Lightweight Concrete Blocks

Lightweight Concrete Blocks

Face Dimensions: 440mm x 215mm

Thickness (mm) Form Paint grade Metres per pack Approx density (Kg/m3) Approx weight (Kg) Standard strength (N/mm2) Approx drying shrinkage (1%) λ(W/mK) at 3%m.c λ(W/mK) at 5%m.c R (m2K/W) at 3%m.c R (m2K/W) at 5%m.c Approx built weight (Kg/m2) Notional fire resistance (HRS) Sound reduction value (dB)
75 S * 11.0 950/1000 6.92 7.3 0.045 0.285 N/A 0.268 N/A 78 N/A 46
100 S * 9.0 950/1000 9.25 3.6/7.3 0.045 0.285 N/A 0.357 N/A 104 2 48
140 S * 6.0 950/1000 12.91 7.3 0.045 0.285 N/A 0.491 N/A 145 3 51
140 H * 6.0 670 9.0 3.6 0.045 0.285 N/A 0.268 N/A 102 2 48
150 S * 6.0 950/1000 13.84 7.3 0.045 0.285 N/A 0.534 N/A 156 6 52
190 S * 5.0 950/1000 17.52 7.3 0.045 0.285 N/A 0.679 N/A 197 6 54
215 S * 4.0 950/1000 19.83 7.3 0.045 0.285 N/A 0.768 N/A 223 6 55
215 H * 4.0 670 14.0 3.6 0.045 0.285 N/A 0.637 N/A 159 2 52

* = To order only

Suitable for use

Further information refer to BS 5628 : Part 1 : 2005 Code of Practice for the structure use of masonry.

Block Composition

Lightweight building blocks are manufactured using crushed and graded volcanic pumice. The material fully complies with the requirements of BS EN 13055 : Part 1 & BS EN 1744 : Part 1. The binder is generally ordinary Portland cement or a propri- etary rapid hardening Portland cement.


Standard quality lightweight blocks are available from stock with a minimum average compressive strength of 3.6N/mm2 . Higher strengths of 7.3N/mm2 are available, but to order only. Further information on high strength lightweight blocks is available from our sales department.

Thermal Properties

The thermal resistance (m2K/W) of the various lightweight blocks is tabulated to provide component values that can be combined with similar information on other components forming external wall construction thus enabling the calculation and comparison of the overall thermal conductivity of different constructional solutions. The K values (W/mK) are based on the standard values of lightweight blocks given in the CIBSE guide A : Environmental Design.

Moisture Movements

Drying shrinkage will not exceed the limiting values specified in BS EN : 772-14 : 2002 when measured in accordance with that specification. Drying shrinkage may not occur if the product is used in permanently damp conditions.

Built in Weight

The figures given are for single leaf construction excluding wall finishes.

Notional Periods of Fire Resistance

Figures given above are for load bearing single leaf, unplastered construction. Lightweight concrete blocks are non combustible and conform to Class 0 rating for the surface spread of flame. For further information refer to BS 5628 : Part 3 : 2005.

Paintgrade Quality

In addition to our standard quality lightweight blocks range, we have available a range of blocks manufactured for the purpose of receiving direct decoration systems. This block should not be used for rendered finishes and it should be noted that it is not intended for fair faced work as the product may be subject to shade and texture variations.

The general properties of this range of blocks is as given for standard quality lightweight blocks.


Lightweight brickettes are available for use in areas of block work where closure or coursing details are required to be carried out in similar density materials.
Brickettes enable this work to be accomplished neatly and provides the sensible alternative to cutting full blocks.

Lightweight Concrete Brickettes

Size (mm) Form No/Pack Approx weight (Kg)
100 x 215 x 65 No frogs or holes 416 1.9

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