layfastSBS

– Superior Elastomeric Modified Asphalt Underlayment for Tile, Shingle & Metal Roofs.

Majority of the quality tile, shingle & metal roofing manufacturers offer 20 plus year warranties, which in most instances covers deterioration associated with their membrane only.  Since the underlayment is the only moisture barrier used in the assembly, employing an inferior quality underlayment with a less life expectancy will compromise the system integrity.

The addition of SBS rubber to asphalt gives layfast an Elastomeric property, which 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. 

layfast SBS is available in three different weights (37, 43 and 70 lbs/100 sq. ft) to meet any budget and design consideration.  

layfast SBS . . .
Superior to Felt.  Here's Why:

• Versatile: IDEAL FOR Tile, Shake, Shingle & Metal Roofs. 
• Economical: For pennies more, offer a superior product to your customer
• Less Decomposition: Fiberglass reinforced (inorganic), doesn’t rot like felt.
• 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.
• ICBO Approved ERS 4083

Here’s how layfast SBS Stacks up to Felt

FELT 30#		layfast SBS Underlayment	layfast SBS Advantage
Breaking Strength	MD40	MD65	Higher Tear Resistance
Compound	Asphalt	Rubberized Asphalt	Increased Longevity
Weight Lbs/100 sq. ft.	26 lb.	38-70 lb	More Protection
Moisture Content	4.1% max.	.42%	More Water Resistant

Technical Information (nominal)	layfast SBS TU35	layfast SBS TU43	layfast SBS TU70*
Weight per Roll  lbs/roll Weight lbs/ 100 sq.ft	75 37	86 43	70 70
Width/Length	40” /65’	40” /65’	40” / 32’
Coverage per Roll	2 Squares	2 Squares	1 Square
Rolls per Pallet	33	33	36

*TU70 is suited for climates requiring extra protection and metal roofs.

layfast SBS Bends . . . But It Won't Break
The addition of SBS rubber to asphalt gives layfastSBS an elastomeric property, which is not available in common felt.  layfast SBS also contains a higher percentage of asphalt for increased waterproofing protection.  Its inorganic fiberglass reinforcement eliminates the rot and deterioration associated with saturated felt allowing sharp bends up to 90 degrees without cracking or fracturing (50 F).  layfast SBS also exceeds ASTM D226 standards for saturated felt. 

Specify layfastSBS
 You have a reputation for quality.  Don’t sacrifice that reputation to save a few dollars on roof underlayment.  Though your clients might not see the difference, they’ll realize the difference for years to come.

layfast SBS is ideal underlayment for tile, shake, shingle and metal roofs.  It’s the perfect upgrade to common 30/40# felt.

So don’t let a drip dampen your reputation.  Keep your beautifully designed roofs reliably leak-free for years to come.  Specify  MBTechnology’s  layfast SBS for spectacular results.

For Architects and Specification Writers:
The following is a suggested specification to be inserted in the tile /shingle / metal roof  section where the underlayment is specified.
Underlayment shall be layfastSBS TU70 as manufactured by MBTechnology (800/621-9281).  The membrane shall comply with all requirements as outlined in ASTM D226 standards for underlayment. Test shall be done by an independent laboratory.  Minimum requirements:

Modifier – SBS Rubberized Asphalt

Reinforcement – Inorganic Fiberglass Mat

Width – 40”

Weight – Minimum of  70-lb./100 sq.   ft.

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

Moisture Content – less than .5% ASTM D226

Applications

Steep Roofing
Application procedures in this pamphlet are presented only as a guideline.  Contractors must comply with the more stringent application requirements published by NRCA, UBC, local governments or tile, shingle and shake manufacturers.

Starting at the low point of the roof install one/two ply of layfastSBS underlayment.  Apply at right angles to the slope of the roof with minimum 2” side laps (4” side lap line is also provided) and 4” end laps.  Secure underlayment with 1” head nails at 12” centers at laps and 24” centers down the centerline of each ply.  Nail end laps 6” on center.  Nailing must be adequate to withstand any traffic or wind conditions expected prior to tile application.  Staples shall not be used for fastening of layfastSBS nor the battens.

Valleys & Eaves
If project conditions require special application methods, please contact MBTechnology for recommendations.  The following is presented as a guideline and is not intended to cover all situations encountered by the contractor.

Apply one/two sheet of layfastSBS underlayment in the valley of the roof and secure every 2? on center.  Cover with metal and nail per code requirements.  All valleys must be sealed with asphalt adhesive.  Install eaves drip metal edging directly to wood deck.  Apply layfast SBS underlayment indirectly to metal using asphalt adhesive, face nailing 6? on center.