Masonry unts - Stone, Brick, and Block

• Stone Masonry:

  Also known as stone craft, is the creation of buildings, structures, and sculptor using stone as the primary material. It is the craft of shaping and arranging stones, often together with mortar and even the ancient lime mortar, to wall or cover formed structures. The stones used for stone masonry should be hard, tough and durable.
• Materials used in stone masonry:

  • Sandstone
  • Limestone
  • Flint
  • Slate
  • Granite
• Random rubble

  The cheapest walls, with mortar laid in cement or lime
• Variations of rubble walls

  • Random rubble
  • Random rubble laid to courses
  • Squared rubble
  • Squared rubble laid to courses
• Ashlar

  A style of cut stone laid with great precision and thin mortar, associated with prestigious buildings
• Ashlar

  • Often used to 'frame' rubble walls at higher elevations or surrounding windows
  • Typically a facing material due to expense, requiring structural backing
  • Some ashlar ran through the wall or used header stones to tie in the outer skin
• Common applications of stone masonry in house construction


  • Enduring structures
  • Architectural features
  • Historic solid walls and rubble walls (still applicable for simple structures like garden walls and stone fencing)
• Notable physical properties of stone masonry

  • Durability
  • Aesthetics
  • Expensive (often used in bespoke designs for wealthier clients)
• Bricks


  Traditionally relied on for load-bearing and internal elements, now predominantly used as the outer skin on cavity wall construction
• Brick materials

  • Clay
  • Concrete
  • Other materials
• Actual brick sizes

  • 215mm long, 102.5mm wide, 65mm high
  • Up to 337.5mm long, 225mm wide, 112.5mm high
• Nominal brick size

  225mm x 112mm x 75mm (including mortar joint)
• Mortar joint width


  Normally 10mm, modified slightly depending on brick tolerance
• Brickwork strength


  Depends on designed strength, mortar type, and pointing used
• Brick frost resistance


  Grade must be used below damp-proof course or ground level, and in frost-prone areas
• Brick properties


  • Good insulation (especially clay bricks)
  • Colour depends on impurities in clay or added pigments
• Blocks

  Larger than bricks, with size determined by the weight a bricklayer can lift with two hands
• Common block size


  440mm × wall width × 215mm
• Wall thickness for blocks

  Commonly between 65mm and 225mm
• Concrete blocks


  Made from cast concrete, with Portland cement as the binder and various aggregates
• Concrete block types


  • Solid
  • Hollow (may be filled with foam for insulation)
• Concrete block standards


  Precast concrete blocks should comply with BS EN 771-3
• Concrete block strength


  Varies, with high-density blocks typically having good compressive strength, while insulating blocks may provide minimal support
• Concrete block properties


  • Tend to shrink slightly over time
  • Thermal expansion can vary
• Clay blocks


  Made from a combination of clay, water, and aggregates (usually sand)
• Clay block properties


  • Used internally in buildings
  • Common size: 290mm long x 215mm high
  • Relatively expensive and seen as a luxury material
  • Can be used to reduce weight if needed
  • Difficult to repair or modify, and presents problems for heavy fixings
• Environmental resistance of blocks


  Strictly defined and controlled by standards, key factors for longevity and market success
• Masonry stonework - In early construction, sandstone and limestone were typically used. Although flint, slate, and granite were also used.
• Ashlar masonry is the most durable type of walling, with large stones cut into regular shapes and dressed on all sides.
• Blocks less than 75mm wide are unsuitable for load bearing walls.
• By varying the quantities of cement and nature of aggregate, blocks with different levels of strength and insulation can be formed.
• Dense blocks


  • Suitable for work above and below ground
  • High density means they are good thermal conductors of heat
  • Unsuitable for cavity walls unless insulation is added
  • Provide good sound insulation
  • Ideal for party walls and loadbearing partitions
• Lightweight blocks


  • Incorporate lightweight aggregates
  • Used for internal skins of cavity walls
  • Slightly more expensive
  • Good insulation
  • Easier to handle
  • Poor sound insulation
  • Unsuitable for party walls
• Autoclaved aerated concrete (AAC)


  A particular type of modern lightweight block
• Aerated blocks

  • Made from cement, lime sand, pulverised fuel ash, and aluminium powder
  • Easy to cut, shape, and will directly take the fixings of screws and nails
  • Specific versions suitable for party walls
  • Most common method of forming the internal leaf
• Concrete blocks

  • Absorb water more readily than brick or stonework
  • Require extra protection such as weather boarding, tile hanging, or render
• Aerated blocks

  • Have a closed cell formation
  • Limit moisture absorption
• Mortar

  • Made from fine aggregate (usually sand), and a binding agent (nowadays usually cement)
  • When mixed with water a chemical reaction called hydration occurs
• Precast block benefits: non-combustible, durable, robust, inert, rot resistant sound reduction, good thermal properties.
• Concrete blocks = lower thermal conductivity especially lightweight blocks thus better insulators than brick.  Little thermal movement, but moisture movement in the form of contraction is common as blocks mature and dry out.