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Dense concrete blocks 22.5N/mm²   to BS EN 771-3

Products / Dense concrete block 22.5N/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 and 140mm 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.
100mm dense concrete block 22.5N/mm²
Dense Concrete Blocks ~ 22.5N/mm² (OVEN-DRY DENSITY approx 2150 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne multiples of no. per pack
440x100x215 21• 48 44 88
440x140x215 29• 34 32 64
•Blocks in excess of 20kg – please use with caution after assessing the risks.
Download UKCA Declaration
THERMAL CONDUCTIVITY: λ*
1.52 W/mK @ 3% m/c (Inside skin)
1.63 W/mK @ 5% m/c (Outside skin)
THERMAL RESISTANCE:
SIZE mm m²K/W at: m²K/W at:
100mm 3% m/c 0.066 5% m/c 0.061
140mm 3% m/c 0.092 5% m/c 0.086
(m/c = moisture content)
WEIGHTED SOUND INSULATION Rw:**
45 dB (100mm single skin, 258kg/m²)
47 dB (140mm single skin, 345kg/m²)
FIRE RESISTANCE:***
100mm  2 hrs
140mm  3 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 22.5N/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 22.5N/mm² (λ1.52) 0.066
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 5.553 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 22.5N/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 22.5N/mm² (λ1.52) 0.066
13mm dense plaster (λ0.057) 0.023
Inside resitance 0.130
Sum of resistances 5.661 m²K/W
Uncorrected U-value 0.177 W/m²K
Mortar correction 0.000
Air gap correction 0.000
Wall tie correction – Ancon ST1-300 0.004
U-VALUE 0.181 W/m²K

U-Value 0.17

Dense concrete blocks/bricks 22.5N/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 22.5N/mm² (λ1.52) 0.066
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 6.544 m²K/W
Uncorrected U-value 0.153 W/m²K
Mortar correction 0.000
Air gap correction 0.007
Wall tie correction – Ancon ST1-300 0.005
U-VALUE 0.165 W/m²K
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