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  • Writer's pictureNick Gradica

Estimating The Cost Of Home and Side Extension In London: A Guide

Side extension and loft conversion North West London

As a UK homeowner, you might consider a house extension in London to expand your living space. While having more room can be exciting, it’s important to understand the costs involved to ensure your project remains within budget.

Expanding your living area can offer many advantages, but it's essential to have a clear grasp of the expenses associated with a house extension to maintain control over your budget.

At NGC Build, we are well-suited to assist you in this endeavour, as our extensive experience in house extension services equips us with valuable practical insights to share. We are one of the leading loft conversion companies in London today.

In this comprehensive guide, we'll explore the anticipated costs of a house extension in London, considering various factors that can impact the overall financial commitment.

How Much Does It Cost To Build Home Extension In London?

According to a recent article by Homebuilding Trending Magazine, the cost of building an extension in the UK is estimated to be around £1,500-£2,250/m² of new internal space (excluding VAT). This means a 30m² kitchen extension could cost somewhere between £45,500-£67,500 plus VAT at 20%.

However, it’s important to note these figures are ballpark estimates and may not match up perfectly with your builders’ quotes or estimates. The final price will depend on various factors such as the size and shape of the extension, materials used, area of glazing, and other soft costs such as surveys, architects’ and structural engineers’ fees, planning application fees and more.

How To Calculate The Cost Of Building A Side Extension In London

Before you start calculating the costs of your home renovation in London, it’s important to have a clear understanding of your goals and the project's scope. You should ask yourself what you want to achieve with the extension.

Do you want an extra bedroom, a larger kitchen, or a new living space? The type and size of your extension will significantly impact the project's overall cost. For example, a cost-effective single-story extension will be less expensive than a larger, high-end multi-story project that could cost significantly more.

In addition to this, it’s always a good idea to seek recommendations from friends, family, and neighbours who have had fitted kitchens recently. Personal experiences can offer valuable insights and help you avoid potential pitfalls.

Factors Affecting A Side Extensions Costs In London

When figuring out your budget, remember that several factors affect how much a house extension will cost.

Consider the size and scope

Naturally, larger extensions require more materials and labour, leading to higher costs. This is why house extension cost per m2 is typically used for initial calculations. The complexity of the design and the addition of amenities like bathrooms or intricate finishes can also increase expenses, but the bulk of your cost is based on size.

The location of the construction and labour involved

The price of building can differ greatly throughout London and the South East. Generally, the nearer you are to the capital city, the more money you'll need. Worker expenses can change depending on where you are and how much work is available. The presence of skilled professionals like construction workers, plumbers, electricians, and carpenters will also make up a significant part of the total expense.

All the design plans involved

Knowing whether a planning permit is needed for your extension in London is crucial. It costs money to obtain it and provide the necessary architectural drawings, both necessary steps in the process. When creating your budget, remember to account for these upfront costs. We advise you always to consult a professional because mistakes with planning approval can be very expensive.

What materials are used

The materials you select, from the foundations you pick to the type of roof you prefer, can greatly affect the expenses of extending your house. Opting for superior or rare materials can raise the overall cost. However, they can bring about long-term savings by lasting longer and requiring less maintenance.

Infrastructure & utilities

Extending utilities such as electricity, plumbing, and heating to the new space can involve additional costs. This might include upgrading your existing systems to accommodate the extension in London. There might also be costs associated with new connections and increased usage of electricity and water, for example.

What Else Adds To The Cost for Home Extension in London?

Beyond the average cost of adding an extension in London to your home, there are several additional expenses some homeowners often overlook. Here’s a list of the additional costs to consider for loft conversions in North west London.

Design and Architectural Fees

Hiring a qualified architect is a crucial step in ensuring the success of your house extension project. Our talented architects play a vital role in creating aesthetically pleasing designs and optimising functionality and compliance with local regulations. Their fees typically account for 10% to 15% of the total project cost. These costs are a worthy investment as they help you achieve a well-planned, structurally sound, and visually appealing extension.

Additionally, our architects bring their expertise to the table, which can result in cost savings in the long run by optimising materials, energy efficiency, and construction techniques, potentially offsetting their fees.

Party Wall Agreements

When your house extension shares a wall with a neighbouring property, it's essential to navigate the legal requirement of obtaining a party wall agreement. This process often necessitates legal advice and can lead to additional expenses. The cost varies depending on the complexity of the agreement and the need for legal consultations. Budgeting for these potential expenses is important to ensure a smooth and legally compliant construction process.

Failing to address party wall agreements properly can lead to delays and disputes, making legal advice a worthwhile investment to protect your interests and maintain neighbourly relations.

Contingency Fund

Building a contingency fund of approximately 10% of your overall budget is a prudent financial strategy for your house extension in London. Unforeseen expenses or design changes can arise during construction, and having a contingency fund ensures you have the financial flexibility to address these unexpected challenges without jeopardising the project's progress.

This fund serves as a financial safety net, allowing you to adapt to changing circumstances, implement necessary adjustments, and maintain the project's timeline and quality. While it may seem like an additional expense, it can ultimately save you from potential financial strain and project setbacks in the long term.

How Long Does It Take To Build A Home Extension In London?

The duration of building an extension in the UK can vary depending on the size and complexity of the project. A typical timeline for building a single-story extension is around 12-14 weeks. However, various factors can affect this timeline, such as the type of extension, the materials used, and the weather conditions during construction.

As per latest research, the length of time required to build an extension can vary between 7 and 15 months, depending on the size and scope of the project.

It's important to note that these timelines are just estimates and may not match perfectly with your builders' quotes or estimates. The final duration will depend on various factors such as the size and shape of the extension, materials used, area of glazing, and other soft costs such as surveys, architects’ and structural engineers' fees, planning application fees, and more.

Try NGC Build For The Perfect Home Extension In London!

Don't know how to get that bigger bedroom or en suite bathroom you've always wanted? Opt for an extension in London with NGC Build!

A loft extension in London requires careful planning and knowledge, from assisting with building code calculations to installing loft insulation and lighting. That’s why NGC Build is here to help you.

NGC Build is a family-run company based in London specialising in residential construction. We have extensive experience with home renovation, loft extension, and loft conversion services, offered at a very reasonable price.

The good news is that we can answer your question about how much an extension will cost today. We have a track record of success in creating dream homes for people like you.

Our services provide high-quality home renovation in London, and we want to give you the most stunning conversions possible!

We will be able to handle your project promptly and efficiently. So, visit our website today and book a free site study with our amazing team of talented architects!


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