Recommended Specification For Dura-Cap® Floor Underlayment For Topping Corrugated
Steel Deck Over Dietrich Industries, Inc. Light-Gauge Steel Framing Ul 2-Hour Fire
Design
Summary
This is the recommended specification for Dura-Cap Floor Underlayment for topping
corrugated steel deck over light-gauge steel framing.
Section Includes
- Dura-Cap Gypsum Concrete
- Maxxon Acrylic
- Corrugated Steel Deck
- Light-Gauge Steel Framing
- Optional Maxxon Sound Mats: Acousti-Mat II or Enkasonic. Or Acousti-Mat 3 reinforced
with Maxxon Crack Suppression Mat (CSM)
- Maxxon Overspray
Quality Assurance
Dura-Cap Installer's Qualifications: Installation of Dura-Cap shall be by an applicator
authorized by the Maxxon Corporation using Maxxon approved mixing and pumping equipment.
Delivery, Storage and Handling
General Requirements: Materials shall be delivered in their original,
unopened packages, and protected from exposure to the elements. Damaged or deteriorated
materials shall be removed from the premises.
Products
Materials
Floor Underlayment: Dura-Cap gypsum cement as manufactured by Maxxon
Corporation, Hamel, MN. All others must receive prior approval.
Sand Aggregate: Sand shall be 1/8 inch (3 mm) or less, washed masonry
or plaster sand, meeting the requirements of Maxxon Corporation Sand Specification
101.
Mix Water: Potable, free from impurities.
Corrugated Steel Deck Primer: Maxxon Acrylic as manufactured by
Maxxon Corporation, Hamel, MN.
Corrugated Steel Deck: Corrugated steel deck conforming to Steel
Deck Institute requirements and meeting L/360 design deflection limitation: minimum
22-gauge (9/16’’ Form Deck) required.
Light-Gauge steel Framing: Dietrich TradeReady C-shaped, No 16
MSG galvanized steel sections, 9 _’’ minimum depths with 1-7/8’’ minimum flanges
and _’’ minimum stiffening flanges as manufactured by Dietrich Industries Inc.
Optional Sound Mats: The following sound mats are listed and optional
in the G 560 fire design: Acousti- Mat II or Enkasonic. Or Acousti-Mat 3 reinforced
with Maxxon Crack Suppression Mat (CSM). All manufactured by Maxxon Corporation,
Hamel, MN.
Floor Underlayment Sealer: Maxxon Overspray as manufactured by
Maxxon Corporation, Hamel, MN.
Mix Designs
General Requirements: Dura-Cap mix proportions and methods shall
be in strict accordance with product manufacturer recommendations.
Execution
Preparation
Structure: Structure shall meet Maxxon Corporation’s minimum deflection
requirements as well as other structural standards, and be certified by a licensed
structural engineer.
Condition and Cleaning Corrugated Steel Deck: Corrugated steel
deck shall be structurally sound. General Contractor shall clean to remove mud,
oil, grease and other contaminating factors before arrival of the Dura-Cap underlayment
crew.
Leak Prevention: All potential leakage areas including pipe penetrations,
screw holes and laps must be caulked.
Priming Corrugated Steel Deck: Prime corrugated steel deck using
the Maxxon Acrylic.
Expansion Joints: Allow joints to continue through the Dura-Cap
at the same width.
Application of Cementitious Flooring
Scheduling: Application of Dura-Cap shall not begin until the building
is enclosed, including roof, windows, doors, and other fenestration. Install after
drywall installation unless tenant finish requirements identify partitioning after
the pour.
Application: Place Dura-Cap at 1 inch (25 mm) minimum over the
top of the flutes, average pour thickness is 1-9/16’’ (40 mm). Spread and screed
Dura-Cap to a smooth surface. Except at authorized joints, place Dura-Cap as continuously
as possible until application is complete so that no Dura-Cap slurry is placed against
Dura-Cap product that has obtained its initial set.
Application of Optional Sound Mats: If this option is chosen it
replaces B above. Place Dura-Cap over the tops of the flutes to a smooth surface.
Once the Dura-Cap reaches full set (2-4 hours) install Acousti-Mat II, Enkasonic
or Acousti-Mat 3 per manufacturer’s recommendations. Dura-Cap thickness over Acousti-Mat
II is 1” (25mm), over Enkasonic 1 _” (38mm). Dura-Cap thickness over Acousti-Mat
3 is 1 _” (38 mm), reinforced with Maxxon CSM.
Drying: General Contractor shall provide continuous ventilation
and adequate heat to rapidly remove moisture from the area until the Dura-Cap is
dry. General Contractor shall provide mechanical ventilation if necessary. Under
the above conditions, for 1-9/16’’ (40 mm) thick Dura-Cap, 10-14 days is usually
adequate drying time. To test for dryness, tape a 24 inch by 24 inch (609 mm by
609 mm) section of plastic or high density rubber mat to the surface of the underlayment.
After 48-72 hours, if no condensation occurs, the underlayment shall be considered
dry. Moisture meters such as Delmhorst G-79 or BD 21000 can be used; also Relative
Humidity Probes are acceptable. Perform dryness test 10- 14 days after pour.
Preparation for Installation of Glue Down Floor Goods
Priming: Prime all areas that receive glue down floor goods according
to the Maxxon Corporation's specifications. Any floor areas where the surface has
been damaged shall be cleaned and primed regardless of floor covering to be used.
Use Maxxon Floor Primer or Maxxon Overspray to prime the Dura-Cap prior to installation
of glue down floor goods. Where floor goods manufacturers require special adhesive
or installation systems, their requirements supersede these recommendations.
Floor Goods Procedures: See the Maxxon Corporation's "Procedures
for Attaching Finished Floor Goods to Maxxon Underlayments" brochure for guidelines
for installing finished floor goods. This procedure is not a warranty and is to
be used as a guideline only.
Field Quality Control
Slump Test: Dura-Cap mix shall be tested for slump as its being
pumped using a 2 inch by 4 inch (50 mm by 101 mm) cylinder resulting in a patty
size of 8-1/2 inches (216 mm) plus or minus 1 inch (25 mm) diameter.
Field Samples: At least one set of 3 molded cube samples shall
be taken from each day's pour during the Dura-Cap application. Cubes shall be tested
as recommended by the Maxxon Corporation in accordance with ASTM C 472. Test results
shall be available to architect and/or contractor upon request from applicator.
Protection
Protection From Heavy Loads: During construction, place temporary
wood planking over Dura-Cap wherever it will be subject to heavy wheeled or concentrated
loads.