Platform LCB
Fiber Reinforced Gypsum Self-Leveling Underlayment
Platform LCB is a gypsum based self-leveling underlayment designed for use directly over wood. The product is reinforced with fibers for superior performance over flexible substrates. Platform LCB may be poured directly over wood without mechanical reinforcement to provide a quick dry, smooth surface for approved floor coverings.
Features and Benefits
- Outstanding flexural strength
- Suitable for plywood and gypsum subfloors
- Durable high strength specialty cement
- Outstanding heal
- Non-alkaline – adhesive friendly
- Withstands construction/renovation traffic
SURFACE PREPARATION
All surfaces must be sound, stable, and clean. Ensure surfaces are free from dust and dirt and any bond breaking materials (silicates, curing compounds, oils). Mechanically remove weak surfaces and any contaminants to sound surface. Always finish cleaning by a final removal of contaminants by vacuum. Any surface must show a tensile pull strength greater than 100 PSI. Any surface with a tensile strength below 100 PSI should be removed mechanically. Do not use chemical cleaners or solvents to prepare any substrate for Platform LCB. Adhesive residue should be scraped or ground to well bonded residue only. Check the adhesive prior to mechanical removal to ensure it does not contain asbestos. Always follow federal and local codes when removing asbestos. Gypsum surfaces shall be sound, stable and free of dust. Wood surfaces must follow local codes, be free of deflection, and made of either plywood or APA rated OSB. If installing over wood, Platform LCB must be at least 3/8” to install without mechanical reinforcement.
Priming
Platform recommends the use of Platform P360 on all surfaces, unless specified by technical services. Check the porosity of the substrate prior to priming. Fill a bottle-cap with water, and drop onto the surface. If the water disappears readily, consider the surface porous.
Porous Substrates
On porous substrates it is necessary to dilute the primer prior to installation, a test area should always be performed prior to priming the entire floor. Platform recommends starting at 4-1 ratio (water:primer), but it is important to remember that each substrate may require a different dilution ratio depending on the porosity of the substrate. Ensure the primer remains wet for 15 minutes after application. If the primer remains wet for less than 10 minutes, increase the dilution ratio and try again on the test area. If the primer remains wet for more than 10 minutes, but less than 15 minutes: increase the dilution ratio but continue priming the remainder of the floor. Platform recommends installing the primer into the floor with a soft bristle broom, but a nap roller or a squeegee may be used if necessary.
Non-porous Substrates
On non-porous substrates dilution is unnecessary. Using a broom or a nap roller prime the floor with a neat coat of Platform P360, ensuring you do not puddle or over-prime the floor.
Wood Substrates
On wood substrates, diluting is unnecessary and discouraged. Wood substrates require a double coat of primer to ensure a film forms. Prime the wood floor with an undiluted coat of Platform P360, and allow to dry. Then, when the first coat is dry, prime the floor again with a second coat of Platform P360. Consult Platform’s technical bulletins for details on priming.
Mixing
Mix 1 bag Platform LCB into 5 quarts (4.75 liters) cool clean water. (10 lbs. to 1 qt. water or 5kg. to 1 liter water). Platform LCB can be mixed in large quantity in mortar mixers or special pumps or in smaller quantities (up to 2 bags) in a 20-40 gallon container. Use only a very clean mixing container that does not contaminate Platform LCB with other material. Pre-dampen container to provide proper first mix. Pour in proper amount of water and then add powder while mixing. Do not over-water. If a problem is encountered while mixing and you are not getting a lump and powder free mix, try starting with 2/3 of proper water, adding powder until just wetted, then adding remainder of water and thoroughly mix at 850-1200 RPM. Mix for at least 2 minutes, but no longer than 3 minutes to a homogenous lump-free mixture. Do not shake.
APPLICATION
Pump or pour contents onto floor. Because Platform LCB is very flowable, allow it to build in one area until it reaches at least desired depth and maintains that depth even as material flows away. Begin at a corner of room or at a deep part of fill. Plan the pour before starting. Either work back and forth along a line of the room or from the center of the room and fill outwards in all directions to keep pouring against the freshest material possible. Lightly work the transition points between pours and material over or under desired depth with a screed, spreader, lightweight float or straightedge to the desired depth. Material should remain highly flowable for 20 minutes and can be walked in for over 45 minutes at normal temperatures. Any imperfection can be smoothed by surface trowelling or drawing a straightedge or smoother over the surface. As material gets stiffer and begins to gel, it may be smoothed or trowelled to a featheredge. Once material begins to gel, stay off the area for about 1.5-2 hours, after which floor should bear foot traffic. In very hot or windy conditions, protect from wind and mist fog floor. Direct sunlight, heat and wind can cause rapid drying of the product which may reduce working time. To avoid rapid drying, provide protection against these elements. Let material continue to dry before covering until evaporative moisture lessens. Moisture level may be checked by a surface moisture meter, a plastic film taped to the floor, or a plastic bucket left on the floor and the area carefully observed for residual surface moisture upon removal. In thin 1/4” applications, Platform LCB may be covered in 4-24 hours depending on drying conditions (temperature, humidity, thickness) and requirements of adhesive and floor covering. For impervious coverings (vinyl, laminate, etc.) be sure Platform LCB is thoroughly dry (at least 16-24 hours). Pours deeper than 3/8” require longer time or forced drying.
Multiple lifts: Platform LCB may be placed in multiple lifts or layers. Allow the previous layer to harden and dry until there is no discernible evaporation. Once dry, prime again with Platform P360 and apply the next Platform LCB layer. Remember thicker areas of product take longer to dry.
NOTE: Temperature and humidity levels affect the drying characteristics of Platform LCB.
LIMITATIONS - For Interior use only - Do not use...
• Where hydrostatic pressure (water) is present or moisture emissions exceeds level permitted for installed floor covering. Platform LCB Underlayment can tolerate any amount of moisture from a concrete slab so long as all of the moisture from the slab will escape past the floor covering. If the floor covering’s moisture permeability does not meet or exceed the moisture content of the slab, Platform recommends moisture remediation. Use Platform EMS, or an approved alternative, to remediate moisture in concrete, consult the Platform EMS data sheet, or call technical services, for more details.
• Where surface or ambient temperature falls to or below 45°F 72 hours before or after installation.
• Over presswood, particle board, masonite, chipboard, single stripwood floors, luaun or similar dimensionally unstable materials susceptible to moving or swelling.
• As a trowelled patch or at less than natural minimum flow thickness.
• Exterior, exposed applications or as a wear surface.
