A double storey extension adds living space to both the ground and first floor of your home, you get the same benefits on the ground floor as a single but usually without the option of roof glazing. The first floor can then add bedrooms, bathrooms, en-suites etc. A good architectural designer will be able to give you the right advice and options to successfully design the space required.
If you want rooms and know where they should go, you need to access them, have light/ventilation and means of escape. With two stories the planning limitations have to be considered as the size and scale means it has to be designed to fit with the existing house. The regulations are stricter than a single storey, specifically regarding fire escape and structure. You need to decide what you want to gain from the build, what you are willing to sacrifice and available budget. Site checks should be carried out on shared boundaries, partywall, mains sewers and if is it a listed building or in a conservation area.
Size and scale of the extension is the priority, how much will you need to build to gain the space and rooms you want. From there the internal layout can be explored, using the existing structure as best as possible to save cost is advisable. Try to avoid creating inner rooms as each habitable room will need an opening window. A double side extension will need to look subservient to the house, typically this is done by pulling the front wall back. Clear glazing in double storey extension will generally not be permitted at first floor level within 7 meters of a boundary. Getting a good balance is important, if the need for a bedroom is driving the extension, you will have to make good use of the ground floor. Double rear extensions have to consider the overshadowing and loss of amenity/outlook form the neighbours if in close proximity to the boundary lines.
Double storey extensions generally need planning permission as the permitted development rights only permit smaller sizes. There are a lot of things to consider before submitting a planning application. How the build will impact the street scene, does it enhance character, does it have any negative effect on the neighbour’s house or garden, does it affect light/privacy/amenity. These are some of the things the planning officer will be checking whilst making their decision.
Our design consultants will give you the best advice on how to achieve your requirements with the best chance of securing planning approval. We will prepare and submit the application on your behalf, then act as your agent talking directly with the council throughout the application.
You will definitely need a building certificate from a building control body, either local authority or private building inspector. We advise gaining the planning permission before paying for the detailed building regulation drawings. Given the additional complexity of meeting the building regulations for a two storey extension it is essential that you get the plans approved prior to commencing. These building regulation drawings will then be submitted for a full plan check, amended if necessary and once approved they will be the standard that is built to and inspection against. Our plans will include all the necessary detail such as structure, passage of sound, disabled access, heat loss, drainage, resistance to moisture, collision, impact, ventilation, light, emergency escape and much more. These drawings will be used when the building control officer inspects the build to ensure the builder is carrying out the works to specification. You can commence work 5 days from submitting to building control, this is the minimum time due to having to consult the water authority.
BUILDING AND BUILDERS
Remember when you finally do come to build only half of the building works will be outside, you should plan and phase exclusion zones with your builder. With the approved drawings you can now approach builders to provide quotation and price. Check that any quotation you consider will be written up clearly and with good detail. You will need to know exactly what is priced for and any additional costs should unforeseen issues arise. We have extensive construction knowledge along to assist you and builder throughout. Use our drawings in line with the quotation and any additional information we don’t provide such as plumbing and electrics is agreed in detail before the first fix goes in. it will be costly changing thing once the initial preparation has been built. Our help and advice doesn’t end once you have the approved plans, we will help you throughout the construction process and visit site if required.