Specifically, the correct thickness depends on what the sheet needs to do. A 3mm solid polycarbonate sheet suits a small indoor sign or display application. The same 3mm sheet on a carport roof in Johannesburg fails within two years under UV exposure and hail impact. A 10mm twin wall multiwall sheet on the same carport lasts 10 to 15 years.
Thickness is not the only variable — construction type matters as much as the millimetre count. A 6mm solid sheet and a 10mm twin wall multiwall sheet are completely different products despite the thickness overlap. One is for glazing and structural applications. The other is consequently for roofing, cladding, and light transmission applications where insulation matters.
At Allrich Trading, we supply polycarbonate sheets across Johannesburg, Cape Town, and Durban for roofing, glazing, and industrial applications.
What Are the Main Polycarbonate Sheet Types and Thicknesses?
Solid Polycarbonate Sheet
Specifically, solid polycarbonate is a single-layer sheet — the same construction throughout its full thickness. Furthermore, it is the correct choice for applications requiring maximum impact resistance, optical clarity, and structural rigidity.
2mm to 3mm — suitable for small indoor display applications, protective covers, and machine guards where impact protection is needed but structural load is minimal. Furthermore, this thickness handles minor impact but should not be used in exposed outdoor positions without UV-stable coating.
4mm to 6mm — the standard thickness range for glazing applications in South Africa — carport side panels, security glazing, shopfront displays, and indoor partitions. Solid polycarbonate at 4mm is approximately 250 times more impact resistant than standard glass of the same thickness. Consequently, it is the standard specification for vandal-resistant glazing across South African commercial environments.
8mm to 12mm — heavy structural glazing, security screens, bank screens, and industrial machine guards requiring maximum impact resistance. Additionally, this thickness range handles significant mechanical load without the deflection that thinner sheets show under pressure.
Best for: glazing, security applications, machine guards, shopfront panels, signage substrates.
Twin Wall Multiwall Polycarbonate
Twin wall multiwall polycarbonate consists of two outer sheets connected by internal ribs — creating a hollow structure that is significantly lighter than solid sheet of equivalent thickness while providing better thermal insulation. Consequently, this is the standard roofing specification across South Africa's residential and commercial market.
4mm twin wall — lightweight roofing for small covered areas, pergolas, and carport side panels. Nevertheless, 4mm twin wall provides limited thermal insulation and is susceptible to denting under hail impact in South Africa's highveld storm season.
6mm twin wall — the most common roofing specification for South African residential carports, patio covers, and small commercial canopies. It balances cost, light transmission, and adequate hail resistance for most residential applications.
10mm twin wall — the correct specification for larger span roofing, commercial canopies, and any application in South Africa's high-hail-risk areas — particularly Gauteng and parts of KwaZulu-Natal where hail events regularly produce large stone sizes. Moreover, 10mm twin wall provides significantly better thermal insulation than thinner alternatives — relevant for covered spaces where temperature management matters.
16mm and above — specialist multiwall configurations for large commercial roofing spans, greenhouse structures, and high-load applications. These thicknesses provide the structural rigidity to span significant distances without intermediate support.
Best for: roofing, patio covers, carports, greenhouse glazing, commercial canopies.
Corrugated Polycarbonate
Corrugated polycarbonate follows the same profile as corrugated IBR or Chromadek roof sheeting — it installs on the same purlins and fixings — a practical retrofit for adding light transmission to existing roofing structures.
0.8mm to 1.0mm — standard corrugated polycarbonate thickness for most South African roofing applications. Moreover, the corrugated profile provides structural rigidity at lower material thickness than flat sheet — consequently allowing spans that flat sheet of the same thickness could not achieve.
Consequently, corrugated polycarbonate should always be UV-stabilised for South African outdoor use. Without UV stabilisation the sheet yellows and becomes brittle within 3 to 5 years under South Africa's UV radiation.
Best for: roof light strips in existing metal roof structures, agricultural buildings, warehouse skylights.
Which Polycarbonate Sheet Thickness Do You Need in South Africa?
| Application | Recommended type | Recommended thickness |
| Small indoor display or signage | Solid | 3mm to 4mm |
| Shopfront or security glazing | Solid | 4mm to 6mm |
| Machine guard or industrial screen | Solid | 6mm to 12mm |
| Residential carport roofing | Twin wall multiwall | 6mm to 10mm |
| Commercial canopy roofing | Twin wall multiwall | 10mm to 16mm |
| Greenhouse glazing | Twin wall multiwall | 10mm |
| Roof light strip in metal roof | Corrugated | 0.8mm to 1.0mm |
| High hail-risk area roofing | Twin wall multiwall | 10mm minimum |
What Else Affects Polycarbonate Sheet Performance in South Africa?
However, thickness alone does not determine how long a sheet performs in South African conditions. Two other factors significantly affect service life.
UV protection — South Africa's UV radiation is among the highest globally. Polycarbonate sheets without UV-stable coating degrade rapidly — yellowing, becoming brittle, and losing impact resistance within 3 to 5 years in direct outdoor exposure. Consequently, quality sheets in South Africa carry a co-extruded UV-protective layer on the exposed face. Specifically, this layer is not an applied coating that can wash off — it is bonded into the sheet surface during manufacture. Therefore, always confirm UV protection is present before purchasing any outdoor sheet.
IK rating for impact resistance — polycarbonate sheets carry an IK impact rating indicating how much impact force they can absorb without cracking. Higher IK ratings suit high-security, high-hail-risk, or high-traffic applications. Additionally, sheets marketed as polycarbonate without an IK rating or UV certification may be lower-grade materials that do not perform to the standard genuine polycarbonate delivers.
Polycarbonate Sheets and Plastic Sheet Products Across South Africa
One Supplier Behind Every Material We Stock
The polycarbonate sheet range we supply connects to the same product capability we apply to self adhesive vinyl, vehicle wraps, rollup banners, and bannerwall across South Africa. The sheeting, the print media, the display materials — it is all the same team, the same supply standard, and the same quality across Johannesburg, Cape Town, and Durban.