We used Shaw Ecoworx carpet tile, which uses a non-vinyl backing that's Cradle to Cradle certified. (Ours came from ecohaus/Environmental Building Supplies in Portland, though it's not available online.) Read on for step-by-step instructions. Most rooms aren't perfectly square, so lay out a row of carpet tiles and experiment until you've found the angle that looks best in the room. Our room is essentially a hallway, so we also wanted to avoid putting a seam directly in the center of the hallway.Carpet tile usually has a direction, indicated with an arrow on the back. The tile should be installed with all the arrows pointing the same way, or in a parquet or checkerboard style, with the arrows alternating, or the different tiles may appear to be slightly different colors when you're done. Place a tile upside down, with the arrow pointing in the right direction, and then measure the distance between the edge of the layout tile and the wall. If your wall is out of square, like ours, measure at several points down the tile... ...then connect the dots. The same technique works if you have irregular shapes. If something's really complicated, it's always worth it to make a template out of cardboard. Cutting tiles is simple. Use a very sharp knife, and change the blade often. Do not push down hard on the blade; it may seem like the right thing to do, but it makes it more likely that you'll go off the line or cut yourself. If the tile is difficult to cut, cut through the backing, fold the carpet back, and trim through the fiber. You can use scissors to trim off any errant fibers. Place the carpet tiles in place; no glue or adhesive is needed if you trim precisely. You can always see the seams with carpet tiles, so we created a pattern by cutting one tile of a darker grey into 2 1/2" strips, which we mixed in with full-size tiles.