Ceiling insulation is one of the most effective ways to improve a home’s comfort and energy efficiency in South Africa. Whether you are a homeowner, builder, or developer, choosing the right type of insulation can reduce energy bills, lower noise, and make your property safer. At Cape Ceilings and Drywalling, we provide expert guidance on the top-performing insulation products available locally, including Knauf, Aerolite, Isotherm, Summit XPS boards, Isoboard, Sisalation Foils, and Cellulose. We have many Types of Ceiling Insulation in South Africa lets taken a deep dive and check this out.
In this guide, we’ll cover each insulation type in detail, provide specifications grids, explain benefits, and highlight energy savings, fire ratings, and installation considerations.
Types Of Ceiling Insulation For Your Home
There are many types of Ceiling Insulation for homes. In this post we have selected the most used Types of Ceiloing Insulation in South Africa.
1. Knauf Ceiling Insulation With Patented ECOSE Technology
Knauf insulation is a premium choice for South African homes and commercial properties. The Patented ECOSE Technology ensures environmentally friendly production, low irritant handling, and excellent thermal and acoustic performance.
Why Choose Knauf?
- Comfort: Keeps homes warmer in winter and cooler in summer.
- Energy Savings: Reduces electricity bills by minimizing heat transfer through ceilings.
- Fire Safety: Non-combustible with SANS Class 1 fire rating for all standard thicknesses.
- Eco-Friendly: Uses bio-based binder, no formaldehyde, low VOC.
Available Thicknesses: 50mm, 75mm, 100mm, 135mm
Knauf Specifications Grid
| Thickness | Width | Length | Density | Thermal Conductivity (k-value) | R-Value | NRC | Fire Rating | Application |
|---|---|---|---|---|---|---|---|---|
| 50mm | 1200mm | 10m roll | 12 kg/m³ | 0.041 W/m·K | 1.22 | 0.90 | Non-combustible | Top-up or new ceilings |
| 75mm | 1200mm | 10m roll | 12 kg/m³ | 0.041 W/m·K | 1.83 | 0.92 | Non-combustible | Standard residential ceilings |
| 100mm | 1200mm | 10m roll | 12 kg/m³ | 0.041 W/m·K | 2.44 | 0.93 | Non-combustible | New construction, high R-value needs |
| 135mm | 1200mm | 10m roll | 12 kg/m³ | 0.041 W/m·K | 3.30 | 0.95 | Non-combustible | High-performance ceilings |
Benefits of Knauf Ceiling Insulation:
- Energy Savings: Can reduce energy costs by up to 30% depending on roof type.
- Acoustic Comfort: NRC 0.90–0.95 absorbs sound efficiently.
- Durable & Safe: No settling, long lifespan, non-combustible.
- Eco-Friendly: Manufactured using sustainable ECOSE technology.
Homeowner & Builder Tip: Knauf 135mm is ideal for new builds requiring maximum energy efficiency. 50mm–75mm works well for topping up existing ceilings.
2. Aerolite Ceiling Insulation
Aerolite is a lightweight, flexible glass wool insulation with excellent thermal and acoustic properties. It is widely used in South Africa for retrofits and new construction.
Key Features:
- Multiple thickness options: 50mm, 75mm, 100mm, 135mm
- High NRC for sound absorption (0.90–0.95)
- Non-combustible, Class 1 fire rating
- Eco-friendly: up to 80% recycled glass content
Aerolite Specifications Grid
| Thickness | Width | Length | Density | Thermal Conductivity (k-value) | R-Value | NRC | Fire Rating | Application |
|---|---|---|---|---|---|---|---|---|
| 50mm | 1200mm | 10m roll | 11 kg/m³ | 0.040 W/m·K | 1.25 | 0.90 | Non-combustible | Top-up insulation |
| 75mm | 1200mm | 10m roll | 11 kg/m³ | 0.040 W/m·K | 1.88 | 0.92 | Non-combustible | Standard ceilings |
| 100mm | 1200mm | 10m roll | 11 kg/m³ | 0.040 W/m·K | 2.50 | 0.93 | Non-combustible | New installations |
| 135mm | 1200mm | 10m roll | 11 kg/m³ | 0.040 W/m·K | 3.38 | 0.95 | Non-combustible | High R-value ceilings |
Benefits:
- Excellent top-up option for older homes
- Reduces heat transfer and noise
- Lightweight and easy to install
3. Isotherm Ceiling Insulation
Isotherm ceiling insulation is another popular choice but has flammable ratings in South Africa (B/B 1/2), meaning it is not recommended for homes where fire safety is critical.
Features:
- Made from lightweight fibreglass
- Flammable, B/B 1/2 rating
- Effective thermal performance initially
- Should be installed with caution in residential spaces
Isotherm Specifications Grid
| Thickness | Width | Length | Density | R-Value | NRC | Fire Rating | Notes |
|---|---|---|---|---|---|---|---|
| 50mm | 1200mm | 10m | 10 kg/m³ | 1.20 | 0.85 | B/B 1/2 | Flammable |
| 75mm | 1200mm | 10m | 10 kg/m³ | 1.80 | 0.88 | B/B 1/2 | Flammable |
| 100mm | 1200mm | 10m | 10 kg/m³ | 2.40 | 0.90 | B/B 1/2 | Flammable |
Important: Best suited for low-risk, non-residential areas due to fire classification.
4. Summit XPS Ceiling Boards
Summit XPS boards are rigid extruded polystyrene boards offering thermal insulation and structural support.
Features:
- High compressive strength
- Water-resistant
- Fire-retardant additives (non-combustible when treated)
- Common in commercial and residential projects for roof ceilings
Specifications Grid
| Thickness | Width | Length | Thermal Conductivity | R-Value | Fire Rating | Application |
|---|---|---|---|---|---|---|
| 25mm | 600mm | 1200mm | 0.033 W/m·K | 0.75 | Class 1 | Ceilings / under slabs |
| 50mm | 600mm | 1200mm | 0.033 W/m·K | 1.52 | Class 1 | Roof insulation |
| 75mm | 600mm | 1200mm | 0.033 W/m·K | 2.28 | Class 1 | High-performance roofs |
Benefits: Lightweight, durable, and easy to install with excellent insulation for flat ceilings and roof decks.
5. Isoboard Ceiling Boards
Isoboard is a lightweight, rigid insulation board made from polyurethane or similar materials.
Features:
- High R-value per thickness
- Easy to cut and install
- Low water absorption
- Fire retardant versions available (check SANS ratings)
Specifications Grid
| Thickness | Width | Length | R-Value | Fire Rating | Application |
|---|---|---|---|---|---|
| 25mm | 1200mm | 2400mm | 0.85 | Class 1 | Ceilings |
| 50mm | 1200mm | 2400mm | 1.70 | Class 1 | Roof ceilings |
| 75mm | 1200mm | 2400mm | 2.55 | Class 1 | Roof ceilings |
6. Sisalation Foils for Roofs
Sisalation is reflective foil insulation, ideal as a radiant barrier under metal or tile roofs.
Benefits:
- Reduces heat gain in summer
- Lightweight and easy to roll out
- Works best combined with fibreglass or board insulation
Specs:
- Thickness: 10–15mm (combined foil layers)
- Reflectivity: >90% radiant heat rejection
- Fire Rating: Class 1 for foil, but combine with fibreglass for full ceiling safety
7. Cellulose Insulation
Cellulose is shredded recycled paper with fire retardants.
Important Notes for South Africa:
- Flammable (B/B 1/2)
- Loses fire retardancy over time
- Can collapse ceilings when wet from roof leaks
- Not widely recommended for residential use
Specifications Grid
| Density | R-Value | Fire Rating | Notes |
|---|---|---|---|
| 40–60 kg/m³ | 2.0–2.5 | B/B 1/2 | Flammable; avoid in SA homes |
| 60–80 kg/m³ | 3.0 | B/B 1/2 | Must be dry; not suitable for wet climates |
Energy Savings and Fire Safety Summary
| Product | Energy Savings | Fire Rating | Best Use |
|---|---|---|---|
| Knauf ECOSE | Up to 30% | Non-combustible | Residential / commercial |
| Aerolite | Up to 28% | Non-combustible | Retrofit and new ceilings |
| Isotherm | Up to 25% | Flammable | Low-risk areas only |
| Summit XPS | Up to 26% | Class 1 | Roof / slab insulation |
| Isoboard | Up to 28% | Class 1 | Ceilings / roofs |
| Sisalation | Up to 15% (reflective) | Class 1 | Radiant barrier under roofs |
| Cellulose | 20–25% | Flammable | Not recommended in SA homes |
Internal Linking Suggestions
- Knauf 135mm Ceiling Insulation
- Aerolite 100mm Insulation
- Isoboard Ceiling Boards
- Summit XPS Ceiling Boards
- Sisalation Foils for Roofs
- 50mm Aerolite Top-Up Insulation
Conclusion
Choosing the right ceiling insulation is essential for comfort, energy savings, and fire safety in South African homes. At Cape Ceilings and Drywalling, we recommend Knauf ECOSE and Aerolite for non-combustible performance, Summit XPS or Isoboard for rigid roof applications, and Sisalation foil as a radiant barrier. Avoid flammable options like Isotherm and Cellulose in residential ceilings.
