HDIII Wall System · Formwork Block · Load-bearing
REI 120 Load-bearing CE · ETA 08/0023

Isotex HD III 44/14 Graphite Wood-Cement Formwork Block

Code: HDIII-44/14

HDIII-44/14 is a 440 mm Isotex wood-cement formwork block with 140 mm graphite EPS and 210 mm concrete core.

0.21U-value W/m²K
13h 15'Phase shift
REI 120Fire rating
44 cmWall depth
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CE · ETA 08/0023 REI 120 EPD S-P-01472 EC8 seismic Bureau Veritas
Thermal performance
0.21 W/m²K

UNI EN ISO 6946 + UNI EN 10355. Independently tested by ITC-CNR.

EN ISO 6946NZEB ✓
Thermal inertia
13h 15' phase shift

Wood-cement and concrete mass absorbs heat by day and releases it at night.

EN ISO 13786
Acoustic performance
Rw 53 dB

Wood-cement absorbs noise at low and high frequencies simultaneously.

EN ISO 717-1
Fire resistance
REI 120

Load-bearing capacity, integrity and insulation maintained. Reaction to fire B-s1,d0. LEPIR II façade test passed.

NF EN 13501-2
01Overview
Compliance summary
✓ CE marked ETA 08/0023
✓ REI 120
✓ EPD S-P-01472
✓ EC8 seismic Zone 4
Primary use
Load-bearing
Suited for the wall type stated. Concrete core thickness determines structural capacity — see Technical Specs for exact figures.
Also suitable
Party walls · stair cores · basements
Higher REI, acoustic separation and structural continuity all met without changing specification.
02Technical specifications

Thermal

U-value (display · 3D)0.21 W/m²K
U-value 3D0.21 W/m²K
U-value 2D0.18 W/m²K
Calculation standardUNI EN ISO 6946 · UNI EN 10355
Phase shift13h 15'
Periodic transmittance Yie0.008 W/m²K
λ EPS (Neopor® BMBcert)0.031–0.034 W/mK
λ wood-cement shell0.10 W/mK
Block density534 ±10% kg/m³

Physical dimensions

Overall wall depth44 cm
EPS insulation14 cm
Concrete cast core21 cm
Shell thickness4.5 cm
Block length500 mm
Block height250 mm
Coverage8 blocks/m²

Acoustic & structural

AcousticRw 53 dB
Test standardUNI EN ISO 10140 · UNI EN ISO 717
Fire resistanceREI 120
Reaction to fireB-s1,d0
Max indicative load49 t/m *
Concrete fill178 L/m²
Block weight95 kg/m²
SeismicEC8 · NTC 2018

* Indicative at RcK ≥ 30 N/mm², inter-floor h 3.00 m. A qualified structural engineer must verify capacity for your project and national code.

03Wall construction
External render
Silicone or mineral render direct to wood-cement face. No mesh or primer required.
15–25 mm
Wood-cement outer shell
Factory-cast. Vapour-permeable. Density 534 kg/m³. 4.5 cm thick.
Integrated EPS — Neopor® BMBcert
Factory-integrated. No site cutting, no thermal bridges.
14 cm
Reinforced concrete core
Poured in situ, S4 consistency. Cast every 5–6 courses.
21 cm
Wood-cement inner shell
Direct plaster or plasterboard without battening. Vapour-open.
Internal plaster / finish
Lime or gypsum plaster applied directly. No stud frame required.
12–15 mm
Isotex system advantage
Factory-integrated layers. No separate insulation trade, no wall ties, no thermal bridging through fixings. Block length 500 mm × height 250 mm = 8 blocks per m². Render externally, plaster internally direct to wood-cement face.
04Installation
  1. 01
    Foundation & DPC
    Prepare foundation to tolerance. Install DPC. Place vertical rebar at 25 cm pitch protruding ~50 cm before first course.
  2. 02
    Dry-stack block laying
    Lay dry — no mortar. Stagger each course by half a block (250 mm). 500 mm block length, 250 mm height, 8 blocks/m².
  3. 03
    Reinforcement placement
    Vertical rebar at 25 cm pitch through cavities. Horizontal rebar in rebate grooves every course.
  4. 04
    Concrete pour — every 5–6 courses
    Filling volume 178 L/m². Keep concrete mid-way through final course. Vibrate with small needle vibrator.
  5. 05
    Curing & finishing
    Blocks remain permanently in place. Render externally and plaster internally after standard curing.
No mortar joints
Dry-stack — no mixing, no waiting. 3–4× faster than traditional masonry.
8 blocks per m²
500 mm length × 250 mm height. Factory-integrated insulation — weathertight as soon as blocks are placed.
Direct finish surfaces
Render externally and plaster internally direct onto wood-cement. No substrate or battening required.
05Certifications
CE · ETA 08/0023
European Technical Assessment
ITC-CNR factory production control. CE marking per EN 15498. EU Construction Products Regulation (CPR). Isotex: European leader with 82% market share in wood-cement sector.
REI 120
Fire resistance
Load-bearing capacity, integrity and insulation maintained 120 minutes. Reaction to fire B-s1,d0. LEPIR II façade test passed.
EPD S-P-01472
Environmental Product Declaration
Bureau Veritas · Accredia. ISO 14025:2006 and EN 15804:2012+A2:2019/AC:2021. Valid until 2029-03-20. Cradle to grave + Module D. 100-year reference service life. 48% recycled/re-used content per m².
EC8 · NTC 2018
Seismic compliance
Eurocode 8 and Italian NTC 2018. Zone 4 verified. 400,000+ eco-sustainable buildings since 1985.
ReMade in Italy
Recycled content
Bureau Veritas certified. 48% per m² recycled/re-used/by-product content. 100% recycled wood from end-of-life pallets. Neopor® BMBcert EPS — Isotex Green (15% recycled) or Isotex Total Green (100% recycled, Class A+).
VOC — Indoor Air Comfort Gold
Indoor air quality
Per UNI EN 16516 · UNI EN ISO 16000-9. Indoor Air Comfort Gold certification. No VOCs released during normal use.
06Isotex HD III 44/14 Graphite Wood-Cement Formwork Block vs traditional cavity wall
SpecificationIsotex systemTraditional cavity wall
Thermal bridges✓ None — integrated EPSWall ties, lintels, reveals
Trades on site✓ 1 (block layer)3–4 minimum
Internal finish✓ Direct plasterBatten + board
Fire rating✓ REI 120 (intrinsic)Separate fire spec
Site waste✓ Minimal — dry-stackMortar, packaging, off-cuts
Seismic✓ EC8 Zone 4 verifiedAdditional engineering req.
07Downloads
Datasheet · PDF
Isotex HD III 44/14 Graphite Wood-Cement Formwork Block technical datasheet
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CE ETA 08/0023 REI 120 EPD S-P-01472
0.21U-value W/m²K
REI 120Fire rating