A brief guide to building terminology

Building in the 21st century is about combining traditional craft skills while moving with the times to utilise new materials and processes.

Materials and processes most commonly used in house building.

Aggregate - small stones and chippings. Different sizes and combinations of aggregates are used for numerous purposes: for example in concrete or as a sub-base material between the ground and the next layer of material.

Graded aggregate - a mixture of particle size. Changing the size ratio produces different qualities in the concrete mix or sub-base.

Bricks - usually made from fired clay but can be made from fine concrete.

Facing bricks - bricks with the appropriate visual appeal -usually clay.

Commons - bricks for areas that will not be seen - usually concrete.

Engineering bricks - high strength bricks used where special structural properties are required.

Blocks - (blockwork) made from concrete; larger than bricks. Cheaper to buy and faster to lay. Used for internal walls mainly but can be used for external walls, in which case, usually rendered.

Cement - the grey powder used to make concrete. Usually manufactured by combining tricalcium silicate (3CaO. SiO2), dicalcium silicate (2CaO. SiO2), tricalcium aluminate (3CaO. Al2O3), and a tetra-calcium aluminoferrite (4CaO) in a kiln.

Cladding - any material used on external walls. In the USA the term used is 'sidings'.

Concrete - a mixture of cement, aggregates and water. Changing the ratios of the constituents determins the characteristics of the concrete.

Foundation / footings - usually the concrete in a trench that supports the structure.

Strip foundations - a foundation for the wall part of the structure.

Raft foundations - a load-bearing concrete slab - necessary when ground conditions are a problem.

Piles - concrete-and-steel (or steel sheets) that go deep into the ground to reach good quality load-bearing strata. Piles can be bored with an auger or driven with a pile driver.


Acoustic - sound insulation between parts of the building. Relies on a combination of high density materials but with discontinuity to prevent sound transmission while preserving structural integrity.

Thermal insulation - relies on low density material, usually mineral fibre, or one of a number of types of special foam products.

Lining - any material used on internal walls - usually plasterboard.

Plaster - usually a gypsum-based compound trowelled on to plasterboard.

Dry-lining - usually plasterboard without a wet plaster overlay. Jointing compounds and scrims may be used to smooth over any joints.

Plasterboard - composite of gypsum with thick paper covering. Usually 9mm or 12mm thick. Has good accoustic and fire resistance properties.

RSJ - Rolled Steel Joist. A steel beam, usually an “I” section. A lightweight alternative to reinforced concrete beams. RSJs may require cladding to meet fire regulations in certain situations.

Reinforced concrete - a combination of concrete and steel bars. The strength of the concrete can be varied by altering the ratio of cement and aggregate grading. There are two types of steel bar reinforcement: mild steel and high yield steel, the choice of which will depend on the assessment of the load to be carried by the beam. Steel mesh reinforcement is used in intermediate floor slabs and raft foundations.

Sarking - in England and Wales usually a fabric which is waterproof yet vapour permeable. This is the underlay beneath the roofing slates or tiles. In Scotland and elsewhere a rigid board is traditionally preferred.

Slates - thin roofing or cladding material. Originally made from Welsh slate in the UK. Composite versions are now available that are more economical and have a similar appearance.

Tiles - roofing or cladding material originally made from clay but now available in a number of cementitious versions. Tiles are usually thicker than slates.

To meet the dual requirments of constructing houses that are inkeeping with the local environment and at the same time meeting ever stricter regulations on energy conservation, global warming, polution and recycling, it is necessary to cherish the old ways but embrace the new by taking the time continually to train and to learn new skills and processes.

M: 07540 579593

Email: charltonspmc@gmail.com

Charltons PMC Ltd. logo.
FMB member.