Question 1

What is a 7n concrete block?

Accepted Answer

A 7n concrete block is defined by a minimum compressive strength of around 7 newtons per square millimetre (7 N/mm²). It meets BS EN 771-3 standards and comes in solid or hollow forms, with typical dimensions 440 mm long by 215 mm high, and thicknesses of 75 mm, 100 mm or 140 mm.

Question 2

What are the typical weights of 7n concrete blocks?

Accepted Answer

Weight varies with thickness and density. For example, a solid dense block 440 × 215 × 100 mm weighs around 18–20 kg.

Question 3

Are 7n concrete blocks different from 7.3 n blocks?

Accepted Answer

In practice, “7n” and “7.3 n” descriptions refer to similar compressive strength - 7.3 N/mm² is a more precise figure found in many dense concrete blocks. This minor difference has minimal impact on suitability, unless project specs call for exact strength values.

7n concrete blocks

100mm Celcon H+H High Strength Grade Plain Face 7.3N Block

Tarmac Topcrete Solid Dense Hollow 7.3N 440 x 215 x 215mm

Masterblock Lightweight Block 7.3N 440 x 215 x 140mm

Thermalite HiStrength Aircrete Block 7N 100mm

AI Masterblock Solid Dense 7.3N 440 x 215 x 140mm

Newlay Newcon Solid Dense Block 7.3N 440 x 215 x 100mm

Thomas Armstrong Dense 7.3n Standard Block 440 x 215 x 140mm

Stranlite 7.3N 140mm Medium Dense Standard Block

Fibolite 7.3N 100mm Lightweight Concrete Blocks