Dense concrete blocks
7.3N/mmto BS EN 771-3

Stowell dense concrete blocks offer the builder a full range of solid concrete blocks with a well-established durability, low drying shrinkage and proven acoustic properties that will fulfil most applications. They are manufactured to BS EN 771-3 using Class 1 limestone aggregates and recycled aggregates.

The blocks are available in a standard face size of 440 x 215mm and in thicknesses of 75mm, 90mm, 100mm, 140mm and 190mm in a standard finish (suitable for rendering).

100mm, 140mm and 190mm wide blocks are available in close texture finish, please CLICK HERE for more information.

7.3N/mm2 (OVEN-DRY DENSITY approx 2000 kg/m3)
Size
mm
nominal
approx
weight kg
no. per
tonne
multiples
of
no. per
pack
440 x 75 x 215 14.0 72 56 112
440 x 90 x 215 16.5 60 48 96
440 x 100 x 215† 18.5 54 44 88
440 x 140 x 215† 26• 38 32 64
440 x 190 x 215† 35• 28 24 48

• Blocks in excess of 20kg – please use with caution after assessing the risks.
† Also manufactured in close texture.

U-Value 0.18 Dense Concrete Block - option 1
Outside resistance 0.040
19mm sand/cement render (λ1.00) 0.019
100mm dense 7.3N/mm2 (λ1.43) 0.070
50mm low emissivity cavity 0.640
50mm foil-faced partial fill PIR/PU board (λ0.022) 2.273
100mm dense 7.3N/mm2  (λ1.33) 0.075
15mm dabs 0.170
45mm phenolic insulation (λ0.020) 2.250
bonded to…
13mm plasterboard (λ0.21) 0.062
Inside resistance 0.130
Sum of resistances 5.729 m2K/W
Uncorrected U-value 0.175 W/m2K
Mortar correction 0.000
Air gap correction 0.002
Wall tie correction – Staifix HRT4-225 0.000
U-VALUE  0.177 W/m2K
U-Value 0.18 Dense Concrete Block - option 2
Outside resistance 0.040
19mm sand/cement render (λ1.00) 0.019
100mm dense 7.3N/mm2 (λ1.43) 0.070
170mm high performance mineral wool (λ0.032) 5.313
100mm dense 7.3N/mm2 (λ1.33) 0.075
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 5.670 m2K/W
Uncorrected U-value 0.176 W/m2K
Mortar correction 0.000
Air gap correction 0.002
Wall tie correction – Ancon ST1-300 0.004
U-VALUE 0.180 W/m2K
U-Value 0.18 Dense Concrete Block - option 3
Outside resistance 0.040
19mm sand/cement render (λ1.00) 0.019
100mm dense 7.3N/mm2 (λ1.43) 0.070
50mm low emissivity cavity 0.640
110mm foil-faced partial fill PIR/PU board (λ0.022) 5.000
100mm dense 7.3N/mm2 (λ1.33) 0.075
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 5.997 m2K/W
Uncorrected U-value 0.167 W/m2K
Mortar correction 0.000
Air gap correction 0.007
Wall tie correction – Ancon ST1-300 0.005
U-VALUE 0.179 W/m2K

THERMAL CONDUCTIVITY: λ*
1.33 W/mK @ 3% m/c (Inside skin)
1.43 W/mK @ 5% m/c (Outside skin)

THERMAL RESISTANCE:
SIZE mm m2K/W at: m2K/W at:
75 3%m/c 0.056 5%m/c 0.052
90 3%m/c 0.068 5%m/c 0.063
100 3%m/c 0.075 5%m/c 0.070
140 3%m/c 0.105 5%m/c 0.098
190 3%m/c 0.143 5%m/c 0.133
(m/c = moisture content)

WEIGHTED SOUND INSULATION Rw:**
44 dB 75mm single skin, 202kg/m2
45 dB 90mm single skin, 230kg/m2
45 dB 100mm single skin, 244kg/m2
47 dB 140mm single skin, 325kg/m2
49 dB 190mm single skin, 431kg/m2

FIRE RESISTANCE:***
75mm (single skin unplastered)
½hr @60% loading
90mm (single skin unplastered) 1 hr
100mm (single skin unplastered) 2 hrs
140mm (single skin unplastered) 3 hrs
190mm (single skin unplastered) 6 hrs

TRANSVERSE TESTING:
100mm minimum 3.5kN

* Calculated from oven dry density
** Calculated using mass law curve – BS8233 (with 2 skins of dense plaster each 25kg/m2)
*** Calculated using table 14 BS5628-3 2005 and BSEN 1996-1-2


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All products are available ex works.
Prices on application.
Telephone our sales office for further information and quotations.