Millions of UK homes have conservatories, and most of them are underused because the roof doesn’t work. Polycarbonate roofs turn the room into a greenhouse in summer and a fridge in winter. Old glass roofs leak or condense. If you’ve been using yours as junk-storage when you’d rather use it as a living room, the roof is almost always the problem.

Replacing the roof transforms the space at a fraction of the cost of a full extension. This guide explains the four main options, typical 2026 UK costs, and when each makes sense.

Typical UK conservatory roof replacement costs in 2026

Roof type	Typical cost (3×3m)	Typical cost (4×4m)	Installation time
Solid (tiled) roof	£7,500 – £11,000	£10,500 – £15,500	1-2 weeks
Warm roof (insulated, plaster ceiling)	£6,500 – £9,500	£9,000 – £13,000	1-2 weeks
Glass replacement (self-cleaning thermal)	£4,500 – £7,500	£6,500 – £10,000	2-3 days
Polycarbonate (basic like-for-like)	£2,500 – £4,000	£3,500 – £5,500	1-2 days

Per m² benchmarks: polycarbonate ~£280-£450; glass ~£500-£830; warm roof ~£720-£1,060; tiled solid roof ~£830-£1,220.

Solid / tiled roof — best thermal, most expensive

Lightweight tile system replacing the transparent roof entirely. Interior ceiling plastered, making the conservatory feel like a real extension. U-value 0.15-0.18 W/m²K — better than most external walls. Winter warmth excellent, summer heat gain eliminated.

Downsides: the space loses the skylight feel. Usually triggers Building Regulations because the space becomes a “real” extension — council fees + structural sign-off typically £500-£900 additional.

Best for: homeowners who want a year-round living room, don’t mind losing the skylight effect, have £8,000+ budget.

Warm roof — middle ground

Insulated roof panels with plaster ceiling inside. Not tiled exterior but significantly warmer than glass or polycarbonate. Exterior is GRP or insulated panel. Can include roof lights for partial skylight effect.

U-value around 0.18-0.22 W/m²K. Cheaper than solid by £1,000-£2,000. Increasingly popular middle choice.

Best for: good thermal performance, some skylight retention, budget £6,000-£9,000.

Glass replacement — keep the feel, add performance

Modern self-cleaning solar-control glass replaces the old roof. Insulating low-E double glazing cuts summer heat gain 40-60% and winter heat loss 30-40% vs old polycarbonate. Retains full skylight experience.

U-value 1.2-1.4 W/m²K — worse than solid/warm but dramatically better than existing polycarbonate (2.8-3.5).

Best for: you love the light and openness, want noticeable comfort improvement without full reroofing, budget £4,500-£7,500.

Polycarbonate — cheapest, shortest-term fix

Like-for-like polycarbonate replacement. Fixes leaks and yellowed panels. Doesn’t meaningfully improve thermal performance. If budget is the constraint, consider saving for another year and doing the glass replacement instead.

Best for: short-term ownership (moving within 2-3 years), strict budget.

Planning permission and Building Regs

• Glass replacement: usually still exempt (same classification as original)
• Polycarbonate replacement: still exempt
• Warm roof: borderline; depends on local Building Control. Usually OK as “replacement with equivalent function”
• Solid tiled roof: typically does require Building Regs approval because the space becomes a “real” extension. Your installer handles the application. Budget £500-£900 for council fee + structural sign-off

Planning permission rarely required unless property is listed, in conservation area, or the roof height increases.

Hidden costs to watch for

• Structural survey — many old conservatory bases can’t support a solid-tile roof without reinforcement. £200-£400 structural engineer visit
• Plaster ceiling — for solid or warm roof, interior plastering adds £500-£900
• Lighting relocation — existing wall lights typically need repositioning. £200-£400
• Scaffolding — most conservatory roof work needs scaffolding; confirm it’s in the quote
• Making good — external rendering or cladding where roof meets house wall. £200-£500

Frequently asked questions

How long does replacement take?

Polycarbonate: 1-2 days. Glass: 2-3 days. Warm or solid roof: 1-2 weeks. Furniture needs moving out of the conservatory during install; you can stay in the rest of the house.

Is a solid roof worth the extra over a warm roof?

Marginally. Tiled has 10-15% better thermal performance than warm roof and a different aesthetic (genuine tiles vs GRP panels). On a 3×3m conservatory the tiled version costs £1,500-£2,000 more for performance gains most homeowners won’t notice. Main reason to choose tiled is aesthetic — it looks like a real extension. If thermal comfort is the goal, warm roof is better value.

Will a solid roof reduce my home’s EPC rating?

Usually improves it — the conservatory becomes a heat-efficient space rather than a thermal liability. Specify the u-value of the new roof system so your EPC assessor can factor it in correctly on next assessment.

Can I DIY polycarbonate-to-solid roof conversion?

No. Structural change requires Building Control sign-off, proper structural calculations on existing base and frame, and FENSA / Building Regs notification. DIY puts you out of compliance, voids insurance, and blocks a future house sale.

Get four conservatory roof quotes

Conservatory roof work varies more than windows — installer experience matters. Findfitter matches with 4 local installers experienced specifically with conservatory roof replacement.

Sources

• UK Building Regulations on conservatory classification
• Energy Saving Trust — thermal performance data
• FENSA installer register