Call us today on

Guide to Planning a House Extension 2018-02-14T14:53:22+00:00

Guide to Planning a House Extension

Homeowners looking for more space are faced with two options: to sell up and move to a bigger house or build an extension? If you are considering building an extension to your existing house here are some important considerations to get clear before you employ an architect and/or builder or all trades company with experience in building house extensions.

planning a house extensionThis Guide covers the initial planning activities that need to be completed before building a house extension:

Practical factors to consider
Finance and Payment
Planning Permission
Building Regulations

Practical factors to consider


Selling a house can be costly when you consider estate agent fees and stamp duty on your next house. Building an extension onto your existing home could work out cheaper than buying a new one and you’d also get the extra space you want.


You might also need to consider access to your extension? Will it be via the house or will extra footpaths and/or driveways need to be built. This could affect planning permission so needs to be carefully planned out. Access for builders will also need to be accounted for. Will there be enough space to transport building materials from the road to the site and will there be enough space for the builders to work in?

Site conditions

Before plans for an extension can be drawn up the actual site of the build must be assessed for factors such as soil conditions, trees and foliage (some trees may require planning permission to cut down), flood risk, rights of way.

Do your homework

Talk to other homeowners who have had house extensions built. You can learn a lot about every stage of the process from planning through to building and completion and take on board some tips on what to include or exclude in your extension, how to cut down on costs without compromising on quality and any reputable builders or all trades companies that carry out house extensions.


guide to planning a house extensionThere are no set costs for building a house extension. Depending on the site conditions (see above) costs for house extensions vary. Obviously the size and features of your extension are factors; the footprint in square metres, how many storeys? how many windows? what type of heating? etc. On average a basic house extension could cost around £10,000 with a higher quality extension costing in the region of £25,000. Shopping around for the best price is always recommended but be sure to balance the cost against the quality of the extension’s internal and external features as well as the quality of your architect and builder.

Finance and Payment

When borrowing money for any building project be prudent and never borrow more than you need without very careful forethought. If you have savings you should seek advice from an expert if it would benefit you in the long term to use then to finance your house extension or whether borrowing is more beneficial. Borrowing options include credit cards (preferably interest-free), a personal loan or a remortgage or secured loan on your existing house. There are also a variety of home improvement loans which are available.

Designers or architects should provide an accurate quotation prior to preparation of the plans and are usually paid on completion of the plans. Builders often stipulate payment according to the stages of the project for example an initial deposit, on completion of principle building work, on interior fittings and overall completion.

Some house extensions qualify for zero VAT depending on the occupancy status of the property and whether or not your contractor is VAT registered.


how to plan a house extensionAlways ask your home insurance provider for a quote for what your new premium might be on completion of the build. Most reputable builders and all trades companies are insured for works they carry out which safeguards against unforeseen circumstances such as damage to the existing property during the build process.

Planning Permission

Your local planning office should always be informed of any proposed house extension builds especially if your house is a listed building or if your extension contains something which includes something which might be considered unusual.

Your new house extension pay or may not require planning permission depending on a number of Permitted Development Rights including:

  • The distance your extension extends from the house.
  • The height of your extension and its relation to your existing property and rear boundary.
  • Type of building materials (must be consistent with your existing house).
  • Whether or not your house is in a Conservation Area, Area of Outstanding Natural Beauty, World Heritage Site.

Building Regulations

All extensions, whether they require planning permission or not, need Building Regulations Approval. A Building Warrant must be granted and applications can be made after getting the relevant information from your architect. Remember, it can take 4-6 weeks for Building Warrant approval so always apply in plenty of time. Contact your local council’s Building Standards Department for more information on how to apply. Find out more about building standards for house extensions.

Designing your house extension

After all the initial activities for planning your house extension you can move on to the more exciting stage of planning what your extension will look like, how many rooms will it have, what interior and exterior features will it have. These are discussed in our Guide to Designing a House Extension.

C Hanlon An All Trades Company

Why Use Us

We aim to excel in our expertise, quality products and achieve a first class service on every project.
To be the best supplier of Trades & Services for both Domestic and Commercial clients.
We promise to give a superior service with a top price everytime! We only employ qualified tradesmen and customer service is our priority.

Do you require domestic or commercial trades services?

For more information or a free quote please call C Hanlon All Trades Company on 0843 289 2038.
Get in touch today!

Contact C Hanlon today for more information about our home extension building services in Glasgow, Edinburgh and Central Scotland.
Call us on
0843 289 2038
C Hanlon can provide all trades services for Residential and Commercial Customers throughout Glasgow and Central Scotland.


If you need to call out a tradesman for an emergency call the C Hanlon 24 hr Emergency Number: 0843 289 2038.