CONDITIONS:
General and Special Conditions shall govern this work.
SCOPE
OF WORK:
This work includes all material, labor, equipment, supervision necessary
for, and incidental to, executing and completing installation of Weather
Deck as manufactured by Mer-Krete Systems/ Mer-Ko Materials a division of Parexlahabra , Inc. This material shall
be installed in strict accordance with the manufacturer’s printed
instructions and only by one of their pre-qualified contractors.
MATERIALS
Weather Deck shall be composed of an initial sheet of asphalt saturated
glass felt; a flexible, glasstrand reinforced waterproof membrane with
integral base flashing; and a synthetic chloroprene latex mastic traffic
surface which meets the requirements of U.S. Military Specification
MIL-D-3134.
Acceptable
physical qualities for this latex mastic deck covering are as follows:
All raw materials
used to produce this waterproof roof deck covering shall be incombustible,
and therefore not represent a potential fire hazard, and, where required,
shall not emit solvents or other recognized pollutants into the atmosphere.
Compositions
of oxychloride cement, epoxies, urethanes, PVC’s, PVA’s,
silicones, solvent thinned elastomer solutions or combinations thereof
will not be considered acceptable under this specification.
All materials
used to formulate this roof deck coating shall be delivered to the job
in unopened bags and pails labeled with the manufacturer’s name
and address as well as the date of manufacture. All materials shall
be completely pre-packaged and pre-blended at the factory.
Underlayment
materials shall be Mer-Ko Underlay-L, Underlayment-C or Underlay-RS.
Vents used
to eliminate subsurface moisture or to relieve vapor pressure shall
be a type approved by the deck covering manufacturer as illustrated
in their printed detail drawings.
*NOTE:
CSI format specifications are available from any Mer-Ko office or at
www.merkrete.com.
SUBSURFACE
PREPARATION
A. CONCRETE: Concrete must have a smooth and uniform
finish properly pitched for drainage as shown on plans and specifications
(1/8" per foot minimum). Lightweight concrete of the cellular,
air-entrenched type is acceptable if the compressive strength is 1000
psi or greater. Concrete employing lightweight absorptive aggregates
is not recommended unless specific requirements are met.
B. WOOD: Use 5/8" exterior grade plywood, designated
“CCX Plugged”, fastened with annular or screw type nails.
Plywood joints must be staggered to avoid any four corners meeting
at one point and joints MUST be blocked between joists. Mix 2 gals.
of Underlay-L Emulsion with one 50 lb. sack Underlay-L Filler and
apply to joint areas, filling joints completely. Embed 71/2 oz. polypropylene
burlap in the wet mixture saturating the burlap completely and apply
additional mixture over the burlap to completely encapsulate the burlap
and allow to dry. One sack filler will fill approximately 200 lin.
ft. of joints.
C. THERMAL INSULATION OR OTHER SURFACES: Consult
manufacturer.
D. DRAINAGE: Drainage is NOT part of the deck covering
system and must be provided for structurally or in the profile of
Mer-Ko Underlay-L underlayment.
INSTALLATION
OF WEATHER DECK SYSTEM
This deck covering shall be installed in strict accordance with the
manufacturer’s printed application instructions and as outlined
below:
* Note: For a One Hour Fire Rated System, See
Weather Deck "One Hour" Assembly Addendum
A.
Initial sheet shall consist of an asphalt saturated glass felt (25
lb. min.) applied to entire flat area terminating 2" from all
vertical surfaces. The edges of this material shall be overlapped
2" and glued.
B. Prime coat and flexible waterproof membrane shall
be applied over initial sheet as follows:
1. Trowel apply a prime coat comprised of 2 parts
filler powder to 1 part neoprene emulsion. All base and edge flashing
areas shall be coated.
2. The waterproof membrane shall be applied over
the dry prime coat to all flat areas using synthetic rubber flashing
paste with glassmat reinforcement. Two coats of flashing paste shall
be applied at a total spread rate of one gallon to 35 sq. ft. of flat
area. All verticals, base and edges shall be flashed in the same manner
using 71/2 oz.- 10" wide strips of polypropylene burlap to reinforce
the base and deck juncture. A second coat of flashing paste must be
applied to fill pinholes.
C.Chloroprene latex mastic traffic surface shall
be installed in two applications. The traffic surface shall smooth
all irregularities and provide an acceptable surface to receive finishing
coats. Mastic materials shall be mixed as outlined in manufacturer’s
application instructions and extend up all base flashings.
D. Finishing coats are applied to the traffic surface
by trowel in one or two coats as the finish surface texture dictates.
Mix chloroprene latex emulsion and dehydrating filler as outlined
in the application instructions. Light sanding may be necessary after
the first finishing coat has hardened.
E. Two coats of Mer-Ko Seal in the chosen color shall
be applied by roller.
F. Heavy duty sealers are available, consult manufacturer.
PROTECTION
After completion, the latex mastic deck covering
