Building Extension Architect Company in London & Essex

How much to build an extension?

Unsurprisingly, the cost of building an extension can vary wildly depending on your requirements. Obviously, it makes sense that smaller, less complicated extensions work out cheaper. However, the location of your property could also play an important factor too.

As a general rule, the cost for good quality single-storey extension in London weighs in between £1,800 and £2,400 per m2 - naturally, prices can fluctuate based on material quality and location.

How to build extensions

There are no set rules in terms of how to build an extension. The best way to get a solid plan in place is to work with a well-experienced architect who will oversee the important factors. The following checklist for building an extension should give you a rough idea of what’s involved:

How to properly design your house extension

Designing a house extension may seem daunting, particularly if you don’t have any previous experience. Few of us undertake more than one major building project in a lifetime, so it’s important to get things right from the get-go.

It might seem obvious, but designs for extensions on houses should always be overseen by a qualified and experienced architect with a long and varied history of successful designs for house extensions. If you’re looking for a reliable extension of house design in Essex and London, working alongside Humphreys & Sons will help you to:

Identify your needs to help you get more out of your project.

Cost of building an extension for your property

Before considering home improvements, one of the most popular questions asked by property owners is “how much does it cost to build an extension?”

Unfortunately, there’s no simple, straightforward answer, because no two extensions are completely alike. The cost of building an extension can fluctuate depending on material costs, the size and scale of the project, the area in which work is being undertaken and lots of other variables.

Cost of building extension: average prices

On average, the cost of house extensions in London (and the wider South-East area of England) sits somewhere between £30,000 and £70,000 for a single storey build, depending on your choices. The simpler the extension, the less the cost of extending a house will be.

For a two-storey extension, a good rule of thumb is to add an additional 50% to the build cost of a standard single-storey development. For example, if a single-storey extension in London was going to cost you £50,000, you could expect to add a second storey for £75,000 in total material costs.

However, the cost to extend a house also involves professional fees associated with the use of a competent architect, fees for planning permission applications, fees to ensure building regulations and fees for a structural engineer to ensure the project is built to last. For these, you can expect to add somewhere between 10% and 15% to your initial extension building costs.

Other considerations

It’s worth remembering that extension building costs can get a little bit more complicated when you start to factor in bathroom or kitchen extensions. If your extension involves a bathroom, you can expect to add somewhere in the region of £5,000 to your costs (again, this can vary depending on the utilities you require).

A kitchen will set you back even further, at approximately £10,000 for an average mid-range kitchen. Fixtures, fittings and worktops will all play a role in how much your new kitchen extension will ultimately cost.

Despite this, the cost of house extensions are usually mitigated by the fact that the added value to the property far exceeds the initial outlay involved in undertaking the work. If the figure initially seems daunting, try not to be too perplexed - you’ll certainly be able to reap the rewards when it comes to getting your house revalued after the building work has been completed.

Building extension planning permission and regulations

An extension to your home is sometimes considered to be a permitted development. In some cases you won’t need to apply for extension planning permission, although it is important to seek the advice of an extension specialist or architect prior to commencing with a project. This is because there are limits and conditions imposed on how large your extension can be and what features it can have.

The world of extension building regulations can be murky and often complex, which is why it is paramount to have an architect on your side. In a worst-case scenario, you could find yourself facing a fine or having to undo any building work at additional cost to yourself - so it’s pertinent to be on the right side of any building extension regulations which might apply.

Do I need planning permission for an extension? What you need to know

If you are extending a terraced or semi-detached house, it is your responsibility to advise any adjoining neighbours of your plans to build an extension under the Party Wall Act (1996). This requirement can also extend to detached houses in some cases.
In some instances, your neighbours may be able to raise an objection against your planning application with your local council, who will then be required to hear both sides of the argument before deciding on whether you will be permitted to build your extension, whether you may need to make amendments to your existing plans, or whether you may be denied permission to extend.

When you’re building an extension, regulations typically apply regardless of the type of property you’re improving upon. The following elements typically have to satisfy the requirements of your local planning authority prior to the construction of your extension:

Drainage/plumbing

If you are in any doubt as to whether you require planning permission or approval under local building regulations, you should liaise with your extension architect and have them query this with your local planning authority on your behalf.

Drawing service for a building extension

To support your case for extension planning permission, you’re going to need professionally-created drawing plans for an extension. At Humphreys & Sons, we can efficiently create drawings for extensions which meet all regulations and standards. Our extension plan drawings are developed using the most powerful design software on the market, and feature all required technical details.

Drawings for extension: the design process

Before creating your house extension drawings, we’ll liaise with you to gain a full understanding of what you want and expect from your extension. Your creativity is the limit - we can take care of planning permission and building regulations and will factor these into your design ideas, and we’ll even advise you during the initial sketch/thought process. We will also offer our experience and expertise, and creative flair at all stages of the project.

Before undertaking the drawing, we’ll arrange to visit the site of the extension to measure the property, discuss ideas and then develop them further using our state of the art drawing and project management software.

We’ll then allow you to see a proof of the plans, which we will require you to finalise. Once the proof has been “signed off”, we can then complete the design in further detail, factoring in building regulations, structural engineering, electrics, pipework and other elements.

How long will my extension design plans take?

We aim to have a proof ready as soon as possible. Naturally, this can vary depending on the complexity of the project, but if you’re happy with our initial ideas then it allows us to move forward. If you require some changes, we’re happy to work with you until we reach a consensus on the design. Once that consensus has been reached, we can submit your application to the local planning authority, confident in the knowledge that we’ve met all relevant regulations. This means you can get to the task of building your extension in next to no time.

What type of building extensions can we help with?

Front of the house extension architect service

Whether you want a front porch extension or a two-storey renovation, we’re here to help. Extending front of house is easy when you use our services. Our team is on-hand to help with everything from front extensions planning permission to CAD designs and project management.

How to easily extend front of house

Adding an extension to the front of your property can often be more complex than building at the rear of the home - particularly if your house is close to a public road. Why not call us to discuss your extension to front of house ideas today? Our team is on-hand to advise and help you get value for money out of your extension project.

Semi-detached house architect service

Semi-detached house extensions are some of the most common improvements to properties in the UK. However, it’s important to understand that extensions on semi-detached houses are subject to greater planning scrutiny than detached properties - the same goes for extending a terraced house.

House extension semi detached rules

The reasons for these additional regulations are quite simple: if you share an adjoining wall with a neighbour, it’s possible that your semi detached extension could impact their property. This is less likely with a side extension to a semi-detached house, although it’s always important to ensure that your project meets all regulations.

Side extensions architect service

Side extensions to houses can add serious value on the property market. At Humphreys & Sons, our team is here to ensure your project meets all local side extension house regulations. We’ll work with you at every step of the way to deliver the perfect extension on side of house in accordance with your budgetary requirements and design preferences.

Extension side of house: start your plan today

There’s no time like the present to start transforming your ideas into reality. Why not contact our extension specialists today to discuss your side of house extension project?

Loft extensions architect service

Loft extensions are an affordable and convenient way to add more space to your property without having to build outwards.There are four main types of loft extension: roof light, hip-to-gable, dormer and mansard. Loft extension cost can vary depending on the type you choose, and some options may not be available to you depending on your property type. For more information on how much loft extensions cost, or for more advice on the right type of loft conversion for your home, please do not hesitate to contact us.

Kitchen extension architect service

Humphreys & Sons offers a complete kitchen extension planning and design service in Essex and London. We combine decades of planning policy expertise and knowledge of building regulations, structural construction methods, spatial planning and the party wall act to ensure you get the best possible value for your project. From conception to fruition, we’re here to ensure your kitchen extension plans go as smoothly as possible.

Kitchen extension cost UK

Kitchen extensions generally cost more than standard extensions. While the cost of kitchen extension projects can vary depending on the fixtures, fittings and materials you opt for, you can expect an average London kitchen extension to cost approximately £10,000 more than a standard one-storey project.

It’s worth bearing in mind that if you’re adding a kitchen extension to your home, you will need to consider factors such as the location and adequacy of plumbing, drainage, gas and electricity. There are decorative measures to consider, too. For example, tiling is a particularly skilled job, and it’s the sort of thing that you’re more likely to hire a professional to complete in comparison to the simple painting of a wall, as good quality tiling is a key feature of any kitchen. When you factor in the cost of tiles, it’s usually more cost-effective to use a professional decorator than to risk damaging and having to replace cracked kitchen tiles.

Plumbing is another consideration. If you’re adding new sinks, dishwashers and drainage, you might also need to hire a qualified plumbing and heating engineer. For further information on why kitchen extensions cost more, why not contact our team who will be happy to advise on the nature of such a project.

Rear extension architect service

If you’re considering a rear extension to a property in London or Essex, Humphreys & Sons can help with everything from cost management to planning and meeting building regulations.

No two rear house extensions are the same. Everything from rear extension cost to design preferences can vary from project to project, and so too can the control your architect has over the entire situation.

For example, some clients might simply require initial advice on the design of a single-storey rear extension, whereas others may want complete project management on a two-story rear extension (also known as a double-storey rear extension). Whatever your requirements, we’re here to ensure that your project runs smoothly, on time and to budget. This means you can sit back and allow us to worry about keeping an eye on the cost of rear extension, the legibility of planning applications and all other administrative issues. You can be as involved as you like, or take a back seat and allow our professionals to oversee the project for you.

Attic extensions architect service: do I need planning permission?

Attic extensions generally don’t require full planning permission, unless you alter or extend the roof space to the point where it exceeds specified conditions or limits. Generally, an attic extension is considered to be a permitted development subject to a volume allowance of 40 cubic metres for terraced properties, and 50 cubic metres for detached/semi-detached properties. Attic extension cost estimates are available from our team - contact us today for further information or to arrange a quotation.

Essex conservatory extension architect service

A conservatory extension is a great way to enhance both the look and value of your home and provides you with the perfect place to entertain friends and family all year round. A single-storey extension conservatory is also one of the easiest forms of home improvement - although things can be as simple or as technical as you like (take kitchen conservatory extensions as an example of a more complex conservatory project).

The cost of a conservatory extension can vary depending on what you expect from the project, the sorts of materials you’re planning to use, the location of your property and whether your home is a “listed” building or not.

For more information on conservatory extension costs, simply contact Humphreys & Sons today and we’ll be happy to explain in detail how we can help you achieve the home improvement of your dreams while adding serious value to your home.

What most architects usually forget!

Humphreys and Sons take pride in providing a thorough and holistic service, rather than just providing the bare minimum to achieve planning permission and building regulations approval, and leaving multiple ‘gaps’ and consequent pitfalls in the design, and the building works.
If you are building over, or near to, or wish to connect into certain types of drain, formal permission is required from the authorities. If this permission is not obtained, your works can be halted on site by the building inspector, or may never be signed off, which can result in severe legal and financial consequences. Humphreys and Sons are experts in this field, and include for such considerations in their designs as a matter of course.

If you are carrying out works to a party wall/shared wall/garden wall, or are building up to the boundary, or are excavating foundations within 3m/6m of a neighbouring structure, you are required under the party wall act to serve formal notice on your neighbour, and undertake various processes as required by The Party Wall (etc) Act 1996, in order for you to legally carry out the works. If these processes are not properly followed, your works can be halted on site, and you can face severe legal and financial consequences. Humphreys and Sons are experts in this field, and include for such considerations in their designs as a matter of course.

The CDM health and safety regulations place strict duties and responsibilities onto the ‘client’ when building works are carried out, and this applies whether you are a client responsible for a huge construction project, or a homeowner carrying out relatively minor works on your home. Fulfilling these duties is entirely your own responsibility, however Humphreys and Sons are experts in this field, and can advise and help you with every step of the way.

If your building is listed, or in a conservation area, there are additional requirements and more restrictions on what can and cannot be done, and more detailed designs and specifications will be required, along with an expert knowledge of your period property, and conservation officer requirements. Humphreys and Sons are experts in conservation matters and period property, and can ensure that your works carried out are all fully legal and compliant, and also that your period property is treated with care and respect.