We’ve all been there. You’ve got three quotes for your home extension. Two of them are sitting in the same ballpark, and then there’s the third one. It’s significantly lower. Maybe £15k or £20k lower. It’s tempting to grab it, sign the contract, and start dreaming about how you’ll spend that “saved” cash on a high-end sofa or a fancy range cooker.
But at Force Builders, we often get the phone call six months later. And it’s usually a rescue mission.
The “Ghost” Materials
When a quote looks too good to be true, it’s usually because the builder hasn’t actually accounted for everything. A common trick? Leaving out the “muck away” costs or using sub-par insulation that barely meets building regs.
If your builder isn’t specifying exactly what grade of timber or what type of glazing they’re using, they aren’t saving you money—they’re just pushing the cost further down the line. You’ll end up paying for it in heating bills or, worse, structural repairs in three years’ time.
The “One-Man Band” vs. A Managed Site
A low-ball quote often comes from guys who don’t have proper insurance, a dedicated project manager, or a reliable chain of subcontractors.
Here’s what happens on a “cheap” job:
- The “Monday Disappearance”: Your builder doesn’t show up because he’s had to jump on another small job to cover his cash flow.
- The “Variation” Trap: They start the job cheap, but every time they pick up a hammer, it’s an “extra.” By the time you’re done, that cheap quote has bloated past the professional one you rejected.
- Zero Aftercare: Good luck getting them back to fix a leaking pipe once the final invoice is paid.
Quality isn’t a luxury—it’s an investment
Building in the UK isn’t getting any easier. Between stricter SAP 10.3 energy ratings and the rising cost of decent structural steel, the numbers have to add up. If a builder is quoting you 2021 prices in 2026, they’re either cutting corners or they don’t understand their own overheads. Both scenarios are a nightmare for you.
Bottom line: A professional quote should be detailed enough to make your head spin. If it’s just two lines on a piece of paper saying “Extension – £50,000,” run a mile.
We’d rather be honest with you about the costs upfront than give you a “fairytale” price and leave you with a half-finished shell of a house. It’s your home—don’t gamble with the foundations.