You have a .25-inch margin of error when installing a wood furring strip ceiling. Some manufacturers require this type of system. The furring strips are nailed perpendicular to the joists. If the joists are exposed, there is no problem. If you are installing these over an existing ceiling, you will need to locate and mark the joists as described under the clip method in the preceding steps.
If you are installing 12x24-inch ties, furring strips must be installed on 12-inch centers. When stapling 24-inch tiles to furring strips, make sure that the tiles run lengthwise along the furring strips.
Use two 8-penny nails at each joist to keep the strips from warping. If you are nailing over a lath and plaster ceiling, longer nails may be needed. You need to penetrate into the joists by at least 1-inch. Use a level to ensure that the strips are level. Use wooden shims where needed.
Step 1 - Install the First Strip as a Guide for the Rest
The first furring strip is flush up against the wall. The second strip is positioned so that its center is the same distance from the wall as the width of the border file that butts against that wall plus .5-inches to allow for the stapling flange of the tile. For example, if the width of the border tile that butts against the wall is 10-inches, add .5-inches to the 10-inch width and position the second strip so the center is 10.5-inches from the side wall.
After installing the second strip, work across the ceiling, nailing furring strips spaced 12-inch on center (from the center of one strip to the center of the next). Be exact nail the final strip flush against the wall.
When two furring strips are joined, the butt joint should always be over the center of a joist. Never allow these joints to fall between joists where they cannot be nailed. Also, stagger the joints so that they form rows which do not fall on the same joist.
Step 2 - Square the Ceiling With Strings
When squaring the ceiling with strings, everything you do must be exact. If the walls meet at true right angles, you can omit this step. Unfortunately, in many homes, especially older ones, this is not the case. In these instances, you must set up strings that are at true right angles and lay the tiles according to these strings. The strings will serve as guides for installing and cutting the border tiles. If you omit this step, the tile ceiling will look misaligned.
Set two strings that run at the level with the new ceiling. They will extend out from each wall a distance equal to the width of the border tiles at that wall. The strings are attached to nails temporarily driven into the walls. The two strings will intersect at a corner. The strings are placed in such a way so as to outline the edge of the two intersecting border rows.
Set up a line so that it is at the level of the ceiling and runs 10-inches from the wall. Do the same with the intersecting string so that it is running 8-inches from the wall. Once these are in place, use a framing square and to determine if the 2 strings are square.
Step 3 - Adjust
If they are just a little off square, the walls may be a few inches off over the distance of the wall. Be sure that each line is runs exactly along each arm of the square. If they are not, adjust the strings that outlines the border row that will be less noticeable from below until the lines are at exact right angles. You now have a square reference from which to install the tiles.
Step 4 - Install
Continue to install the furring strips until the project is complete. Ensure that the strips remain square as you proceed in order to create the desired results. Continue to Part 5 of this series for information on finishing the project.