Recommended Specification for Commercial Topping® Floor
Underlayment over Vinyl Asbestos Tile
Summary
This is the recommended specification for Commercial Topping Floor Underlayment over vinyl
asbestos tile.
Section Includes
- Commercial Topping Floor Underlayment
- Maxxon Floor Primer
- Maxxon Overspray
Quality Assurance
Installer's Qualifications: Installation of Commercial Topping 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 Commercial Topping,
building interior shall be enclosed and maintained at a temperature above 50 degrees F (10 degrees
C) and below 100 degrees F (37.7 degrees C) until structure and subfloor temperature are
stabilized.
Products
Materials
Floor Underlayment: Floor underlayment compound shall be Commercial Topping as
manufactured by Maxxon Corporation, Hamel, MN. All others must receive prior approval.
Sand Aggregate: Sand shall be silica aggregate meeting requirements of Maxxon Sand
Specification 101.
Mix Water: Potable, free from impurities.
Subfloor Primer: Maxxon Floor Primer
Sealer: Maxxon Overspray
Mix Designs
General Requirements: Commercial Topping 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 Commercial Topping underlayment crew. Remove any loose vinyl asbestos tile.
Leak Prevention: Fill cracks and voids with a quick setting caulk or patching material where
leakage of Commercial Topping could occur.
Priming Subfloor: Prime VAT using the Maxxon Floor Primer per Maxxon Corporation
recommendations.
Expansion Joints: Allow joints to continue through the Commercial Topping at the same width.
Application of Cementitious Underlayment
Scheduling: Application of Commercial Topping 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 Commercial Topping from 1/2" (13 mm) minimum over vinyl asbestos tile.
Over concrete, it can be featheredged. Spread and screed the Commercial Topping to a smooth
surface. Except at authorized joints, place Commercial Topping as continuously as possible
until application is complete so that no Commercial Topping slurry is placed against Commercial
Topping 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 Commercial Topping is dry. General Contractor shall
provide mechanical ventilation if necessary. Under the above conditions, for _ inch (19 mm)
thick Commercial Topping, 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 the pour.
Preparation for Installation 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: Commercial Topping 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 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 Commercial Topping 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.
Protection
Protection From Heavy Loads: During construction, place temporary wood planking over
Commercial Topping wherever it will be subject to heavy wheeled or concentrated loads.