Conservatory Roof Repairs or Full Replacement? Making the Right Investment Decision
A complete guide for Kent homeowners: When to repair, when to replace, and how to protect your investment.
The Bottom Line
Repair makes sense for conservatories under 10 years old with sound structures—professional cleaning extends life while you plan ahead.
Replacement wins financially for conservatories 15+ years old. A solid roof costs £12k-£16k but adds £20k-£28k to property value, saves £400+/year on heating, and transforms the space into year-round living.
Key metric: Solid roofs achieve U-values of 0.15 W/m²K vs 2.4 W/m²K for old polycarbonate—15x better insulation.
How to Tell If Your Conservatory Roof Needs Attention
Before spending money on repairs or replacement, you need to understand what is actually wrong with your existing roof. The symptoms you can see often point to deeper issues that simple cleaning will not fix.
Problems with Polycarbonate Roofs
Polycarbonate was the go-to material for conservatory roofs throughout the 1990s and 2000s. It was cheap, lightweight, and easy to install. The problem is that polycarbonate has a functional lifespan of roughly 10 to 15 years before it starts to break down.
The breakdown happens at a chemical level. UV radiation attacks the polymer chains, causing photo-oxidation. You’ll notice this first as yellowing or clouding of the panels. Many homeowners assume their roof is just dirty, but this discoloration is the material changing at a molecular level. No amount of cleaning will reverse it.
⚠️ Coastal Properties Beware
If you live near the Kent coast—around Whitstable, Margate, or Dover—degradation happens faster. Salt spray from the sea acts like sandpaper on the surface, creating tiny scratches that trap dirt and algae while accelerating the breakdown of the UV protective layer.
Problems with Glass Roofs
Glass roofs last longer than polycarbonate, typically 20 to 25 years, but they fail in different ways. The main issue is seal failure between the two panes of double-glazed units.
Once a seal fails, moisture gets inside the unit. You’ll see this as condensation or misting between the panes—what the trade calls a “blown unit.” This isn’t just ugly. The insulating gas escapes, the desiccant becomes saturated, and the thermal performance collapses.
The Hidden Damage Behind Leaks
Water dripping into your conservatory is the most common reason people call for repairs. But the visible leak is usually just a fraction of the water getting into the structure. Water travels along internal channels of glazing bars, often ending up far from where it entered.
This is why repeated repairs to persistent leaks often represent wasted money. You’re treating the symptom while the underlying problem continues to get worse.
Quick Diagnosis Guide
Use this guide to assess what your symptoms actually mean and whether repair or replacement makes more sense.
| What You See | What It Means | Can Repair Help? | Replacement Needed? |
|---|---|---|---|
| Yellowing/clouding | UV damage to polycarbonate | Temporary improvement only | Yes, if panels brittle |
| Misted glass units | Seal failure, moisture inside | Individual units can be replaced | Yes, if >30% affected |
| Leaks at glazing bars | Degraded rubber gaskets | Yes, gasket replacement | Yes, if leaks return |
| Sagging or bowing | Structural failure | No—safety issue | Mandatory |
| Extreme temps | Poor insulation, heat loss | Minor improvement only | Yes, main upgrade reason |
| Mould on ring beam | Cold bridging, condensation | Cleaning removes mould only | Yes, need better insulation |
Professional Cleaning and Maintenance
For conservatories that are structurally sound—typically those under 10 years old or built with high-quality aluminium frames—professional cleaning and maintenance can add years of life. This approach is different from basic window cleaning.
What Professional Grooming Includes
- Pure Water Systems: Purified water fed through pole systems dries without residue, unlike tap water which leaves mineral deposits
- No Pressure Washers: High-pressure can blast open weather seals and force water into internal channels
- Frame Restoration: Specialist products remove oxidation and restore original brightness to uPVC
- Track & Hinge Maintenance: Vacuuming, cleaning, and lubricating moving parts
- Seal Treatment: Silicone-based lubricants keep rubber seals pliable
- Gutter Clearance: Blocked gutters cause more damage than most people realise
Professional Cleaning Costs (2026)
| Service | What’s Included | Cost Range | Frequency |
|---|---|---|---|
| Standard Exterior Clean | Glass, polycarbonate, external frames | £125 – £195 | Quarterly |
| Roof Only Clean | Roof panels and decorative finials | £10 – £15 per panel | Twice yearly |
| Full Valet (Deep Clean) | Complete interior/exterior, gutters, frame restoration, seals | £475 – £650 | Annually |
| Gutter Clearance | Removal of debris from gutters and downpipes | £40 – £80 | Twice yearly |
| Frame Restoration | Chemical treatment for discoloured uPVC or aluminium | £100 – £300 | As needed |
The Limits of Grooming
Professional cleaning keeps your conservatory looking good and prevents water damage, but it cannot change the fundamental thermal performance of the roof. A spotlessly clean polycarbonate roof still has a U-value of around 2.4 W/m²K—poor by modern standards.
Professional grooming is the right choice for maintaining a younger conservatory, preparing for sale, or keeping costs down when thermal performance isn’t a priority.
When Replacement Makes More Sense
When your goal shifts from maintaining what you have to genuinely improving performance, roof replacement becomes the obvious choice. The market for replacement conservatory roofs has matured considerably, and homeowners now have access to materials that transform conservatories into year-round rooms.
Understanding Thermal Performance
The key metric for roof performance is the U-value, which measures how much heat escapes through the material. Lower numbers mean better insulation. Here’s how different options compare:
The difference is stark. A solid roof loses heat more than 15 times slower than an old polycarbonate roof. This fundamentally changes whether the room is comfortable to use in winter without running expensive heating constantly.
Replacement Options Compared
| Feature | Polycarbonate | High-Spec Glass | Solid Tiled Roof |
|---|---|---|---|
| Cost (4m x 4m) | £2,700 – £4,000 | £3,200 – £4,800 | £12,000 – £16,000 |
| U-Value | 1.6 – 2.4 (Poor) | 1.0 – 1.2 (OK) | 0.12 – 0.18 (Excellent) |
| Lifespan | 10 – 15 years | 20 – 25 years | 50+ years |
| Rain Noise | Poor (loud) | Good (reduced) | Excellent (silent) |
| Light Transmission | Good | Excellent | None (solid) |
| Value Added | Neutral/Negative | Slight Positive | Significant Positive |
⚠️ Warning: Avoid “Clad-Over” Systems
Some contractors offer a cheap alternative called clad-over, which involves fixing insulation and timber directly over the existing polycarbonate without removing it. This is dangerous:
- Adds weight to frames designed only for lightweight plastic
- Traps moisture that causes rot
- Creates fire risks
- Does not meet Building Regulations
Any reputable installer will remove the old roof completely.
The Financial Case: Repair vs Replace
This needs to be viewed as a financial decision, not just a maintenance one. While replacement costs more upfront, the ongoing costs of keeping an inefficient roof can be substantial.
The Hidden Cost of Poor Insulation
A conservatory with a polycarbonate roof acts like a giant heat sink in winter. It draws warmth from your house and dumps it outside. Government energy data suggests this can add over £400 per year to your heating bills. Over a decade, that’s £4,000 or more—before you count recurring cleaning and repairs.
What Does Your Conservatory Add to Property Value?
This is where the numbers get interesting. Surveyors acting for mortgage lenders often value traditional polycarbonate conservatories at zero. They’re viewed as temporary structures. In some cases, a run-down conservatory is seen as a liability, with removal costs factored into the valuation.
A conservatory with a certified solid roof, Building Regulations approval, and high thermal performance is different entirely. Agents often reclassify these as habitable rooms or single-storey extensions. In Kent and the South East, this can add 5% to 7% to total property value.
A Real-World Comparison
Consider a typical detached property in Kent with a 12 square metre conservatory:
❌ Scenario A: Groom and Repair
✓ Scenario B: Solid Roof Replacement
The Message Is Clear
Repair consumes money without building value. Replacement requires capital but generates wealth.
The £14,900 difference between scenarios isn’t just about comfort—it’s about whether your conservatory is a liability or an asset.
Planning and Building Regulations in Kent
For homeowners in Kent, there are specific requirements you need to understand before starting work.
Building Regulations: When They Apply
Changing from a translucent roof to solid material counts as a material alteration under Building Regulations. You must obtain Building Control sign-off.
This involves proving: (1) the existing foundations and frames can support the new roof weight, and (2) the new roof meets Part L thermal standards—typically a U-value below 0.18 W/m²K.
⚠️ Kent-Specific Planning Rules
Canterbury City Council and Dover District Council have implemented Article 4 Directions in numerous Conservation Areas, including parts of Dour Street in Dover, Middle Street in Deal, and Canterbury city centre.
In Article 4 areas, any external alteration—including changing roofing materials—requires full planning permission. Councils may refuse solid roofs if they harm visual character. Check GIS maps before ordering materials.
Special Considerations for Coastal Properties
Kent’s extensive coastline introduces environmental challenges. If you live within five miles of the sea, these factors affect your choices:
- Salt Spray Damage: Replace standard steel screws and hinges with marine-grade stainless steel. Ask for marine-grade powder coating (60+ microns) on aluminium components.
- Wind Loading: Coastal areas around Dover and Folkestone experience higher wind loads. Solid roofs offer superior resistance to wind uplift and eliminate wind noise.
Making Your Decision
The right choice depends on your specific circumstances. Here’s how to think about it:
🔧 Choose Grooming & Maintenance If:
- Your conservatory is less than 10 years old
- The structure is sound with no sagging or warping
- You have a limited budget
- You’re preparing to sell and want a quick cosmetic improvement
- You only use the space seasonally and thermal performance isn’t a priority
✓ Choose Solid Roof Replacement If:
- You plan to stay in the property for 5+ years
- You want genuine year-round usability
- Your conservatory is older than 15 years with recurring repair costs
- You want to add genuine value to your property
- You live in a high-value area where the investment will be recouped through equity
🪟 Choose High-Performance Glass If:
- You need to preserve natural light
- Your conservatory is north-facing
- You live in a conservation area where solid roofs may not receive approval
- You’re upgrading from old materials and want improved thermal performance without losing the glazed feel
The Key Takeaway
Whatever you decide, the key is making an active choice rather than drifting into repeated repairs that consume money without building value. For homeowners in Kent and surrounding areas, understanding the specific planning constraints and coastal conditions in your location should inform that decision.
Frequently Asked Questions
How long does a polycarbonate roof last?
Polycarbonate roofs have a functional lifespan of 10-15 years. After this, UV degradation causes yellowing, clouding, and brittleness. In coastal areas where salt spray accelerates degradation, the lifespan may be shorter.
How much does conservatory roof replacement cost?
For a typical 4m x 4m conservatory in 2026: polycarbonate £2,700-£4,000, high-performance glass £3,200-£4,800, solid tiled roof £12,000-£16,000. Prices include installation, Building Control fees, and internal finishing.
Do I need Building Regulations approval?
If replacing a translucent roof with a solid tiled roof, yes. This is classified as a material alteration requiring Building Control sign-off. You need to demonstrate structural support capability and Part L thermal compliance (U-value below 0.18 W/m²K).
Does a conservatory add value to my house?
Traditional polycarbonate conservatories are often valued at zero by mortgage surveyors. A conservatory with a solid roof, Building Regulations approval, and high thermal performance can add 5-7% to property value in the South East.
Why is my conservatory too hot in summer and too cold in winter?
Poor insulation. Polycarbonate and older double glazing have high U-values, meaning heat passes through easily. In summer, solar radiation creates a greenhouse effect. In winter, heat escapes rapidly. Only roof replacement properly fixes this.
Can I use a pressure washer on my conservatory?
No. High pressure can blast open weather seals, dislodge glazing tapes, and force water into internal channels—creating the very leaks you’re trying to prevent. Professional cleaners use pure water fed pole systems instead.
How long does roof replacement take?
A straightforward replacement typically takes 5-10 working days. This includes removing the old roof, installing the new structure, adding insulation, and completing internal finishing. Most work can proceed regardless of weather.
Will a new roof affect my EPC rating?
Yes, positively. A thermally inefficient conservatory drags down your EPC score. Upgrading to a highly insulated solid roof improves energy efficiency ratings. Some lenders offer preferential green mortgage rates for energy-efficient homes.
Ready to Transform Your Conservatory?
Whether you need professional cleaning to maintain your existing conservatory or you’re ready to explore replacement options, our team covers Kent and the South East with expert advice tailored to your situation.
