135mm Knauf Insulation
135mm Knauf Insulation
Comfort starts above your ceiling. 135mm Knauf insulation is a glass mineral wool ceiling blanket made with ECOSE® Technology. Each roll covers 9m², measures 7.5m × 1.2m and has a published South African material R-value of 3.38m²·K/W.
Check the current roll price, calculate your whole-roll quantity and plan your ceiling insulation order below.
starts above the ceiling.
01 / Plan your order
Comfort, by the roll.
One product. Clear coverage. The quantity you need.
per roll
R97,27 per m² ·
Materials pricing. Confirm delivery charges, availability and any installation requirements before ordering.
02 / Plan your project
Your ceiling. Your numbers.
Calculate the whole rolls needed for your ceiling area.
For several rooms, enter their combined ceiling area.
Choose an allowance for your project. Whole-roll rounding may provide extra material already.
Your material estimate
Enter your ceiling area to calculate the whole rolls needed.
Delivery and installation excluded. This is a quantity and materials estimate, subject to the final quotation.
03 / Know what you are buying
The numbers that matter.
Roll size, coverage and material performance.
- Roll dimensions
- 7m x 1.2m
- Coverage per roll
- 9 m²
- Material R-value
- R3.38
- Ordering unit
- One whole roll
Dimensions and coverage are nominal. Material R-values are in m²·K/W; the complete roof and ceiling has a separate system R-value.
135mm Knauf insulation / The buying guide
Comfort above.
Clarity below.
Build your ceiling order around the details that matter: thermal performance, roll coverage and a quantity that fits your project.
135mm Knauf insulation is a flexible glass mineral wool ceiling blanket made with ECOSE® Technology. Each roll provides a nominal 9m² of coverage. Explore the specification, compare the current material price and use the calculator to turn your ceiling measurements into whole rolls.
01 / Meet the material
A thoughtful layer
of everyday comfort.
135mm Knauf insulation is designed for pitched roofs insulated at ceiling level. It sits above the finished ceiling, helping manage heat transfer through this part of your building.
01 / Thermal comfort
Slow the movement of heat.
The blanket helps limit heat entering from a warm roof space and warmth escaping through the ceiling during colder conditions. Choose its thermal resistance to suit the project specification.
02 / Fire classification
Non-combustible mineral wool.
Knauf declares Euroclass A1 reaction to fire for this Ceiling Roll. The material classification is separate from the fire resistance of a complete ceiling assembly.
03 / Practical format
Flexible coverage, by the roll.
The lightweight blanket is supplied in compressed packaging. Confirm whether the order is Uncut or Combi-cut, then plan the cuts around the actual ceiling layout.
The ECOSE® difference
A plant-based binder.
135mm Knauf insulation uses ECOSE Technology. Knauf describes this binder as plant-based, with no added formaldehyde. Its mineral wool products made with ECOSE carry Indoor Air Comfort Gold certification for low emissions.
Make an informed choice
Look beyond the pack.
The natural brown colour comes from the binder rather than added dyes. Keep the manufacturer’s product information with your order if the project requires documentation about materials or indoor emissions.
02 / Know what you are ordering
135mm Knauf insulation:
the essential numbers.
Use thickness and thermal resistance to confirm the product. Use the roll dimensions and coverage to prepare the quantity.
Ceiling Roll / Uncut or Combi-cut
One roll.
Nine square metres.
A nominal length of 7.5m multiplied by the full 1.2m width gives 9m². Cutting a roll into narrower strips changes its shape, while the total nominal area stays the same.
| Property | Value |
|---|---|
| Nominal thickness | 135mm |
| Length × full width | 7.5m × 1.2m |
| Coverage per roll | 9m² |
| Material R-value / South Africa | 3.38m²·K/W |
| Material R-value / European reference | 3.35m²·K/W |
| Reaction to fire | Euroclass A1 |
Why are two R-values published?
The manufacturer’s South African reference uses a 23°C mean temperature; the European reference uses 10°C. For this page, 135mm Knauf insulation is shown with the South African material value of 3.38m²·K/W.
Check the format before delivery.
Uncut material is supplied at full width for cutting to suit. The listed 135mm Combi-cut format has an 800mm + 400mm split. Ask which format is available when placing the order.
Match the building specification.
Before choosing 135mm Knauf insulation, confirm the required roof and ceiling performance with the person responsible for the project specification. The material R-value describes the blanket; the complete construction needs its own assessment.
03 / Put the price in context
Compare the roll.
Budget for the ceiling.
The useful 135mm Knauf insulation price is the one you can relate to your measured ceiling area and complete material order.
Check the current product price above. Then use the calculator to estimate the whole-roll quantity before confirming delivery and any installation work.
01
Price per whole roll
Start with the displayed price and its VAT label. Keep the same VAT basis when comparing quotations, and check availability for your required quantity.
02
Price per square metre
Divide the roll price by 9. This gives a comparable material rate for 135mm Knauf insulation using its nominal coverage, before cutting and fitting.
03
Your material subtotal
Multiply the current roll price by the rounded-up quantity. Confirm delivery charges and installation separately so the material estimate fits into your full project budget.
04 / Turn area into an order
Measure the space.
Count complete rolls.
Calculate 135mm Knauf insulation quantities from the actual area receiving the blanket. Add a suitable cutting allowance, divide by 9 and round up.
Step 01
Measure each ceiling.
For a rectangular area, multiply length by width in metres. Split an irregular footprint into smaller rectangles, then add the results without counting overlapping areas twice.
Step 02
Review the cutting plan.
Ask the installer which allowance suits the layout. Awkward corners, access openings and the usefulness of offcuts can affect the amount needed beyond the measured area.
Step 03
Round up to whole rolls.
Use the adjusted area to calculate the order. For example, 100 ÷ 9 = 11.11 rolls, so the quantity becomes 12 complete rolls.
Worked example / 100m²
Twelve rolls provide
108m² of nominal coverage.
For a 100m² ceiling, 135mm Knauf insulation needs 12 rolls at either 0% or 5% allowance. At 10%, the adjusted requirement becomes 110m² and the order increases to 13 rolls.
| Allowance | Whole rolls | Coverage bought |
|---|---|---|
| 0% | 12 | 108m² |
| 5% | 12 | 108m² |
| 10% | 13 | 117m² |
Why can two allowances give the same result?
Whole-roll rounding already creates spare nominal area in some orders. Both 100m² and 105m² fit within 108m² of purchased coverage. Check the cutting plan before treating every remaining square metre as usable.
What if the work covers several rooms?
Add the separate ceiling areas first, then calculate the combined order for 135mm Knauf insulation. Keep the room measurements with your estimate so the installer can check the scope and proposed allowance.
Measure the work you actually intend to complete.
A property’s advertised floor area can include spaces outside the insulation project. Record the bedrooms, living areas, passages and any other included ceilings individually. If the specified surface slopes, confirm its actual area rather than using an unadjusted floor measurement.
Keep separate quantities for areas using a different thickness or product. A combined ceiling measurement is useful only when the whole area receives the same specified material. Label each part of a mixed order clearly so the supplier can match rolls to the intended rooms.
05 / Prepare for the job
A clear plan.
A consistent finish.
Plan the delivery and fitting of 135mm Knauf insulation together. Good measurements are most useful when the installer can reach and complete the full specified area.
Before the rolls arrive.
Confirm the delivery address, access arrangements and a suitable storage area. Keep a copy of the quantity calculation with the order, including the measured area and the allowance selected.
Store the material dry, under cover and off the ground. Knauf advises against using wet, contaminated or damaged product. Inspect delivered packs before installation starts.
Agree on what the order includes.
State whether you need materials only or assistance with fitting. Agree who handles access, preparation, any existing insulation and packaging removal. Include the required completion date in your enquiry.
Confirm the installation details.
Before fitting 135mm Knauf insulation, ask the installer to check the roof space, existing material and specified arrangement. Resolve access, service clearances and ventilation details before work begins.
Keep the manufacturer’s current installation and handling guidance available on site. Check coverage at edges, access points and difficult corners as part of the completed work.
Keep useful records.
Retain the product specification, invoice and any installation information with your property records. If later work disturbs the ceiling insulation, those details help identify the material and the intended arrangement.
06 / Your questions
Buying 135mm Knauf insulation?
Start here.
Quick answers about coverage, quantities, product format and ordering.
8 practical answers
How much does one roll cover?
Each roll of 135mm Knauf insulation covers a nominal 9m² before cutting and fitting. Use that figure with your measured ceiling area and selected allowance.
How many rolls do I need for 100m²?
Order 12 rolls with no added allowance, or with a 5% allowance. Both calculations round up to 108m² of purchased coverage. A 10% allowance requires 13 rolls, providing 117m².
What is the South African material R-value?
The published figure is 3.38m²·K/W. Knauf also lists a European reference of 3.35m²·K/W using a different mean temperature. Keep the reference basis consistent when comparing specifications.
Does Combi-cut provide extra coverage?
No. Separating an 800mm strip and a 400mm strip preserves the original total area. At 7.5m long, their areas are 6m² and 3m², which still add up to 9m².
How do I compare the price per m²?
Divide the current whole-roll price by 9. Compare products of the required thickness and thermal performance, using the same VAT basis. Include the rounded quantity when comparing complete material orders.
Can it be used above an existing ceiling?
135mm Knauf insulation may suit an existing ceiling where access and the building specification allow. Have the roof space and any existing insulation assessed before agreeing on the installation.
Is installation included in the roll price?
Treat the displayed price as the material price unless an installation service is expressly included in your quotation. Confirm fitting, delivery and preparation separately before placing the final order.
What details should I send with an enquiry?
Include the product thickness, calculated quantity, delivery suburb and required date. Add your ceiling measurements and say whether you need supply only or installation assistance.
Bring the details together
Your ceiling.
Your next step.
Plan your 135mm Knauf insulation order using the measured area, whole-roll quantity and current product price. Keep the estimate ready when confirming availability and delivery.
Technical reference: Knauf Ceiling Roll datasheet, September 2025 ↗. Product information checked 8 October 2026. Dimensions and coverage are nominal; confirm the supplied format when ordering.
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