Recommended Specification For Dura-Cap® Floor Underlayment For Wood Frame Commercial Construction
Summary
This is the recommended specification for Dura-Cap Floor Underlayment for wood frame commercial construction.
Selection Includes
- Dura-Cap gypsum cement
- Maxxon Floor Primer
- Maxxon Overspray
Quality Assurance
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.
Site Conditions
Environmental Requirements: Before, during and after installation of Dura-Cap, building interior shall be enclosed and maintained at a temperature above 50 degrees F (10 degrees C).
Products
Materials
Gypsum Cement: 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 requirements of Maxxon Corporation Sand Specification 101.
Mix Water: Potable, free from impurities.
Subfloor Primer: Maxxon Floor Primer
Sealer: Maxxon Overspray
Mix Designs
General Requirements: Mix proportions and methods shall be in strict accordance with product manufacturer recommendations.
Execution
Preparation
Condition and Cleaning of Subfloor: Subfloor shall be structurally sound. General Contractor shall clean subfloor to remove mud, oil, grease, and other contaminating factors before arrival of the Dura-Cap underlayment crew.
Leak Prevention: Fill cracks and voids with a quick setting patching or caulking material where leakage of Dura-Cap could occur.
Priming Subfloor: Prime the subfloor using the Maxxon Floor Primer. Priming instructions vary according to the type of substrate, multiple coats may be necessary.
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 3/4 inch (19 mm) minimum over wood frame, 1/2 inch (13 mm)
minimum over plank or poured in place concrete. 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.
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 3/4 inch (19 mm) thick
Dura-Cap, 5-7 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. Perform dryness test 5-7 days after pour.
Preparation for Installatin of Glue Down Floor Goods
Sealing: Seal all areas that receive glue down floor goods with Maxxon Overspray according to
the Maxxon Corporation's specifications. Any floor areas where the surface has been damaged
shall be cleaned and sealed regardless of floor covering to be used. 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 it's being pumped using a 2 inch by 4
inch (50 mm by 101 mm) cylinder resulting in a patty size of 8 inches (203 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 modified ASTM C 472. Test results shall be available to
architect and/or contractor upon request from applicator.
Portection
Protection From Heavy Loads: During construction, place temporary wood planking over
Dura-Cap wherever it will be subject to heavy wheeled or concentrated loads.