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How to Cut the Cost of Your Extension Project

Building an extension can be a tricky balancing act between creating a space you love and sticking to a tight budget. However, with some careful planning, you can achieve both. Below are some essential tips on how you can avoid spiralling costs on your project.

Professional advice from: Chris McIvor B.SC (Hons)

Plan ahead “Careful planning is key to controlling costs,” says Chris McIvor. “It prevents unnecessary expense further down the line.

“Pay particular attention to mechanical and electrical planning, such as where power outlets and sockets go,” he says. “The cost of moving these around later on in the development often catches people out – and can quickly escalate.”

📷 Brosh Architects Set your own costs Georgie Noone recommends you establish your own budget right from the start. “It sounds simple,” she says, “but going into a project with a realistic and affordable self-budget will make everything else that follows easier.”

Allocate budgets “Be very clear in your contractual agreement exactly how much is being allocated to every aspect of the project,” Chris advises. “Even if you haven’t yet chosen the worktop, for example, allocate a budget for it.

“This not only keeps you focused on your total spend,” he says, “it also helps prevent you from using the money elsewhere – it’s spoken for.”

“Once you’ve employed your design and build professional, the exact budget for your project needs to be agreed, in writing.

“You should be given a full breakdown of costs relating to this budget, as well as a schedule of works, so you know how the project will be run and within what timeframe,” she says. “Once a contract is in place, the design and build professional has to deliver the project on budget and on time.”

📷 L&E (Lofts and Extensions) Communicate clearly Georgie stresses the importance of communication throughout your extension project. “In my opinion, this is the most crucial point,” she says. “Communication needs to be open and transparent. You want to understand every step, and any potential unavoidable deviations from the original plan.”

If you’ve employed a project manager, they need to “clearly understand your thought process and react to your changing needs,” she adds. “Any changes normally impact on the budget, so they need to be discussed and agreed in writing.”

Her advice is to be proactive and inquisitive throughout your project. “Check in frequently, and don’t be afraid to question things,” she says. “This is your extension.”

Don’t overextend We often think bigger is better when planning an extension, but our experts advise caution if you want to stay on budget. “It’s important not to overextend and blow your entire budget on the biggest extension,” Leena Tulsidas says. “You also want to ensure the costs don’t outweigh the profit gained when selling.”

She recommends you think about maximising your existing space, too. “While extending your property, you should also consider how the rest of your ground floor will be used,” she says. “If you’re likely to be left with unused space, you may want to think about how you can use that area efficiently and incorporate it into your extension.”

📷 David Butler Photography Consider the structure Leena points out that both the size and design of your extension can impact on structural costs. “If you’re building a large or long extension, you may require much larger steel beams to provide the necessary support. The larger the beams get, the larger the costs,” he says.

“Speak with your designer or structural engineer to see whether there’s a solution that uses shorter steels, or doesn’t require as many,” she advises. “You can keep this in mind right from the get-go when designing your new space.”

📷 Trevor Brown Architect Choose wisely A smart way to stay on budget is to think carefully about which elements you want to spend more on. “There are ways of compromising without necessarily appearing to compromise,” says Chris.

“For example, you could select a simple, cheaper kitchen cupboard but choose not to compromise on your worksurface, as this will help deliver the wow factor you want,” she says.

“Trust me,” she adds, “if the worktop is impactful, no one will even notice the cupboard, which is essentially a box below it.” 📷 VELUX Work out your windows Glazing is another area where you can compromise. “This can be an expensive aspect of the build, so use a mixture of aluminium and uPVC cleverly,” Katie advises. “Bifold doors over a certain size should be aluminium, but windows can be uPVC to keep costs in hand.”

Leena agrees and says, expensive than traditional materials, such as bricks and blockwork, especially when working with large, bespoke sizes.

“If you’re trying to maximise the amount of glazing while keeping the costs down,” she adds, “look into openings and skylights that come in standard sizes. You’d be surprised at the effect a large roof window can have on your room, and, if finished well, it certainly doesn’t have to look like the budget option.”

📷 Stephen Turvil Architects Talk to your neighbours If your extension requires consent from your neighbours, it’s worth talking to them right from the start. “Dissent from neighbours can increase the costs, as they’re able to appoint their own independent surveyors, whose costs you will be liable for,” says Leena.

“You can save money by talking to them about your scheme and understanding any concerns they may have, so you can address them beforehand.”

📷 Magic Projects London Ltd Think long-term When you’re working out your budget, also consider any extra outlays that could arise later on. “The price of extending doesn’t only include those immediate design and build costs,” says Leena. “You can save money in the long run by doing things efficiently from the start.”

She recommends you make sure your contractors are experienced and skilled. “Incompetent builders can leave you with problems later on,” she says, “costing you more than doing it to a high standard the first time.”

Also consider your energy costs. “Insulating and draughtproofing your home will protect it against heat loss,” Leena says. “Double glazing is also effective for retaining heat, which can save you some money on the heating bills.”

Lastly, she suggests opting for more energy-efficient appliances. “Although these appliances have a high initial cost, you will most certainly get the return on them,” she says.

Tell us… Are you planning to extend your home? Will you be following any of these tips to stay on budget, or do you have any extra advice of your own? Share your thoughts, ideas and tips in the Comments section.


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