Layfast SBS Underlayment for tile, shingle & metal roof.

LayfastSBS – Superior Elastomeric Modified Asphalt Underlayment for Tile, Shingle, and Metal Roofs

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 Layfast an electrometric property that is not available in common felt.  Layfast SBS 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 Layfast SBS.  By specifying Layfast 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 Layfast is mechanically fastened, thus allowing the system to breathe.

Layfast SBS . . . Superior to Felt.  Here’s Why:

  • Versatile:
    ICC approved (Report #4083) and ideal for tile, shake, shingle, and metal roofs.
  • Economical:
    For pennies more, offer a superior product to your customer.  Typical increased cost to use Layfast 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:
    Layfast has been used successfully for more than 10 years.

Here’s How Layfast SBS Stacks up Against Felt:

Breaking StrengthMD40MD65Higher Tear Resistance
CompoundAsphaltRubberized AsphaltIncreased Longevity
Weight Lbs/100 sq. ft.26 lb.38-70 lbMore Protection
Moisture Content4.1% max.0.42%More Water Resistant

Layfast SBS is available in three weights.
Technical Information (nominal)Layfast SBS
TU35
Layfast SBS
TU43
Layfast SBS
TU70
Weight lbs/roll758670
Weight lbs/100 sq. ft.
374370
Coverage per Roll2 Squares2 Squares 1 Square
RECOMMENDED USAGEShingleTile/ Shingle/ MetalTile/Metal

Samples
For samples and technical questions, please contact us at:

MBTechnology
188 S. Teilman Ave.
Fresno, CA 93706-1334 U.S.A

Phone:         800-621-9281
Fax:            559-233-4607
E-Mail:         info@mbtechnology.com

For Architects and Specification Writers
Since Layfast is still mechanically fastened (like 30/40# felt), there is no change in drawings/specifications.  To specify Layfast, insert the following language in thetile/shingle/metal roof specification section where the underlayment is specified. For tile and metal roofs, we recommend the use of TU70; for shingle roofs, we recommend the use of TU43.

 

Underlayment shall be LayfastSBS TU70/TU43, as manufactured by MBTechnology (800-621-9281).  The membrane shall comply with all requirements as outlined in ASTM D226 standards for underlayment and approved by ICC.  Application shall be done in accordance with manufacturer’s most recent specification manual.  Minimum requirements:

 

Compound:
SBS Rubberized Asphalt

Reinforcement:
Fiberglass Mat

Weight:
Minimum of 43—70 -lb./100 sq. ft.

Breaking Strength:
MD 65 lb./in. ASTM D226, CD 46 lb./in.

Moisture Content:
less than 0.5% ASTM D226

Reports:
Independent Test Result on layfast in accordance with ASTM D226
ICC Report: layfast SBS

Application Guide:
PDF

Layfast SBS Brochure:
PDF

 

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