are appropriately qualified for the works they carry out. Gas Safe registered where required. Electrical works are carried out by Part P certified electricians in accordance with BS 7671 (18th Edition Wiring Regulations).

We work with a carefully selected team of skilled tradespeople and take full project management responsibility for every commission. Regardless of who is on site, we are accountable for the standard of every element — from first fix through to final handover. That accountability is what our fixed-price contract and workmanship warranty reflect.

We respond to all new enquiries within one working day. If your project sounds like a good fit, we'll arrange a brief discovery call at a time that suits you — followed by a no-obligation site visit to assess your space in person. From there, we prepare a detailed, fixed-price written quote.

There's no pressure and no obligation at any stage. We want to understand your project properly before making any commitments — and we expect the same in return.

No. You can get in touch at any stage — whether you have detailed architectural drawings or just an idea you'd like to explore. For larger projects such as extensions and full renovations, we can recommend suitable architects and structural engineers if you haven't yet appointed them, and we'll coordinate with your design team throughout.

Every project has a dedicated point of contact — one person who knows your project in detail and is available to answer questions throughout. We provide regular progress updates and flag any issues immediately rather than allowing them to accumulate.

We believe that clear, consistent communication is as important as quality workmanship. You should never have to wonder what's happening on your site.

Yes — entirely. The price agreed in writing before work begins is the price you pay at the end. We do not add supplementary charges, revise our quote after seeing the site, or present you with a final bill that diverges from what was agreed.

The only exception is if you request changes to the scope of work during the project. Any variation to the agreed scope is priced separately, agreed in writing, and added to the contract before it is carried out — never after the fact.

We build rear extensions, side return extensions, double-storey extensions, and wrap-around extensions across South London. Each type has different structural, planning, and cost considerations — and we'll help you understand the options that are appropriate for your property during our initial consultation.

Many extensions — particularly single-storey rear extensions within certain size limits — fall under Permitted Development rights and do not require a full planning application. However, this depends on your property type, location, and the size and design of the proposed extension. If your property is in a conservation area, listed, or is a flat, different rules apply.

We will advise you on the likely planning position during our initial consultation and can coordinate the application process on your behalf if required.

Yes. We coordinate with structural engineers and manage the Building Regulations process as part of our full project management service. We act as your single point of contact throughout and handle all documentation on your behalf — though clients who prefer to stay more closely involved in the process are welcome to do so.

A full bathroom installation typically includes: full strip-out of the existing space; all plumbing works including first and second fix; waterproofing; tiling (floor and walls); installation of all sanitaryware, fixtures, and fittings; any associated electrical works (including extractor fan and heated towel rail); and full decoration. We can also supply sanitaryware and tiles if preferred, or work with materials you have already sourced.

Either. Many clients prefer to select their own tiles, sanitaryware, and fixtures, in which case we work to your chosen specification and supply any additional materials required. Alternatively, we can supply and fit everything — including a curated selection of materials suitable for your budget and aesthetic. Both approaches are accommodated within our fixed-price model.

Yes — this is one of the most common scenarios we encounter. Kitchen renovation within a full house renovation or alongside an extension is something we coordinate regularly. We manage all associated trades — structural, plumbing, electrical, plastering, tiling, and joinery — under a single fixed-price contract.

A properly converted garage can become almost anything: a home office, a gym, an additional bedroom, a self-contained studio, or a playroom. The key is ensuring the conversion is done properly — correctly insulated, damp-proofed, wired, and finished to a standard that makes the space feel genuinely habitable rather than like a converted garage.

We manage the full scope: structural preparation, insulation, electrical supply, plumbing connections where required, plastering, flooring, and decoration.

Yes. Garden offices and outbuildings are bespoke commissions we take on. We construct them to the same standard as the main house — fully insulated, wired, finished, and ready to use as a genuine working environment. If you have something specific in mind, get in touch to discuss it.

Yes. We can coordinate the planning application process on your behalf, working alongside your architect or with architects we recommend. We have experience managing applications for extensions and larger residential projects across South London, and we understand the considerations that typically apply in different areas and property types.

Permitted Development (PD) rights allow certain types of work — such as small single-storey rear extensions — to be carried out without a full planning application, provided they meet specific size and design criteria. Full planning permission is required for works that exceed these parameters, for listed buildings, and for properties in conservation areas where PD rights are restricted or removed.

Both routes require Building Regulations approval separately — planning permission is not the same as Building Regulations sign-off, and both may be required for your project. We will guide you through which applies to your situation.

In many cases, yes — though this depends on the scale of the work. For bathroom renovations, kitchen refits, and some extensions, clients typically remain in the property with manageable disruption. For full house renovations or major structural works, vacating the property is usually more practical and we will advise you honestly on this before work begins.

You will have a dedicated point of contact throughout — one person who knows your project in detail. We provide regular progress updates, flag any issues immediately, and are always reachable by phone or email. You should never have to wonder what is happening on your site or when the next stage will begin.

Construction involves complexities that occasionally reveal themselves only once work has begun — particularly in older properties. When issues arise, we communicate immediately, explain clearly, and propose a solution. We never conceal problems, and we never allow them to become your burden after the fact. Full project accountability means we take responsibility for finding the right resolution.