Find tips and information on using a level, dealing with different room configurations, and how to deal with potential problems encountered when planning a floor installation.

April 10, 2018
family room, modern lighting, fireplace

One of the most common problems in planning a floor installation is out-of-square walls. Walls seldom define a room squarely, but you can make paper-and-pencil adjustments much more easily than you can rebuild a wall. Below, we show you how to deal with common homeowner problems such as imperfect squares and wavy walls. See what you can do to make the space work for you.

Getting Started


To determine if the area is square, use the 3-4-5 triangle method: Snap a chalkline on the floor or tack a mason's line at the midpoints of each pair of opposite walls. From the intersection measure out on one line a distance of 3 feet. Tape the line at that point and measure and tape a distance of 4 feet on the other line. Now measure the distance diagonally between the tapes. If it's 5 feet exactly, the floor is square. Adjust the lines, if necessary, until they are perpendicular. Now measure from the lines to the out-of-square walls at each end and post this measurement on your drawing.

Wavy walls may also affect your drawing. Check them with a 4-foot level and represent the condition on your drawing as accurately as possible.

Check the floor to determine if it is level and flat. If the floor is not level, it won't affect the final look unless you are also tiling a wall. But floors must be reasonably flat (within 1/8 inch in 10 feet) to keep the tile from cracking.

Wavy Walls


Wavy walls can result in edge tiles with uneven cuts. Use a 4-foot level to check the surface of the wall near the floor. If the problem is not severe, the cuts may not be noticeable.

When drawing a layout plan, try the following solutions. Minor variations in a wall surface may actually "disappear" if hidden under a baseboard.

More severe depressions in a wall can be leveled with a skim coat of thinset prior to tiling the floor. Feather the edges of the skim coat to blend in with the level surface. Skim-coating, however, requires proper preparation of the wall so the mortar will stick. You will also have to tile the wall, paint it, or cover it with another material.

How to Lay Out a Rectangular Room


In a rectangular or square room, pencil in reference lines at the midpoints of the walls and draw in tiles on both axes. If you have the tiles, lay them out on the floor to make your drawing more accurate. Adjust the placement of the lines so the pattern ends in even borders if possible.

How to Lay Out an L-Shape Room


When laying out an L-shape room, position the lines so they carry from one room to the other. Adjust them so the layout results in even borders if necessary.

How to Lay Out a Diagonal Room


To establish lines for a diagonal layout, first pencil in lines at the midpoints of the room. Then on each axis mark an equal distance from the intersection. Extend these points until the extensions intersect. Draw diagonal lines from the intersections through the midpoint.

What if the Floor is not Square?


An out-of-square floor surface will result in tapered tiles on at least one edge. Draw the tiles on your layout plan to minimize the visibility of the tapered tiles. Modify the grout width, hide cut edges under baseboards, or arrange your layout so the tapered edges fall behind furniture. Try a diagonal layout or a larger, irregular tile to hide the tapered edges. In extreme cases, you can shim out the wall and rebuild it.

What if the Floor is Not Level?


An out-of-level floor creates tapered wall tiles at the floor. A diagonal wall layout may hide a minor condition. For severe problems, install a floor covering other than tile or level the floor.

Pro Tip: Plan Full Tiles in Doorways


When you are preparing a dimensional layout plan, draw the tiles in so a full tile will fall with its edge in the center of a doorway. If you can't set a full tile in the doorway because your plan already incorporates wide border tiles, you may be able to minimize the effect of a cut tile with a threshold in the doorway. If the tile continues into an adjoining room, center a tile at the doorway, if possible, so an even portion falls in each room.


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