What Are the Disadvantages of Polycarbonate Sheets in South Africa
Polycarbonate sheets are one of the most widely specified glazing and covering materials across South Africa — and for good reason. Impact resistance, UV stability, thermal insulation, and lightweight construction make polycarbonate sheets an excellent choice for a wide range of roofing, glazing, greenhouse, and industrial applications across Johannesburg, Durban, and Cape Town.
But polycarbonate sheets are not the right material for every application. And at Allrich Trading — as one of South Africa's leading suppliers of polycarbonate sheets — we believe the most valuable thing we can do for our customers is give them an honest picture of both what polycarbonate sheets do well and where their limitations lie.
Understanding the disadvantages of polycarbonate sheets before you specify and purchase is how you avoid costly mistakes — wrong material for the wrong application, premature failure, and unnecessary replacement costs. This guide covers every significant disadvantage of polycarbonate sheets in the South African context — with practical guidance on how each limitation can be managed or avoided with the correct specification.
Why an Honest Disadvantages Guide Matters in South Africa
Most polycarbonate sheet content you will find in South Africa focuses exclusively on the benefits. That content is useful — but incomplete. The real test of a material is not how it performs in ideal conditions. It is how it performs under South Africa's specific challenges — extreme UV radiation, high summer temperatures, coastal salt air, sandstorm abrasion, and the wide temperature cycling between South African winter and summer.
In these conditions, some of polycarbonate's limitations become significantly more consequential than they would be in a milder climate. Understanding those limitations specifically in the South African context is what separates a successful polycarbonate sheet specification from one that disappoints within 12 to 24 months.
Disadvantages of Polycarbonate Sheets in South Africa
Disadvantage 1 — Susceptibility to Scratching
Polycarbonate sheets — particularly standard grades without hard-coat surface treatment — are significantly more susceptible to surface scratching than glass. The surface hardness of standard polycarbonate is relatively low compared to glass, acrylic, and other glazing alternatives.
Why this matters in South Africa: South Africa's sandstorm events — particularly in inland regions like Johannesburg and the Northern Cape — expose polycarbonate sheet surfaces to fine abrasive particles that cause micro-scratching over time. In coastal areas like Durban and Cape Town, wind-driven sand and salt particles create the same surface abrasion effect. Over months and years, this micro-scratching accumulates into visible surface haze that reduces light transmission and degrades the appearance of the polycarbonate sheet.
How to manage this limitation:
- Specify hard-coat treated polycarbonate sheets for any South African application where sandstorm or wind-driven particle abrasion is a risk
- Use soft, clean microfibre cloths for surface cleaning — never abrasive pads, brushes, or scouring agents
- Rinse polycarbonate sheet surfaces with clean water before wiping — never wipe a dry, dusty polycarbonate surface
- For applications where scratch resistance is critical — consider whether acrylic sheet or glass may be a more appropriate specification
Disadvantage 2 — Thermal Expansion and Contraction
Polycarbonate sheets have a significantly higher coefficient of thermal expansion than glass or aluminium. This means they expand and contract substantially with temperature changes — and South Africa's wide temperature range creates significant thermal movement demands on any polycarbonate sheet installation.
The numbers in South Africa's context: Polycarbonate sheet expands approximately 0.065mm per metre per degree Celsius of temperature change. In Johannesburg, where temperatures can range from below 5°C on winter nights to above 40°C on summer afternoons — a single sheet may expand and contract by 2.5mm or more per metre of panel length across the seasonal cycle. A 4-metre polycarbonate sheet panel in Johannesburg may move by 10mm or more across the annual temperature cycle.
Why this matters: If polycarbonate sheets are installed without adequate expansion gaps in their mounting systems — which is a very common installation error in South Africa — the thermal movement stresses the panel edges, distorts the mounting frame, and can cause cracking, buckling, or premature delamination of multiwall cells.
How to manage this limitation:
- Always allow the correct thermal expansion gap in any polycarbonate sheet mounting system — minimum 3mm per metre of panel length as a general guide
- Use flexible gaskets and sealants rated for thermal movement in polycarbonate sheet installations
- Never drill fixing holes in polycarbonate sheets without oversizing the hole to allow for thermal movement
- Work with Allrich Trading's technical team to confirm correct expansion allowances for your specific panel size and South African climate zone
Disadvantage 3 — UV Degradation Without Proper Coating
This is perhaps the most consequential disadvantage of polycarbonate sheets in the South African context — and it is one that is completely avoidable with correct specification.
Standard polycarbonate without UV-protective coating degrades rapidly under South Africa's extreme UV radiation. The degradation process — called photo-oxidation — causes the polycarbonate to yellow, become brittle, lose impact resistance, and eventually crack and crumble. In South Africa's high-UV environment, this process can reduce an unprotected polycarbonate sheet from clear and flexible to yellow and brittle within 12 to 24 months of outdoor exposure.
The two UV protection approaches:
Co-extruded UV coating: The UV-protective layer is permanently bonded to the polycarbonate sheet surface during manufacture — it cannot be removed, scratched off, or degraded independently of the polycarbonate itself. This is the correct specification for any South African outdoor polycarbonate sheet application. Allrich Trading supplies co-extruded UV-protected polycarbonate sheets as standard for outdoor applications.
Surface-applied UV coating: A UV-protective film or coating applied to the surface of the polycarbonate sheet after manufacture. This approach is significantly less durable — the coating can be removed during cleaning, scratched away during abrasion events, or delaminate from the polycarbonate surface. It is not recommended for South African outdoor applications.
How to manage this limitation:
- Always specify co-extruded UV-protected polycarbonate sheets for any South African outdoor application — never standard unprotected grades
- Confirm with your supplier that the UV protection is co-extruded — not surface-applied
- Allrich Trading supplies UV-protected polycarbonate sheets with the correct co-extruded specification for South African outdoor conditions
Disadvantage 4 — Lower Optical Clarity Than Glass or Acrylic
Polycarbonate sheets — even in clear grades — do not match the optical clarity of glass or high-quality acrylic sheet. Standard polycarbonate transmits approximately 85% to 88% of visible light compared to 92% for standard float glass. The polycarbonate also has a slight inherent yellowish tint in standard grades that becomes more noticeable over time as UV exposure causes gradual yellowing even in UV-protected grades.
Why this matters for South African applications: For applications where optical clarity is the primary requirement — display glazing, retail showcase glazing, or premium architectural glazing — polycarbonate's lower optical clarity is a genuine limitation. In these applications, glass or optical-grade acrylic is often a more appropriate specification.
When this disadvantage does NOT matter: For roofing, canopy glazing, greenhouse glazing, noise barriers, and industrial safety applications — where light transmission rather than optical precision is the requirement — the 5% to 7% difference in light transmission between polycarbonate and glass is not a meaningful disadvantage.
How to manage this limitation:
- For applications requiring maximum optical clarity — specify glass or optical-grade acrylic rather than polycarbonate
- For diffused light applications (greenhouse, canopy, skylight) — consider opal or diffused polycarbonate grades where even light distribution is more important than clarity
Disadvantage 5 — Chemical Sensitivity
Polycarbonate sheets are sensitive to a range of chemicals that are commonly encountered in South African commercial, industrial, and domestic environments. Certain solvents, cleaning agents, and adhesives can cause crazing, cracking, or permanent surface damage to polycarbonate sheets.
Chemicals that damage polycarbonate sheets:
- Aromatic solvents — benzene, toluene, xylene — damage the polycarbonate surface and cause crazing
- Ketone-based solvents — acetone, MEK — dissolve polycarbonate and cause rapid surface destruction
- Strong alkaline cleaning agents — cause surface etching and permanent cloudiness
- Many solvent-based adhesives and sealants — cause polycarbonate crazing at the bond line
- Petrol and diesel fuel — cause surface damage on prolonged contact
Why this matters in South Africa: South African industrial, agricultural, and commercial environments frequently involve chemical exposure — cleaning agents, fuel spills, agricultural chemicals, and industrial solvents. Standard polycarbonate sheets in these environments can be permanently damaged by routine chemical contact that would not affect glass or stainless steel alternatives.
How to manage this limitation:
- Always check chemical compatibility before cleaning polycarbonate sheets — use only mild soap solutions or specialist polycarbonate cleaning products
- Use only silicone-based sealants and polycarbonate-compatible adhesives in any polycarbonate sheet installation
- For chemically aggressive environments — consider whether polycarbonate is the appropriate material or whether PVC sheet or other chemically resistant alternatives are more suitable
Disadvantage 6 — Higher Cost Than Some Alternatives
Quality polycarbonate sheets — particularly co-extruded UV-protected multiwall grades from reputable manufacturers — carry a higher upfront cost than some alternative materials. This cost difference is particularly significant when compared to corrugated PVC sheeting or standard fibreglass panels used in some South African agricultural and industrial applications.
The total cost of ownership argument: The higher upfront cost of quality polycarbonate sheets is consistently justified by their longer service life, lower maintenance requirements, and significantly better performance — particularly in South Africa's demanding outdoor conditions. A cheap corrugated plastic roofing panel that fails within 3 years in a Durban coastal environment costs more in total than a quality polycarbonate sheet that lasts 10 to 15 years in the same conditions.
When cost is a genuine constraint: For very large-area, low-exposure applications — agricultural tunnels, temporary structures, and back-of-house industrial roofing — where the performance advantages of polycarbonate sheet over cheaper alternatives are not critical, the cost difference may be a valid specification consideration.
Disadvantage 7 — Flammability Compared to Glass
Standard polycarbonate sheets are combustible — they will burn when exposed to direct flame, though they do not support sustained burning and self-extinguish when the flame source is removed. This is a fundamental difference from glass, which is non-combustible.
South African building regulation implications: South African building regulations and fire codes specify non-combustible cladding and glazing materials for certain building types and locations — particularly in high-risk areas, areas adjacent to fire escapes, and buildings above certain occupancy classifications. Standard polycarbonate sheets do not meet non-combustible material specifications.
How to manage this limitation:
- Specify flame-retardant (FR) grade polycarbonate sheets where fire performance is a specification requirement
- FR-grade polycarbonate sheets significantly reduce combustibility and meet many South African building regulation fire performance requirements
- Always confirm fire performance requirements with your structural engineer or local municipality before specifying polycarbonate sheets on any building project
Disadvantage 8 — Surface Haze Over Time
Even with UV protection, polycarbonate sheets gradually develop surface haze over their lifespan — a slight reduction in light transmission and optical clarity caused by the cumulative effects of UV exposure, micro-abrasion, and surface oxidation. This haze is slow to develop under South African conditions with quality UV-protected polycarbonate — typically becoming noticeable only after 8 to 12 years of outdoor exposure.
Managing surface haze:
- Specialist polycarbonate restoration products can remove light surface haze and restore optical clarity
- Regular cleaning with appropriate products slows haze development
- Hard-coat treated polycarbonate sheets develop haze significantly more slowly than standard grades — the harder surface resists micro-abrasion that contributes to haze formation
When Polycarbonate Sheets ARE the Right Choice Despite These Disadvantages
Understanding polycarbonate's disadvantages does not mean avoiding polycarbonate — it means specifying it correctly for the right applications. Polycarbonate sheets remain the best available material for many South African applications despite these limitations:
Where polycarbonate sheets remain the correct specification:
- Roofing and canopy systems where impact resistance, lightweight construction, and thermal insulation are primary requirements
- Greenhouse glazing where diffused light transmission, impact resistance, and thermal performance matter more than optical clarity
- Industrial machine guarding where impact resistance and operator visibility are both required
- Noise barrier systems where transparency, impact resistance, and lightweight construction are all needed simultaneously
- Any application where glass breakage risk makes glass an unsafe specification
Polycarbonate Sheet Supply Across Johannesburg, Durban and Cape Town
Johannesburg's high UV intensity, extreme temperature cycling, and dust/sandstorm conditions make correct polycarbonate sheet specification particularly important. The scratching, thermal expansion, and UV degradation disadvantages are all amplified in Johannesburg's inland environment. Allrich Trading supplies UV-protected, hard-coat treated polycarbonate sheets to Johannesburg buyers with specifications matched to the highveld climate's specific demands.
Durban's coastal salt air and high humidity environment creates specific polycarbonate sheet specification challenges — chemical sensitivity to salt deposits and surface abrasion from wind-driven coastal particles both accelerate the disadvantages covered in this guide. Allrich Trading supplies Durban buyers with polycarbonate sheet grades specifically rated for KwaZulu-Natal's coastal conditions.
Cape Town's combination of summer UV, winter rain, and strong coastal wind creates a demanding dual-season polycarbonate sheet specification environment. Cape Town's wind-driven particle abrasion is a particular concern for standard polycarbonate sheet surface integrity. Allrich Trading supplies Cape Town buyers with hard-coat treated, UV-protected polycarbonate sheets suited to the Western Cape's demanding conditions.
How to Specify Polycarbonate Sheets Correctly in South Africa
Step 1 — Confirm UV protection is co-extruded. For any South African outdoor application — always specify co-extruded UV-protected polycarbonate. Never standard unprotected grade. Confirm with your supplier.
Step 2 — Specify hard-coat treatment for abrasion-exposed applications. Any South African application exposed to wind-driven sand, dust, or particles — specify hard-coat surface treatment to resist the scratch disadvantage.
Step 3 — Allow correct thermal expansion gaps. Confirm the required expansion gap for your panel size and South African climate zone with Allrich Trading's technical team before installation.
Step 4 — Confirm chemical compatibility. Identify all chemicals the polycarbonate sheet will be exposed to in your specific application. Confirm compatibility before specifying.
Step 5 — Consider FR grade for fire-sensitive applications. Confirm South African building regulation fire performance requirements for your project before specifying standard polycarbonate sheet.
Step 6 — Work with a specialist supplier. Allrich Trading supplies polycarbonate sheets across South Africa with technical knowledge matched to South African conditions — giving you the honest, complete picture you need to make the right specification decision.
Supply Polycarbonate Sheets From Allrich Trading — With Honest Specification Advice
The disadvantages in this guide are not reasons to avoid polycarbonate sheets — they are reasons to specify them correctly. A correctly specified polycarbonate sheet from Allrich Trading — co-extruded UV protection, hard-coat surface treatment where required, correct installation allowances for thermal expansion, and the right grade for the right application — will outperform every alternative for its intended purpose over a 10 to 15 year lifespan in South African conditions.
Allrich Trading supplies premium polycarbonate sheets across Johannesburg, Durban, and Cape Town. Contact our team to discuss your application, get honest specification advice, request product samples, or get a supply quote for your next polycarbonate sheet project.
Frequently asked questions
Here are some common questions about our company.
The main disadvantages of polycarbonate sheets in South Africa are scratch susceptibility, high thermal expansion requiring correct installation gaps, UV degradation without co-extruded UV coating, lower optical clarity than glass, chemical sensitivity to certain solvents and cleaners, higher upfront cost than some alternatives, combustibility compared to glass, and gradual surface haze over time. Each disadvantage can be managed with correct specification and installation practice.
Yes — standard polycarbonate sheets without co-extruded UV protection yellow rapidly under South Africa's extreme UV radiation, typically within 12 to 24 months of outdoor exposure. UV-protected polycarbonate sheets with co-extruded UV coating resist yellowing significantly — maintaining clarity for 10 to 15 years under South African outdoor conditions. Always specify co-extruded UV-protected grades for any outdoor South African application.
Yes. Standard polycarbonate sheets scratch more easily than glass or acrylic. South Africa's sandstorm and wind-driven particle conditions accelerate surface micro-scratching. Hard-coat treated polycarbonate sheets significantly improve scratch resistance and are the recommended specification for South African applications where abrasion exposure is a risk.
No. Polycarbonate sheets are not suitable for applications requiring non-combustible cladding under South African building regulations, applications requiring the optical clarity of glass, or applications with prolonged exposure to solvents and chemicals that damage polycarbonate. Allrich Trading can advise on whether polycarbonate sheets are the correct specification for your specific South African building application.