4 Top tips to stay on budget when extending your home
Extending your home is an exciting project, but it can quickly become a financial nightmare if the process is not planned carefully. Here are our 4 top tips to help you stay on budget and ensure your home extension goes smoothly without unexpected financial stress.
1/ Assess what you really need from the beginning
Take the time from the outset to clearly define what you need from your home extension, thinking about what what currently does and doesn’t work both spatially and functionally. Consider how you will use the new space and what features are most important to you. At 4 S Architecture we can assist with this as we are experts at spatial analysis and distilling a wide range of aspirations into a concise architectural brief. A smaller footprint than you originally thought may be sufficient, for instance, to meet your needs while allowing you to allocate your budget to higher-quality finishes.
Figure 1: Our Zig Zag House in South London features space, light along with high quality flooring, joinery and worktop finishes to meet the needs of the family. Image credit: Henry Woide.
2/ Set aside a 15% contingency budget
While we endeavour to reduce risk of unexpected issues on site through early surveys, construction projects are however notorious for unforeseen issues, and material and labour costs often increase because of political or supply chain issues beyond a contractor’s control. We therefore recommend you set aside a 15% contingency fund on top of your estimated construction costs. This extra buffer will help cover unforeseen site conditions, price increases on materials, and minor changes in the project scope as it progresses. By planning for these potential costs from the outset, you'll avoid financial surprises and ensure your project stays on budget.
Figure 2: Extra contingency was set aside on our Secret Garden house to deal with potential issues related to unexpected underground drainage and ground conditions.
3/ Avoid mid-project changes
Once construction has started, try very hard not to change your mind. Changes made on-site are significantly more expensive than those made during the planning phase. Last-minute alterations can cause delays, increase labour costs, and lead to wasted materials. To prevent this, make sure all decisions are finalised before the first brick is laid.
Figure 3: Our client initially thought they wanted more space, but ended up keeping the footprint small and using the budget on quality finishes. Image credit: Henry Woide.
4/ Allow for VAT and consultant fees
Figure 4: Consultants on our secret garden house in addition to us as the architect included a structural engineer, an ecologist, an underground drainage engineer, and a garden designer.
It’s crucial to remember that construction costs and consultant fees are usually quoted exclusive of VAT so don’t forget to allow 20% for VAT. Consultant fees (including architectural fees) tend to be around 20% of the construction budget so you’ll need to factor that into your overall project budget to cover fees for a structural engineer, party wall surveyor, measured surveyor, underground drainage engineer and a garden designer. A quantity surveyor could also be appointed if you want more cost certainty before developing the detailed technical drawings. Properly accounting for these expenses will give you a more accurate picture of the total cost of your project and help you avoid budget shortfalls.
By carefully assessing your needs up-front, setting aside a contingency and a consultant budget, and avoiding changes during construction you can keep your home extension project on budget.
Please contact us if you would like to work with us on your home extension project. Our design slots are currently fully booked, but we are taking bookings for early 2025.