Double Storey Extensions in York and Harrogate

Double storey extensions are an incredible way to completely transform your home, while minimising costs at the same time. We provide all kinds of two storey extensions across the York and Harrogate areas, and work directly with you to create the perfect design for your home. They are the perfect addition to create both space and value, while minimising the costs from having foundations on only one floor.

CK Architectural York - Double Storey Extensions
CK Architectural York - Double Storey Extensions



Designs as significant as double storey extensions need a lot of time and nurturing in order to reach their full potential. The space is equivalent on both floors, after all, so utilising both is essential to getting a design you really love without wasting any space.

A prime example of this is that bedrooms in your double storey extension need to have light, ventilation and means of escape. With two stories, the planning limitations must be considered as the size and scale mean that the extension has to be designed to fit with its environment.

The regulations are stricter specifically about fire escape and structure, so these are key areas of focus too. You need to decide what you want to gain from the build, what you are willing sacrifice, and how much you should spend to make the project perfect for your needs.


Once you know the room sizes required and how to access and ventilate them, you then need to make the external work with the existing house. There are limitations in the planning guide for two storey extensions, as they have more impact their surroundings. We like to work with and enhance existing areas where possible, as this means less new building, lower costs and a smaller impact too.

Many design options involved in a double storey extension will be centred around the aesthetics of the extension from the outside as well as the inside, as this can influence decisions from all parties. 

A double side or front extension will need to look subservient to the house, and typically this is done by pulling the front wall back. Rear extensions should consider the overshadowing and loss of amenity/outlook from the neighbours if near the boundary, as this too can influence approvals.

CK Architectural York - Double Storey Extensions
CK Architectural York - Double Storey Extensions


Double storey extensions generally need planning permission, as the permitted development rights only permit small sizes. There are a lot of things to consider before submitting a planning application, as there is a long list of factors that are reviewed before granting.

Some good questions to ask yourself are:

  • How does it impact the street scene?
  • Does it enhance character?
  • Does it have negative effect on the neighbours?
  • Does it affect light/privacy/amenity?

These are 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, and then act as your agent talking directly with the council throughout the application.

Take a look at our guide on outlining the planning permission application here for more.

On top of your planning permission for a double storey extension, you’ll also need a building certificate from a building control body, either local authority or private building inspector. Given the additional complexity of meeting the building regulations for a two-storey extension, we advise gaining the planning permission before paying for the detailed building regulations drawings to make sure you’re not wasting any money in case of rejections.

These building regulations 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, drainage
  • resistance to moisture
  • collision
  • impact
  • heat loss
  • ventilation
  • light
  • emergency escape

These drawings will be used when the building control officer inspects the build to ensure the builder is carrying out the works correctly. You can commence works 5 days from submitting to building control, as this is the minimum time due to having to consult the water authority.



Once you have all of your drawings and approvals, it’s time to move on to completing the project and approaching builders to provide quotation and price. We offer project management across the whole of York and Harrogate if you’re looking for expert management, but if you choose to do it solo, we’re still here to offer some advice:

Choose a builder that you can trust to carry out the work and ideally has a good track record.

Remember that only half of the building works will be outside; you should plan and phase exclusion zones with your builder.

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.

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.

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