Local Architectural Designers | Essex | House Extensions

This article gives you a good introduction to everything that is, an extension.

This article covers every property in England but should you be based in the South East or London regions we can provide a FREE Site Meeting and a FREE quotation for your necessary works, always tailor-made for your project. Give us a call or drop us an email to find out more.

What's The Process & Time Scales?

The Government have worked to make single-storey extensions much quicker and easier to complete than days gone past. You can also extend further than ever before for a limited time only. If you are looking to extend your home under Permitted Development then you can still benefit from a much faster process.


Should you require Planning Permission (extending beyond the rear wall of the house more than 3 meters for a terraced or semi-detached property, or 4 meters for a detached property) then you may require Planning Permission. Having to apply and then wait for Planning Permission can add up to 10 weeks to your project time.


Regardless of your Permitted Development Rights you will always be required to complete a Building Control Application and ultimately obtain approval for these works. This process will involve a Structural Engineer, at Design Spec we can assist with all of your necessary third parties and offer everything within a fixed fee pricing structure. A building control application can take anywhere between 4 to 12 weeks to complete.

How Much Will It Cost Me?

As Building Regulations are constantly updating and amending to cater for materials, heating, insulating and housing needs, these figures will always fluctuate but a good rule for thumb for a general 3 bedroom house to have simple single-storey rear extension would cost in the region of £50,000 in the South East and will naturally cost at least £60,000 for a similar design in London. London build prices can fluctuate massively depending on your postcode, access, parking etc.


Another good rule of thumb to follow for the South East is a build cost of £1,400 per square meter of new floorspace created. This cannot be used in London but is a great starting point for homeowners to better understand the cost of their new extension.

Want To Know The Exact Price?

Is It Even Possible?

Before embarking on your extension project, just consider the below points. At Design Spec we offer a FREE property consultation to help you decide on whether or which style of extension would work best for you, your family and your property!

  1. you cannot cover your entire garden with new extension space.

  2. You must maintain natural light to all habitable rooms (not including Wc, bathroom etc.).

  3. No extensions can block light into neighbouring buildings.

  4. The ceiling height in your new extension should not be less than 2 meters. In rooms with sloping ceilings, the ceiling must be higher than 2 meters for 50% of the roof span.

  5. If you choose to extend your home by utilising a conservatory then bare in mind you cannot remove the existing rear doors to the property. Once the doors have been removed this conservatory will technically become an extension but would fail Building Regulations based on heat loss, structure and possibly many other reasons!

Although the below points may not prevent you constructing your new home extension they are certainly worth bearing in mind from day one.

  1. Small gardens may suffer when reduced even further as a result of house extensions

  2. Poor designs can deprive plants of much-needed sunlight

  3. Useless fragments of outside space, disjointed and cut off from the main garden

  4. Lack of daylight and the feeling of space from a poor understanding of how light flows through your home and house extensions

  5. Light that intrudes with usability of technology such as TV's and computer screens

  6. Passive solar gain that brings welcome heat in the winter but discomfort in the summer

  7. Designs that boldly incorporate an altogether different style with great potential, but which produces a disjointed building.  

Benefits Of An Extension.

The number 1 benefit of an extension is the value it adds to your property. On average, an extension will earn you £14,000 profit! This means regardless of your needs and goals with your property you know that your money is safely invested.


Another benefit, of course, would be the extra space and living area that will be achieved through this. This could be an extra bedroom, bathroom, living room, you name it, an extension can provide it!


There are many benefits to an extension. Whatever your query regarding your extension, contact us today for a FREE quote, FREE meeting and dedicated management.  


This means regardless of your needs and goals with your property you know that your money is safely invested.

For our clients seeking commercial gain, we have a proven track record of achieving the maximum ROI for our clients, regardless of project size and budget. 

Considering an Extension?

Simply provide the below details and a member of our team will get back to you!


Where To Find Us

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Suite 1C Warren House,

10-20 Main Road,


Essex SS5 4QS

Innovation Centre,

Boundary Road,

Colchester CO4 3ZQ

Suite 1B, The Stables, Cannons Mill Lane, Bishops Stortford CM23 2BN

Vision 25, Electric Avenue,

Innova Park, Enfield EN3 7GD