CSCS Roof Felting key terms

A careful examination of what in your work could cause harm to people, so you can weigh up whether you have taken enough precautions or should do more to prevent harm.

A document that describes the safe system of work for a task, including the sequence of steps, the hazards involved, and the control measures to be used.

Equipment worn or held by a person to protect against one or more health and safety risks, such as gloves, safety footwear, helmets, and eye protection.

A formal written system used to control certain types of high-risk work, ensuring that specified precautions are taken before and during the task.

Work involving open flames, sparks, or heat that could ignite materials, such as welding, grinding, or using a blowtorch; requires special precautions and often a permit.

A dark, sticky, waterproof substance obtained from petroleum refining or natural deposits, used as a binder and waterproofing agent in roofing felts and coatings.

Bitumen blended with styrene-butadiene-styrene polymer to improve flexibility, elasticity, and low-temperature performance, commonly used in roofing membranes.

Bitumen modified with atactic polypropylene polymer to increase heat resistance and hardness, often used in torch-applied membranes for high-temperature performance.

A material such as polyester or glass fibre embedded in a bituminous membrane to provide strength, dimensional stability, and resistance to tearing or puncturing.

A bituminous sheet material with a heat-activated adhesive backing that is bonded to the substrate by melting the bitumen with a gas torch.

A bituminous or synthetic sheet with a pressure-sensitive adhesive backing that bonds to the substrate without the need for heat or additional adhesive.

A liquid coating applied to a substrate to improve adhesion of the waterproofing membrane and to seal dusty or porous surfaces.

A membrane installed on the warm side of insulation to restrict the passage of water vapour into the roof construction, helping to prevent condensation.

Material used to reduce heat transfer through the roof, typically installed above or below the waterproofing membrane depending on the system design.

A roof construction where the insulation is placed above the structural deck and below the waterproofing, keeping the deck at a temperature close to that of the interior.

A roof construction where the insulation is placed between or below the structural deck, leaving a ventilated void above it to remove moisture and prevent condensation.

The surface to which the waterproofing membrane is applied, such as concrete, timber, or metal decking.

The structural surface of a roof that supports the insulation and waterproofing system, often made of concrete, timber, or profiled metal.

The slope of a roof surface, expressed as an angle or ratio, designed to allow water to drain to outlets or gutters.

The overlap between adjacent rolls or layers of membrane, which must be sufficient to ensure a watertight joint and is typically specified by the manufacturer.

The overlap between the long edges of adjacent membrane rolls, usually narrower than the end lap and critical for watertightness.

The overlap between the short ends of membrane rolls, often wider than the side lap to provide a secure joint.

The joint formed where two pieces of membrane overlap and are bonded together, by torching, adhesive, or other approved method.

The vertical extension of the waterproofing membrane at edges, walls, or parapets, turned up to prevent water ingress.

A piece of material, often metal or membrane, used to waterproof junctions between the roof and other building elements such as walls, chimneys, or penetrations.

The method of securing and sealing the top edge of an upstand or flashing to prevent water from getting behind the waterproofing.

A fitting that allows water to drain from the roof into the rainwater system, such as a gully or spout.

Any object that passes through the roof waterproofing, such as a pipe, vent, or cable, requiring a sealed detail to maintain watertightness.

A system of equipment, such as a harness and lanyard, designed to stop a person's fall and minimise injury if a fall occurs.

A barrier installed along the edge of a roof or opening to prevent people from falling.

A system of barriers or guards placed at the edges of a roof to prevent falls of people or materials.

A tool that mixes fuel gas with air or oxygen to produce a hot flame, used for heating and melting bitumen in torch-on membrane application.

A portable device containing an extinguishing agent, used to put out small fires; required on site during hot works.

The system of falls, outlets, and gutters that removes water from the roof surface to prevent ponding and water ingress.

The accumulation of water in depressions on a roof surface that does not drain away within a specified time, often indicating insufficient fall or deflection.

A raised, bubble-like defect in a membrane caused by trapped air or moisture expanding under heat, which can lead to membrane rupture.

The formation of ridges or folds in a membrane, often due to poor installation, thermal movement, or inadequate bonding, which can lead to premature failure.

A method of testing a roof's watertightness by temporarily ponding water over the surface and observing for leaks, typically before the final finish is applied.

A non-destructive test for electrically conductive membranes or liners, where a high-voltage spark is passed over the surface to detect pinholes or defects.