Synthetic Underlayment. Yes, the roof tars can irritate the respiratory tract and aggravate the condition of a person with asthma or other lung conditions. People with asthma should avoid breathing roof tar fumes. This hardwood felt paper is necessary to greatly reduce the chance of any moisture coming up through the subfloor and will help protect the new hardwood flooring. Felt paper is installed under hardwood flooring to provide an extra layer of moisture protection and also to dampen sound.
You will need to install it under your wood floors if a padding is not already attached to the hardwood planks. When using pound asphalt paper, you should not overlap the seams. Unsourced material may be challenged and removed. Tar paper is a heavy-duty paper used in construction. Tar paper is made by impregnating paper or fiberglass mat with tar, producing a waterproof material useful for roof construction. Prospectors during the California gold rush covered the roofs of their temporary shacks with roofing felt , also known as felt paper or tar paper.
Fast forward years and roofing felt is still the most popular roofing material now used as an underlayment being installed today. That, however, may be about to change. Tar paper and roofing felt are somewhat similar in that they both shed water.
It's a generic term and sometimes used synonymously with roofing felt because they are used the same way. Tar paper is less wind and sun resistant than other underlayment systems. If your roof does not have a steep pitch, you can use This weight of felt is a good economic choice if you have a standard roof. But if your roof has a steep pitch, 30 is a better option because it is thicker and tears less during installation.
The next improvement came in the form of heavier papers. Asbestos was used as a waterproofing agent with great success, but as researched emerged detailing the health hazards of that material, use of asbestos in construction had to be discontinued.
Felt underlayment may be made from either organic or fiberglass substrate, although the organic is much more common. It's called "organic" underlayment because it has a cellulose base.
Felt underlayment is water-resistant, but not waterproof. Fifteen-pound felt has a perm rating of about 5, although this number can rise in high-humidity conditions. Thirty-pound felt is more resistant to damage during installation of the roof-covering material, and will protect the roof longer if it should somehow become exposed to weather. The difference is obvious, once you see them together. Thirty-pound felt is much thicker and stiffer. Underlayment: overlap comparison.
In low -slope roofs, which include up to , felt courses should overlap a minimum of 19 inches. This will provide a double layer of underlayment across the entire roof. In steep-slope roofs and steeper , the upper courses of felt underlayment should overlap lower courses by at least 2 inches.
You can see the difference between the underlayment overlapped 19 inches on the roof to the right and overlapped 2 inches on the roof to the left.
In Figure 1 the lower roof is low slope with a inch overlap and the upper roof is steep slope with a 2-inch overlap. Felt is usually fastened with staples, but in high-wind areas, plastic windstrips may be used along the edges to prevent tearing. Edge Metal Laps Felt underlayment should overlap the edge metal at the eaves and be overlapped by edge metal on the rakes.
A number of ASTM standards exist which offer specifications for asphalt-saturated felt. Loss of Volatiles. Over time, volatile compounds in the asphalt will dissipate, and the underlayment will become more fragile and moisture-absorbent. This will happen more quickly when felt is exposed to heat.
The source of heat may be a warm climate, a particular type of roof-covering material, or poor roof-structure ventilation. Anywhere felt underlayment is exposed directly to sunlight, UV radiation will accelerate its deterioration.
These poorly-bonded shingles were attached with staples on a home located in a high-wind area. Installation Damage. Rubberized asphalt underlayments are manufactured to meet different requirements: They may have polyethylene or polyester bonded to the upper surface to provide non-skid and weather-resistant qualities. In Germany the architect Gilly was first to become interested in tar paper roofing, and recommended it in his architecture for the country.
Nevertheless the new style of roof covering was but little employed, and was finally abandoned during the first year of the 19th century. It was revived again in , when people began to take a renewed interest in tar paper roofs, the method of manufacturing an impermeable paper being already so far perfected that the squares of paper were dipped in tar until thoroughly saturated. The roof constructed of these waterproof paper sheets proved itself to be a durable covering, being unimpenetrable to atmospheric precipitations, and soon several factories commenced manufacturing the paper.
The product was improved continually and its method of manufacture perfected. The good qualities of tar paper roofs being recognized by the public, they were gradually adopted. The costly pine tar was soon replaced by the cheaper coal tar. Square sheets of paper were made at first; they were dipped sufficiently long in ordinary heated coal tar, until perfectly saturated.
The excess of tar was then permitted to drip off, and the sheets were dried in the air.
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