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Topic - Subfloor |
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1. |
Q: What type of moisture conditions exist that can cause problems in resilient flooring installations? |
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A: Concrete Floor Moisture -- Concrete floors directly in contact with the ground are never completely dry. Also, the moisture content of new concrete is high, regardless of grade levels. Resilient floors may be seriously affected when installed directly over concrete which is not sufficiently dry. Wood Floor Moisture -- Wood floors constructed on sleepers directly over on-grade or below-grade slabs are susceptible to ground moisture penetration. Such moisture is trapped under the resilient flooring, resulting in deterioration of wood fiber. For this reason, resilient floors are not recommended for installation over this type of subfloor. Surface Moisture -- Resilient floors may be installed in areas where excessive moisture may be spilled on the floor. Providing that the correct adhesive has been used and the floor has minimal seams, there will be no damage to the floor. However, water should be mopped up immediately, and the floor should never be intentionally flooded. |
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Q: What is meant by porous and nonporous in relation to subfloors? |
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A: A porous substrate is one that is capable of absorbing water or liquid, such as concrete or wood. Liquid beads up on the surface of nonporous floors. These are typically existing resilient flooring. If there is any doubt as to porosity of the substrate, it can be checked easily by placing a few drops of water on the surface. If the water is quickly absorbed, the substrate is porous. If the water beads up and remains on the surface, the substrate is nonporous. |
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3. |
Q: What is meant by grade level? |
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A: Grade level, when speaking of resilient flooring, is where the flooring will be installed in relation to the ground around the building. A suspended or above-grade subfloor is one that has a minimum of 18" of well-ventilated air space beneath it. Normally, this would be over the basement, but in some homes, this could be over a crawlspace. An on-grade subfloor is one that is in direct contact with the ground or over a fill that is in direct contact with the ground. A below-grade subfloor is one which is partially or completely below the ground surrounding the building and is in direct contact with the ground or over fill which is in direct contact with the ground. |
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4. |
Q: What does it mean when ZAXXON says for commercial and institutional environments, the compressive strength of floor fills, patches, and toppings must be 3,500 psi? |
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A: Compressive strength is expressed in pounds per square inch. This means the material can withstand 3,500 pounds per square inch without breaking. |
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5. |
Q: What is lightweight concrete? |
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A: Lightweight concrete is concrete made with lightweight aggregate, (shales, clays, pumice, etc.) or with the addition of chemicals that foam and produce air spaces in the concrete as it hardens. This should not be confused with products which are manufactured and used as floor fills and toppings. |
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6. |
Q: What is the most common moisture test method? |
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A: The calcium chloride test kit, which is a quantitative test, is the method recommended by most, if not all, resilient flooring manufacturers. This test, now an industry standard, ASTM F 1869, must be run in all areas where there is a concern for moisture. Calcium chloride tests are normally run for 60-72 hours depending upon the manufacturer. The results are expressed in terms of pounds per 1000 square feet per 24 hours. To install resilient flooring, the results must be 3 to 5 pounds/1000 sq. ft/24 hours or whatever the flooring manufacturer recommends. Calcium chloride test kits can usually be purchased from flooring and sundry supply distributors. This test is covered under ASTM F 1869, "Standard Test Method for Measuring Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride." |
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7. |
Q: Which reading on the pH scale is considered neutral? |
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A: The pH scale runs from 0 to 14, with 7 being neutral. Below 7 is considered acidic while above 7 is alkaline. |
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8. |
Q: What should I do if I test for alkali and it measures above 9 pH? |
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A: Flooring adhesives are designed to be alkali resistant up to a pH of 9. Above 9, the alkali becomes excessive and can actually burn your skin and start to dissolve concrete aggregate. Alkali comes to the surface of concrete with water and once the water evaporates, it leaves the alkali salt residue. If alkali is too high, it is best to use clear water or soda water to clean the surface, allow the concrete to dry, and retest. Traditionally, acids have been used to "neutralize" the concrete, but acids may leave a residue that is as detrimental to the flooring installation as the alkali. Excessive alkali may cause white deposits at tile joints and when excessive, may actually corrode or burn the edges of the tile. It can build up under flooring causing bumps to occur. Alkali may eat away at adhesive, causing failure of the bond and damage to the flooring itself. Alkali can also cause dusting of the concrete surface. Alkali testing can only show the amount of alkalinity at the time the test is run and cannot be used to predict long-term readings. |
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9. |
Q: What causes alkali at tile joints? |
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A: White, salt-like particles at tile joints are normally an indication moisture has carried alkali to the surface of the flooring. This condition is not usually noticeable in open areas where there is a lot of foot traffic, but can occur under furniture and in corners where there is no traffic. Mopping with clear water will keep the alkali from building up at tile joints. Alkali can cause serious damage to flooring so testing for moisture and alkali should be done before any resilient flooring installation takes place on concrete. |
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10. |
Q: How can you remove curing agents from a concrete slab? |
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A: Terrazzo or concrete grinder, drum sander or a polishing machine equipped with a heavy-duty wire brush. |
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11. |
Q: Is staining from a construction adhesive covered under the ZAXXON warranty? |
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A: No. Stains of this nature are not covered under any ZAXXON warranty. |
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12. |
Q: What kind of Sub-Floors can be used? |
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A: Concrete Sub-Floors(on-grade,suspended,or below-grade) Zaxxon vinyl tile may be installed directly onto dry concrete sub-floors without the use of lining fele.The concrete sub-floor should be a dry (moisture content nor exceeding 3 pounds per cubic foot),smooth,level surface (undulations nor exceeding 1/8 in 10 lineal feet),free from score marks,grooves or depressions,and free from all foreign materials or residues such as paint, oil,adhesives,sealers,soil,or other extraneous substances that can inhibit proper tile adhesive bond to sub-floor.Concrete curing compounds are not recommended.If the use of such compounds is specified,Zaxxon Inc.should be consulted in advance of installation or acceptance of the sub-floor.Pan construction suspended concrete floors may require additional time for proper curing.The moisture content of these floors also should nor exceed 3 pounds per cubic foot at time of floor tile installation.Radiant heated floors should not exceed a maxinum temperature of 80 degrees Fahrenheit.The recommended temperature at the time of installation is 70F degrees. Epoxy adhesive must be used in this situation.
Wood Sub-Floor: *1/4 minimum thickness APA Underlayment Grade Plywood.Thicker Plywood should be used as circumstances dictates such as more extreme sub-floor irregularities. *1/4 minimum thickness Service Class Underlayment Grade Hardboard meeting the requirement of the US Product standard PS1-83.Hardboard should be untempered and installed smooth side up. *Wood sub-floors must be solid,well nailed at the joists and free from movement.All paints,wax,grease,dirt,dust,or any other extraneous materials must be removed to insure proper adhesive bond. *Particle boards,strand boards,flake boards are not recommended or approved for resilient underlayment.
Existing Resilient Floors: Zaxxon vinyl tile may be installed over existing resilient flooring provided the existing floor is firmly bonded to the sub-floor, is smooth and free of all waxes,finishes,grease,paints,soil,dust,or other extraneous material.
Rough or Uneven Surfaces: Rough or uneven surface must be smoothed before installation of tile.A two part patching compound such as a latex under layment is recommended.If the area to be smoothed is large or the surface has cracks and/or severe undulations, a cementitious based leveling compound or crack filler may be needed.Please contact Zaxxon for additiongal information. |
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