Hidden House Extension Cost in London and How to Avoid It

London homeowners who want to expand their living space have many options, but one of the most common is a house extension. Whether you are adding an extension to your kitchen, doing a loft conversion, or expanding the side or rear of a home, there are many benefits. You can see higher property value, functionality, and a more comfortable living environment.

Most know they must pay for materials and labour, but more goes into the total house extension cost. Some homeowners don’t factor in unexpected expenses or “hidden” costs. These can add up to several thousands of pounds more than one might expect to spend. What are some of the unexpected expenses that you might experience? Keep reading to find out:

Planning and Design Costs

There are various costs associated with the planning and design process. For instance, many homeowners don’t fully understand the cost of professional design or structural assessments.

Another thing that can surprise homeowners during the planning and design process is planning permission fees. Most extensions don’t have to go through this process since they fall under permitted development, but in some cases, planning approval is required, which comes with fees.

Another cost that might come into play is party wall agreements. If you are extending near a shared wall, you might need to have some type of legal agreement with your neighbour. This can add legal and surveyor costs, too.

The best thing you can do is work with a design and build company like Build Abode. Thanks to the expertise of our Design Director, Jessica, and our transparent pricing policy, you will know about these fees from the start.

Site Preparation and Unexpected Structural Issues

Other costs might sneak in when you go through the site preparation phase of a home extension. For instance, some properties require a lot more excavation than others. Older homes might require reinforcement before an extension can be done. All of this increases costs.

Due to environmental laws, there could be added costs, too. For instance, older homes in London might have asbestos, requiring a specialist to remove it. Speaking of the environment, some homes have issues like dampness or poor drainage, which require work before the extension can begin.

The best way to avoid these costs is to have a complete site survey before beginning. Since unexpected issues can always occur, it’s a good idea to lower your budget by about 10% to cover these.

Utility Relocation and Upgrades

Gas, water, and electrical lines must be moved during a house extension, which can be costly. Another thing to keep in mind is upgrading the boiler and heating system. For instance, if you are adding extra rooms, your current boiler might not be large enough to heat the new space.

Homeowners might also have to add sockets and lighting or upgrade wiring to meet regulations or make the space more functional.

At Build Abode, we assess utility needs early in the planning process and add them to your quote.

Building Regulation Compliance

There might also be costs associated with building regulation. All extensions must meet UK building regulations. Inspections and certifications are also usually required. Another thing that homeowners might not realise is they may have to pay more for home insurance costs, as you might have more space or coverage.

In London, the disposal of construction waste can be costly. This also should be factored into the total house extension cost.

Interior Finishing and Landscaping Costs

Adding finishing touches can also add to the total cost of a home extension. Things like paint, flooring, or plaster might be more expensive than you think.

Construction can also affect your garden space, and you may need to rebuild it with new plants or landscaping.

When you add more space, you have to fill it, so the cost of new furniture should also be a consideration.

Build Abode Offers a Transparent House Extension Cost from the Start

At Build Abode, we are happy to offer our clients a transparent quote for a house extension. This helps to significantly limit the hidden costs often associated with a home extension. We would love to meet with you and offer a complimentary consultation to learn more about what we can do for you.