Top 5 Hidden Building Costs Homeowners Often Forget
When you’re planning a building project, it’s natural to focus on the more obvious, big ticket items — construction quotes, kitchen and bathroom fittings, maybe even those super drool-worthy sliding doors. But some of the biggest project stresses come from the small (but essential) costs that aren’t always obvious – or even thought about at the start…before you even get to the fun of deciding where your kettle is going to sit in your new kitchen (or if you’re going to have a boiling water tap!).
Here are five hidden costs that catch many homeowners by surprise — and how you can plan for them from day one.
1. Professional Fees and Surveys
Other than your architect’s fee, you may also need to budget for other professionals, such as a:
- Measured survey
- Structural engineer
- Energy assessor
- Ecologist
- Arboriculturalist
- Planning consultant
- Planning application fees
- Building Control fees
- Party Wall surveyor
Some surveys — like asbestos surveys, drainage surveys or soil tests — may also be necessary depending on your site.
Your architect should be able to give you an indication of which consultants are likely to be needed, at your very first meeting. Sometimes there are surprises, but an experienced and knowledgeable architect should have a pretty good idea.
Ask early for a full breakdown of likely professional fees, so you can factor them into your budget.
2. Site Set Up and Access Costs
Before the builder can even start, the site might need clearing, fencing or even temporary roadways for heavy vehicles.
If access is tight (say, through a terraced house), you might need specialist equipment or extra labour — which is rarely cheap.
A good builder and architect will flag access issues during the design stage to avoid last minute headaches.
3. Service Connections and Upgrades
If you’re planning on enjoying a fully automated home, you might even need to upgrade your electricity supply to 3 phase! While this isn’t really the norm – many projects do need changes to water, electricity or gas supplies.
Upgrading a consumer unit (distribution board), moving a gas meter or connecting to a new drain run can cost hundreds — or thousands — and sometimes isn’t included in a builder’s basic quote.
If you’re extending, loft converting or remodelling significantly, assume some allowance for service upgrades.
4. VAT and Tax Surprises
VAT can be a major cost — and it applies differently depending on the nature of your project.
For example, most home extensions and renovations are subject to 20% VAT on labour and materials – but, some energy saving measures or conversions (like turning a non-residential building into a home) may qualify for a reduced rate.
We would consider it to be pretty unusual for a builder not to be VAT registered.
Always check whether quotes are including or excluding VAT – and please get professional advice (as in a VAT specialist accountant) to be sure about what rates apply to your specific project.
5. Contingency for Unexpected Works
Once the builder opens up walls, floors or roofs, expensive surprises often appear. These might be things such as: rotten timbers, old wiring, asbestos or unstable foundations.
We recommend a contingency allowance of at least 15% — and for good reason. It’s not pessimism, it’s for your protection.
If the contingency isn’t needed, it’s a real bonus. But if it is, you’ll be relieved that you planned ahead.
Building projects are exciting, but you will be less stressed in the long run if you start with a realistic expectation of where your numbers are heading.
By understanding the full financial picture — not just the obvious costs — you’ll be better equipped to make decisions calmly, confidently and without panic.
Our pre-design consultation meeting – with follow up fee proposal – is designed to give you a clear roadmap, including realistic costs, next steps and what to expect along the way.