HDIII Wall System · Formwork Block · Load-bearing

REI 120 Load-bearing CE · ETA 08/0023

Isotex HD III 44/20 Graphite Wood-Cement Formwork Block

Code: HDIII 44/20

The Isotex HDIII 44/20 formwork block is used to create external load-bearing walls. Inside the formwork, there is an insulating insert in eco-sustainable EPS, made of Neopor® BMBcert by BASF up to 100% recycled (Biomass). It has a thickness of 44 cm and a continuous insulating insert of 20 cm, with a concrete cast thickness of 15 cm, as per technical standards. Thermal transmittance U=0.15 W/m²K. The block has the exclusive features of the entire Isotex product range. The wood is mineralised with a natural mineral that makes it inert, therefore resistant to fire (REI120), parasites and atmospheric agents. It has a thickness of 44 cm and a continuous insulating insert of 23 cm, with a concrete cast thickness of 12 cm. Thermal transmittance U=0.11 W/m²K. The wood is mineralised with a natural mineral that makes it inert, therefore resistant to fire (REI120), parasites and atmospheric agents. Reaction to fire B,s1-d0. Excellent facade fire behaviour (Lepir2 Test).

0.15U-value W/m²K

16h 22Phase shift

REI 120Fire rating

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CE · ETA 08/0023 REI 120 EPD S-P-01472 EC8 seismic Bureau Veritas

Thermal performance

0.15 W/m²K

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

EN ISO 6946NZEB ✓

Thermal inertia

16h 22 phase shift

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

EN ISO 13786

Acoustic performance

Class I (best)

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)	0.15 W/m²K
Calculation standard	UNI EN ISO 6946 · UNI EN 10355
Phase shift	16h 22
λ EPS (Neopor® BMBcert)	0.031–0.034 W/mK
λ wood-cement shell	0.10 W/mK
Block density	534 ±10% kg/m³

Physical dimensions

Block length	500 mm
Block height	250 mm
Coverage	8 blocks/m²

Acoustic & structural

Acoustic	Class I (best)
Test standard	UNI EN ISO 10140 · UNI EN ISO 717
Fire resistance	REI 120
Seismic	EC8 · NTC 2018

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.

Reinforced concrete core

Poured in situ, S4 consistency. Cast every 5–6 courses.

—

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

01
Foundation & DPC
Prepare foundation to tolerance. Install DPC. Place vertical rebar at 25 cm pitch protruding ~50 cm before first course.
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.
03
Reinforcement placement
Vertical rebar at 25 cm pitch through cavities. Horizontal rebar in rebate grooves every course.
04
Concrete pour — every 5–6 courses
Keep concrete mid-way through final course. Vibrate with small needle vibrator.
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+).

06Isotex HD III 44/20 Graphite Wood-Cement Formwork Block vs traditional cavity wall

Specification	Isotex system	Traditional cavity wall
Thermal bridges	✓ None — integrated EPS	Wall ties, lintels, reveals
Trades on site	✓ 1 (block layer)	3–4 minimum
Internal finish	✓ Direct plaster	Batten + board
Fire rating	✓ REI 120 (intrinsic)	Separate fire spec
Site waste	✓ Minimal — dry-stack	Mortar, packaging, off-cuts
Seismic	✓ EC8 Zone 4 verified	Additional engineering req.

07Downloads

Datasheet · PDF

Isotex HD III 44/20 Graphite Wood-Cement Formwork Block technical datasheet

Free download

↓ Free

Certificate · PDF

CE certificate — ETA 08/0023

Free download

↓ Free

BIM objects · Request

Revit + ArchiCAD + IFC

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HDIII Wall System family

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U = 0.11 W/m²K

Formwork Block

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Specify Isotex HD III 44/20 Graphite Wood-Cement Formwork Block

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CE ETA 08/0023 REI 120 EPD S-P-01472

0.15U-value W/m²K

REI 120Fire rating