The cheapest quote is almost never the cheapest job. After twenty-five years of building across the West Midlands, we have seen more “bargain” extensions turn into £40k overruns than we care to remember. Here is what really drives cheap quotes, and what to look for instead.
Where cheap quotes hide the money
PC sums and provisional sums
“PC sum of £5,000 for kitchen” means the builder has budgeted £5,000 for your kitchen but the actual figure will be whatever you spend. If your dream kitchen is £18k, that’s a £13k variation added to the “fixed” price. Some cheap quotes hide behind PC sums for tiles, flooring, sanitary ware, lighting and kitchens — adding up to tens of thousands of add-ons.
“Not included” lists
Check what is explicitly excluded from the quote. A common trick is to exclude “making good the existing house”. Then you get charged extra when the render around your new extension needs redoing.
No structural engineer allowance
Any extension with load-bearing changes needs a structural engineer (typically £600–£1,500). If the quote doesn’t include this line item, you will be paying it separately.
No party wall allowance
If your build affects a shared wall, you need party wall notices and possibly surveyors. Fees range from £750 to £3,000 depending on complexity.
Waste removal and skip hire
Cheap quotes sometimes exclude waste removal. On a typical extension you generate 3–5 skip-loads of waste, at £250–£400 each.
Value engineering that becomes value destruction
The cheap quote may use budget bi-fold doors that lock badly, thinner insulation that fails Building Regs, and PC-sum kitchens from budget lines. You end up with a build that meets the price but not the standard.
What a proper fixed-price quote looks like
Our quotes include:
- Detailed line-by-line breakdown by trade
- Every material and finish specified by brand and model
- All planning, Building Regs, structural engineer and party wall fees
- Waste removal and skip hire
- Making good of existing house where new meets old
- Full VAT breakdown
- Payment schedule tied to build stages
- Contingency stated separately, spent only with agreement
The variation clause: read the small print
Every fixed-price contract has a variation clause. Read it. Ours allows variations only where:
- You request a change to the specification (you asked for a different kitchen brand)
- Something genuinely unforeseen is discovered (rotten joists behind existing plaster)
- You change the scope (added a downstairs cloakroom)
Anything discovered because we did not survey properly is our problem, not yours.
What we hear from clients who used cheaper builders first
- “The final bill was £20k more than the quote”
- “They walked off site when we questioned an invoice”
- “The plasterer never came back to snag”
- “Six months later the roof was leaking”
Fixing bad building work is always more expensive than doing it properly first time.
The real cost calculation
When comparing quotes, mentally add:
- +£5k–£15k for likely undisclosed extras
- +£2k for professional fees typically excluded
- +£1k–£2k for waste removal
- +£10k–£30k for likely remedial work over 5 years
Once you do that, the “cheap” quote is often the most expensive.
Free honest quote
We provide fully itemised fixed-price quotes across Redditch, Birmingham, Solihull and Warwickshire. If we can’t do the job for the price we quote, we won’t quote for it. Contact CK Construction on 01527 521835 or use our contact form.
Serving homeowners across Worcestershire, West Midlands, Gloucestershire and the wider region.