Wood Wool Cement Panels: Acoustic, Fire and EPD Data for Designers

Wood wool cement panels sit between timber and concrete. Spruce is shredded into long strands, coated with a mineral binder and pressed into boards. Manufacturers promote them as exposed acoustic ceilings in schools and swimming pools, and as insulation boards in roofs and walls, with fire classes of B-s1,d0 or better in the documents we read.

This guide separates what documents support from what they do not. Manufacturer figures are attributed to their exact document, EPDs were opened and checked against their registries where we could, and where we found nothing we say so.

What are wood wool cement panels and how are they made?

Wood, binder and water

The product standard EN 13168 covers factory-made wood wool boards and slabs for building thermal insulation, with or without facings, and the documents we read pair it with EN 13964 for suspended ceilings (catalogue entry read; the standard text is paid).^[18][1] The binder differs by maker. According to Troldtekt's EPD, a panel as production input is 41.7 % cement, 29.6 % wood, 28.3 % bound water and 0.5 % accelerator, using Portland cement from Aalborg Portland in a traditional white or a FUTURECEM version.^[9] Heradesign's EPD describes a magnesite-bonded panel of 34 % spruce, 50 % inorganic binder, 5 % magnesium sulphate and 11 % water, with no biocides or fire retardants.^[14] Celenit's EPD gives 37 % cement, 38.1 % wood, 9.7 % water, 15 % calcium carbonate and 0.2 % setting accelerator for its N board.^[16] The three recipes are different products, not versions of one.

Wood wool width

The fineness of the strands changes both the surface and the use. Celenit's EPD says its insulation boards use 3 mm wood wool and its acoustic boards 2 or 1 mm, from the same plant and raw materials.^[16] Troldtekt offers fine (1.5 mm), ultrafine (1.0 mm) and extreme fine (0.5 mm) structures, and Heradesign's Superfine has a 1 mm fibre width.^[5][13] A research paper on the acoustics of these boards describes them as inhomogeneous, with density and wood-to-binder ratio varying between samples (abstract read).^[19]

How do wood wool cement panels perform?

Thermal conductivity and density

Acoustic grades are not insulation grades. At their declared λ, a 25 mm Troldtekt acoustic panel has a thermal resistance of about 0.30 m²K/W and a 25 mm A2 panel about 0.26 m²K/W (our calculation, 0.025 ÷ 0.083 and 0.025 ÷ 0.096; neither document states a resistance).^[1][2] Celenit's insulation board has a lower λD of 0.065 W/mK and its EPD lists RD of 0.75 m²K/W at 50 mm.^[16] The printed Celenit RD values sit below thickness ÷ λD for several thicknesses (25 mm: 0.025 ÷ 0.065 = 0.38 against 0.35 printed) and the EPD does not say why.^[16] The Heradesign documents give three different conductivity figures for the range: 0.09 W/mK on the Superfine datasheet; λD 0.090 W/mK for most products in the declaration of performance table, including Fine 25 mm and Superfine, and 0.100 W/mK for Micro and Plano; and 0.11 W/(mK) to EN 12667 for Fine 25 mm in its EPD. For Fine 25 mm the declaration (0.090) and the EPD (0.11) therefore differ, and neither document explains why.^[11][12][14]

Sound absorption

Absorption depends on the panel, the air space behind it and any acoustic lining. Troldtekt's product pages state a sound absorption class up to A and αw up to 1.00 depending on set-up for both its acoustic and A2 panels, yet its declarations of performance list sound absorption as NPD, and the product pages point to separate sound measurement documents that we did not open.^[1][2][5] The Heradesign datasheet is more specific: a 25 mm Superfine panel with a 200 mm total ceiling height and no acoustic lining is listed at αw 0.70 (LH), absorption class C, NRC 0.70, and its product page lists 35 mm Superfine at αw 0.70 (LH), rising to 1.00 with an added 25 mm mineral acoustic layer.^[11][13] Heradesign's declaration of performance, unlike Troldtekt's, declares αw values, listing two entries for Superfine 25 mm at 0.65 (LH) and 0.70 (LH) without stating the build-up.^[12] None of these Heradesign documents states the test standard. A TU/e conference paper reports that normal-incidence absorption of these boards could be predicted from bulk density and thickness alone with the Johnson-Champoux-Allard model (abstract read).^[19] The practical point: compare absorption only at the same build-up and thickness, and ask for the test report.

Fire

Troldtekt's declarations of performance state B-s1,d0 for its acoustic and design panels and A2-s1,d0 for the A2 panels, with different notified bodies named in each (Technische Universität München HFM, notification 0797, in the August 2026 declaration; Bureau Veritas Certification Denmark, notification 0615, in the November 2024 one); the A2 data sheet repeats A2-s1,d0.^[1][2][4] Troldtekt's data sheet also lists a K1 10/K2 10 fire resistance capability to EN 13501-2 and a cladding class K1 10/B-s1,d0 for the acoustic panel.^[3][5] Heradesign's declaration states B-s1,d0, its datasheet lists EI 30 under a usability certificate for a stated structure, and its EPD says no fire retardants are used.^[11][12][14] Celenit's EPD gives B-s1,d0 for all N, R, RA and RAB boards.^[16] A declaration of performance classifies the product as tested, not your ceiling build-up. Heradesign's EI 30 refers to a structure set out in a usability certificate, and the Troldtekt documents we read do not say on which build-up the K-class was determined.

Moisture and durability

Troldtekt's website says its panels suit swimming pools and shower rooms, cites Danish Technological Institute documentation for up to 98 % moisture load, and says dimensions change by 0.005 % per percentage point of air humidity (manufacturer statements; the test report was not opened).^[6] Its storage document is more cautious: wood absorbs and releases moisture, so swelling and shrinkage cannot be completely prevented, damp panels can shrink and crack at joints, and panels should be acclimatised for 7 days battened or 14 days stacked, also for humid rooms and outdoor installation.^[7] Heradesign states a maximum dimensional change of ±1 ‰ at 23 °C and 50 % relative humidity, humidity resistance up to 90 % RH, and use indoors or in roofed outdoor areas not directly exposed to rain.^[11] Its EPD adds that after an unforeseen flood the panels are fully functional again after drying (manufacturer statement).^[14] Service life is stated inconsistently: Troldtekt's website says at least 50–70 years and that its EPDs use 50, while the EPD we opened states 60 years; Heradesign's EPD uses 50 years; Celenit's uses 60.^{[6][9][14][16]} We found no independent long-term field study.

What do the EPDs show?

We opened three EPDs, one from each company. They are all EN 15804+A2, but differ in programme, database, declared unit and declared modules, so they sit in separate rows and are not comparable.

Reading notes. The negative totals come from counting biogenic carbon taken up by the wood; each EPD books it back out as a biogenic emission in its end-of-life modules, so we do not net it against the fossil emissions. Heradesign's EPD does so in C4 "in accordance with the requirements of EN 15804+A2" while also stating that in its landfill scenario the biogenic carbon remains in the panel; we report both statements without resolving them.^[9][14][16] Troldtekt's EPD, for example, declares biogenic CO₂ re-emitted in modules C3 and C4 regardless of time horizon, with GWP-total of +7.47 kg CO₂e per m² in C3 for its incineration scenario and +6.40 in C4 for landfill.^[9] Troldtekt's registry record gives validity to 2030-08-30 and version date 2026-01-22, while the PDF prints valid to 22-08-2030 and shows the document reference as MD-24138-EN_rev1 on the cover and MD-23138-EN_rev1 in the footers; we did not resolve these differences.^[9] The Heradesign EPD was read from a copy hosted by Heinze; IBU's published-EPD list includes EPD-KNA-20240452-IBA1-EN but shows no validity date.^[14] Celenit's EPD was read from a copy hosted on ecologicalbuildingsystems.com; the International EPD System registry entries for Celenit N (EPD-IES-0025755:002) and the acoustic AB family (EPD-IES-0025754:002) show status valid, and for the acoustic family we read only the registry page.^[16][17]

How do the product documents compare?

The table lists what each document says, with the standard or condition as printed. Rows for different grades (acoustic, A2, insulation) are not like-for-like, and a missing value means the documents we read do not state it.

These are different grades and set-ups, so the table shows who has documented what, not which board performs better. Troldtekt's declarations list compressive strength CS(10)300 for the acoustic and A2 panels, Celenit lists at least 200 kPa at 10 % deformation for N boards from 15 to 40 mm, and Heradesign's datasheet lists ball impact class 1A for panels from 25 mm; Troldtekt's data sheet lists ball impact 1A without a thickness, and its product page specifies 1A for 35 mm panels.^{[1][2][3][5][11][16]}

What happens at end of life?

The three EPDs make different assumptions. Troldtekt declares three scenarios: incineration with energy recovery as the prescribed treatment, recycling into soil improver in Denmark, and inert-waste landfill.^[9] Heradesign declares landfill only, noting that uncontaminated panels can be reused or composted and that, in the manufacturing plant, waste panels can be recycled into binder (manufacturer statements).^[14] Celenit assumes 100 % landfill as a precaution while saying the product can be recovered in selective demolition.^[16] Troldtekt's take-back instructions, dated October 2025, accept only clean new offcuts and waste from building sites, only unpainted panels or panels in its standard colours, require a signed agreement tied to the purchase invoice, and leave transport and a per-tonne charge with the customer; they apply where transport to Denmark makes sense.^[8] Whether any of these routes is available for a given project depends on location and contract, and the documents do not say how much material is actually returned.

When to specify it, and when not

It suits

• Interior ceilings and walls that need sound absorption with some fire performance, such as classrooms and sports halls. Heradesign lists ball impact class 1A for panels from 25 mm and Troldtekt for its 35 mm panels; the standard grades are B-s1,d0, with an A2-s1,d0 variant from Troldtekt that its product page positions for areas such as means of escape.^{[2][3][5][11]}
• Humid interiors where the maker's humidity limit is documented for the exact product. Troldtekt cites up to 98 % moisture load and offers C5 screws for chlorinated atmospheres; Heradesign's stated limit is 90 % RH.^[6][11] The limits differ, so check the document for the product you are specifying.
• Projects that want a documented product. All three companies have EPDs, Troldtekt and Knauf publish declarations of performance (we did not open one from Celenit), and Troldtekt and Heradesign products hold Cradle to Cradle certificates in the registry, although the EPD results cover different system boundaries and the C2C registry entry for Heradesign expires within days of our check.^{[9][10][14][15]}
• Insulation-grade boards in assemblies designed for them. Celenit's N boards have a lower λD (0.065 W/mK) than the acoustic grades and an EPD that declares a 60-year service life, but resistance is small (0.75 m²K/W at 50 mm), so boards of this type are an addition to the build-up rather than a substitute for a full insulation layer. That last point is our interpretation of the declared values.^[16]

It may not suit

• Where dimensional stability at the joints must be perfect. Troldtekt states swelling and shrinkage cannot be completely prevented and asks for battening and acclimatisation; Heradesign gives a movement limit of ±1 ‰.^[7][11] Plan joint widths and installation conditions accordingly.
• Where colour must be uniform. Troldtekt's data sheet says colour variation may occur in natural wood and natural grey and recommends mixing panels during installation, and Heradesign's datasheet says the rough fibre and panel surface can cause deviations in colour and appearance.^[3][11]
• Where the panels will be exposed to rain or pollutants. Heradesign says its panel is for interiors and roofed outdoor areas not directly exposed to environmental influences; Troldtekt says its panels can be used outdoors, for example under overhangs, but neither document we read sets a use class.^[6][11]
• Where the panel alone must deliver thermal or fire performance for the assembly. Heradesign's EI 30 refers to a structure in a usability certificate, the Troldtekt documents we read do not state the build-up behind its K-class, and the declared λ values of acoustic grades are high for insulation.^[1][3][11]
• Where low embodied carbon is the deciding criterion. The three EPDs give fossil A1–A3 emissions of +5.13 to +6.65 kg CO₂e per m² for the declared products, on different boundaries, and the documents we read do not compare wood wool boards with other ceiling or insulation products, so they cannot show how a board compares with an alternative.^[9][14][16]

Against named alternatives

We did not read manufacturer documents for mineral wool, gypsum or timber-slat acoustic ceilings, so this page makes no like-for-like comparison with them. For wood-based insulation that does not use a mineral binder, see the wood fibre insulation and cellulose insulation profiles. We read no documents on wood wool cement boards as permanent formwork, so this page does not cover that use. Climate-specific guidance is not given in the documents we read beyond the humidity ranges quoted above.

Suppliers whose documents we read

Frequently asked questions about wood wool cement panels

The bottom line on wood wool cement panels

Wood wool cement panels are a documented, mineral-bonded way to get absorption, a B-class or better fire classification and tolerance of humid rooms in one surface, with the caveat that the documents differ on moisture limits, movement and set-up-dependent acoustics. Before specifying, ask for the declaration of performance, the sound absorption test report for your build-up, the current EPD and its registry status, the certificate behind any Cradle to Cradle claim, and the end-of-life route available in your country.

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