30 Ways to Save Money on Your Home Extension Project

Adding space to your home doesn’t have to break the bank. Whether you’re working with a tight budget or simply want to keep a close eye on spending, Rebecca Foster shows how to get the best value for money with these 30 tips for saving on your home extension project.

1) Plan the size of your extension carefully

Building a smaller addition doesn’t mean it’ll be cheaper. There’s an economy of scale on every project, so you’ll want to strike a balance somewhere in the middle to get maximum value per m2.

“For every job there are site set up and running costs – insurance, scaffolding, skips etc. The smaller the job the higher these are as a percentage,” says James Munro, director at Granit Architects. “There’s a sweet spot where the job is big enough to build efficiently, without it being so complicated and prolonged that it swings the other way.”

2) Types of extensions

The scheme that offers best value (single-storey, double-storey, side-return or loft extension) hinges on the unique features of your existing property and what you hope to gain from the project.

On a per m2 basis, double-storey additions tend to reap high returns as you’re building one set of foundations and roof for potentially double the floor space than what you’d get with a single-storey structure.

If you’re looking to add value to your home, however, a loft conversion might be the best way to go. The costs will also be influenced by what you need to do to the existing structure, too, in terms of re-jigging the layout.

Learn more: How to Price Up Your Home Extension

3) Designing your extension

Building your extension in a straightforward shape will be cheaper to execute. The moment you start to add curved walls, clever angles or cantilevered structures, you can expect costs to rise.

This extension by Granit Architects was completed on a modest budget. To keep costs down, standard door sizes were specified. Photo: Andrew Beasley

4) Fixed-price design extensions

It’s hard to know how much your extension will cost, but an architect can help you determine the best areas to spend money for maximum wow factor. If you’re working to a tight budget, it makes sense to invest money in your architect at the pre-planning design stage of the project, rather than having them administer the contract later on.

“Like many practices we offer a fixed fee up to planning, before moving into something more bespoke after that,” says Simon Drayson, director at George & James Architects.

5) Get detailed drawings done

Spend plenty of time in the design phase to avoid headaches later. “At the early concept stage, we undertake a review of estimated costings on a m2 figure to ensure we’re not getting carried away with a design that’s going to be prohibitive,” says Ben Embrey, senior associate at Base Architecture.

6) Extension construction methods

Be sure to use a build method your contractor is familiar with to avoid having to go back and fix any mistakes later. “A traditional build of brick and block, or block and block with render is hard to beat in terms of cost efficiency,” says James from Granit. “The cost benefits of offsite construction kick in at larger scales.”

This compact extension was designed by A2studio. Stained vertical cladding was used to accent the part of the structure that projects out, providing wow factor without breaking the bank. Photo: Rick McCullagh

7) Put robust contacts into place

Even if you’re undertaking a small project, a large sum of money is going to change hands. A contract doesn’t have to be a vast tome – just a five-page document that outlines where you, the client, and your builder stand.

Having everything nailed down – particularly regarding when payments will be made and what happens in the event of any dispute – could pay dividends later.

8) Seek multiple contractor quotes

Obtain three to five quotes when you put the project out to tender – this will give you a good feel for the market rate for the job. Remember, though – cheapest isn’t always best.

If a quote looks too good to be true, ask yourself how the builder came to this sum and triple check the elements that are (and aren’t!) included.

9) Check what is covered by quotes

There’s a difference between getting an estimate for a job and getting a quote. “For quotes, you need to create a tender pack that includes architectural plans, technical plans, structural design, schedule of works and specification.

It should also have a list of client supply items and a pricing schedule against whish the builder will input prices,” says Johnny Lovett from Parkwood Builders.

“Sending out this information means all the invited builders have a standardised set of info and a pricing schedule to complete and you’ll get prices back in the same formatted document. This will make your tender analysis a lot simpler.”

10) Think twice before moving loadbearing walls

If your project involves drastic changes to the floorplan, consider the cost implications that will be involved in re-locating load bearing partitions. “This has significant cost,” says James Munro. “New steels or structural timber and associated works are much more work than re-plastering and decorating.”

11) Stick to your extension design

Making ad hoc alterations as you progress through the build may cause costs to spiral. “The golden rule of construction is not to change your mind once the building contract has been signed,” says Simon from George & James.

“It can lead to additional construction costs from the builder and professional fees from the architect, amongst others, for abortive or additional work.”

To keep costs down, the owners of this house tracked down some materials abroad. The parquet flooring establishes a luxurious aesthetic and was sourced for just £7 per m2. The project was delivered by Parkwood Builders

12) Re-use materials

As well as helping you save money on buying new items, recycling elements from your existing home will save on skip hire costs as you’ll be generating less waste. Bricks, roof tiles and slates could all be incorporated into your new extension. “For example, the table in my kitchen is made out of old decking joists with legs fabricated from the old garage purlins,” says Ben. “It cost me £30 in screws, paint and wood stain.”

13) Recycle your kitchen

The same logic applies to units and appliances – if they’re still in good condition, install your new kitchen-diner until your finances have recovered from the project. At that point, you’ll be in a better position to invest in a new suite.

14) Project management

Taking on this role yourself is one way to save pennies. However, don’t underestimate the time, skill and organisation that’ll be required to run the build effectively. If you’re working to a tight budget, it may be that you can share some of the management responsibilities with your contractor. The builder could manage construction until watertight stage, for instance, at which point you could take over and manage the rest of the sub-contractors.

15) Hire good builders & trades

This is probably one of the most important tips on this list. Hiring reputable professionals will save you pouring money down the drain on remedial work that might be needed to correct sub-standard jobs.

“Carry out pre-tender due diligence by researching builders in your area. Look out for those affiliated with trade organisations like the Federation of Master Builders,” says Johnny from Parkwood. “These companies have been through a stringent process to achieve accreditation.”

Read more: 15 Wow-Factor Kitchen Extensions