Chipping Away

Chipping Away


Posted By on Feb 7, 2014

Chipping Away We discuss how. Part of the way Crews using a bond coat must perform a partial chip-out. It’s important to remove the plaster immediately under the tile line and around fittings. This allows the plaster or exposed aggregate to be gradually feathered in and wrapped around penetrations, so that they are at the same elevation and prevent leakage or water migration behind the tile. To chip around the tile, professionals saw cut at least once immediately underneath to allow the material to come off cleanly. This causes the least damage to the tile. Some just cut immediately under the tile, at the joint. Others add a second saw cut, running parallel anywhere from 3 to 12 inches below. Then they knock out the material between the two saw cuts. When you make two cuts and hit it with the jackhammer, it comes out in a small section. It’s more of a controlled area that you’re taking off. That whole piece comes off. After that, I can get a lot more aggressive for the next few inches down. Some use an angle grinder to make the cuts while others uses hand grinders with a 4-inch diamond blade. Skipping this step can damage the tile over time. There are guys who won’t undercut, won’t chip, and they just roll the new finish into the existing tile. That runs into a potential problem with water getting down behind the new finish because you’re not really sealing off the top of that new finish. You’re basically exposing it to water penetration. When doing this, only cut about as deep as the tile. Professionals know the tile is only 3/8-inch thick, so that’s all they’re going down. They’re not cutting any deeper than they have to. How far to cut beneath the tile depends partly on what type of finish is being used. Plaster and finer exposed aggregates only need to be applied about 3/8-inch thick, so it’s fine to chip out less of the existing plaster underneath the tile. However, when dealing with a pebble finish or other material that must be applied more thickly, a greater amount of space should be opened up underneath the tile. This gives plasterers more room to gradually feather in the material until it sits flush with the tile surface. Crews use a similar technique around the fittings, placing a cut approximately 6 inches outside the fittings and then removing the finish material. For floor returns or in-floor cleaning heads, some professionals prefer to cut approximately 12 inches. Next, crews must check for areas where debonding, commonly called delamination, has occurred. These are nicknamed “hollows.”...

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