Felt roofing underlayment is typically available in two types.
15 or 30 felt under metal roof.
Generally speaking roofing felt is a felt paper that is soaked in asphalt and other water resistant compounds to produce a membrane.
With metal roofing its also a good idea to put a layer of red rosin paper between the felt or ice water.
That is the quesation.
Asphalt saturated heavy duty roofing felt is available in 15 and 30 pound weights.
It serves as a moisture barrier as well as a slip sheet.
Plywood or osb roof deck so 15 20 or 30 will work for any shingle roof the type i recommend depends on roof slope.
The best underlayment for metal roofs.
There are several types of felt underlayment including both organic reinforced and inorganic reinforced.
When hot roof construction is done a roof with no ventilation a breathable underlayment is recommended.
Underlayment must also act as a secondary weather barrier in case the roof fails.
Felt is commonly sold in either 15 or 30 rolls measuring 36 inches wide.
What is roofing felt.
30 felt is typically thicker stronger and may be less prone to tearing or ripping off during installation or weather events.
The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material.
The main advantage of using felt roofing underlayment is cost.
The traditional and most common material used for roof underlayment on a steep slope metal roof is non perforated asphalt impregnated felt underlayment.
Felt paper or not under metal rofing.
Traditionally metal roofs have used standard 30 pound felt paper underlayment.
15 lb felt paper weighed 15 pounds per 100 sq.
The difference between 15 lb and 30 lb roofing felt paper.
In the old days common felt was 15 lb felt and 30 lb felt and a roll of the first held 4 squares and weighed 60 lbs while a roll of the second held 2 squares and weighed 60 lbs.
Of course it is a bit more technical than that but this is the basic idea behind how felt works.
Make sure the product is designed to be used under metal.
The house is in eastern tn.
Once again this is used on cold roof construction.
The best weight for roofing felt is the 30 pound product because it provides thicker and.
Historically roofing felt paper was named for weight.
Other say need felt because of sweating and it will root the osb 30 felt or not.
15 came perforated for use as a ply sheet for built up roofing.
Most codes and good roofing practice would require felt.
Felt paper is commonly produced with a certain number of recycled products and coated with asphalt.
One roofing square and 30 lb felt paper weighed 30 pounds per square.
