Skip to main content

A superior elastomeric modified asphalt underlayment for tile, shingle, and metal roofs.

LayfastSBS® Roofing Underlayment

LayfastSBS® is a superior and competitively priced alternative to traditional 30 and 40 lb organic felt. The addition of SBS rubber to asphalt gives LayfastSBS® an elastomeric property that is not available in common felt. LayfastSBS® contains a higher percentage of asphalt for increased waterproofing. Its inorganic fiberglass reinforcement eliminates the rot and deterioration associated with saturated felt.

LayfastSBS® is available in three weights, 35-43-70 lbs/square. It can be used in lieu of 30 and 40# felt as an underlayment under shingle, tile, and metal roofs.

LayfastSBS® is ICC (formerly ICBO) approved and complies with ASTM D226 standards, which most tile, shingle, and metal manufacturers require.

Download the LayfastSBS® Brochure
Download the LayfastSBS® Application Guide
Download the LayfastSBS® ICC Report

LayfastSBS® Meets requirements of Class A Fire Rating in accordance to ASTM E-108-20a-UL 790

Helps protect against dangerous flame spread and penetration into the interior
Provides a critical layer of extra protection between your roof covering and deck to resist wind-driven rain (or moisture from other sources) that can cause damage to your roof structure

We have developed a motion graphic video which you can use to present features and benefits of LayfastSBS® to your customers (Home owners, Architects, etc.).

LayfastSBS® in the better choice, in the long run.
Most of the quality tile, shingle, and metal roofing manufacturers offer 30+ year warranties – these usually cover deterioration of tile and shingle only. Since the underlayment is the only moisture barrier used in the assembly, employing an inferior underlayment with a shorter life expectancy will compromise the system’s integrity.

Addition of SBS rubber to asphalt gives LayfastSBS® an elastomeric property that is not available in common felt. LayfastSBS® contains a higher percentage of asphalt for increased waterproofing. Its inorganic fiberglass reinforcement eliminates the rot and deterioration associated with saturated felt.

The majority of architects and contractors have realized the necessity of a better underlayment, such as self-adhesive membranes, for valleys and eaves. Most self-adhesive membranes are manufactured with SBS-modified asphalt, which is the same compound used in LayfastSBS®. By specifying LayfastSBS® in the field and a self-adhesive membrane in valleys and eaves, you are specifying a 100% SBS underlayment system throughout the roofing system and prolonging the waterproofing capability. In contrast to self-adhesive membranes LayfastSBS® is mechanically fastened, thus allowing the system to breathe.

LayfastSBS®…Superior to Felt. Here’s Why:

Versatile
ASTM D226, ASTM D4869, ASTM D6757 and ICC Approved (Report #4083).

Warranty
LayfastSBS® is backed by 10, 20 and 30 year material warranty, please refer to warranty section for system assembly and sample warranty.

Steep Slope (Limited Material Warranty)
LayfastSBS® 10 year limited material warranty. One layer of TULF40, TU35 or SupercapSBS®

LayfastSBS® 15 Year Limited Material Warranty. LayfastSBS® 15 year limited material warranty. One layer of TU43

LayfastSBS® 20 Year Limited Material Warranty. Two layers of TU35 or TULF40

LayfastSBS® 30 Year Limited Material Warranty. Two layers of TU43 or one layer of TU70

Economical
For pennies more, offer a superior product to your customer. Typical increased cost to use LayfastSBS® in place of felt is about $0.02–$0.08/square foot.

Less Decomposition
Fiberglass reinforced (inorganic) does not rot like felt. Felt is reinforced with recycled paper – and you have seen what happens to paper products, like newspaper, after they are left out in the weather.

More Elastic
SBS rubberized asphalt provides a more pliable and elastic membrane. Minimizes buckles and wrinkles by laying flatter and smoother…saving time.

Durable
Side laps do not curl up over time. Does not scuff or tear easily and is less susceptible to damage from other trades.

Proven Track Record
LayfastSBS® has been used successfully for more than 20 years.
LayfastSBS® is available in three weights.

Samples
For samples and technical questions, please contact us at:
MBTechnology 188 S. Teilman Ave. Fresno, CA 93706-1334 USA Tel: 800-621-9281 Fax: 559-233-4607 E-Mail: info@mbtechnology.com

A Full Line of Quality Roofing Products and Systems

How can we help you today?

  • Schedule a FREE roof assessment*

  • Connect with a sales representative

  • Order samples of MetalflexSBS®

*MBCare inspection is currently available for commercial buildings only.

contact-1
I'm A...