UK builders running Google Ads properly are achieving 45-180x ROAS on £20k extension queries (SEO For The Trade benchmarks). The wide range reflects account quality, not sector volatility. Well-run accounts targeting specific extension and renovation keywords with purpose-built landing pages convert at the high end. Poorly-run accounts waste budget on broad targeting and homepage destinations. The gap between the best and worst accounts in the same city is enormous.
This is the practical playbook for UK builder Google Ads in 2026. Real numbers, real campaign structures, and the specific moves that compound on builder accounts. Pairs with our builder sector page.
The 45-180x ROAS reality
The maths underpinning the headline:
- CPL on extension queries: £30-£70
- Conversion rate from lead to discovery call: 30-50% (high because the lead is high-intent)
- Conversion rate from discovery call to booked project: 20-40%
- Average extension project value: £20,000-£50,000
- Net effect: roughly £200-£800 of revenue per £1 of ad spend, depending on account discipline
The campaign structure that works
Campaign 1 · Emergency repair (small ticket)
Roof leaks, structural damage, urgent repairs. Smaller tickets (£500-£3,000) but fast conversion and high frequency. Anchors the account during slow seasons for big builds.
Campaign 2 · Planned work (large ticket)
Extensions, kitchen renovations, bathroom renovations, loft conversions, garage conversions. £20k+ tickets, longer buyer cycle, where the 45-180x ROAS lives. SKAGs (single keyword ad groups) cut CPC by 30-50% per SEO For The Trade analysis.
Campaign 3 · Area-specific
Geographic targeting in postcode-level concentric rings around the service area. Bid premium on the most competitive local terms; bid efficiently on the wider catchment.
Campaign 4 · Brand defence
Bidding on the business name. Cheap clicks, prevents competitors from intercepting branded traffic. 5% of budget.
Cost calculator landing pages
The single biggest unlock on UK builder Google Ads accounts is replacing static service pages with interactive cost calculators. The pattern:
- User lands on the page from a paid click
- Inputs: rough dimensions (m²), finish level (standard / premium / luxury), scope (single / double-storey / wraparound)
- Output: rough cost range ("£35,000-£55,000 for a single-storey extension at standard finish")
- Email gate: send the personalised PDF with breakdown, build timeline estimate, and your portfolio
Conversion rate from cost-calculator pages: 8-15% vs 2-4% on static service pages. The calculator captures the researcher who wasn't ready to fill a contact form but was happy to play with numbers.
The portfolio is the case
Outcome Marketing's analysis of 15 UK builder websites identified portfolio quality as the biggest differentiator. What works:
- Real photos of completed projects, not stock
- Before/after sliders on every project
- Project dimensions stated explicitly (3m x 4m extension, 60m² loft conversion)
- Rough cost ranges where you're comfortable publishing them
- Build duration stated ("completed in 8 weeks")
- Client testimonial from each project, short, named, dated
The 30-90 day buyer cycle
UK builder buyers don't convert in week 1. The average cycle from first ad click to booked project is 30-90 days. The implications for the marketing stack:
- Track conversions on a 90-day attribution window, not 30 days
- Build email nurture sequences that span 60+ days
- Retarget aggressively on Meta after the first website visit
- Use AI live chat to qualify and capture researchers who aren't ready to fill the form
- Patience: month 1 results aren't the picture; month 3 results are