How much does an extension cost?

House extensions in the UK generally cost between £750 and over £3,600 per square metre, with typical projects ranging from £40,000 for small, standard builds to over £100,000 for large, high-spec extensions (excluding VAT). A standard 30m² extension often costs around £60,000, while two-storey projects can exceed £100,000-£155,000.

How much does an extension cost UK?

The average house extension cost in the UK varies significantly but generally falls between £1,800 to £3,000 per square metre, with single-storey adding around £1,500-£3,000/m² and two-storey £1,800-£2,500/m², depending heavily on size, location (London is pricier), finish quality (basic vs. premium), and features like bifold doors or kitchens, with total project costs often ranging from £30,000 to £100,000+.
 

How much does a 3m by 4m extension cost?

A 4m x 3m extension (12m²) in the UK typically costs £20,000 to £36,000+, averaging around £1,800 to £3,000 per square meter, but can vary significantly based on quality, finishes (kitchen/bathroom add-ons), and labour, potentially ranging from a basic shell to a high-end, fully fitted space. Expect costs for standard quality materials around £2,200-£2,900/m², with higher-end finishes pushing costs upwards.
 

What is the 50% rule for house extension?

The "50% rule" for house extensions in the UK (under Permitted Development) states that your new extension, plus any previous extensions and outbuildings, cannot cover more than 50% of the total land (curtilage) around the "original house", meaning the house as it stood on July 1, 1948, or as first built,. This rule ensures you don't build over most of your garden, but you must also consider other limits, like height, proximity to boundaries, and avoiding front-facing extensions, or you'll need planning permission. 

Do I need an architect for a 3M extension?

You don't need an architect for small or straightforward projects, but if you're planning a rear, side, or two-storey extension, or converting a loft, basement, garage, or building an annex, hiring one is highly recommended to ensure safety, legality, and a good design.

How Much Does a House Extension Cost in 2025 (UK)? | Architect Explains

How much does an extension cost in the UK in 2025?

Average Cost To Build An Extension In 2025

Based on building to a standard specification, you can expect building an extension to cost on average (when using a mid-benchmark contractor): Ground-floor rear extension– £86,686, or £2,890 per square metre. Double-storey rear extension– £143,926, or £2,399 per square metre.

How long do extensions last?

For example, tape-in and sew-in extensions usually last around six to eight weeks. After that, they need to be adjusted or removed. If Keratin bond is done by a professional, the extensions can last up to six months. And you need to take good care of them.

What is cheaper than an extension?

Garage Conversions

Conversions are usually cheaper than a traditional extension, but they do involve structural work, insulation, flooring, and sometimes raising ceilings or adjusting doors. However, if you're looking for more space instead of changing what you already have, then an external structure is the way to go.

Is an extension worth it in 2025?

A professionally designed home extension in London can boost both space and functionality — the two biggest drivers of buyer demand. While a basic conservatory might add around 5%, a well-executed ground-floor extension typically adds 10–15%, depending on finish quality, layout, and location.

How much is a 20 sqm extension?

As a rule of thumb, building a home extension in London – just the shell – is going to cost you at least £2,000 per square metre. So, the cost of a 20 sqm extension would start from £40,000 (not including VAT).

What size of an extension can I build without planning?

You can build an extension or conservatory to the rear of your house as long as it: Does not increase the original floor area of the house by more than 40 square metres.

Can you wash hair with extensions?

Brush First: Gently brush your extensions to remove tangles before washing. Water Temperature: Use lukewarm water, as hot water can damage both your natural hair and extensions. Shampooing: Apply a sulfate-free shampoo. Oribe and Leaf & Flower are both safe for hair extension.

How much is a full set of hair extensions?

A full set of hair extensions can cost anywhere from under $100 for temporary clip-ins to over $1,000-$4,000 for professional, semi-permanent methods like fusion, depending heavily on the type (clip-in, tape-in, micro/nano ring, keratin), hair quality (synthetic vs. human, Remy, virgin), salon expertise, location, and length/volume needed. Expect DIY clip-ins to start around $100-$300, while salon-installed tape-ins, micro/nano rings, and keratin bonds often range from $250 to $800+ for the initial application.
 

Do extensions fall out easily?

Improper installation or the use of the wrong products can cause hair extensions to slip out more easily. When extensions aren't installed correctly, or the bonds become loose, they may not stay in place as they should. Another common reason for hair extensions falling out is aggressive brushing.

What is the cheapest way to build an extension?

The cheapest way to build an extension involves a simple, rectangular design, avoiding complex shapes and integration with the main house, using standard-sized windows/doors, choosing basic materials like flat roofs, doing some work yourself (DIY), and focusing on permitted development to skip planning fees. Maximizing standard features and avoiding custom elements are key to keeping costs down. 

What is the cheapest way to add a room to your house?

5 ways to add a room to a house cheap

1. Build a bump-out addition. ...
2. Finish a basement or attic. ...
3. Create a FROG (finished room over garage) ...
4. Add a sunroom. ...
5. Consider a smaller addition.