This dense concrete common brick is a compact ballast unit used to fine-tune the loading of solar PV ballast trays and racking feet where a full-size block is too large or too heavy for the available space or point loading.
Measuring 215 x 100 x 65mm, this is a Marshalls Dense Concrete Common Brick, a standard 20N/mm² compressive strength dense concrete brick manufactured to BS EN 771-3.
20N/mm²
Compressive Strength
Please Note
This brick's 3kg approximate weight is based on the standard dense concrete brick density for a 215 x 100 x 65mm unit; individual manufacturers do not publish a single confirmed per-brick weight figure, so treat this as a guide and confirm actual delivered weight against your ballast calculation.
Fine Ballast Adjustment
The smaller format allows precise fine-tuning of ballast tray loading where full-size 17kg blocks would overshoot the required weight.
High Compressive Strength
Rated at 20N/mm², considerably higher strength than the standard 7.3N dense block, giving excellent durability under sustained outdoor loading.
Frost & Thaw Resistant
Dense concrete construction is resistant to frost and thawing as well as rain, suitable for permanent outdoor exposure.
Gains Strength With Age
Concrete brick construction continues to gain strength over time, improving durability across the working life of the PV installation.
BS EN 771-3 Compliant
Manufactured to BS EN 771-3: 2011, the British/European standard for masonry units.
Easy to Handle & Distribute
Light enough for single-handed placement into ballast trays, cradles, or between racking feet.
Physical Specification
Weight
Approx. 3kg (guide figure — see note above)
Dimensions (L x W x H)
215 x 100 x 65mm
Compressive Strength
20N/mm²
Standards & Compliance
Manufacturing Standard
BS EN 771-3: 2011
Weather Resistance
Frost and thaw resistant, rain resistant
Thermal Performance
Good thermal control
Application
Primary Use
Fine ballast adjustment for solar PV ballast trays and racking feet
Also Suitable For
General building and landscaping brickwork
Installation
Loaded loose into ballast trays or cradles per mounting system design
Important Safety Information
Always calculate total ballast requirements using your mounting system manufacturer's wind-load tables. Mixing brick and block sizes is common practice for fine-tuning total tray weight, but the total mass, not the unit count, is what must meet the engineering requirement.
What's the difference between this brick and the 17kg ballast block?
This brick is a smaller, lighter unit (215 x 100 x 65mm) used to top up or fine-tune ballast tray weight, while the 17kg block (440 x 215 x 100mm) is the primary bulk ballast unit. Many installers combine both to hit an exact target weight.
Can I mix these bricks with the 17kg blocks in the same tray?
Yes — combining block and brick sizes is a common way to reach a precise total ballast weight per tray or per module without excess. Confirm the combined total meets your system's wind-load requirement.
Is this brick suitable for pitched roof ballast systems?
Some rail-less and lightweight pitched-roof systems use smaller ballast units like this brick for ridge, verge, or hip ballasting. Always confirm compatibility with your specific mounting system's installation manual.
Does the brick need mortar or fixing?
No — when used as PV ballast, the brick is loaded loose into an approved ballast tray or cradle and relies on its mass, not mortar fixing, to provide ballast weight.
What compressive strength does this brick have compared to a standard block?
This brick is rated at 20N/mm², considerably higher than the 7.3N rating of the standard dense ballast block, though for ballast purposes total mass matters more than compressive strength.
