Acryldach is a roofing system built from acrylic sheets — specifically PMMA (Polymethyl Methacrylate) — designed to let natural light flood a space while still providing full protection from rain, wind, and UV radiation. The word itself is German: “Acryl” means acrylic, “Dach” means roof. Put them together and you get a name that describes the product perfectly — a roof made of acrylic.
In plain terms, Acryldach is a “let the light in” roofing solution. It works especially well for patios, pergolas, carports, skylights, greenhouses, and commercial atriums — anywhere you want shelter without turning the space underneath into a dark, enclosed box. It transmits up to 92% of visible light, weighs roughly half as much as glass, and when properly installed with quality UV-coated panels, can last 20 to 30 years with minimal maintenance.
Quick Reference: Acryldach at a Glance
| Feature | Detail |
|---|---|
| Material | PMMA (Polymethyl Methacrylate) — acrylic |
| Light Transmission | Up to 92% |
| Weight vs. Glass | ~50% lighter |
| Impact Resistance | ~17x stronger than glass |
| Lifespan | 15–30 years (quality panels with UV coating) |
| Maintenance | Low — mild soap and water |
| Best Uses | Patios, pergolas, carports, skylights, greenhouses, atriums |
| Cost (materials) | £15–£50 per sq. metre depending on type and thickness |
| Eco Credentials | Recyclable in many regions; VOC-free manufacturing available |
| Key Risk | Thermal expansion — requires proper installation |
The Material Behind the Name: What Is PMMA?
PMMA — Polymethyl Methacrylate — is a transparent thermoplastic that most people know by its brand names: Plexiglas, Perspex, or ACRYLITE. It was first developed in the 1930s and has been used in architectural glazing, vehicle lighting, aquariums, and medical devices for decades.
What makes it compelling as a roofing material comes down to a handful of physical properties:
- It transmits up to 92% of visible light — higher than most standard glass
- It weighs 50% less than glass of equivalent thickness
- It is 10 to 20 times stronger than glass under moderate impact
- It has excellent UV stability — quality panels don’t yellow the way cheaper plastics do
- It does not rust, rot, or corrode — ever
The one behaviour that installers must account for is thermal expansion. PMMA expands and contracts significantly with temperature changes — its coefficient of linear thermal expansion sits around 90 to 110 × 10⁻⁶/K. That sounds technical, but the practical implication is simple: if you fix acrylic panels too rigidly, they crack. When installed correctly — with oversized mounting holes, appropriate edge clearances, and non-binding fasteners — that expansion is harmless. The roof moves a little. Nothing breaks.
Types of Acryldach Systems
There is no single Acryldach product. The term covers several distinct systems, each suited to different applications.
| Type | Structure | Best For |
|---|---|---|
| Solid flat sheets | Single layer, clear or tinted | Skylights, patio covers, balcony roofs |
| Corrugated panels | Wave-shaped for added rigidity | Sheds, warehouses, agricultural buildings |
| Multiwall / twinwall | Internal hollow chambers for insulation | Greenhouses, winter gardens, energy-conscious builds |
| Liquid PMMA coating | Applied cold, fast-curing membrane | Flat roofs, terraces, waterproofing existing roofs |
| Cast vs. extruded sheets | Cast = better clarity; extruded = more economical | Cast for visual quality; extruded for budget projects |
The distinction between cast and extruded sheets is worth understanding before you buy. Cast sheets are made by pouring liquid acrylic into moulds — the result is excellent optical clarity, better scratch resistance, and higher dimensional stability. Extruded sheets are manufactured through a continuous process, which makes them cheaper and more uniform in thickness, but they sacrifice some optical quality. For a patio roof where you just want light and weather protection, extruded works fine. For a feature skylight in a commercial space where clarity matters, cast is worth the premium.
Key Benefits: Why People Choose Acryldach
The reasons architects, contractors, and homeowners choose acrylic roofing over alternatives aren’t complicated. They stack up clearly:
Natural light. This is the primary reason. A patio with an Acryldach roof feels like outdoor living. An atrium under acrylic panels feels open. Spaces that would otherwise be dark and uninviting become genuinely pleasant to be in. Clear acrylic transmits 92% of visible light — comparable to the best low-iron glass but at a fraction of the weight and cost.
Weight savings. Glass roofing requires heavy framing and substantial structural support. Acrylic weighs half as much, which means lighter frames, simpler foundations, and lower total project costs. One documented European stadium project that switched from glass to acrylic roof panels ended up with a structure 40% lighter, requiring significantly fewer steel supports — with identical visual clarity for spectators.
Durability. Quality Acryldach panels handle rain, wind, hail (with appropriate thickness), UV radiation, and temperature swings without structural deterioration. They don’t rust. They don’t rot. They don’t corrode. The main enemy is poor-quality panels without proper UV stabilization — those yellow over time and destroy the whole point. Buy quality and the material outlasts most alternatives.
Low maintenance. Mild soap and water is genuinely all the cleaning an Acryldach roof needs. No specialist products, no annual treatments, no professional maintenance contracts.
Design flexibility. PMMA can be cut, shaped, tinted, frosted, or patterned. You can specify panels in clear, opal, bronze, blue, green, or custom tints. Frosted and prismatic options distribute light evenly, which is useful for reducing glare in commercial spaces. Curved sections are achievable in ways that glass simply cannot match cost-effectively.
Acryldach vs. The Competition
Before committing to any roofing material, the honest comparison matters.
| Feature | Acryldach (PMMA) | Glass | Polycarbonate | Metal |
|---|---|---|---|---|
| Light Transmission | Up to 92% | ~90% | 75–88% | None (opaque) |
| Weight | Low (50% of glass) | High | Very low | Medium |
| Impact Resistance | Moderate (17x glass) | Low | Very high (250x glass) | High |
| Scratch Resistance | Good | Excellent | Poor | Good |
| UV Stability | Excellent (quality panels) | Excellent | Fair (degrades faster) | N/A |
| Thermal Expansion | High — needs allowance | Low | Very high | Medium |
| Insulation | Moderate (better multiwall) | Good (IGU) | Similar to acrylic | Good |
| Lifespan | 15–30 years | 25–30+ years | 10–15 years | 30–50 years |
| Cost | Medium | High | Low–medium | Medium–high |
| Maintenance | Very low | Low | Low | Low |
The polycarbonate comparison is the one that causes most confusion because both materials look similar and appear in the same applications. Polycarbonate is tougher — significantly so, roughly 250 times the impact resistance of glass versus acrylic’s 17 times. In areas with severe hailstorms or heavy debris risk, that matters. However, acrylic wins on optical clarity, scratch resistance, long-term UV stability, and weather appearance. Polycarbonate degrades and yellows faster than quality UV-stabilized acrylic. If you’re choosing between them for a patio or greenhouse, and impact resistance isn’t the dominant concern, acrylic typically looks better for longer.
Where Is It Actually Used?
The application range is broader than most people expect.
| Application | Type of Use | Panel Choice |
|---|---|---|
| Residential patio covers | Shelter with light | Clear flat or corrugated |
| Pergolas | Partial shelter, aesthetics | Clear or tinted flat sheets |
| Carports | Weather protection, light | Corrugated or flat |
| Sunrooms / conservatories | Year-round living space | Multiwall for insulation |
| Skylights | Roof lighting | Cast flat sheets |
| Greenhouses | Maximum light, temperature control | Twinwall or multiwall |
| Commercial atriums | Design feature, daylighting | Clear flat sheets |
| Mall walkways and canopies | Covered passage with light | Flat or corrugated |
| Industrial rooflights | Daylighting reduces energy costs | Corrugated or flat |
| Transit shelters | Weather protection | Impact-resistant corrugated |
Greenhouses deserve particular mention. Twinwall and multiwall panels are the standard choice because the internal chambers provide both light diffusion and thermal insulation — two things plants need simultaneously. The diffused light that comes through multiwall panels is actually better for plant growth than direct sunlight through single-layer glass because it reaches leaves at multiple angles rather than creating hot spots.
Installation: What You Actually Need to Know
Installation is where Acryldach projects either succeed or fail — and most failures come from ignoring the thermal expansion issue.
The fundamental rules are:
Allow for movement. Drill holes larger than the fastener diameter. Leave edge clearances. Use non-binding fasteners with rubber washers. The panel needs to be able to slide slightly as temperatures change. A panel trapped rigidly in a frame on a hot summer day will crack. It is not a question of if — it is a question of when.
Match thickness to span. There is no universal answer to “what thickness do I need?” It depends on the span between supports, expected wind loads, likely debris impact, and local building codes. A 4mm panel works for short spans in sheltered areas. Longer spans or exposed locations need 6mm, 8mm, or thicker. Follow manufacturer specifications for your specific conditions.
Slope matters. Acryldach roofs need sufficient slope for water runoff. A minimum pitch of around 5 degrees is generally recommended. Flat or near-flat installations allow water pooling, which eventually causes problems regardless of how good the panels are.
Professional installation vs. DIY. Simple carport or patio cover projects with clear manufacturer guidelines are achievable for a competent DIYer. Complex rooflines, larger spans, and projects that need to meet building regulations are best handled professionally. The cost of getting the thermal expansion detail wrong — cracked panels, failed seals — is higher than the cost of a good installer.
Maintenance: Simpler Than You Think
This is one of Acryldach’s genuine strengths.
Clean it with warm water and a mild soap or dedicated plastic cleaner. Use a soft cloth or sponge — never abrasive pads, steel wool, or scouring agents, which scratch the surface permanently.
Things to avoid: solvent-based cleaners, petrol, window-cleaning products containing ammonia. These attack the acrylic surface and cause surface crazing over time.
Check the sealants and fixings annually. Acrylic itself doesn’t fail — sealants and fixings sometimes do after years of thermal cycling, and catching those early prevents water ingress.
With quality UV-stabilized panels and correct installation, you should expect a clear, well-functioning roof for 20 to 30 years.
Cost: What to Budget
Acryldach is not the cheapest roofing option upfront — but it’s not the most expensive either, and the lifecycle cost picture is genuinely competitive.
| Project Type | Estimated Materials Cost | Notes |
|---|---|---|
| Simple patio cover (20m²) | £300–£600 | Basic corrugated or flat panels |
| Pergola with tinted panels | £400–£900 | Tinting adds cost |
| Greenhouse (multiwall) | £600–£1,500 | Multiwall insulation panels |
| Commercial skylight | £1,500–£5,000+ | Cast sheets, professional fitting |
| Liquid PMMA flat roof coating | £50–£120 per m² | Installed cost including labour |
The gap between cheap and quality acrylic panels is significant. Budget panels without proper UV stabilization may cost 30–40% less at purchase but yellow within 5 to 7 years — at which point you’re replacing them anyway, having lost the light they were supposed to provide. Quality UV-stabilized panels from reputable manufacturers cost more upfront and last three to four times as long. The maths consistently favours the better product.
FAQs
What is Acryldach? It is a roofing system made from acrylic (PMMA) panels or coatings. The name comes from German — “Acryl” (acrylic) + “Dach” (roof). It provides weather protection while transmitting natural light.
How long does Acryldach last? Quality UV-stabilized panels last 20 to 30 years with proper installation and basic maintenance. Cheap panels without UV protection can yellow and degrade within 5 to 7 years.
Is Acryldach better than polycarbonate? It depends on the application. Acrylic offers better optical clarity, scratch resistance, and long-term UV stability. Polycarbonate offers higher impact resistance. For most residential and light commercial applications where clarity matters, quality acrylic is usually the better long-term choice.
Can I install Acryldach myself? Straightforward projects — patio covers, simple pergolas — are achievable for a competent DIYer following manufacturer guidelines carefully. The critical detail is allowing for thermal expansion in every fixing. Complex or large-span projects are better handled professionally.
How do I maintain an Acryldach roof? Warm water and mild soap, applied with a soft cloth. Check sealants and fixings annually. Avoid solvents, abrasives, and ammonia-based cleaners.
Is Acryldach eco-friendly? PMMA is recyclable in regions with facilities that accept it. Manufacturing can be VOC-free. By maximising natural daylight, an Acryldach roof reduces dependence on artificial lighting — which has genuine energy saving implications over decades of use.
What is the difference between cast and extruded acrylic panels? Cast panels offer better optical clarity and scratch resistance. Extruded panels are more economical and consistent in thickness. Choose cast for visual quality applications; extruded works well for functional weatherproofing where optical perfection matters less.
Conclusion
Acryldach is not a complicated concept. It’s a roof that lets light in. What makes it worth understanding is how well-engineered that simple idea has become — PMMA panels that transmit 92% of visible light, resist UV degradation for decades, weigh half what glass weighs, and ask almost nothing of you in return except an annual wipe-down and correctly installed fixings.
The market is moving in its direction. Architecture increasingly prioritises natural light, energy efficiency, and structures that feel open rather than enclosed. Acryldach delivers all three without the weight, cost, or complexity of glass alternatives.
The one lesson every installer eventually learns: give the panel room to breathe. Thermal expansion is not a flaw to be fought — it’s a property to be designed around. Do that correctly and an Acryldach roof will still be working beautifully twenty years from now, letting in the same 92% of light it did on the day it was installed.
