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Dense concrete blocks 7.3N/mm²   to BS EN 771-3

Products / Dense concrete blocks 7.3N/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 75mm, 100mm and 140mm in a standard finish (suitable for rendering). 100mm and 140mm wide blocks are available in close texture finish.


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 blocks 7.3N/mm²
7.3N/mm² (OVEN-DRY DENSITY approx 2000 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne multiples of no. per pack
440 x 75 x 215 14 72 60 120
440 x 100 x 215† 19 53 44 88
440 x 140 x 215† 27• 37 32 64

† 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.

Download UKCA Declaration
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:
75mm 3% m/c 0.056 5% m/c 0.052
100mm 3% m/c 0.075 5% m/c 0.070
140mm 3% m/c 0.105 5% m/c 0.098
(m/c = moisture content)
WEIGHTED SOUND INSULATION Rw:**
44 dB (75mm single skin, 202kg/m²)
45 dB (100mm single skin, 244kg/m²)
47 dB (140mm single skin, 325kg/m²)
FIRE RESISTANCE:***
75mm @60% loading  ½hr
100mm  2 hrs
140mm  3 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 NA 3.2 BS EN 1996-1-2 : 2005 (unplastered separating load bearing single leaf walls)
(m/c = moisture content)

U-Value 0.18

Dense concrete blocks 7.3N/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 7.3N/mm² (λ1.33) 0.075
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 5.562 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 7.3N/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 7.3N/mm² (λ1.33) 0.075
13mm dense plaster (λ0.057) 0.023
Inside resitance 0.130
Sum of resistances 5.670 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 0.182 W/m²K

U-Value 0.17

Dense concrete blocks 7.3N/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
110mm foil-faced partial fill PIR/PU board (λ0.018) 5.356
100mm dense 7.3N/mm² (λ1.33) 0.075
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 6.553 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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