Roof Structure: Components and Design
A basic roof consists of rafters, ceiling joists, and a ridge board. More complex roofs include braces, valley rafters and jack rafters. The fascia board is the long wooden board behind the gutters.
Let’s get a look at a roof structure diagram to map the roof parts. Rafters are from one end of the roof to the other and act as a support system. The outer rafters at the ends are "common rafters" while between those are "roof rafters". The roof truss is the framework for timbers supporting the roof. It holds struts, rafters and posts.
The roof ridge runs horizontally along the peak of a sloped roof. Hip and ridge shingles are for this roof part. Decking closes and reinforces the roof structure and provides a nailbed for shingles. The eaves are roof edges overhanging a wall. The soffit is the underside of the eaves.
Structural Components of a Roof
The four basic parts of a roof are the roof deck, the underlayment, the shingles, and the ridge cap. The roof deck is the base of the structure, typically made from plywood or oriented strand board (OSB). The underlayment provides weather resistance and can include tar paper, felt paper, or specialty water-resistant membranes.
The roofing structure is essentially the frame that your roof will be constructed on. The structure is a series of trusses, beams and rafters that give the roof its shape and that the roof sheathing is laid upon. Rafters are one big aspect of a roof’s frame. Purlins are additional support for the roof load.
Roof Covering and Aesthetic Features
Roof covering serves as the first line of defense against rain, snow, hail, and UV rays. It also helps to insulate your home and enhance its overall aesthetic appeal. Proper installation of these components is essential for the structural integrity of the entire roof system. Fascia can add an aesthetic element to a property, giving it a more finished look.
The structural elements of a roof are hidden away once the roof has been built. They provide the overall shape of it, however, and are often tasked with distributing its weight along the main building. Ridge boards are thick planks made of timber and metal, placed horizontally along the roof’s peak. Roof trusses are intermediate planks placed in triangular patterns, with the exact angle depending on the number of bearing points.
Understanding Roof Trusses and Decking
The structure of your residential roof begins with the truss. Decking, or roof sheathing, closes and reinforces your roof and provides a nail bed for roofing materials. Underlayment, or underlayment membrane, providing cushioning and waterproofing for your roof. Roof decking connects all structural elements and places where waterproofing materials are installed.
Builders install purlins to enhance prospective roof spans without incurring additional expenditures or jeopardizing wall integrity.
The Peak of the Roof: Ridge Cap
What is the part on top of the roof? The ridge cap tops the peak, while hip and ridge shingles cover this part.