Aggregate - Broken stone, gravel or sand used with cement to form concrete or mortar. Aggregates may be coarse or fine and are often used in construction of “soakaways”

Air brick/vent - A perforated brick built into the wall to provide air for ventilation purposes. Used for instance, to ventilate the underside of a wood floor or a roof space.

Architrave - A moulding around a doorway or window opening. It usually covers the joints between the frame and the wall finish, thus providing a neat finish and hiding any shrinkage gaps which may occur.

Asbestos - Material used in the past for insulation and fire resistance. Can sometimes be a health hazard – specialist advice should be sought if asbestos is found.

Asbestos Cement - Cement mixed with 15% asbestos fibre as reinforcement. It is fragile and will not usual bear heavy weights!  Hazardous fibres may be released if cut or drilled.

Asphalt - Black, tar-like substance, designed to be impervious to moisture. Used on flat roofs and floors.