Kooltherm K10W White G2 Soffit Board
Opening Offer: 5% off orders over $1,000, 7% over $2,500, 10% over $4,000. Ends 30 November. Offer details
Measure the wall, ceiling or roof area and take about 10% off for studs, joists and purlins.
Dispatch: Most orders are processed the same day. Metro delivery: Usually 1–3 business days. We do our best to get most items out on the next business day.
Delivery to VIC and NSW: $55 in metro Melbourne and metro Sydney, $99 in the outer ring around both cities, $149 anywhere else in the two states · Local pickup from Epping, VIC by arrangement · Shipping details
Kingspan Kooltherm K10 G2W White Soffit Board is the white-faced version of the K10 G2 phenolic soffit board, for concrete soffits and ceilings that stay exposed to view. It is CodeMark certified for NCC compliance.
White face, same core
The phenolic core and the declared R-values are the same as K10 G2. The lower facing is white aluminium foil where K10 G2 has a highly reflective one. In a car park or any slab underside left in view, the board itself can be the finished surface. Under a concrete roof with no ceiling, Kingspan's total R-values for the white face are lower than for the reflective K10 G2.
Thickness and R-value
Thermal conductivity is 0.022 W/m·K at 45 mm and thicker. The range runs from 25 mm at R1.10 to 100 mm at R4.60, all in 2400 x 1200 mm boards.
Fire and certification
Fire classification is NCC Group 2, with a spread of flame index of 0 and smoke development of 3 or lower. FM 4880 approval covers 25 to 119 mm. The core is fibre-free, and the 10 year warranty is subject to the full Kooltherm terms.
Sold by the pack
Each thickness option is one full Kingspan pack: 12 boards (34.56 m²) at 25 mm, falling to 3 boards (8.64 m²) at 90 mm and 100 mm. Only 40 mm and 50 mm are stocked. The other eight thicknesses are made to order and take about 10 business days.
Thickness, R-value, pack and compliance figures are in the table below.
Technical data
Kingspan technical data sheet (PDF)Sizes stocked
| Nominal thickness | Declared R-value at 23 °C | Board size | Boards per pack | m² per pack | Product code | Supply |
|---|---|---|---|---|---|---|
| 25 mm | R1.10 | 2400 x 1200 mm | 12 | 34.56 m² | 100000044995 | Made to order, about 10 business days |
| 30 mm | R1.30 | 2400 x 1200 mm | 10 | 28.80 m² | 100000044696 | Made to order, about 10 business days |
| 40 mm | R1.75 | 2400 x 1200 mm | 8 | 23.04 m² | 100000043532 | Stocked |
| 45 mm | R2.05 | 2400 x 1200 mm | 7 | 20.16 m² | 100000048558 | Made to order, about 10 business days |
| 50 mm | R2.30 | 2400 x 1200 mm | 6 | 17.28 m² | 100000043533 | Stocked |
| 60 mm | R2.75 | 2400 x 1200 mm | 5 | 14.40 m² | 100000046794 | Made to order, about 10 business days |
| 70 mm | R3.20 | 2400 x 1200 mm | 4 | 11.52 m² | 100000060528 | Made to order, about 10 business days |
| 80 mm | R3.65 | 2400 x 1200 mm | 4 | 11.52 m² | 100000043534 | Made to order, about 10 business days |
| 90 mm | R4.10 | 2400 x 1200 mm | 3 | 8.64 m² | 100000086050 | Made to order, about 10 business days |
| 100 mm | R4.60 | 2400 x 1200 mm | 3 | 8.64 m² | 100000049479 | Made to order, about 10 business days |
Thermal
| Thermal conductivity, 45 mm and thicker | 0.022 W/m·K at 23 °C |
|---|---|
| Thermal conductivity, 25 to 44 mm | 0.023 W/m·K at 23 °C |
| Test standard | AS/NZS 4859.1:2018 and ASTM C518-2017 |
Declared R-values match the standard K10 G2, but under a concrete roof with no ceiling the white face gives lower total R-values than K10 G2's reflective foil.
Fire
| NCC group number | Group 2 (AS 5637.1:2015 and AS ISO 9705) |
|---|---|
| Spread of flame index | 0 |
| Smoke development | 3 or lower |
| SMOGRA-RC | 100 m²/s² x 1000 or lower |
| FM Approval | FM 4880, UBC 26-3 Class 1, for thicknesses 25 to 119 mm |
Early fire hazard properties are tested to AS 1530.3, and the FM approval covers ceiling and soffit installation only, with non-combustible walls.
Physical
| Compressive stress | On average over 100 kPa at 10% compression (AS 2498.3) |
|---|---|
| Water vapour transmission | Over 35 MN·s/g (ASTM E96 Part B) |
| Core | Fibre-free rigid thermoset closed cell phenolic |
| Upper facing | Tissue based |
| Lower facing | White aluminium foil, bonded during manufacture |
Compliance and warranty
| Certification | CodeMark certified for NCC compliance |
|---|---|
| Thermal rating | Declared to AS/NZS 4859.1:2018 |
| Warranty | 10 years, residential and commercial, subject to the full Kooltherm warranty terms |
| Management systems | ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certified manufacture |
Fitting notes
Fix each 2400 x 1200 mm board straight to the concrete soffit with at least 11 insulation fasteners that have a head diameter of 35 mm or more, which works out at 3.81 fixings per m². Kingspan's pattern puts four fasteners along each long edge, 50 to 150 mm in from the edge, and three along the middle. Fewer fixings would not be FM approved. Joints can be staggered or squared, and are taped with 96 mm wide white Kingspan Insulation Tape on a facing wiped clean of dust and oil. Where wind pressure can reach the soffit, check the need for extra fixings against the Australian wind load standards. Fit the board tight to fire collars but leave the collar face uncovered so the collar can activate. Cover exposed board edges with white tape lapped at least 48 mm onto the face, or a metal C-section. Boards that have got wet should not be used. Install to AS 3999:2015 and AS 3000:2018, and keep the foil facing clear of un-insulated cables and fittings.
Figures are taken from the Kingspan data sheet for Kooltherm K10 G2W White Soffit Board, KIAU0032 Issue 13, February 2024. Boards per pack, product codes and supply times are from Kingspan's Kooltherm product list. The manufacturer document is linked above. Kingspan can change specifications without notice, so check the current sheet before specifying on a job.
Common questions
Can I buy a single board?
No. Kooltherm boards are sold in Kingspan's full packs, and each thickness option is one pack of 2400 x 1200 mm boards. A pack runs from 12 boards (34.56 m²) at 25 mm down to 3 boards (8.64 m²) at 90 mm and 100 mm.
Which thicknesses are in stock?
40 mm and 50 mm are stocked. The other eight thicknesses (25, 30, 45, 60, 70, 80, 90 and 100 mm) are made to order by Kingspan and take about 10 business days.
What R-value does the finished soffit get?
Kingspan's totals assume 150 mm of concrete. Under a concrete roof with no ceiling, 50 mm gives RT2.5 heat flow in and RT2.6 out, and 90 mm gives RT4.3 and RT4.4. Under an unenclosed sub-floor the figures are RT2.4 and RT2.6 at 50 mm, and RT4.2 and RT4.5 at 90 mm.
Can the board be left exposed as the finished ceiling?
Yes, that is what the white aluminium foil facing is for. It is a Group 2 material under the NCC, but CodeMark CM20201 excludes public corridors of Class 3 and 9a buildings for the aged, people with disability, children and healthcare, and Class 9b and 9c public corridors, unless the building is sprinkler protected. It is also excluded from fire-isolated exits and fire control rooms.
How many fixings does each board need?
At least 11 insulation fasteners per 2400 x 1200 mm board, each with a head of 35 mm diameter or more, which is 3.81 fixings per m². Kingspan say fewer fixings would not be FM approved. Where wind pressure can reach the soffit, check whether extra fixings are needed.
How are the joints, edges and fire collars finished?
Tape the joints with 96 mm wide white Kingspan Insulation Tape. Exposed edges take the same white tape lapped at least 48 mm onto the face, or a metal C-section. Fit the board tight around fire collars but never cover the collar face, which has to stay exposed for the collar to activate.
Is it the same board as K10 G2?
Same fibre-free phenolic core, same 2400 x 1200 mm board and the same declared R-values, from R1.10 at 25 mm to R4.60 at 100 mm. The lower facing is what changes: highly reflective aluminium foil on K10 G2, white aluminium foil on K10 G2W. Under a concrete roof with no ceiling the reflective K10 G2 reaches higher total R-values, while Kingspan's totals under an unenclosed sub-floor are the same for both.
Cannot see your question? Ask our team and we will get you an answer.
Answers use the Kingspan data sheet for Kooltherm K10 G2W White Soffit Board (KIAU0032 Issue 13, February 2024), the Kooltherm K10 G2 data sheet (KIAU0030 Issue 13, February 2024) for the comparison, CodeMark certificate CM20201 and Kingspan's pack quantities for each thickness.