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Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.

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Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.

Services

Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.

Services

Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.

Services

Call 020 8037 7332 or get an instant estimate online.

How to plan and design an extension

Writer: LCCL Construction
LCCL Construction
Jan 18, 2017
5 min read

Updated: Nov 2


Why not add an extension or loft conversion to your current home? make the most of what you have by extending. At Lccl Construction we look at ways of improving your home from traditional to contemporary extensions and loft conversions. We are experts at creating unique spaces that match your unique style and needs. As follows we will look at how to plan and design an extension.

Have a construction project and need an architect or builder?

For a free consultation with us. info@lcclconstruction.co.uk


Barnet single story extension

Not sure whether your project needs planning permission? Enter your postcode and tick what you want to build — we look up the conservation areas, Article 4 directions and listed buildings for you, and you see which parts are permitted development and the from-price for each. Lawful Development Certificate included on every permitted development job.

For many there are lots of reasons for an extension, you might be looking for more space, you will have a new member of the family or add value to your home or love the area you live in and don't want to move. The cost of moving plus adding agent fees with uncertainties in property market, investing in your house makes an attractive prospect.

Know your areas and be aware

Before any work starts and that plan for your beautiful project, it is recommended to talk to your estate agents and find out what is going on in the area, is there a lot of renovations or what are the prices like. Would you add value by adding extra space at all?

Research your area

If your area is full of young professionals, family friendly extension is not the way to go. Ask your neighbor that has done an extension have they added value? ask you estate agent what value can be added if you renovate or add an extension to your home?

What is popular what are the trends

At Lccl Construction we find that people want simple, light and airy spaces a blank canvas people can decorate as per personal specification. While using natural materials to create modern extensions that are warm and functional.

There is an epidemic of more and more people working from home hence the studies are being popular choice to extend, a garage converted into a study or an office, an extension to accommodate a large kitchen and living area.


Barnet builders

Why have an architect? why employ one?

‘It sounds obvious, but builders specialise in building things and architects specialise in designing spaces, Going straight to a builder means you miss out on the crucial design stage.

By using an architect, you’ll end up with a home that’s right for you and that you’ll love living in. Remember, too a badly designed extension can actually reduce the selling price.’

You can hire an architect to manage all of the building process, including helping you secure planning consent and building regulation certification, finding a suitable builder, monitoring progress, standards and safety on site, arranging input from specialists and overseeing construction to completion. We offer a full architecture services please find out more here.

‘Your relationship with your architect is very important, so it’s crucial to find someone you’re confident you can work with,’

Setting your project Budget


Hadley wood builders

‘Clients are sometimes cagey about money ‘ but if you give your architect a budget, they can assess what’s possible. ‘And discuss it as a team – your architect may even be able to do a job for less, in which case you could have more to spend on fittings.

A general rule of thumb is to allow £150 per sq ft of development, and remember you aren’t just thinking about the extension, but the existing space inside, too.

If you opt for less expensive fixtures and fittings, you could squeeze this down to £100, but equally, if you go for higher quality this could rise to £200 per sq ft.

Bear in mind that, on top of the build budget, there will be architect, engineer and builders’ fees, government VAT and building control and planning costs, too.

Don’t forget to allow a contingency fund of 10 per cent or more for unforeseen circumstances.

What is the cost of the loft conversion and house extension?

You can use our "instant quote calculator" and find out the cost in seconds! for both design and build, architecture services or just construction services depend what stage you are in and what you have so far completed.


We have experience of over 15 years in design and construction of loft conversions and home extensions in London and Hertfordshire areas and have worked out a unique calculation formula that you can find out to what your house extension and loft conversion will cost in seconds.


How can Lccl Construction be of help?


Do you require a loft conversion and house extension to add extra space?

Then look no further get in touch with us for a detailed free no obligation quote. We can accommodate a very quick turnaround. Our loft conversions and house extensions come with a 12-month workmanship guarantee, and a 10-year LABC structural warranty is available.


Use our instant quote calculator for a quote about your project whether construction only or design and build.


Use our Free consultation call booking system to schedule a call at the time and date that suits you best.

Telephone: 020 8037 7332

Email: info@lcclconstruction.co.uk


Can it be done under permitted development?

A single-storey rear extension of 3 m on a terrace or semi (4 m on a detached house), a side-return infill and a side extension up to half the original width are permitted development on a house outside a conservation area or Article 4 street — no planning application, just a Lawful Development Certificate, which we apply for on every one. Fixed-price permitted development extensions start from £42,000 inc. VAT (£35,000 + VAT) at economy specification, design and build inclusive, and the 6 m / 8 m larger home extension goes through a 42-day prior approval notification rather than a full application. See our permitted development projects page for every product with its from-price and the checks we run before we confirm a project qualifies.

Not sure whether your project needs planning permission? Enter your postcode and tick what you want to build — we look up the conservation areas, Article 4 directions and listed buildings for you, and you see which parts are permitted development and the from-price for each. Lawful Development Certificate included on every permitted development job.

Aleksandar Madari (Anderson), founder of LCCL Construction

ABOUT THE AUTHOR

Anderson — founder, LCCL Construction

Anderson founded LCCL Construction in Finchley N3 in 2004 and still leads the design of every project; our own team then builds it under one contract, from the first survey to the completion certificate. The company has won two LABC Building Excellence Awards: Best Residential Extension in London 2024 (Bohun Grove, East Barnet) and London Regional Winner 2026, Best Conversion or Alteration to an Existing Home (Weech Road, Hampstead). LCCL is an NFB member and an LABC Registered Partner.

Every guide on this site is written from real LCCL projects. If you are planning your own, call 020 8037 7332 or book a free 30-minute consultation call.

What clients say

Verified reviews, quoted exactly

average rating is 5 out of 5
“We are very happy with the services from Lccl, Alex has done a great job on design and construction. We have used Lccl in the past for our rear house extension and have come back to instruct Lccl for our loft conversion too to our house in North London. As…”

Mia M · Google Reviews

average rating is 5 out of 5
“Everyone at LCCL Construction was skilled, trustworthy and worked to the highest standard. I am delighted with our loft conversion, it is exactly what we wanted and I highly recommend the company - they have transformed the quality of my home. Overall it…”

KashImaging · Google Reviews

average rating is 5 out of 5
“We are very pleased to have used Lccl Construction to do full house renovation and loft conversion to our edwardian terraced house. Project involved total strip out of interiors and remodelling repositioning the interior walls, electrical and plumbing…”

neil smith · Trustpilot

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Aleksandar Madari (Anderson), founder of LCCL Construction

Start with a figure, then a conversation.

Get an instant estimate for your postcode, or book a free 30-minute call with our team. Call us on 020 8037 7332, Monday to Saturday 08:00–18:00.

One team, one contract, one point of contact — from first sketch to handover.

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