Rainscreens and Curtain walls

Rainscreen

a cladding that stands off from a moisture resistant breather membrane on the outside of a building roof or wall, creating a ventilated cavity and to allow drainage and evaporation. They give visual continuity to the outside of a building.

Lining

a covering/coating for an inside surface

Demountable partition

a partition that can be taken down and moved without involving wet trades or damage to finishes, mainly used for office buildings. It is held in place by screw acks or a receptor channel. There are many systems, the best being relocatable, but in general partitions which are easiest to move also give the lowest sound insulation.

Cold bridge

a piece of conducting substance that passes through a wall and carries heat through it. Therefore the inner surface of the wall round the substance will be warm in summer and much colder in winter than the remainder of the wall, causing condensation to form there.

Pantile

a single-lap interlocking roof tile shaped like a shallow 'S' made of clay or concrete. Standard British small clay pantile measures 355 x 240mm.

Gypsum

a solid white mineral which is heated and used as a binder in gypsum plasters. Also the final stage of these plasters after they have set. Mainly mined, but also an industrial by-product. Saturated gypsum can cause sulphate attack on mortar and concrete.

Stanchion

a steel column

Natural bed

a stone is laid on its natural bed when its bedding planes are horizontal. This is advisable for load bearing stones, especially out doors.

Lath

a thin, narrow strip of straight-grained wood used under roof shingles or tiles, on lath and plaster walls and ceilings to hold plaster, and in lattice and trellis work

Powder coating

a tough durable factory-applied organic coating on metals, such as aluminium or galvanised steel. Available in many colours, powder coatings are sprayed on followed by heat curing to give a film thickness of 50-100microns.

Lining paper

a wall covering made entirely of paper

Fibre cement

cement with cellulose fibre reinforcement, which makes the material even stronger. It is considered as a material physically suited for construction products such as cladding and roofing. Comes as lightweight cement boards which act like waterproof plasterboard. Can also be used as small slates.

Bimetallic action

corrosion from dissimilar metal contact. Can be avoided by separating metals using bitumous paint or rubber insulator

Unitised system

A curtain wall made of large glazed units which are fully factory assembled, lifted into place by a crane and bolted to the building structure.

Stick system

A curtain wall mostly assembled on site, from the interior of the building or from flying scaffolding. Mullions and transoms are bolted to a lightweight framework fixed to the face of a building followed by the fitting of glazing and opaque panels.

Cover(concrete)

Extra thickness of concrete to protect the reinforcement as concrete corrodes. Depends on exposure to elements e.g. seawater. Depth of concrete elements should be a min of 100mm to get cover either side of reinforcement. For reinforced columns, the min depth should be 200-250mm

GRC

Glass fibre reinforced concrete. Used mainly in exterior building façade panels and as architectural precast concrete. Somewhat similar to fibre cement siding and cement boards. It can be extremely lightweight and thin but can be brittle and is relatively expensive

GRP

Glass fibre reinforced polyester, or plastics. Can come in different colours and formed into any shape. Often used as a rainscreen, hung on a steel or concrete frame. Or has rubber gaskets at seams to create a sealed cladding. However, it is weak, expensive and subject to UV degradation

Geotextile felt

permeable fabrics, which, when used in association with soil, have the ability to separate, filter, reinforce, protect or drain. Typically made from polypropene or polyester, the fabrics can come in three types: woven, needle punched or heat bonded.

Structural glazing

system of bonding glass to a building's structural framing members utilizing a high strength, high performance silicone sealant. Dynamic wind loads are transferred from the glass, by the structural silicone sealant, to the perimeter structural support.

Spalling

the crushing of an edge or corner of masonry or precast concrete or the general flaking of a surface. Commonly happens under window sills.

Render

the mortar or other mix used for rendering or stucco work

Plain tile

the traditional flat roof tile of concrete or burnt clay which has a slight spherical camber. Its standard size in britain is 265 x 165 mm and 10-15mm thick. Has at least two nibs an the head and two nail holes.

Sandpaper

tough paper coated with powdered abrasive such as emery, garnet or glass. Different grades of coarseness are used for sanding, flatting-down, rubbing-down, wet rubbing and polishing

Shiplap boards

weather boards of rectangular cross section with a rebate cut on each edge fitting into corresponding rebates on the neighbouring boards.

Feather-edged boards

weatherboards tapered from 16 to 6mm

Patent glazing

glass or similar materials used as an external cladding, usually for industrial buildings such as factories and warehouses. Most systems have strips of glass supported on two edges by metal glazing bars up to several metres long which are set at 600mm spacings.

Oil paint

high quality paint containing a large percentage of drying oil such as linseed, soya or tung oil, and a synthetic resin such as alkyd. It dries by evaporation of any solvent, then the oxidisation of the oil which usually has driers. Oil paints are used for final paints, usually in gloss, undercoats, and some primers.

Plaster dabs

liquid dabs of plaster used to fix angle beads and similar metal trim. For angle beads they are at 600 mm intervals, for plasterboard they are 300mm spacing horizontally and 450mm vertically

Expanded metal lathing

metal lath- any of a variety of metal screening or deformed and expanded plate used as a base for plaster. The metal lath is attached to wall studs or ceiling joists

Profiled metal cladding

metal panels of various shapes, heights, thickness and materiality used for a variety of different buildings. Panels come in standard dimensions and can come with integrated insulation. Deeper corrugations increase strength of panel. Direction of corrugations depends on the way the panels are spanning, but should avoid horizontal so water can run off.

Metal sheet cladding

metal sheet (zinc, aluminium, copper etc.) used to clad timber frame buildings. The metal sits on top of geotextile felt on plywood, battens behind to provide ventilation, breather membrane, insulation between studs, vapour barrier, plasterboard.

Curtain wall

non loadbearing façade cladding, usually with sheets of glass held in a metal frame, giving a decorative and durable external skin to a building while saving weight and space. Similar to patent glazing, but used in offices and public buildings. Can also be held by patch plates and fins to give an uninterrupted surface on one side (rail to stop people walking into fins). Complete systems are factory made and quickly erected on site by specialists allowing early enclosure of the building. Installation usually involves no wet trades. Some systems allow openings to be left in the façade, giving the crane access for later trades. Most systems have aluminium bars with grooves for gasket glazing and drainage, and thermal breaks in cold climates. Weather tightness against driving rain is achieved by pressure-equalised joints and drained ventilated joints.