Loose-lay carpet uses carpet cut into square tiles that can be glued onto a concrete or plywood subfloor. Instead of dealing with bulky and heavy rolls of carpet, an installer of loose-lay only needs to pull the tiles from a box and glue them down with their stitching facing the same direction. Arranged like this, with the tiles placed tightly against one another, the floor covering can be almost seamless to the eye of someone walking across it. Loose-lay is a much easier job for a single worker than rolled carpet would be.
Prepare your subfloor. A concrete floor needs to be smooth, clean and dry. If you have a vinyl or tile floor, it must be smoothed by applying a smoothing compound to the lower spots (a scraper works well for this) and letting the compound dry. If you are installing the carpet over a wooden floor, lay down a sheet of plywood nailed down with nails hammered in every three feet. Turn off any underfloor heating at least 48 hours before putting down carpet tiles.
Mark guide lines on the floor with chalk. To get your tiles straight, you need to mark two intersecting lines going straight across the room. These need to meet at a 90-degree angle. The lines must also meet at a point where the width of the room is such that when you lay tiles across it, the cut tiles required to fit the carpet to the walls are at least 1/4 the width of a full tile. This intersection point must itself be located well away from the wall to allow for the proper laying pattern.
Apply glue to the backing of the tiles according to the instructions on the glue package.
Lay the tiles down on the floor starting at the point where your chalk lines intersect. They should be laid in a "staircase" pattern, with the first row going all the way across the room (except for any cut tiles), then the second row one tile shorter, the third row one tile shorter still and so on. This will give you the straightest lines.
Ensure that the tiles are snug against each other, but not pressing hard enough to cause buckling or bending. They should also be laid down with all the fibres pointing in the same direction. This is indicated by arrows printed on the bottoms of each tile, which should all point the same way as the tiles are put down.
Finish the installation by cutting tiles with a utility knife to fit around the outside of the pattern to bring the carpet snug against the walls and around protrusions and doorways. When you turn any subfloor heating back on, turn it on low to avoid thermal shock to the newly glued tiles.