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Dense concrete blocks/bricks 10.4N/mm² to BS EN 771-3

Products / Dense concrete blocks/bricks 10.4N/mm²

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.


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


All products available ex works. Prices on application. Please contact the sales office for further information and a quotation. For information on packaging click here.
Dense Concrete Block ~ 10.4N/mm² (OVEN-DRY DENSITY approx 2050 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne multiples of no. per pack
440x100x215† 20 50 44 88
440x140x215† 28• 36 32 64
440x190x215 38• 26 24 48
† Also manufactured in close texture. Click here for photos and further information. 
•Blocks in excess of 20kg – please use with caution after assessing the risks.
Coursing Bricks ~ 10.4N/mm² (OVEN-DRY DENSITY approx 2050 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne no. per pack
215x100x65 2.8 340 452
215x140x65 4.2 240 296
Download UKCA Declaration
THERMAL CONDUCTIVITY: λ*
1.39 W/mK @ 3% m/c (Inside skin)
1.49 W/mK @ 5% m/c (Outside skin)
THERMAL RESISTANCE:
SIZE mm m²K/W at: m²K/W at:
100mm 3% m/c 0.072 5% m/c 0.067
140mm 3% m/c 0.101 5% m/c 0.094
190mm 3% m/c 0.137 5% m/c 0.128
(m/c = moisture content)
WEIGHTED SOUND INSULATION Rw:**
45 dB (100mm single skin, 249kg/m²)
47 dB (140mm single skin, 331kg/m²)
49 dB (190mm single skin, 439kg/m²)
FIRE RESISTANCE:***
100mm  2 hrs
140mm  3 hrs
190mm  6 hrs
* Calculated from oven dry density
** Calculated using mass law curve - BS8233 (with 2 skins of dense plaster each 25kg/m²) 
*** Calculated using table NA 3.2 BS EN 1996-1-2 : 2005 (unplastered separating load bearing single leaf walls)

U-Value 0.18

Dense concrete blocks/bricks 10.4N/mm² to BS EN 771-3
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
50mm foil-faced partial fill PIR/PU board (λ0.022) 2.273
100mm dense 10.4N/mm2 (λ1.39) 0.072
15mm dabs 0.170
37.5mm phenolic insulation (λ0.018) 2.083
bonded to…
13mm plasterboard (λ0.21) 0.062
Inside resistance 0.130
Sum of resistances 5.559 m²K/W
Uncorrected U-value 0.180 W/m²K
Mortar correction 0.000
Air gap correction 0.002
Wall tie correction – Staifix HRT4-225 0.000
U-VALUE 0.182 W/m²K

U-Value 0.18

Dense concrete blocks/bricks 10.4N/mm² to BS EN 771-3
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 10.4N/mm2 (λ1.39) 0.072
13mm dense plaster (λ0.057) 0.023
Inside resitance 0.130
Sum of resistances 5.667 m²K/W
Uncorrected U-value 0.176 W/m²K
Mortar correction 0.000
Air gap correction 0.000
Wall tie correction – Ancon ST1-300 0.004
U-VALUE 0.180 W/m²K

U-Value 0.17

Dense concrete blocks/bricks 10.4N/mm² to BS EN 771-3
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
100mm foil-faced partial fill PIR/PU board (λ0.018) 5.556
100mm dense 10.4N/mm² (λ1.39) 0.072
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 6.550 m²K/W
Uncorrected U-value 0.153 W/m²K
Mortar correction 0.000
Air gap correction 0.007
Wall tie correction – Staifix HRT4-225 0.005
U-VALUE 0.165 W/m²K
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