Documents - ASOF

Quick Reference Product Guide

ASOF FAQs

Q. Where are Asphalt Saturated Felt Underlayments used? 
A. They are used in a residential roof system between the roof deck and the primary roof covering. Felts are also used between exterior sub-walls and the primary exterior wall covering for moisture control.

Q. Why is the product required under asphalt shingles?
 A. When used under asphalt shingles it serves as a secondary water resistant membrane against wind-driven rain. Asphalt shingles by themselves are individual roofing components that are subject to uplift by strong wind. Rain that is blown under the shingle is subject to leaking through a seam in the roof decking without a Felt Membrane to deflect it.

Q. What other benefits do they provide? 
A. Asphalt Saturated Organic Felts provide protection from rain in the case individual shingles are damaged or dislodged. Underlayments also minimize "picture framing" of shingles, which is the visible outline of deck panels typically caused by irregularities in roof decking. Underlayments protect asphalt shingles from resins in plywood substrates that can cause damage and a shorter life.

Q. Is there any effect on the Class of fire rating my roof will receive by using an asphalt organic felt underlayment? 
A. Yes. Using the appropriate Underlayments along with the proper decking materials and shingles will help in meeting Class A and/or Class C fire ratings. A shingle by itself is not fire-rated, although it is part of a roof assembly. In many municipalities, a Class A and/or a Class C fire rating is required by code or ordinance for all roofing assemblies.

Q. When should asphalt saturated organic felt be covered? 
A. Immediately! Asphalt saturated organic felt underlayments by themselves are not a waterproof roofing system. Underlayments should be covered by the primary roof covering immediately to protect the integrity of the material as a secondary water-resistant membrane within the roof system.

Q. How should felt underlayments be stored and under what conditions be applied?
 A. They should be stored on end and in the dry. Underlayments should be applied to a smooth, dry roof deck, free of debris. Care should be taken not to damage the product with foot traffic once applied. Damaged product should be replaced before covering.

Q. What are the roll dimensions? 
A. Typically the product comes in 2 Square (200 s.f. of roof coverage) or 4 square (400 s.f. of coverage) rolls and a variety of weights. See specifications for more information.

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Asphalt Saturated Organic Felts

Asphalt Saturated Organic Felts are manufactured from premium quality organic mat and saturated with high-grade asphalt.

Usage

Asphalt Saturated Organic Felts are designed as an underlayment product to be applied over the roof deck prior to the installation of asphalt shingles. Install Asphalt Saturated Organic Felts as a secondary barrier to moisture caused by wind-driven rain and ice damming.

Products

15# ASTM Specification Felt

Meets ASTM D226, Type I
Dimensions- 144' X 36"
Coverage per Roll- 4 Squares
Approx. Sq. Ft. per Roll- 432 Sq. Ft.

30# ASTM Specification Felt

Meets ASTM D226, Type II
Dimensions- 72' X 36"
Coverage per Roll- 2 Squares
Approx. Sq. Ft. per Roll- 216 Sq. Ft.
Also available in 18" Split (108 Sq. Ft.) Roll

PRO 15 Specification Felt

Meets ASTM D4869, Type I
Dimensions- 144' X 36"
Coverage per Roll- 4 Squares
Approx. Sq. Ft. per Roll- 432 Sq. Ft.

PRO 30 Specification Felt

Meets ASTM D4869, Type II
Dimensions- 72' X 36"
Coverage per Roll- 2 Squares

No. 15 Specification Felt

Meets ASTM D4869, Type I
Dimensions- 144' X 36"
Coverage per Roll- 4 Squares
Approx. Sq. Ft. per Roll- 432 Sq. Ft.

No. 30 Specification Felt

Meets ASTM D4869, Type I
Dimensions- 72' X 36"
Coverage per Roll- 2 Squares
Approx. Sq. Ft. per Roll- 216 Sq. Ft.
Also available in 18" Split (108 Sq. Ft.) and Jumbo (180 Sq. Ft.) Rolls

No. 15 Non-Spec Felt

Dimensions- 144' X 36"
Coverage per Roll- 4 Squares
Approx. Sq. Ft. per Roll- 432 Sq. Ft.

No. 30 Non-Spec Felt

Dimensions- 72' X 36"
Coverage per Roll- 2 Squares
Approx. Sq. Ft. per Roll- 216 Sq. Ft.

Storage and Handling

Asphalt Saturated Organic Felts require protection from damage and the weather. Store rolls upright in a dry location and never install when wet or over a wet roof deck.

General Precautions

Asphalt Saturated Organic Felt rolls shall not be installed when wet
The roof deck must be clear of all debris and moisture prior to installing the Felt.
Do not walk on the Felt before fastening it into proper position on the roof deck.
Install the primary roof covering immediately after installation of the Felt.
Observe all Occupational Safety and Health Administration (OSHA) safety requirements during installation.
Organic Felts must be installed as per Tarco published installation guidelines. Follow the National Roofing Contractors Association (NRCA) roofing manual and relevant application guidelines from the Asphalt Roofing Manufacturers Association (ARMA).
Local codes may supersede these instructions. Check with the local building code administrator for specific requirements.

Application

Organic Felt rolls must be installed horizontally, from the bottom of the roof deck.
The first layer of Felt rolls must be installed to cover the entire bottom edge of the roof deck to facilitate the water shedding ability of the Felt.
Anchor the top corner of the Felt roll after it has been properly positioned in place; then spread the roll across the roof. Care must be taken to roll out the Felt smoothly and to avoid any wrinkles as the Felt is unrolled across the roof.
Install fasteners at least eight inches at the top and middle edges and at the eave along the deck.
At slopes between 2:12 and 4:12 pitch, install a double layer of Felt as follows. Apply a minimum 19 inch wide strip of Felt parallel to and starting at the eaves, fastened sufficiently to hold in place. Starting at the eave, apply a full width Felt roll, overlapping successive sheets 19 inches, fastened sufficiently to hold in place.
At slopes 4:12 and greater, a single layer of Felt rolls shall be installed parallel to and starting at the eaves, over lapped at least two inches, and fastened sufficiently to hold in place.
The second course of Felt should be aligned with the roof edge and overlap the first course as described above, according to the roofing slope. Fasten the Felt to the deck and repeat the pattern.
Continue to install the next course of Felt from the roof edge and overlap with the previous course as described above, according to the roof slope. If a new roll is required to complete the installation to the end of the roof, overlap the new roll over the prior roll by at least four inches. Use the same fastening pattern for the top, the middle and the bottom of the roll for all subsequent courses.
The top of each subsequent course should be fastened intermittently to hold the edge in place until the next course is applied. Make certain to secure the fasteners at the bottom of the next course to hold the top of the previous course.
Continue this pattern until the top of the roof. Fasten the top course if it terminates at the top edge of the roof. Otherwise, overlap the Felt over the ridge and fasten it. Repeat the process from the bottom of the other side of roof deck as described above, depending on the slope of the roof.
In valleys, lay a vertical section of the Felt in the middle, along the length of the valley prior to installing a horizontal course of the Felt. If more than one section of Felt is installed in the valley, start at the bottom and overlap the top section by at least two inches to ensure proper shedding of water.
Fasten the Felt in the valleys using the same pattern, taking care to avoid wrinkles. If wrinkles are formed while fastening the Felt, slice the wrinkles and fasten them flat to the deck. Then seal the cuts with waterproofing cement.

Warranty

Asphalt Saturated Organic Felts are warranted to be free from manufacturer's defects.