Top tips for planning an extension

Top tips for planning an extension

An extension is a cost-effective way to create more liveable space that can completely transform your home. We have seen a rise in homeowners opting to extend their property rather than moving house. There are many factors to consider when you decide to extend your home to ensure the new space complements your property and lifestyle. Here are some tips when planning a house extension to help the project run smoothly.

Set a realistic budget

Firstly it is vital to calculate an accurate budget for your extension project. Try not to underestimate any costs, include expenses such as insurance and planning application. Discuss your budget with your potential builder to make sure they can build within your budget. Communication between you and any hired professionals is key to keeping within your budget. Manage your budget by regularly monitoring your project progress and all expenses. We recommend homeowners include a 10%/15% contingency of their overall budget.

Clarify the reason for your extension

Make sure you identify your reasons for the house extension you are planning. Some common reasons are to improve your house layout, create an additional bedroom or living room, to increase the property value or update the property style. Once you have identified this it will make the planning process easier and you are more likely to achieve your dream extension.

Planning permission and neighbours

Planning regulations depend on the size and placement of your planned extension so planning permission may be required. Most house extensions require approval under the Building Regulations. We always recommend contacting your local planning officer to check if planning permission is required. You can also find guidance on the Planning Portal website. Discuss your extension requirements with your architect or builder; they can advise you on any potential issues that may arise during the planning process. Try to keep lines of communication open with your neighbours and be aware of the neighbouring properties. Inform your neighbours before applying for planning permission to give them a chance to view any objections to give you time to consider any changes needed. If you do not give them the opportunity before you apply for planning permission they will have the chance further down the line which could cause more expense such as redrafting the designs and resubmitting the planning application.

Decide where you would like to extend

Next you need to decide where you would like your house extension. You should also decide if you would like it to be single, two or even three storey. The size of your extension can vary depending on the space available, planning permission and budget. Keep in mind the landscaping and exterior of your house. The garden is often overlooked when planning an extension so consider how much outdoor space you require before planning the size of the extension. Your architect or builder can help you decide which option is the best for your requirements, location and surroundings.

Consider your setting and materials

It is important to research various materials to decide which would work best for your extension. This will depend on the desired look of the house extension, the style of the property and also building guidelines. The extension should complement the property, some would like it to blend in and others would like to create a focal point. Either way, make sure you are clear with your architect and builder what you envisage.


An extension to your house must be built to a reasonable standard to comply with the building regulations so the team you hire needs to be reputable. It is important the trades you hire have good recommendations. Communicate with their previous clients and view the projects before making your decision. For more peace of mind you can look for professionals that are part of an industry Trustmark association like Federation of Master Builders or Which? Trusted Trader.


It is important to plan in advance and set a realistic timetable for the project. Keep in mind the project may over-run as changes and hold ups may arise. Be clear with your architect and builder on what type of home design you desire and make a full inventory including the required finishing touches. Be aware of the time it takes for a house extension project to be complete and consider the time of year.

Are you planning a house extension? Let us know in the comments below.

Add a comment