Thornton Roofing: Article About Roof Underlayment
Although waterproofing is the most notable purpose for the underlayment that is placed between a roof deck and its covering materials, protection from extreme temperatures, high winds and loud sounds is also an important function. A properly installed felt, synthetic or rubberized asphalt barrier adds to the energy efficiency of the structure and, even in relatively arid climates, is necessary for the prevention of roof leaks. Thornton roofing specialists can offer helpful advice about the best type of underlayment for any home or commercial building. Eaves and valleys are normally covered with a membrane first in case of damaged flashing or winter ice dams. From there, the underlayment is spread over the roof deck and stapled or nailed in place.
If builder's felt is the chosen underlayment material, it may be difficult to lay but will provide more water resistance than its synthetic counterpart. It is asphalt saturated paper that is constructed from either fiberglass or organic substrate. The 30 pound block is thick and stiff in comparison to the 15 pound product and is harder to install. Whether the roof is steep or flat, the underlayment must be overlapped.
The roofing experts at Roof Worx of Thornton CO can assist you with any questions regarding flat roofing or siding.
A low slope requires about 19 inches of overlap so that most of the surface has a double layer, and a two inch overlap works well for a very steep slope. Eaves and rakes have an edge made of metal that the underlayment must overlap. The worker begins the project at the roof edge and smooths out the wrinkles as he progresses toward the ridge. Every side should be covered before the underlayment is attached to the ridge area.
For a less expensive option, synthetic polymers are available. They are usually made from either polyethylene or polypropylene and are lighter than felt. They offer strong UV protection, resist fungal growth, stay wrinkle free and are easy to install because they are not heavy. On the other hand, synthetic underlayment doesn't always comply with local building codes. Wicking can also be an issue. These manmade materials are attached to the roof deck by the same process as builder's felt, but they do not necessarily need to overlap the edge metal on the rakes or at the eaves.
Self adhering materials that are similar to rubber are used as underlayment too. The general term for them is "rubberized asphalt." Since they automatically seal around fasteners and some rolls have a selvedge edge, they are highly watertight. As with roofing felt, rubberized asphalt must overlap the eaves' or rakes' edge metal.