If you’re considering increasing the size of your home in Manchester or Cheshire with a traditional house extension and have not yet appointed an Architect there are a few things to consider first.

These will save you a great deal of time and money if you can get this right before employing an Architect. Of course, any Architect worth their weight will help you make these decisions, but the more you can do yourself the more cash you will save with these guys, (and Architects know how to compile charges LOL).


Larger living space, Larger Kitchen, Or a completely new room, Home Office, Children’s play room, Home Gym or other ground floor enlargement.

All of the above should be achievable within a single-story extension whether on the side, rear even the front (planning allowed).

Or do you need an extra or larger bedroom/s. If you are looking solely for extra bedrooms but no requirements for extra ground floor living space you may be better considering a Loft Conversion, (please see our dedicated page on that subject).  However, if you are looking for extra bedrooms and also ground floor living space then A double story extension may be for you.

A good guide when considering a ground floor single story extension would be in the region of £1,200.00 per M2. This will depend on many variables. The depths that will need to be excavated to find good ground for the foundations (all builders will usually have a nominal depth they price for, ours is 900mm deep. Then when construction starts building inspectors visit to inspect the ground. They may request that foundations need to be dug deeper than the nominal depth, and this will create extra charges.)

Next to consider will be “Does the site have good easy access?” if builders can easily get to the site to place materials and remove rubble then standard prices will usually comply. If builders need to work around difficult sites, such has mid terraced properties with no roads at the rear, then workers and materials may need to be taken through difficult routes, so extra charges may incur.

The other remaining variable would be your alterations, such has specialist windows, bi folding doors, or other external finishes.

Lastly there will be internal finishes to consider.

Then considering a double story extension costs per M2 there would be in the region of £1,850.00 M2

This is a very difficult topic to discuss, as every different local authority has very different views on what will, and what will not be allowed. The best advise we can give here is to firstly consider “Do I actually need planning permission?”. The reason for this question is, there is such a law called (Lawful Permitted Development LPD rules). These rules basically say that a Home Owner can develop their property without the need for a full planning application, so long as they comply with certain rules.

  1. The volume of the new extension must be under a certain cubic meterage, for most houses this will be 40M3. This is actually a substantial extension.
  2. The development must not stand higher that 4M from the ground, (so this rules out double story extensions)
  3. The development must be either on the side or the rear of the property.
  4. And finally, the property must not be in a conservation area.

If all of the above can be met you may not be required to apply for planning permission for your project, so you will only be required to apply for building regulation approval. If you can not be sure if your project will or will not go through under LPD laws, or you know it will not because you may require a double story extension, then you can make an appointment with the local authority planning officer and simply ask their advice if a certain project is likely to go ahead or not. They are obliged by law to give you this advice free of charge.

We at David John would be more than happy to discuss all these possibilities, and please be aware we can also compile plans and take care of the full process for you. Please look at our dedicated page on Architectural drawing services.

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If you have a project fast approaching, we’d love to get involved. Get in touch and we’ll take it from there.

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