Glasswool ceiling insulation
100mm Knauf Insulation
Clear coverage for a well-planned ceiling. 100mm Knauf insulation is a glass mineral wool ceiling blanket made with ECOSE® Technology. Each roll covers 12.12m², measures 10.1m × 1.2m and has a published material R-value of 2.50m²·K/W.
View the current roll price, compare the cost per square metre and calculate your whole-roll quantity below.
starts above the ceiling.
01 / Plan your order
Comfort, by the roll.
One product. Clear coverage. The quantity you need.
per roll
R77,74 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
- 10.10 x 1.2
- Coverage per roll
- 12,12 m²
- Material R-value
- R2.5
- 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.
100mm Knauf insulation / The buying guide
Choose with confidence.
Order with clarity.
The right ceiling order starts with a clear specification and a reliable measurement. Bring both together before choosing your roll quantity.
100mm Knauf insulation is a glass mineral wool ceiling blanket made with ECOSE® Technology. Its 10.1m × 1.2m roll provides 12.12m² of nominal coverage, with a published material R-value of 2.50m²·K/W. Use this guide to check the product, compare material costs and plan the quantity for your ceiling.
01 / Understand the product
Made for the space
above your ceiling.
100mm Knauf insulation is intended for pitched roofs insulated at ceiling level. The finished ceiling stays below the blanket, while the material helps resist heat passing through the insulated area.
01 / Thermal resistance
Help manage heat flow.
Ceiling insulation helps reduce heat gain from a warm roof space and heat loss during colder conditions. Choose the required performance first, then calculate how much material the project needs.
02 / Material classification
Non-combustible mineral wool.
Knauf lists this Ceiling Roll as Euroclass A1 for reaction to fire. That describes the insulation material; a complete ceiling assembly has separate performance requirements.
03 / Flexible format
Coverage you can plan.
The lightweight blanket comes in compressed packs for transport and storage. Confirm the supplied roll format before organising cutting, handling and access to the ceiling space.
ECOSE® Technology
A plant-based binder.
100mm Knauf insulation uses ECOSE Technology, Knauf’s plant-based binder with no added formaldehyde. Knauf reports Indoor Air Comfort Gold certification for the low emissions of its mineral wool products made with ECOSE.
The binder also gives the material its natural brown colour without added dyes. Keep the product documentation available if the project specification includes requirements about material composition or indoor emissions.
The practical choice
Look at the whole specification.
When considering 100mm Knauf insulation, compare the named product, thickness, thermal resistance and roll area together. A large roll can reduce the number of packs in an order, but the performance requirement still determines which material belongs in the building.
Share the same specification with everyone preparing quotations. Clear information makes it easier to compare offers, identify a different product and avoid ordering on thickness alone.
Buying for a homeowner or a contractor?
For a homeowner, the starting point is a confirmed specification and a list of the ceilings included in the work. Ask the installer to check both before placing the material order. For a contractor, attach the agreed product details to the quotation and keep a separate quantity for each thickness required. When several people are involved in purchasing, delivery and fitting, use the same product name throughout. This helps the person accepting the delivery check it against the actual job rather than a general request for ceiling insulation.
02 / Match the building specification
Is 100mm Knauf insulation
right for your project?
Check the required thermal resistance before comparing quantities. The figures below apply to Knauf Ceiling Roll in the listed Uncut and Combi-cut formats.
The essential numbers
12.12m² per roll.
R2.50 material performance.
These two figures answer different questions. Coverage determines the order quantity for 100mm Knauf insulation. R-value describes the blanket’s resistance to heat flow.
The manufacturer’s South African reference uses a 23°C mean temperature. Its European reference also lists 2.50 for this thickness, using a different reference temperature.
| Property | Value |
|---|---|
| Thickness | 100mm |
| Roll length | 10.1m |
| Full roll width | 1.2m |
| Coverage per roll | 12.12m² |
| Material R-value | 2.50m²·K/W |
| Reaction to fire | Euroclass A1 |
100mm and 135mm serve different specifications.
The 100mm roll covers more area than the 135mm roll, while the thicker product has greater published material thermal resistance. Select 100mm Knauf insulation when its performance matches the specified construction.
If a drawing or quotation calls for 135mm, keep that requirement until the person responsible for the design confirms a suitable change. A lower pack count does not make the products interchangeable.
Confirm Uncut or Combi-cut.
Uncut material provides the full width for cutting to suit. The listed Combi-cut format separates into 800mm and 400mm widths. Confirm which format is stocked and how it suits the intended installation.
Splitting a Combi-cut roll preserves the total nominal area. At 10.1m long, the two strips provide 8.08m² and 4.04m² respectively, adding up to the same 12.12m².
A useful comparison
Compare coverage
alongside resistance.
Keep both columns with your buying notes. They help explain why an order for a thinner roll can contain fewer packs while providing a different thermal specification.
| Thickness | Roll coverage | Material R-value |
|---|---|---|
| 100mm | 12.12m² | 2.50 |
| 135mm | 9m² | 3.38 |
Confirm the complete construction.
The suitability of 100mm Knauf insulation depends on the building and its specified roof arrangement. The blanket’s material R-value is one part of that assessment. Keep the project specification with the order and resolve any uncertainty before buying.
If you are comparing suppliers, ask each to state the area per roll on the quotation. A similar-looking pack or matching thickness does not establish identical coverage. Check the named range and supplied format against the manufacturer’s data, then recalculate the order using that product’s figures before deciding which quotation offers the best value.
R-values are in m²·K/W. Check Knauf’s published Ceiling Roll information ↗.
03 / Understand the cost
Know the roll price.
Plan the full order.
Compare the 100mm Knauf insulation price using both the nominal square metre rate and the whole-roll quantity your project needs.
The current product price above is your starting point. Use the calculator to estimate materials, then confirm availability, delivery and any fitting work before completing the purchase.
When comparing quotations for 100mm Knauf insulation, check that each offer covers the same product, quantity and VAT basis. Keep any transport or labour charges visible so you can compare the complete scope.
01
One whole roll
Use the displayed selling price and check its VAT label. The purchasing unit is a roll, so the amount ordered must accommodate the rounded quantity.
02
The equivalent price per m²
Divide the roll price by 12.12. This puts the cost of 100mm Knauf insulation on a nominal area basis, which is useful when comparing roll sizes.
03
The material subtotal
Multiply the roll count by the current roll price. This accounts for the full packs purchased, including any nominal coverage left after the measured ceiling area is filled.
04
The delivered project cost
Confirm transport and any installation separately. Give the supplier the delivery suburb, required date and access details so the quotation addresses the actual order.
04 / Work out the quantity
Your measurements.
A clear roll count.
Calculate 100mm Knauf insulation from the ceiling area receiving the blanket. Add the selected cutting allowance, divide by 12.12 and round up to a whole roll.
Step 01
Measure the included areas.
Multiply each rectangular ceiling’s length by its width in metres. Divide irregular spaces into smaller sections, calculate them individually and add the areas without counting overlaps twice.
Step 02
Choose a fitting allowance.
Discuss cuts and offcuts with the installer. The right allowance depends on the layout, access and proposed fitting method. Use a considered figure for the work being planned.
Step 03
Round up the final result.
For 100mm Knauf insulation, divide the adjusted area by 12.12. For example, 100 ÷ 12.12 is about 8.25 rolls, so the purchase quantity is nine complete rolls.
Worked example / 100m² ceiling
Nine rolls provide
109.08m² of nominal coverage.
At 0% or 5% allowance, nine rolls cover the calculated requirement. At 10%, the target becomes 110m², which exceeds nine rolls by 0.92m². The order therefore increases to ten rolls.
This example shows why a small change in the adjusted area can add a full pack to an order for 100mm Knauf insulation.
| Allowance | Whole rolls | Coverage bought |
|---|---|---|
| 0% | 9 | 109.08m² |
| 5% | 9 | 109.08m² |
| 10% | 10 | 121.2m² |
Several rooms in one order.
A 5m × 4m room has a 20m² ceiling. A 4m × 3m room adds 12m², giving 32m² in total. With a 5% allowance, the adjusted area is 33.6m² and the order becomes three rolls, providing 36.36m².
Combine measurements only where all included areas receive 100mm Knauf insulation. Keep separate lines for areas requiring another thickness or a different product.
Record what the measurement includes.
Label bedrooms, passages and living areas on a simple sketch. Note any ceilings outside the work scope. This gives the supplier and installer a clearer picture than a single unverified property floor-area figure.
Offcuts need a practical plan.
Nominal coverage is the area of the uncut material. The shape of leftover pieces affects whether they can be used in another part of the ceiling. Review this before assuming all purchased area will fit the job.
The calculator for 100mm Knauf insulation handles area, allowance and rounding. It does not design the cutting layout or assess roof access, so keep those checks with the installer.
Check units before submitting.
Enter dimensions in metres and ceiling area in square metres. For a flat ceiling, measure its footprint. If the specified insulation surface slopes, confirm the actual surface area before using it in the calculation.
A small room can leave a larger remainder.
For a 20m² ceiling with a 5% allowance, the adjusted area is 21m². Two rolls provide 24.24m², leaving 3.24m² beyond that adjusted requirement. The purchase still needs two complete rolls. If the same job includes another suitable ceiling area, consider the combined cutting plan before ordering the rooms separately. Keep the material specification consistent across those areas.
Compare the rate with the actual spend.
The displayed price per square metre uses nominal roll coverage. Your material spend per measured ceiling square metre also reflects whole-roll rounding. To calculate that project figure, divide the complete roll subtotal by the original ceiling area. For a small order, it can be higher than the nominal product rate. Keep delivery and installation separate when making this comparison.
Keep the estimate easy to check.
Write down the original area, chosen allowance and calculated roll quantity together. If a room is added or removed, update the area and recalculate the whole order. This avoids carrying an old quantity into a revised quotation.
05 / Prepare for fitting
Plan the delivery.
Prepare the ceiling space.
A useful plan for 100mm Knauf insulation covers the material, access and work sequence. Agree on those details before the delivery date.
Assess an existing ceiling first.
For a retrofit, ask the installer to inspect access, existing insulation and the condition of the roof space. Identify any preparation needed before setting the final material quantity and installation date.
Adding 100mm Knauf insulation over an existing layer needs a project-specific assessment. Identify what is already there and its condition, then confirm the proposed arrangement with the person responsible for the specification.
Make room for the delivery.
Choose a dry storage position under cover and off the ground. Knauf’s guidance says damaged, contaminated or wet material must not be used. Inspect packs when they arrive and protect them until fitting begins.
Confirm who will accept and check the delivery. Keep the order details available so the delivered thickness, format and quantity can be matched to the quotation.
Agree on installation responsibilities.
Clarify whether the order is for material supply or includes a separately quoted installation service. Identify who handles preparation, access arrangements, existing material and removal of packaging.
Before installing 100mm Knauf insulation, resolve the specified fitting method, ventilation paths and service clearances. Keep current manufacturer guidance available for the installer rather than making assumptions from a product photograph.
Check the completed work.
Include edges, openings and awkward ceiling sections in the final inspection. The order quantity is only one part of completing the specified area consistently.
Keep your invoice and product details with the property records. If later electrical or roof work disturbs the insulation, ask for the affected sections to be checked and put back to the agreed arrangement.
Send a useful order enquiry.
Include 100mm Knauf insulation, the measured ceiling area, selected allowance, whole-roll count and delivery suburb. Add the required date and whether you need fitting assistance. If measurements are provisional, say so clearly so the quantity can be confirmed before dispatch.
Coordinate the order with the work sequence.
If the ceiling forms part of a larger renovation, agree when the insulation should arrive with the person managing the work. Note any rooms that will be completed at a later stage. Confirm how the remaining 100mm Knauf insulation will be stored between stages and who will check the material before it is fitted. Discuss any change in the planned quantity before dispatch, and confirm the supplier’s terms for unopened surplus packs rather than assuming returns will be accepted. Keep the final agreed quantity on the order confirmation.
06 / Before you order
100mm Knauf insulation:
your questions answered.
Check the coverage, specification and buying details before completing your material order.
8 practical answers
How much area does one roll cover?
One roll of 100mm Knauf insulation covers a nominal 12.12m² before cutting and fitting. Allow for the ceiling layout when deciding how much of the purchased material can be used.
How many rolls cover a 100m² ceiling?
Nine rolls provide 109.08m² of nominal coverage. That meets a 100m² requirement with either 0% or 5% allowance. A 10% allowance increases the target to 110m² and requires ten rolls.
What is the published material R-value?
The material R-value is 2.50m²·K/W. Use this figure with the building specification when considering 100mm Knauf insulation. It describes the blanket rather than the complete roof and ceiling construction.
Can 100mm replace specified 135mm Knauf?
The two thicknesses have different thermal resistance and roll coverage. Keep the specified product unless the person responsible for the design confirms a change. Recalculate quantities whenever the chosen product changes.
Does splitting Combi-cut double the coverage?
No. The 800mm and 400mm strips together still provide 12.12m². Treat them as parts of the original roll when planning your 100mm Knauf insulation order.
How is the price per square metre calculated?
Divide the current price per roll by 12.12. The order subtotal still uses whole rolls, so compare the final quantity as well as the nominal area rate. Confirm VAT and delivery terms on each quotation.
Is fitting included in the product price?
Treat the displayed price as the material price unless your quotation expressly includes installation. State what work you need and confirm delivery, preparation and fitting as part of the agreed scope.
Can I order before final measurements are ready?
You can prepare an enquiry with a provisional area, but identify it as an estimate. Confirm the measured area and roll quantity for 100mm Knauf insulation before completing the material order.
A clear specification. A practical order.
Turn your measurements
into the next step.
Use the calculator to plan your 100mm Knauf insulation quantity, review the current roll price and keep your delivery details ready for confirmation.
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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