Roseville Roofing: Article About Importance Of Underlayment
Underlayment is a material installed between a roofing material, such as asphalt shingles, and the bare roof sheath. This material is generally required by building codes but may only be necessitated for new construction. A primary purpose of such material is affording temporary protection while a roof cover is being installed. A common problem faced in new construction is that roofs and even interiors will remain exposed because of the sheer amount of roofing that needs to be performed.
Most Roseville roofing professionals will install underlayment for reroofing projects as well. Although the building code may not apply in such scenarios, it is a good practice, many roofing manufacturers advise it, many insurance companies demand it and many homeowners request it. This is because underlayment serves as a moisture barrier, which means that if water does seep beyond the shingles, such material will provide a secondary barrier against leakage. The waterproofness of material used in these scenarios is gauged using a permeability rating.
Underlayment also serves two other very important purposes for many homes: fire resistance and the avoidance of chemical degradation. Materials used for underlayment are usually fire retardant and increase the fire resistance of the entire roof. In fact, this type of material is usually the only way to achieve a Class A fire rating when installing wood shingles or shake.
The roofing experts at Allstate Roofing of Roseville CA can assist you with any questions regarding gutters or residential roofing.
Underlayment also helps to ensure that chemicals in the roof material do not react with chemicals in the treated boards used for sheathing because of the chemical degradation that this can cause.
Although not required in all areas, underlayment can serve as an ice barrier. In cold climates, ice can form on a roof, remain there for a long period and actually melt from the bottom up due to heat from the home. This kind of melting ice on a roof is called an ice dam, and it can actually force water beneath the shingles covered by ice. Ice barriers are used to ensure that water does not reach the roof structure.
Homeowners should always require new underlayment when they have their roof replaced, and they should ensure that the appropriate underlayment for the roof and the climate is chosen. Note that on steep roofs underlayment is generally not used and may be detrimental, which is why a roofer may recommend against it. Some homeowners opt to install a second shingle layer over a first in order to avoid the cost of a tear off, but keep in mind that this practice prevents inspection and replacement of the underlayment.