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Stowlite medium dense blocks/bricks 7.3N/mm² to BS EN 771-3

Products / Stowlite medium dense blocks/bricks 7.3N/mm²

The Stowlite concrete block offers the builder an alternative product midway in the range between the dense concrete block and the high performance Fibotherm block. Stowlite blocks are widely used in a number of applications where high insulation is not such a priority. Being lighter than the standard dense block, handling is easier, often making savings on foundations and labour.


Standard Stowlite blocks provide a good finish for rendering. Stowlite 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.
Medium Dense Blocks ~ 7.3N/mm² (OVEN-DRY DENSITY approx 1500 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne multiples of no. per pack
440x100x215† 14.5 68 44 88
440x140x215† 19.5 51 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.
Coursing Bricks ~ 7.3N/mm² (OVEN-DRY DENSITY approx 1500 kg/m³)
Size mm nominal (L x W x H) approx weight kg no. per tonne no. per pack
215x100x65 2.2 465 452
215x140x65 2.8 360 312
Download UKCA Declaration
THERMAL CONDUCTIVITY: λ*
0.63 W/mK @ 3% m/c (Inside skin)
0.67 W/mK @ 5% m/c (Outside skin)
THERMAL RESISTANCE:
SIZE mm m²K/W at: m²K/W at:
100mm 3% m/c 0.159 5% m/c 0.149
140mm 3% m/c 0.222 5% m/c 0.209
(m/c = moisture content)
WEIGHTED SOUND INSULATION Rw:**
44 dB (100mm single skin, 200kg/m²)
46 dB (140mm single skin, 262kg/m²)
FIRE RESISTANCE:***
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)

U-Value 0.18

Stowlite medium dense blocks/bricks 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 Stowlite 7.3N/mm² (λ0.63) 0.159
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 5.646 m²K/W
Uncorrected U-value 0.177 W/m²K
Mortar correction 0.000
Air gap correction 0.002
Wall tie correction – Staifix HRT4-225 0.002
U-VALUE 0.181 w/m²K

U-Value 0.18

Stowlite medium dense blocks/bricks 7.3N/mm²
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) 0.159
13mm dense plaster (λ0.057) 0.023
Inside resitance 0.130
Sum of resistances 5.754 m²K/W
Uncorrected U-value 0.174 W/m²K
Mortar correction 0.000
Air gap correction 0.000
Wall tie correction – Ancon ST1-300 0.004
U-VALUE 0.178 W/m²K

U-Value 0.16

Stowlite medium dense blocks/bricks 7.3N/mm²
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 Stowlite 7.3N/mm² (λ0.63) 0.159
13mm dense plaster (λ0.057) 0.023
Inside resistance 0.130
Sum of resistances 6.637 m²K/W
Uncorrected U-value 0.151 W/m²K
Mortar correction 0.000
Air gap correction 0.007
Wall tie correction – Staifix HRT4-225 0.005
U-VALUE 0.163 W/m²K
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