• Kirton Construction


Updated: Feb 28


It’s been a few years now since you moved into your house and things are going great. That said, space has become a bit tight recently and you’ve been thinking more seriously about that extension that you talked out previously.

Whether it is a single or double storey or a wraparound extension, there are some key considerations when starting such a project. Failing to properly plan an extension could end up costing you time or money that you did not expect.

Here are some things that need attention before you start building your home extension:

1. BUILDING REGULATIONS. Your new extension may require permission through building regulations before you start. Even if permission is not required, there will still be some building regulation criteria that must be met. For more information about planning permission, click here.

2. HOW MUCH SPACE DO I NEED? It is worth advice from the right person before deciding on the size of your extension. Research local architects or, if you are using a building company, find out whether they can undertake design and planning as well as building work.

3. WILL MY EXTENSION ADD VALUE TO MY PROPERTY? Economically you want the value of your property to increase more than the cost of your extension.

4. WHERE ARE THE SEWERS? It is not necessarily possible to build over or near a sewer, especially if it is a shared one. Contact your water board for more advice and be aware that proximity to sewers can increase the cost of a build.

5. SERVICES. Will your extension need electricity, water and gas? If so, plan where power-requiring facilities are going to be situated before work is undertaken to allow proper planning of power supplies and ventilation.

6. EXTENDING ABOVE A SINGLE STOREY. Although appealing, it is not necessarily a simple task to extend a single storey into a double storey. A lot will depend on the strength of the existing build and it can even be more cost efficient to demolish a single storey and start again.

7. HEATING. Specifically, water. If you are planning a large extension you will need to find out if your existing heating system (boiler, radiators etc) can effectively cope with the extra space. If it can’t, you will want to consider downsizing the extension or considering different heating methods like electric or solar.

8. ACCESS. This applies for two reasons. Firstly, will you have enough access to complete the build? If your house is md-terrace you may have restricted access to the rear of your property anyway which could prevent certain building methods or machinery. Secondly, will your extension have a significant impact on another part of your property such as parking or vehicular access to the rear etc?

9. MATERIALS AND APPEARANCE. It is often easy to spot an extension to an existing property. Consideration should be made as to the materials that are used in order to make your extension blend well with the existing property. This may mean sources uncommon products and you will need to decide if this is worth the time and expense.

10. LIVING ON SITE. The scope of your extension may have a fundamental impact on your ability to live on site whilst building work is carried out. Make sure you consider this and plan alternative accommodation if required.

11. BUILDING OFF SITE. As the name implies it is possible to have components of your extension build off site and then delivered to your home for assembly. This can reduce cost as well as disruption to your day to day living.

12. FINDING THE RIGHT PROJECT MANAGER. This is important. You should take time to find the right person to manage this project. Whoever you choose should work closely with you to manage your needs. This is your home and you will know what you want better than anyone else. If you are confident to manage then you can undertake this position yourself.

13. PARTY WALL ACT. This relates to your rights to build your extension right up to the boundary of your property. It is always worth considering your neighbours- after all, you will need to live next door to them. However, it is also worth understanding your rights to build your ideal extension too. You can find out more about the Party Wall Act here.

14. PRIVACY. By increasing your living space your windows and doors will be in a different place via your extension. Make sure you consider what properties overlook your extension and take measures to ensure privacy as required. Consideration should also be given to how much sunlight will enter the property and what screening will be needed to ensure comfortable use.

15. DO YOU LIVE IN A CONSERVATION AREA? If you do you will need to find out what you are allowed by way of an extension. Local authorities control right on areas of conservation in order to maintain their character and you should contact your local authority accordingly.

16. CONTINGENCY BUDGET. Things can change throughout the duration of a building project. You should try to make sure you have funds put aside for anything that might crop up from extra building work to optional extras that you want after starting the build.

17. SITE INSURANCE. It may not be enough for your builder to have public liability insurance in case of error. You should enquire about having site insurance for your extension. Also consider self-build insurance if you are doing the work yourself.

18. HOW MANY WINDOWS CAN I HAVE? Typically, the amount of glazing is limited to 25% of that of the area of the floor space of your extension in order to comply with part L of Building Regulations. Make sure you comply with this in order to get permission to build what you have planned.

This is not an exhaustive list, but you can see that a lot needs to be considered when planning a home extension. Take your time to involve the right skilled people in your extension project and make sure that you understand their experience and qualifications and check out their previous work too.

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1 Lakeview Court,  Spitfire Close, Ermine Business Park

Huntingdon, Cambridgeshire, PE29 6UA