Q&A 2016: Answers to installation queries
I haven’t done a Q&A column here in Coverings in over a year, and a few things came up on projects this month that I felt were worth sharing. Have questions? Please send them here to Coverings, [email protected], and we will dig into the subject on a future column. In the meantime, here are some that came across my desk recently.
Q: Why do you (and many floor covering manufacturers) recommend against lauan plywood for underlayment?
A: Lauan (pronounced lu-on and sometimes spelled luan) was originally developed for doors and comes from trees found in rainforest areas such as The Philippines. Lauan has become a generic term for ¼-inch wood underlayment, but there are big differences between lauan and a true ¼-inch plywood underlayment. Back in the 1970s and 1980s when I started in the business, we used lauan underlayment for resilient flooring and it was good quality for a while. However, as supplies of mahogany, which made a good underlayment, became depleted, other types of woods started to be used in lauan and the quality went down. We had boards with soft spots, voids and/or or inconsistent thickness that lead to denting and joint-telegraphing complaints. Before long, many flooring manufacturers issued specific warnings about the risks of using lauan.
Today, there are better alternatives for underlayment — you can specify a minimum of ¼-inch for residential use and 3/8-inch for commercial. Three-ply hardwood plywood underlayment from Canada and five- to seven-ply birch, (often known as Arctic, Baltic or Russian birch) are sold under a number of brand names. These branded products perform well and have a manufacturer’s warranty, which you will rarely see in lauan or standard plywood, even a good plywood like A/C grade. Regardless of what underlayment you use, make sure it’s recommended by the flooring manufacturer for the flooring you are installing and make sure the underlayment manufacturer recommends it for the end use of the finished floor: commercial versus residential.
Q: I have a customer complaint on tile because of a “hollow” sound in some of the tiles when they tap on the floor. Nothing has cracked and the floor looks good, but they are worried about future cracking in the tile.
A: Sometimes with dips in a floor you can get a small void under tile that someone would hear if they tapped on the floor. Depending on the tile and how much weight the floor may be subjected to, this could be a potential source of cracking. To prevent this, make sure your have a look at the substrate before starting the job. Use a metal straightedge to see if you have any dips. Check around the perimeter especially because sometimes a slab or a poured topping layer can “fall off” a little around the edge. Don’t take any chances — an extra hour or so to patch the floor will go a long way to preventing these types of problems.
Don’t assume you can use thinset mortar to fill in these voids – that’s not always a workable solution. With commercial grade products like porcelain or epoxy terrazzo tile, I’d be surprised to see it crack in moderate commercial traffic unless there was heavy rolling traffic. However, to convince the owner there would not be a problem in this case, the installer offered to give a longer installation warranty to avoid having to start replacing tiles.
Q: I have a carpet tile installation with gapping seams. The product is in a small retail store and was supposed to be able to be installed with no adhesive. Is the tile shrinking?
A: The installation of carpet tiles needs to be snug up against any walls or fixtures, especially with loose-lay or self-adhesive tiles. I remember specifically two different projects that had gaps in the tile in some areas. In that retail store, it was a cushion-back carpet tile that was gapping in the centre of the room. I removed a few of the baseboards and found that the tile was tight up against the wall.
However, it was not installed that way originally; the installer left a gap around the edges and the tile shifted once it was exposed to traffic. It was repaired by using an adhesive in the last row against the wall so that the tile was locked in place. In another case, the job was being done in phases and the installer was not able to finish the floor right up to one wall. Very soon after being exposed to traffic, the tile “walked” that created little gaps. Once they installed the last row up to the wall, everything stayed fine.
A variety of carpet tile, resilient floor tile and engineered plank floors can be installed loose-lay. However, I try to ask questions about the traffic in the area before I recommend these systems for commercial use. Sometimes adhesive is a better way to go for high-traffic areas. If you DO install loose-lay, pay attention to the manufacturer’s specifications regarding space around the perimeter and also how long a run you can install without adhesive. Sometimes, locking-in the tile with a row that’s adhered is recommended.
Q: I’m working on a glue-down, vinyl plank job. I used a moisture meter to test the concrete and got a four out of six. Is it all right to install the floor per the manufacturer’s instructions?
A: I often hear from flooring contractors or installers that use moisture meters to decide whether or not to install a new floor. There are a lot of easy-to-use electronic meters on the market that are valuable for various purposes, but one of those purposes is not to make a “go or no-go” decision on installing a floor. There are no manufacturers of resilient flooring or adhesive that recognize these results. Meters are valuable as a spot-test for surface moisture at that spot in the slab at that point in time. Some use this as a way of deciding if further testing is needed. Meters used for testing moisture in wood floors do not correlate over to the moisture within the concrete.
Gypsum underlayment manufacturers may recommend meters as a way of determining if their product is dry enough to install floor coverings. Just remember that moisture meter testing on concrete is not a way to decide “go or no-go” for a flooring installation. The two recommended methods are ASTM F 1869 Calcium Chloride test and ASTM F 2170 Internal Relative Humidity probe test. These tests, especially F 2170, provide a much more scientific and accurate test result than a hand-held meter and these results are recognized by manufacturers, where the hand-held meter is not.