Back to the Mail Bag: Answers to Your Resilient Floor Questions
Q: What causes a heat-welded vinyl seam installation to act as a “dirt catcher?”
A: The main reason is the seam was skived too soon. When the seam is skived while the weld rod is still hot, that weld rod is easily stretched. The skiving knife will stretch the center of the rod up as it cuts it off. Another reason for the problem could be that the rod was not cut off in two passes. The first cut should be done with the trim plate, and the second pass should be the final and flush cut.
Q: What are your thoughts about the use of cementitious patching compounds over cutback adhesive?
A: I feel that placement of a patching compound designed for installation over cutback adhesive is a misunderstood process. The cutback adhesive must be taken down to a thin, smooth residue before any attempt is made to go over it with a patching compound. Installations over cutback that has not been scraped down to a smooth residue are prone to failure, especially if they are subject to moderate to heavy traffic or rolling-load traffic. Cutback trowel ridges provide a flexible ridge between a hard setting product, and any amount of traffic will allow the ridges of patching compound to move due to the flexibility of the cutback. This results in the crumbling of the patching compound.
Q: When installing an underlayment over an existing wood substrate, should one attempt to fasten the new underlayment to the floor joists?
A: Absolutely not! The subfloor is supposed to be fastened into the floor joists. The underlayment is designed to be fastened into the subfloor only.
Q: When doing a flash-coved installation, I have a difficult time stopping the inside corners from tearing at the base of the cove stick. Do you have any suggestions to help prevent this from occurring?
A: After the cutout for the inside corner is made, lift up the piece of material and place a 6-inch piece of strapping tape diagonally across the back of the material at the juncture of the two cuts. When installing the material, leave the tape on and adhere the material into place. The tape will keep the pressure of the installation from tearing the material from the backside.
Q: How do you feel about the double-faced tape systems that are used beneath seams?
A: For installations of materials that require the use of seam sealers, the double-faced tape method is a great way to stop adhesive contamination of the seam. The adhesive used to adhere the floor still needs to be allowed adequate open time, the seam itself must be rolled with a hand roller, and the seam sealer needs to be applied down into the seam.
Q: Heat-welded seams in linoleum do not seem to hold as well as welded seams in sheet vinyl. What are your observations?
A: You are absolutely correct. The seam weld in linoleum, unlike vinyl products, does not make use of a fusion process. The welding of linoleum is based on more of a bonding process than a fusion. For this reason, never attempt to substitute a vinyl rod for a linoleum rod, or vice versa.
Q: What is the best way to finish an expansion joint in concrete?
A: The best way to handle an expansion joint in a concrete slab is to honor the joint. All of the resilient manufacturers recommend that expansion joints be honored or covered with expansion joint covers. Expansion joints are designed to expand and contract with changes in slab temperature. This expansion and contraction will create problems with materials that are installed directly over the joints.
Q: What are the requirements for installing resilient flooring over a radiant-heated floor?
A: The radiant-heated floor should be in operation and stabilized, and the floor temperature should not be allowed to exceed 85º F. Excessive heat in the floor can soften resilient material and create indentation problems, adversely affect adhesives, and even cause discoloration of the material.
Q: What’s the best way to keep a heat-welded seam clean when it will be exposed to heavy soil and traffic during the construction phase?
A: The best way is to coat the seam with either a floor sealer (not seam sealer) or to apply a high-quality floor polish. The floor sealer, or polish, will fill the pores in the heat-weld rod and thereby keep soil from getting into those pores.
Q: Do you think the pattern of fasteners along the edges of underlayment should be closer than 3 to 4 inches?
A: I feel that the 3 to 4 inch requirements are adequate for underlayment panels. The key is to keep the fasteners close enough to the panel edge. Most underlayment manufacturers recommend that the fastener be held within 3/8 inch of the joint. This, coupled with the spacing of 3 to 4 inches, will provide an adequate hold of the joint. The only time I will close the pattern is when the subfloor is in question. Another important requirement is that the underlayment joints be offset from the subfloor joints.
Q: How soon after installation should vinyl composition tile (VCT) be stripped?
A: Actually, VCT manufacturers do not want a stripper used on their tile for a minimum of 30 days. The manufacturers use a “fast-track” finish on their tile to eliminate the need for stripping. The use of a floor stripper, which is highly alkaline, can lead to the deterioration of the tile adhesive before it’s had a chance to cure properly. This can lead to edge curl of the VCT and possible failure of the installation.