HOME CLINIC — On Installing a Ceiling -

HOME CLINIC - On Installing a Ceiling -

HOME CLINIC; On Installing a Ceiling

By JOHN WARDE
Published: April 7, 1991

SUSPENDED or dropped ceilings are easy to install. Consisting of lightweight panels supported by a grid of metal strips hung from the existing ceiling, or from joists above an unfinished ceiling, they are an excellent way to conceal overhead pipes, ducts and wiring, as well as dilapidated ceilings too costly to repair.

Suspended-ceiling kits come in a wide range of panel designs, colors and textures. Before buying one, draw to scale on graph paper an outline of the ceiling.

Use paper having quarter-inch squares, each representing one or two square feet. Include all corners and alcoves, and show the positions of overhead light fixtures, columns, pipes and ducts. Only fluorescent lights are safe to install above suspended ceilings.

Using the outline, buy panels of a particular size — 2 x 2 and 2 x 4 feet are standard — and plan the layout of strips and panels.

Runners are the main strips in a grid. They span the length of the ceiling and run perpendicular to the joists. Runners exceeding 10 feet, the longest standard length, can be made by joining them end to end.

Secondary strips called cross tees span the width of the ceiling. They are short segments whose ends fit into slots in the runners.

To be fastened around the room are strips of right-angle channel called molding. The kits also include screw eyes and wires, used to suspend the strips from the ceiling.

With the kit ready to assemble, first mark the desired height of the ceiling onto the walls. One way is to measure along one wall from the floor to the desired height. Then measure the height of a molding strip, usually three-quarters of an inch, and mark the wall at the combined height.

Make several marks at this height on each wall, and then connect the marks by snapping a chalked string stretched between them against the wall. Check the accuracy of the lines with a long builder’s level.

Another method to mark long walls or rooms with uneven floors is to use a water level for each mark. A level can be made by filling a long flexible tube of clear plastic with water and marking one or both ends about eight inches from the opening.

Two people are needed to use a water level. One holds an end so that the mark on it is at the desired ceiling height. The other person moves the remaining end up and down where the second mark is to be made. When the water level observed by the first person is even with the desired ceiling height, the water level observed by the second person will be at the same height.

After marking the walls, nail molding strips against them so that their top edges are on the chalked lines. Where strips meet at inside corners, overlap the ends.

At outside corners, trim the horizontal flange of one strip to a 45-degree angle and remove a portion of the adjoining strip’s vertical flange equal to the strip’s width. Overlap the ends. Strips can be cut with aviation-style, metal-cutting shears.

Determine the locations for the runners from the layout plan drawn on the scaled outline. Stretch reference strings between opposite molding strips as a guide for mounting the runners. To attach reference strings, tie the string to a nail, then tap the nail behind the molding at the correct spot.

Repeat the process to mark the locations for the cross tees. Make sure all intersecting strings form right angles. For suspending the runners, install screw eyes in the existing ceiling or in the joists at four-foot intervals. Position the eyes above the reference strings; the first and last eye for each runner should be within two feet of a wall.

Attach hanger wires to the eyes by twisting each wire around itself three times. At the exact height of the strings, bend the wires at right angles. Cut the runner strips to length or assemble them by locking together strips of sufficient length, as described in the kit’s instructions. Then set the first runner into place by resting its ends on the horizontal flanges of the molding strips. Insert the free ends of the hanger wires through the mounting holes in the runner, but twist each wire only once to hold it temporarily.

Place a level against the runner to verify it is horizontal. Make adjustments if necessary; then secure the wires by wrapping each one two or three more turns around itself. Install the remaining runners the same way, then fit the cross tees between them. Work in rows from the center of the ceiling outward. Cross tees do not need wires; their ends fit into slots in the runners. Near walls, trim the ends of tees so that they rest on the molding. Check each row of tees with a level before installing the next row.

When the grid is complete, remove the reference strings and install the ceiling panels. Starting at the center, pass the panels upward through the grid openings and then lower them gently until their edges rest on the runner strips and cross tees.

Install translucent plastic panels below light fixtures the same way. If a panel will not lie flat, wire ends or the tabs of joined runners may be causing an obstruction.

For the perimeter of the ceiling, cut panels with a sharp knife so that they fit the grid openings. Lay the panel on a flat work surface, mark the panel on its good side for cutting and then slice through it with a knife held square to the surface.


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