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  • Writer's pictureJessica Foster

How is Roof Construction Regulated?

The roof of any building is on the front line between the rest of the structure and exterior forces such as rain. So, it’s crucial that all parts of roof construction are handled with expertise and care, to ensure that not only the roof is impervious, but that the rest of the structure is kept safe. The International Residential Code sets minimum guidelines so that both these conditions can be met.

One force that must be accounted for is wind and how it can enter under the roof into the attic. Collar ties are used to tie rafters together the top part of the roof to keep the roof from spreading. The exact location is the upper third of the attic space according to the IRC, and collar ties must not be less than 1x4 inches nominal, and spaced not more than 4 feet on center. Ceiling joists also provide support for the rafters and are continuous throughout the structure, but opposite of collar ties, they contribute to keeping the bottom part of the roof from spreading. The IRC regulates the size of ceiling joists based on criteria such as the joist spans. These regulations ensure that the roof is kept together when it is met by wind forces, so that the roof isn’t moved, or in extreme cases, ripped off.

To continue on with support, trusses are an integral part for roofs. A truss is a triangular framework that supports the roof, put in the space above a room. Before a truss is installed, a design drawing must be prepared which includes: location of all joints, required bearing width, slope/depth, span and spacing, and so on. Another requirement is that a truss can’t be altered in any shape or form unless it is approved by a professional. Trusses must also be braced to prevent them from moving, helping create lateral stability.

Another aspect of roof construction that is crucial is ventilation. During extreme heat, proper ventilation helps the air flow in the attic space, keeping this area cool while also keeping moisture build up regulated. This can cut costs to air conditioning, and keeping moisture in check will protect the rest of the building from damage. The IRC states that ventilation openings shall have a least dimension of 1/16 inch minimum and 1/4 inch maximum. Aside from some exceptions due to climate, the minimum vent area shall be 1/150 of the area of the vented space. For ventilation,these openings need to open to outside air while keeping things such as birds, rodents, and snakes out. There must also be insulation clearance, so that insulation does not block the flow of air.

Roofs are an integral part of any building, and multiple components go into making sure they are up to dealing with exterior forces. When it comes to your renovation project, the last thing you want to do is pay the price of a poor roof installation. Here at Fine Remodeling, we are your Delaware contractor experienced with the guidelines set by the IRC and other facets of roof construction, making sure that not only is your roof up to code, but that it goes beyond just satisfactory. Call to review your next project with us so you can be sure it’s done right the first time.

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