Designing your home extension is no longer as simple as it used to be. This page introduces some of the additional considerations that your designer needs to provide for, like environmentally sustainable ‘green’ building technology and renewable energy. It also suggests how you can achieve quite a lot of this at low cost yourself. .


Today, the design of any new building has to be about more than the room sizes, materials and appearance, or old style home extension design plans.

Today, we are in the age of green buildings, eco-homes, and environmentally sustainable design.  This applies equally as much to house extension designs, as to any other building. 

Working With The New Regulations

Whatever your house extension ideas, your home extension architect, or other architectural designer, will need to address the requirement that all new extensions incorporate sustainable design solutions.  This includes ‘on site renewables’ for energy efficiency, ‘Sustainable Urban Drainage’ (SUDS) systems for rainwater collection, use and disposal, designing for dismantling, reuse and recycling, building materials, and possibly even architectural salvage.

Who Is An Architect And Who Is Not?

Here we must insert a note of caution about self-described ‘architects’.  Only professionally qualified practitioners registered with the Architects Registration Board are legally allowed to call themselves ‘Architects’.  This used only to be members of the Royal Institute of British Architects (RIBA), but since the UK’s membership of the EU and our being subject to its freedom of employment laws, enabling foreign practitioners to practice here, this has had to be extended to include anyone who has an architectural qualification.  

Understanding the Planning & Building Regulations

However, this does not mean that any such house extension architect producing home extension ideas fully understands the rules and regulations governing planning and building in the UK.  Often they do not.     
Also, this ‘loophole’ has encouraged many people who have set up as building designers in the UK to describe themselves as ‘Architects’ when in fact it is illegal for them to do so. In most cases they do not even understand that they are breaking the law by doing this. Often they do not understand the planning and building regulations either. Such people might more properly be referred to as house plan designers.

Architects, Architecture, and Architectural Technology

In the UK an Architect very often seeks to be a ‘conceptualiser’; to come up with artistic architectural ideas for buildings and their surrounding environment/s. Once they have completed their architectural design, the ‘mechanics’ of how this should be built may be turned over to an architectural technologist or architectural technician. This is the person usually charged with making the architectural design ‘buildable’, ensuring that it meets all the planning and building regulations, and that it can be built within the agreed cost parameters.

Basic Home Extension Designs Ideas
No matter how basic your home extension plans; whether you want a house extension:-
•    above a garage
•    as a side extension
•    to extend the back of your property as a one or two storey extension
•    to convert the roof into bedrooms and bathroom
•    to take the roof off and extend by building a complete new additional floor
•    to turn an outhouse, stable or garage block into additional space
•    in any other form

…, you are most likely to need this to be professionally designed.

And to achieve your Grand Design extension plans you will need an architectural designer who is familiar and comfortable with all of the home extension and other considerations raised on this page, as well as appropriate extension methods, home maintenance, house decorating and, of course, home extension costs. Last but not least you will need him or her to be familiar with the house extension planning rules.

Green Design Group
Green design is about more than environmental sustainability and sustainable development. It is about a holistic ecological ethos and working toward building a ‘green planet’. For example ‘Green’ designers see health and fitness achieved via home exercise, as being equally as important as your home office (which now earns ‘points’ under the Code for Sustainable Homes’).  

So, Green designs for your home extension plans should look to incorporate home exercise equipment and home education areas, as well as many other things  Remember that sustainable environmental designs will not only observe  Green design specifications, they will also embrace Design for recycling –v- Design for durability, and the potential for your design to achieve Passive House standards. (Being roughly the equivalent of Code for Sustainable Homes level 4, for a brief introdction to these please see Passivhaus standard)

Extension Architect Costs

Whatever you refer to the person who designs your building extension as, it is likely that you will want to keep an eye on the costs of this service. Given the enormity of the task, as outlined here, and whether or not they operate from a home base or garden office using house design software or drawing ‘on the board’ with pen and ink (still quite prevalent and productive of some excellent designs), it is most unlikely that you will ever get “Free” home extension plans; unless these are a present from some close friend or family member. Even then, do remember that, as in many things, you only get what you pay for!

However, you can get an idea of what an RIBA qualified architect would be likely to charge for your home extension plans from this home extension design costs comparison site. You can also get quite extensive house extension free or at very low cost from Simply Build Extensions, providing your project is real, has been thought through and has a fair chance of going ahead.     

Do It Yourself Design

A good way to keep at least your initial design costs down is to produce you own sketch ideas. In conjunction with our sister company Timbertecs  Simply Build Extensions and the Benfield Advanced Timber Technology Group have developed a free, downloadable DIY Extension Design Tool to help you do this. When you have worked out your own extension plans and ideas, they then also provide a low cost ‘part and part’ professional service to draw up your sketches for discussion with your local planning officer.  Once you have agreed the basics with the planners, Simply Build Extensions can produce detailed planning and building regulations drawings for you to save money by submitting these yourself – or they can do this for you.

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