All About Roofing Shingles and Materials
There are four main components common to most roof systems: a lumber framework, felt underlay, a roof covering, and flashing (waterproofing at joints). The options in these four areas are shown and explained here, along with some supplementary items used with the materials shown.
Seek advice from manufacturers when deciding how to install tiles or shingles on a roof. Although it may seem easy to replace like with like, newer regulations may require a different method. If you are planning a new roof, the installation method will be influenced by the pitch of roof, chosen tile type, and prevailing weather conditions. For example, some tiles hook over furring strips that help hold tiles in place. However, in an area prone to driving winds, it may be necessary to nail down some or all of the tiles. Special tiles for ridges and hips are usually secured with mortar, as are verge details. However, many new properties have ridges, hips, and verges finished using waterproof gaskets and screws.
Most popular. Wooden shakes are similar to shingles, but are handmade so have a rougher appearance. A wooden shingle (image 1) is usually made from cedar or redwood and is machine-sawn for smoothness. Asphalt shingles (image 2) may be reinforced with fiberglass for strength and fire resistance and come in sheets of several shingles.
Concrete tiles mimic clay designs and are made to interlock easily. Examples are plain concrete tile (image 1); pan concrete tile (image 2); Roman concrete tile (image 3).
Clay tiles give a traditional look, but cost more than concrete. Plain clay tiles have nail holes and double-lap tile with nibs at the rear (image 1). Pan clay tiles are interlocking single-lap tiles (image 2), and Roman clay tiles have ridges that align all the way down the roof with interlocking single-lap tiles (image 3).
Strong and durable, slate provides long-lasting roofing and is more lightweight than other tiles (image 1). Cheaper synthetic slates are another option (image 2).
Tile manufacturers now produce tiles shaped specially to finish different roof details. Cloaked verge tiles lap over the edge of a gable to finish the roof line neatly, and eliminate the need for any mortar to finish the verge (image 1). Hip tile and hip iron, also known as bonnets, are placed along the hip of a roof. Ridge tiles can be used instead, with a hip iron at the eaves to support them (image 2). Valley tile is shaped tile used in valleys in place of a flashing system (image 3). Ridge tile is an arched tile used to cover a ridge. May also be used along a hip, depending on the roof design (image 4).
For a small repair, choose felt to match what is already on the roof. If you need to lay new felt, think about whether you need it to be breathable—for instance, because the roof space is insulated and/or ventilated in a particular way. Breathable felt, often colored, allows moisture inside the roof to escape, but prevents moisture that is outside from getting in (image 1). Bitumen-reinforced felt, normally black, is very effective waterproof barrier (image 2). Plastic felt is an alternative to bitumen-reinforced felt, both non-breathable. The sheets should overlap to the dotted line (image 3).
Straps and Plates
Metal straps and plates are used to hold lumber together in roof structures—especially in modern trusses. These types of joints and plates make installation much more straightforward, as there is no need to cut complex wooden joints. Since roof structures have so many joints, they can be a considerable timesaver. There are several designs of restraint straps made for various uses and roof types. This rafter fits across the end rafters next to a gable and attaches to the wall (image 1). A timber connector is used to connect trusses to a wall plate and has small holes for fasteners (image 2). A truss clip fastens to a joist and is used to connect trusses to a wall plate (image 3). A heavy-duty truss hanger is more robust and used for deeper joists (image 4).
Flashing Tools and Materials
The waterproofing materials used in valleys, abutments, around chimneys, or at any other joint between different parts of a roof, are known as flashing. Metal flashings such as tin and lead are the most traditional type, and are still widely used despite modern alternatives. Lead flashing, a traditional flashing material, is hardwearing, waterproof and malleable, so it can be easily molded into the desired profile (image 1). Self-adhesive flashing repair is applied over damaged flashing for a repair. Primer may be needed before application (image 2). Glass-reinforced polyester (GRP) is now commonly used as an alternative to lead flashing for valleys and abutments (image 3). A lead dresser is for shaping lead along abutments and over different shaped tile profiles. It has curved and flat faces to suit all roof shapes (image 4).
Poor ventilation in a roof is a major cause of mold. There are a number of different options for ventilating a roof. Ridge and tile vents can be joined with ducting to waste pipes or devices such as a bathroom exhaust fan, but they must not be used instead of a flue for extracting hot combustion gases unless this use is specified by the manufacturer. Tile vents have an integrated vent. They are often plastic, and need to be installed with an underlay seal (image 1). Ridge vents offer direct ventilation channels through the ridge. This may be as part of ridge-tile or in the form of channels that are installed along the lower edge of the tiles as they are laid in place (image 2). Fascia vent clips onto fascia. The channels in the lower section allow for airflow through fascia and into loft space (image 3).