7 Top Tips to Help keep House Extension Costs Down

7 Top Tips to Help keep House Extension Costs Down

Adding an extension to your home is an ideal way to increase your living space instead of moving house. An extension should also improve the value of your property. The work involved varies depending on how large you want the extension to be. It’s easy to become over-ambitious and increase your budget beyond what you can afford.

However, Aaron Donovan of AD Services has plenty of tips to help your finances stay on track. Aaron has been building extensions as an independent contractor for ten years and has more than twenty years of expertise in all aspects of building work.

1. Take Your Time When Planning an Extension

Deciding on how much space you want to add often depends on whether you want to remain in the property or hope to make a quick sale. Planning an extension for your use means you can include features you specifically want such as an open-plan living space. Extending to add value to make a profitable sale means you should think about what most buyers are looking for.

You’ll need to appoint a qualified architect to draw professional plans. An architect will interpret your ideas about what can be achieved. They will also advise on what you can’t do such as placing too much stress on existing foundations. The size of the architect’s fee usually varies depending on how complicated your plans are. You can save money by simplifying your ideas.

2. Ensure Your Extension is Legally Acceptable

You must submit your architectural plans to the local planning department. It usually takes between eight and twelve weeks for your extension plans to be dealt with. However, it’s an important stage of the process that you should never overlook. Many people have rushed to begin their building work only to have their plans rejected or amended. This can increase your costs considerably as you may have to demolish what you’ve already built.

Even completed extensions must be removed if you have not been accurate with measurements or used incorrect materials. Waiting for approval keeps your costs down by avoiding paying for corrective work. In any case, a reputable building contractor won’t start work unless your plans have been approved.

3. Obtain Detailed Quotes

Building contractors charge individual fees which usually depend on the amount of work and the cost of the materials. Some building companies might use a larger workforce. This can increase your total costs, but they’ll complete the job in a shorter time frame. A contractor with a limited number of employees usually takes longer to build your extension.

You should obtain three quotes to give you an idea of the costs involved. Each builder often uses a different supplier where they may purchase materials at a discount. An itemised estimate should help you work out your budget more accurately.

4. Be Aware of Your Options

Understanding which materials are available for your extension can help reduce your costs. For instance, real slate for the pitched roof of a side extension or versatile garden building can be expensive. Reclaimed slate is much sought after as it’s a high-quality material that costs less than new.

However, synthetic rubber slates are often a very good alternative. They look and perform like real slate, but they are faster to install. This can keep your costs down considerably as you won’t have to pay for so many days of work.

5. Plan for the Unexpected

Nearly every building project experiences a setback. It can be through discovering underground pipework that must be avoided or having an item such as a window frame unexpectedly break. When planning your home extension budget, you should always include a small sum of money as a contingency fund. It can help withstand the final costs should unforeseen circumstances cause further work.

6. Consider Appointing a Project Manager

Some extensions are large, luxurious projects that are like building a completely new home. If your extension fits this description, it could be cost-effective to hire a professional project manager. He or she will keep everyone on a timetable. They’ll help keep your costs down by getting supplies delivered on time, preventing workers from standing idle. By organising all aspects of your extension’s building work, a professional project manager should keep your costs within budget.

7. Find Alternative Accommodation

Many building contractors charge a reduced fee if you move to temporary accommodation while the work is in progress. It leaves the builders free to work uninterrupted, enabling them to complete the job much faster. You might need to pay for placing items in storage and a short lease on a rented property. However, the cost can balance out favourably if you have relatives willing to take you in or if they own a caravan you can borrow.


An extension can improve your home and add real value. You can keep your extension costs down by doing your research thoroughly before starting. Check out different options for materials and features. Have the patience to wait for planning permission as approval can avoid costly mistakes. It’s important to find a reputable building contractor who will keep your costs as low as possible.


Ciaran Clarke