CEILING INSULATION GUIDE
Best Ceiling Insulation South Africa
Compare Aerolite, Knauf, Isotherm and Factorylite ceiling insulation based on R-values, thermal performance, acoustic properties, fire performance and suitability for South African homes.
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Best Ceiling Insulation South Africa
Choosing the best ceiling insulation in South Africa depends on your climate, roof construction, required thermal performance, budget and whether acoustic performance is also important.
South African homeowners can choose from several proven ceiling insulation products, including Aerolite ceiling insulation, Knauf ceiling insulation, Isotherm insulation and Factorylite. While all of these products can reduce heat transfer through the ceiling, there are important differences in their composition, R-values, acoustic performance, fire properties and available thicknesses.
For most residential applications, 135mm ceiling insulation is an excellent starting point. However, choosing insulation based on thickness alone can be misleading. The R-value, material type and quality of installation ultimately determine how effectively the insulation resists heat flow.
In this guide, we compare the leading ceiling insulation products available in South Africa using real product specifications and practical installation considerations to help you choose the right insulation for your home or project.
Table Of Contents
What Is the Best Ceiling Insulation in South Africa?
There is no single ceiling insulation product that is best for every South African home. The right choice depends on the required R-value, insulation thickness, climate, roof construction, acoustic requirements and budget.
For most residential applications, Aerolite and Knauf ceiling insulation are excellent choices where high thermal and acoustic performance are priorities. Isotherm ceiling insulation provides a polyester alternative that is soft and comfortable to handle, while Factorylite insulation offers a practical glasswool solution for residential and commercial applications.
For new installations, 135mm ceiling insulation is generally a much better choice than thinner insulation where the roof space allows it. However, thickness should never be considered on its own. The actual R-value of the insulation tells you far more about its resistance to heat flow.
Our Quick Comparison
Best all-round thermal & acoustic performance: Aerolite or Knauf
Best polyester option: Isotherm
Best for comfortable handling: Isotherm
Best value: Depends on current price, thickness and R-value
Recommended approach: Compare the R-value and performance specifications before comparing price
Most importantly, good insulation must be installed correctly and continuously across the ceiling. Gaps, compressed insulation and uncovered areas can reduce the overall thermal performance of the ceiling, regardless of which insulation product you choose.
What Makes Good Ceiling Insulation?
The best ceiling insulation cannot be determined by thickness or price alone. Several factors affect how well an insulation product will perform in a South African home, including its R-value, thickness, material composition, fire performance, acoustic properties and quality of installation.
Understanding these factors makes it much easier to compare Aerolite, Knauf, Isotherm and Factorylite on their actual performance rather than simply choosing the cheapest insulation roll.
R-Value and Thermal Performance
The R-value measures the insulation’s resistance to heat flow. The higher the R-value, the greater the material’s resistance to heat passing through it.
This is particularly important in a ceiling because a significant amount of heat can be transferred between the living area and the roof space. During summer, ceiling insulation helps reduce heat entering the rooms below. During winter, it helps slow the loss of heat from the home.
When comparing ceiling insulation products, always compare the R-value at a similar thickness rather than assuming that two products of the same thickness provide identical thermal performance.
Insulation Thickness
Thickness has a major influence on thermal performance, but thicker does not automatically mean better unless the material also provides an appropriate R-value.
Common ceiling insulation thicknesses in South Africa include 50mm, 75mm, 100mm and 135mm, with some products also available in other thicknesses.
For a new residential ceiling insulation installation, we generally favour 135mm insulation where the roof construction and available space allow it. Installing adequate insulation from the beginning usually makes more sense than choosing a thinner product and having to improve the insulation later.
Fire Performance
Fire performance should be considered when choosing any material installed inside a roof or ceiling cavity.
Different insulation materials have different fire classifications and characteristics. These should be assessed using the manufacturer’s current technical documentation rather than assuming that all ceiling insulation products behave in the same way when exposed to fire.
This is one area where the differences between glasswool and polyester ceiling insulation become particularly important, and we compare these materials in more detail further down this guide.
Acoustic Performance
Good ceiling insulation can provide more than thermal protection. Fibrous insulation can also help absorb sound travelling through the ceiling and roof structure.
This can be particularly useful in homes affected by traffic, aircraft, rain and other external noise, as well as buildings where improved indoor acoustic comfort is required.
Where acoustic performance is important, look at measurable information such as the manufacturer’s Noise Reduction Coefficient (NRC) rather than relying only on descriptions such as “soundproof” or “acoustic insulation”.
Material Type
Most residential ceiling insulation products considered in this guide fall into two main categories:
Glasswool insulation – including products such as Aerolite, Knauf and Factorylite.
Polyester insulation – including Isotherm.
Both types can provide effective thermal insulation, but they differ in areas such as thermal performance, fire characteristics, acoustic performance, handling and price.
We will compare these differences directly later in this guide.
Installation Quality
Even excellent ceiling insulation will underperform if it is badly installed.
Insulation should provide consistent coverage across the ceiling while avoiding unnecessary gaps and compression. Particular attention should be given to roof timbers, electrical installations, access hatches and other areas where breaks in the insulation layer can occur.
For this reason, the question should not only be “Which ceiling insulation is best?” It should also be “Which product will provide the required performance when correctly installed in this particular roof?”
Ceiling Insulation R-Values Explained
The R-value of ceiling insulation is one of the most important specifications to compare when choosing insulation for a South African home. It measures the material’s resistance to heat flow — the higher the R-value, the greater its resistance to heat passing through it.
This makes R-value a far more useful comparison than thickness alone.
What Does R-Value Mean?
An insulation product with a higher R-value provides greater resistance to heat transfer than a product with a lower R-value.
During summer, ceiling insulation helps slow heat transfer from the hot roof space into the rooms below. During winter, it helps reduce heat loss from the heated interior of the home into the colder roof space.
Ceiling insulation therefore works throughout the year. It does not simply “keep a house warm”.
Product R-Value vs Total Installed R-Value
It is important to distinguish between the R-value of the insulation material and the total R-value of the complete ceiling or roof system.
For example, 135mm Aerolite Soft Touch has a material R-value of approximately R3.38 m²·K/W. Once the thermal resistance of other building components and air layers is included, the total installed system R-value can be higher.
This distinction is important when comparing insulation products. A manufacturer may quote the R-value of the insulation itself, while building regulations may refer to the required thermal resistance of the complete building element.
For a fair product comparison, we therefore compare material R-values at equivalent or similar thicknesses wherever possible.
Why 135mm Ceiling Insulation Is Popular
Increasing insulation thickness generally increases thermal resistance.
This is why 135mm ceiling insulation has become an important thickness for residential applications. It provides substantially greater thermal resistance than thin layers of insulation while still being practical to install in many conventional South African roof spaces.
As one example:
135mm Aerolite Soft Touch: R3.38
100mm Aerolite Soft Touch: R2.50
50mm Aerolite Soft Touch: R1.28
The difference is significant. The 135mm product provides considerably greater resistance to heat flow than the 50mm version.
This is also why we would generally not recommend choosing ceiling insulation purely because a thinner product has a lower purchase price.
R-Value Should Be Compared With Other Properties
A high R-value is important, but it should not be the only consideration.
When comparing Aerolite, Knauf, Isotherm and Factorylite ceiling insulation, also consider:
- Fire performance
- Acoustic performance
- Material composition
- Available thicknesses
- Installation requirements
- Durability
- Suitability for the particular building
- Cost per square metre at the required thermal performance
The objective is not simply to buy the thickest roll or the product with the largest number on the packaging. It is to achieve the appropriate thermal performance for the building using a suitable insulation system that is correctly installed.
100mm vs 135mm Ceiling Insulation – Which Is Better?
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One of the most common questions when choosing ceiling insulation is whether 100mm or 135mm insulation should be installed.
If we compare the same insulation material, the answer is straightforward: 135mm insulation generally provides greater thermal resistance than 100mm insulation. However, the correct thickness should ultimately be selected according to the product’s R-value, the building’s energy zone and the required thermal performance of the complete roof and ceiling system.
How Much Difference Does 35mm Make?
The difference between 100mm and 135mm may not sound substantial, but the additional insulation can produce a meaningful increase in thermal resistance.
Aerolite Soft Touch provides a useful example:
| Aerolite Thickness | Material R-Value |
|---|---|
| 50mm | R1.28 |
| 100mm | R2.50 |
|
135mm |
R3.38 |
Moving from 100mm Aerolite to 135mm Aerolite increases the material R-value from R2.50 to R3.38.
That is approximately 35% more thermal resistance from the insulation layer.
This is why we generally prefer installing the appropriate higher-performance insulation during the initial installation rather than choosing a thinner product simply to reduce the upfront cost.
Is 135mm Ceiling Insulation Required in South Africa?
South African energy-efficiency requirements should not be reduced to a rule that every home simply requires “135mm insulation”.
SANS 10400-XA:2021 specifies thermal-performance requirements for roof and ceiling assemblies according to South Africa’s energy zones. The required performance is expressed as an R-value, rather than simply specifying one insulation thickness for every product and every building.
Different insulation materials can require different thicknesses to achieve a similar R-value because their thermal conductivity differs.
For this reason, two insulation products that are both 135mm thick should not automatically be assumed to provide identical thermal performance.
When Would We Choose 135mm?
For many new residential ceiling insulation installations, 135mm glasswool insulation is an excellent option where it provides the required R-value and can be installed correctly within the roof space.
We would particularly favour the higher-performing option when:
- The home currently has no ceiling insulation.
- The roof space provides sufficient room for the insulation.
- Heating and cooling costs are a concern.
- The homeowner wants better year-round thermal performance.
- The difference in installed cost between 100mm and 135mm is relatively small.
Ceiling insulation is normally expected to remain in the building for many years, so saving a relatively small amount by installing substantially less thermal resistance is not always good value.
When Can 100mm Insulation Make Sense?
There are applications where 100mm ceiling insulation can be appropriate.
These can include situations where the particular product and roof system achieve the required thermal performance, where space is restricted, or where insulation is being added to an existing insulated ceiling.
The important point is that 100mm should not automatically be selected simply because it is cheaper.
Compare the actual R-value and intended application first.
What About Adding Insulation to an Existing Ceiling?
A different approach can be taken when a home already has insulation but the existing layer is insufficient.
Rather than automatically removing insulation that is still in good condition, it may be possible to install an additional insulation layer over the existing material to improve the overall thermal resistance.
The existing insulation should first be inspected for moisture damage, contamination, severe compression, gaps or deterioration.
Where additional insulation is installed, good coverage remains essential. The objective is to create a consistent thermal barrier across the ceiling rather than simply increasing insulation thickness in isolated areas.
Our Recommendation: Compare R-Value Before Thickness
When deciding between 100mm and 135mm ceiling insulation, don’t make the decision on thickness or price alone.
Compare:
- The insulation material
- Product R-value
- Required thermal performance
- South African energy zone
- Existing roof and ceiling construction
- Existing insulation, if any
- Installed cost per square metre
For many South African residential applications, 135mm glasswool ceiling insulation provides an excellent combination of thermal performance, practicality and long-term value, but the correct specification should always be determined by the requirements of the particular building.
Aerolite Ceiling Insulation Review
Aerolite ceiling insulation is one of South Africa’s best-known glasswool insulation products and has been used in residential and commercial buildings for many years. It combines strong thermal performance with very good acoustic absorption and is available in several thicknesses for different ceiling insulation requirements.
For homeowners looking for high-performance bulk ceiling insulation, 135mm Aerolite Soft Touch is particularly worth considering.
Aerolite R-Values and Specifications
Aerolite is manufactured from glasswool and is supplied in flexible rolls that can be cut and fitted across the ceiling.
| Aerolite Thickness | Roll Size | Coverage | Material R-Value |
|---|---|---|---|
| 50mm | 10m × 1.2m | 12m² | R1.28 |
| 100mm | 6m × 1.2m | 7.2m² | R2.50 |
| 135mm | 5m × 1.2m | 6m² | R3.38 |
The 135mm Aerolite provides a material R-value of approximately R3.38 m²·K/W, compared with R2.50 for the 100mm product and R1.28 for the 50mm product.
This makes the 135mm option particularly attractive where higher thermal resistance is required.
Aerolite Acoustic Performance
One of Aerolite’s strengths is that it provides both thermal insulation and sound absorption.
The fibrous glasswool structure absorbs sound energy rather than simply reflecting it. This can help reduce noise transmission through the roof and ceiling construction.
Published NRC values include approximately:
135mm Aerolite: NRC 1.10
100mm Aerolite: NRC 0.90
50mm Aerolite: NRC 0.70
This makes Aerolite particularly worth considering for homes affected by external noise such as traffic, aircraft and rain on roofing, or where improved indoor acoustic comfort is desirable.
Aerolite Fire Performance
Fire performance is another important consideration when comparing ceiling insulation materials.
Aerolite glasswool has a Class A/A 1/1 fire classification, making its fire properties one of the reasons we regard it as a strong ceiling insulation option.
Fire performance should always be considered alongside the complete ceiling and roof construction and the manufacturer’s installation requirements.
Advantages of Aerolite Ceiling Insulation
Aerolite offers a strong combination of:
- High thermal resistance at appropriate thicknesses
- Excellent acoustic absorption
- Good fire performance
- Multiple thickness options
- Flexible installation in conventional roof spaces
- Long history of use in South African buildings
Are There Any Disadvantages?
Like other glasswool insulation products, Aerolite needs to be cut and installed correctly.
Installers should use appropriate protective clothing and equipment when handling insulation. Poorly fitted material, unnecessary compression and gaps in the insulation layer can also reduce the thermal performance of the completed installation.
This is not unique to Aerolite — correct installation is important with any bulk ceiling insulation.
Is Aerolite One of the Best Ceiling Insulation Options?
Yes. Aerolite is one of the products we would place on the shortlist when comparing the best ceiling insulation available in South Africa.
Its combination of thermal resistance, acoustic absorption and fire performance makes it particularly well suited to residential ceiling insulation.
For homeowners choosing between 100mm and 135mm Aerolite, we would generally favour the 135mm option where the additional thermal performance is appropriate for the building and the roof space allows it.
The final decision should still consider the required R-value, climate zone, existing ceiling construction and installed cost rather than selecting a product based on brand name alone.
Knauf Ceiling Insulation Review
Knauf ceiling insulation is a high-performance glass mineral wool insulation used for thermal and acoustic insulation in South African homes and buildings. It has become a popular alternative to traditional glasswool products, particularly because of Knauf’s ECOSE® Technology.
Knauf insulation combines strong thermal performance with excellent sound absorption, making it one of the products we would seriously consider when choosing ceiling insulation for a residential property.
What Is Knauf ECOSE® Technology?
One of the main differences between Knauf and conventional glass mineral wool insulation is the binder technology used in its manufacture.
ECOSE® Technology is Knauf Insulation’s bio-based binder technology. It contains no added formaldehyde or phenol and gives the insulation its distinctive natural brown appearance rather than the traditional yellow colour associated with many glasswool products.
The material is also soft and flexible, making it relatively easy to cut and fit around roof timbers and other obstructions when installing ceiling insulation.
Knauf R-Values and Specifications
Pleass note these are values do not reflect the R-value 0.40 for ceiling cavity spece and insulation. All total R-values must include R-value 0.40.
| Knauf Thickness | Roll Size | Coverage | Material R-Value |
|---|---|---|---|
| 75mm | 12.8m × 1.2m | 12m² | R1.85 |
| 100mm | 10.10m × 1.2m | 7.2m² | R2.50 |
| 135mm | 7.5m × 1.2m | 6m² | R3.38 |
Knauf Ceiling Insulation R-Values
Knauf ceiling insulation is available in several thicknesses, including 50mm, 75mm, 100mm and 135mm, allowing the appropriate product to be selected according to the required thermal performance.
As with Aerolite, the important specification is not simply the thickness of the insulation but the R-value achieved at that thickness.
Where higher thermal performance is required, we generally favour the thicker Knauf ceiling insulation options rather than selecting a thinner roll purely because it has a lower initial cost.
Excellent Acoustic Performance
Acoustic performance is one of Knauf insulation’s major strengths.
The open, fibrous structure of glass mineral wool absorbs sound energy and can help reduce sound transmission through ceiling and roof constructions.
The 135mm Knauf insulation has an NRC of approximately 1.15, making it particularly attractive where both thermal insulation and sound absorption are important.
This can be useful in homes exposed to traffic, aircraft, rain on metal roofing and other external noise sources.
Knauf also manufactures dedicated acoustic insulation products for applications where sound control is a primary requirement.
Fire Performance
Glass mineral wool has inherently strong fire characteristics, which is an important consideration for insulation installed within roof and ceiling spaces.
The fire classification of the particular Knauf product being specified should always be checked against the manufacturer’s current technical documentation and the requirements of the complete ceiling or roof system.
Fire performance is one of the areas we consider particularly important when comparing glasswool and polyester ceiling insulation.
Advantages of Knauf Ceiling Insulation
Knauf offers a particularly strong combination of:
- High thermal performance
- Excellent acoustic absorption
- ECOSE® bio-based binder technology
- No added formaldehyde or phenol in the ECOSE® binder
- Soft, flexible material
- Strong fire characteristics
- Several thickness options
- Suitable for residential and commercial applications
Are There Any Disadvantages?
Knauf is still a fibrous glass mineral wool product and should be installed using appropriate work practices and protective equipment.
As with all bulk ceiling insulation, poor installation can also compromise its performance. Gaps, excessive compression and uncovered sections of ceiling should be avoided.
Price and availability can also differ between insulation brands and regions, so Knauf should be compared on installed cost and thermal performance, rather than the price of an individual roll alone.
Is Knauf One of the Best Ceiling Insulation Options?
Yes. Knauf is one of our strongest choices when comparing the best ceiling insulation available in South Africa.
Its combination of thermal performance, excellent acoustic absorption and ECOSE® Technology makes it particularly attractive for homeowners looking for a premium glass mineral wool ceiling insulation.
For applications where both thermal and acoustic performance are important, Knauf deserves serious consideration alongside Aerolite.
The final choice between Knauf and Aerolite will often come down to the required R-value, available thickness, acoustic requirements, installed price and personal product preference rather than one product being universally better than the other.
Isotherm Ceiling Insulation Review
Isotherm ceiling insulation is a polyester bulk insulation product widely used in South African homes. Unlike Aerolite and Knauf, which are manufactured from glass mineral wool, Isotherm is manufactured from polyester fibres.
Its biggest practical advantages are its soft feel, ease of handling and polyester construction, making it particularly popular with homeowners and DIY installers who prefer working with a non-glasswool insulation material.
Isotherm is available in several thicknesses, including 50mm, 75mm, 100mm, 135mm and 145mm, depending on the required application and thermal performance.
How Is Isotherm Different From Glasswool?
The most obvious difference is the material itself.
Aerolite and Knauf use fine glass mineral wool fibres, while Isotherm uses thermally bonded polyester fibres.
This gives Isotherm Insulation a noticeably different feel. The material is soft, flexible and comfortable to handle and can be cut to fit between roof timbers and around obstructions.
For DIY installations, this handling characteristic can be a significant advantage.
Isotherm Thermal Performance
Isotherm provides effective bulk thermal insulation, but products should be compared using their published R-values rather than thickness alone.
Polyester and glasswool products do not necessarily achieve identical thermal resistance simply because they are the same thickness.
For this reason, when comparing 135mm Isotherm with 135mm Aerolite or Knauf, the correct approach is to compare the manufacturer’s R-value for each product rather than assuming that 135mm of every insulation material performs equally.
Isotherm is also available in 145mm, providing another option where greater insulation thickness is required.
Isotherm Thickness & Thermal Performance
Important: Isotherm R-values shown below are manufacturer-published nominal values. Actual thermal performance depends on the product being supplied at the specified thickness and density.
| Thickness | Coverage per Roll | Material R-Value |
|---|---|---|
| 50mm | 8 m x 1.2m | R 0.79 |
| 75mm | 8m x 1.2m | R 1.18 |
| 100mm | 6m x 1.2m | R 1.57 |
| 135mm | 5m x 1.2m | R 3.14 |
| 145mm | 5m x 1.2m | R 3.37 ? |
Isotherm and Moisture
Polyester fibres do not readily absorb moisture into the fibre itself, which can be an attractive characteristic in insulation applications.
However, this does not mean that roof leaks or condensation should be ignored. Any bulk insulation can perform poorly when a roof or ceiling system has an unresolved moisture problem.
Roof leaks should therefore be repaired before new ceiling insulation is installed.
Acoustic Performance
The fibrous structure of polyester insulation also provides sound-absorbing properties.
Isotherm can therefore contribute to improved acoustic comfort as well as thermal insulation, particularly by helping absorb sound energy within the ceiling and roof cavity.
Where acoustic performance is a major priority, however, we recommend comparing published acoustic test data rather than assuming that all bulk insulation products provide the same level of sound absorption.
Fire Performance
Fire performance is an important consideration when comparing polyester insulation with glass mineral wool.
The two materials have different fire characteristics, and the relevant manufacturer fire classification and building requirements should be considered when specifying the insulation.
We compare the differences between glasswool and polyester ceiling insulation in greater detail later in this guide.
Advantages of Isotherm Ceiling Insulation
Isotherm offers several practical advantages:
- Polyester fibre construction
- Soft and comfortable to handle
- Easy to cut and install
- Available in multiple thicknesses
- Good thermal insulation performance
- Sound-absorbing properties
- Suitable for many residential ceiling applications
- Popular option for DIY insulation projects
Are There Any Disadvantages?
The main point to understand is that comfortable handling does not automatically mean better thermal performance.
Isotherm should still be compared with Aerolite, Knauf and other ceiling insulation products according to the R-value required for the building.
Depending on the thickness and required thermal performance, a polyester product may also require a different thickness from a glass mineral wool product to achieve a comparable R-value.
Price per roll can also be misleading because roll dimensions, coverage and thermal resistance differ between products. Comparing the cost per square metre at the required R-value provides a much more meaningful comparison.
Is Isotherm One of the Best Ceiling Insulation Options?
Yes, particularly for homeowners who prefer polyester insulation.
Isotherm’s greatest strengths are its comfortable handling, polyester construction and established use as residential ceiling insulation in South Africa.
For a professional installation where maximum thermal, acoustic and fire performance are the main priorities, we would compare Isotherm carefully against products such as Aerolite and Knauf using their actual technical specifications.
For a homeowner specifically looking for a polyester ceiling insulation, however, Isotherm remains one of the most obvious products to consider.
Ultimately, the best choice depends on whether your priority is thermal performance, acoustic performance, fire characteristics, handling, price or a combination of these factors.
Factorylite Roof & Ceiling Insulation Review
Factorylite insulation is a flexible glasswool insulation product manufactured by Isover and designed primarily for industrial and commercial roof applications. Unlike the unfaced ceiling insulation products commonly installed above residential ceilings, Factorylite is supplied with a reinforced foil or metalised foil facing.
This makes Factorylite particularly suitable for metal-roofed buildings such as factories, warehouses, workshops, agricultural buildings and commercial properties, where thermal insulation and condensation control are important considerations.
Although Factorylite can form part of a roof insulation comparison, its intended application is different from conventional residential ceiling insulation such as Aerolite, Knauf and Isotherm.
Factorylite R-Values and Specifications
Factorylite is available in 50mm, 75mm, 100mm and 135mm thicknesses.
| Factorylite Thickness | Width | Material R-Value |
|---|---|---|
| 50mm | 1200mm | R1.28 |
| 75mm | 1200mm | R1.92 |
| 100mm | 1200mm | R2.56 |
| 135mm | 1200mm | R3.46 |
The 135mm Factorylite provides an R-value of R3.46 m²·K/W, giving it substantial thermal resistance where the higher thickness can be correctly incorporated into the roof system.
Factorylite has a published thermal conductivity of approximately 0.039 W/m·K.
Why Does Factorylite Have a Foil Facing?
One of the major differences between Factorylite and conventional ceiling insulation is its facing.
Factorylite can be supplied with reinforced foil, white metalised foil or black metalised foil, depending on the application.
The facing forms part of the complete roof insulation system and is particularly useful in metal-roof construction, where the insulation can help reduce heat gain and heat loss while also assisting with condensation control.
The finished facing can also provide a neat visible underside in applications where there is no conventional ceiling below the roof structure.
Factorylite Fire Performance
Factorylite is manufactured from non-combustible glasswool, making fire performance one of its significant advantages for commercial and industrial roof applications.
This is particularly important in larger buildings where insulation may cover substantial roof areas and where the fire properties of construction materials form an important part of the overall building specification.
The requirements of the complete roof assembly and the relevant building regulations should always be considered when specifying insulation.
Thermal and Acoustic Performance
Factorylite provides both thermal and acoustic insulation.
Its glasswool structure helps resist heat transfer while also absorbing sound energy. This can be particularly useful underneath metal roofing, where rain, machinery and external environmental noise can contribute to uncomfortable internal noise levels.
The insulation also helps create more stable internal temperatures by reducing heat transfer through the roof construction.
Where Is Factorylite Best Used?
Factorylite is particularly well suited to:
- Factories
- Warehouses
- Workshops
- Commercial buildings
- Agricultural buildings
- Metal roof systems
- New over-purlin roof insulation installations
- Selected existing industrial roof upgrades
This is where Factorylite differs significantly from Aerolite, Knauf and Isotherm.
If the objective is simply to insulate above the ceiling of a conventional house, we would normally compare residential ceiling insulation products first.
If the insulation forms part of the metal roof system itself, Factorylite becomes a much more relevant option.
Advantages of Factorylite Insulation
Factorylite offers several important advantages:
- High thermal resistance at appropriate thicknesses
- Non-combustible glasswool construction
- Foil-faced roof insulation system
- Good acoustic properties
- Helps control condensation
- Available in multiple thicknesses
- Long service life
- Particularly suited to metal roofing
- Suitable for large commercial and industrial roof areas
Are There Any Disadvantages?
Factorylite is a more specialised product and should not automatically be selected simply because its R-value compares favourably with residential ceiling insulation.
The roof construction and installation method need to be considered.
Factorylite is commonly incorporated into metal roof systems and can require support wires, correct tensioning and appropriate treatment of the foil joints. Compression at purlins can also affect the thermal performance of the insulation.
It is therefore important to select Factorylite as part of a properly designed roof insulation system, rather than treating it as an ordinary insulation roll.
Is Factorylite the Best Ceiling Insulation?
For a conventional residential ceiling, Factorylite would not normally be our first choice simply because it is designed primarily as an industrial and commercial roofing insulation system.
For factories, warehouses and other metal-roofed buildings, however, Factorylite can be an excellent insulation choice.
Its combination of glasswool insulation, foil facing, high R-values, fire performance, acoustic absorption and condensation control makes it particularly well suited to these applications.
The lesson is important: the “best insulation” is not necessarily the product with the highest R-value. It is the insulation product that provides the required performance and is designed for the particular roof or ceiling system.
Frequently Asked Questions About Ceiling Insulation
What is the best ceiling insulation in South Africa?
There is no single insulation product that is best for every application. For most residential ceilings, high-quality bulk insulation such as Aerolite or Knauf provides excellent thermal performance when the correct thickness is installed. The condition of the roof space, required R-value, budget and installation method should all be considered.
What thickness of ceiling insulation should I use?
For many South African homes, 135mm ceiling insulation is a popular choice because it provides substantially better thermal resistance than thinner 50mm, 75mm or 100mm products. The required thickness ultimately depends on the insulation material, its R-value and the climatic zone of the building.
Is Aerolite or Knauf insulation better?
Both are high-quality glass mineral wool insulation products with excellent thermal and acoustic properties. The better choice can depend on the required thickness, R-value, availability and price. We recommend comparing the actual technical specifications rather than choosing insulation based on brand name alone.
Is Isotherm better than fibreglass insulation?
Isotherm polyester insulation has advantages including comfortable handling and no glass fibres. However, the best insulation should be selected according to measurable properties such as R-value, thickness, density, fire performance and long-term consistency, rather than material type alone.
Does thicker ceiling insulation make a difference?
Yes. Increasing insulation thickness generally increases thermal resistance, provided the product maintains the required density and is installed correctly. A higher R-value reduces the rate at which heat passes through the ceiling.
Can I install new ceiling insulation over existing insulation?
Often, yes. Existing insulation can sometimes be retained and additional insulation installed over it, provided the original material is dry, in reasonable condition and does not create installation or safety problems. The roof space should be inspected before adding another layer.
Does ceiling insulation keep a house cool in summer?
Yes. Ceiling insulation works in both directions. During summer it reduces heat entering the home through the roof and ceiling. During winter it reduces heat escaping from the heated interior.
How long does ceiling insulation last?
Good-quality ceiling insulation can provide effective thermal performance for many years when correctly installed and protected from water, physical damage and excessive compression. Product quality and correct installation are important to its long-term performance.
Should ceiling insulation be compressed to fit?
No. Bulk insulation should generally be installed at its intended thickness. Compressing insulation can alter its thermal performance. It should be cut and fitted neatly around obstructions rather than forced into spaces that are too small.
What should I compare when choosing ceiling insulation?
Compare the material R-value, installed thickness, density, fire classification, coverage per pack or roll, durability and cost per square metre. Price per roll alone can be misleading because different insulation products cover different areas and provide different levels of thermal resistance.