Furring Strip Ceilings - Layout and Installation
When you enter a room, the walls and the floor treatments are usually what first get your attention. Those surfaces are generally where the greatest dollar values are invested into exotic woods and fine stone materials, along with finishing trims and decorative panels.
The ceiling, however, can also offer a surface worth investment to complete and enhance the overall decorative aspect of the space, bringing out the specific style of a chosen period design.
Whatever materials you use, you'll probably add a ceiling treatment of some kind to cover up the overhead framework, electrical wiring, plumbing pipes, and ductwork. This can conceal ceiling damage, cover up an outdated texture like popcorn surfacing, or provide extra insulation or soundproofing.
There's practically an infinite array of different types and styles of tiles and other ceiling treatments to choose from made of PVC vinyl, laminate, steel, tin, copper, mineral fiber, urethane, or simply drywall.
The amount of work or DIY expertise required to install the various treatments also varies with the methods of installation, which can be as simple as gluing up to an already existing surface to build a more intricate support gridwork.
The easiest way to finish a ceiling is by using ceiling tiles applied directly to drywall with construction adhesive or—if the framing from the above floor is exposed—by stapling the ceiling tiles to a furring strip grid skillfully added to the overhead framing.
These types of installation are very different from the suspended ceilings in the way that their installation is done, which makes it much more permanent as opposed to the ease with which suspended ceiling tiles can be removed or replaced, and leaving you with easy access to your electrical and plumbing network laid out between the floor joists above and the lowered ceiling, leaving you the extra space.
Furring Out a Surface
Furring out is a technique used to build out walls and ceilings to form a true and leveled surface, also making it much more stable prior to attaching the wallboard or other treatment to it.
It can also be used to create a space where the extra depth of at least 3-inches (75 mm) or more makes room for wiring, ductwork, plumbing pipes, or insulation. That airspace can also be used for soundproofing walls and ceilings when used with the right insulation materials made to absorb sound waves and vibrations.
Furring strips made from wood or metal are generally used on already built framework structures and add a more stable gridwork onto which a ceiling or wall covering can then be applied and attached securely.
A wall or ceiling wooden frame doesn’t always provide you with a series of perfect boards, each one as straight as the next one. Quite the opposite, it often leaves you with some areas higher than others if you bother to check the evenness with a long straight edge—thus the need to fur out the surfaces.
As you attach the furring strips to such frameworks with either slight or marginal discrepancies throughout, you’ll find that most defects can be corrected with skillful placement of spacers and wedges under the furring strips to raise the dips to the same level as the higher spots to create a flat, even, and true surface whether on the ceiling or the walls.
Furring out is essential to ensuring that you’ll always get a flat and smooth surface when the project is complete while adding more opportunity to screw or nail the ceiling and wall treatment in many more places than if fastening directly to the framed structure.
Furring Strips - Their Nominal and Actual Sizes
The wood furring strips, also known as furring boards or strapping, are narrow pieces of lumber manufactured in several nominal thicknesses, namely 1-inch, 5/4, and 2-inches which translate into actual measurements of just over 5/8”, 3/4”, 15/16”, 1-3/8”, or 1-1/2”, the difference removed at the planning stage of manufacturing, and they’re generally available in 2 or 3-inch widths.
Furring strips are also manufactured in steel and aluminum according to specific profiles, such as the hat strip and the “Z” strip. Each style comes in a variety of sizes, especially for the common depths of 1/2-in. to 1-1/2 in but also larger.
The hat channel strips have a cross-sectional view looking somewhat like a brim hat with the center flat to be attached to the framework, while the two opposite flanges can provide a screwing base to the drywall or surface treatment.
The “Z” strip has a cross-section appearance resembling a somewhat kind of a Z shape but with the middle section at a right angle instead of slanted, also providing a flat surface to screw into the existing framework and another to secure the surface panels with some mechanical means.
Step 1 - Planning Your Overhead Installation
With your acquired knowledge of furring strips, it’s now time to plan your ceiling layout. The first thing is to determine the total square footage of your ceiling and how many tiles you’ll need to cover it.
1.1 - Multiplying the room’s length by its width will provide you with the total net square footage (square meters) you have to cover. If the room is not rectangular, an easy solution is to sketch out its overall shape onto graph paper, using the squares on the paper to represent square feet or square meters.
Once your sketch is complete, you just have to count the squares to get your total. This method can be a little difficult for an accurate count, though, if the tiles are not to be installed at right angles, as the severed corners at one side of the room could possibly—but not always—be used on the opposite side wall.
But once you determine the net total, you should then multiply it by 1.1 to add an extra 10% that will make up for the waste created when trimming or from unforeseen mistakes and damages.
With the tile boxes always having their total coverage specified in square feet or square meters printed on the box, you can simply divide that number into your overall square footage (square meters) to figure out the total amount of boxes you’ll need to complete the job.
1.2 - The next step will be to figure out how you should have your rows of tiles placed on the ceiling. A few rules should be followed to present your room with a pleasing esthetical appearance, such as:
a) The border tiles, which are the rows of tiles running along the outside perimeter of a room, should be at a width greater than 1/2 tile.
b) The rows running along opposite walls should always be at identical widths.
For example, let's use a room 9-ft 8-in. wide by 12-ft 4-in. long.
Laying Out the Width
The wall-to-wall width being at 9-ft 8-in. would logically present you with nine full tiles across the room with 4-in. left to divide between the two opposite borders, or 2-in. borders. This would provide symmetry, but the 2-in. row against the wall wouldn’t be very pretty to look at.
If you use eight instead of nine full tiles across the ceiling, that will leave you with 20-in. overall to be divided equally between both of the opposite borders. Providing you with 10-in. borders at each side wall, it will make the installation much more pleasing to look at, with the border tiles being at only 2-in. less than a full tile width.
Step 2 - The Length Layout
You can now work out a similar layout in the other direction, following the same directions outlined in step 1.2 but for the length instead of the width of your ceiling.
In our example, 12-ft 4-in. would convert to 11 full-size tiles and two 8-in. border tiles. In this way, all four border rows of a rectangular or square room are more than 6 inches, and the two opposing border rows are of equal widths.
The 12” by 24” tiles
The layout for 24-in. long tiles can be done the same way, except that the 8-in. border width calculated in the length layout now has to be extended to another 12-in. for the extra length on the tile to make it 20-inches long for the border tiles—the incision in the center of the longer tiles will leave the installation with the same appearance as the square groove and tongue tiles.
Step 3 - Planning Your Grid Layout
Before you start to install your furring strips to the ceiling, you must first make sure to carefully establish a perfectly squared-off rectangle to guide you as you put the tiles in place. In many homes, especially older ones, the walls dividing the rooms don’t always meet at true right angles.
In such instances, you must set up an outline representing the perimeter of all the full (uncut) tiles once installed and centered within the ceiling surface.
3.1 - Install furring strips along the outmost perimeter of the ceiling. All the furring strips forming the grid will have to be installed perpendicular to the ceiling joists with two nails or screws at each intersection to prevent them from cupping. The fasteners should penetrate into the joist at least 1-in. deep to provide adequate stability.
If the grid is to be installed over an already finished ceiling, you’ll need a stud-finder and a chalk line to locate and mark the exact location of each joist. The thickness of materials covering the joists should be considered when choosing the proper length of nails or screws to be used.
3.2 - You will then need to improvise to cover the gaps between the rows of furring strips where they meet with the walls at both ends, and bridge the gaps between the strips with short furring pieces to offer a solid surface where you can fasten the finishing edge moldings and the tiles.
3.3 - Unless it is perfectly square, a room has two opposite long walls and two opposite shorter walls. With your measuring tape, find and mark on the ceiling the center of each of the two short walls.
After placing a nail on each of the marks, hook your chalk line on one of the nails and stretch it to the other nail wrapping it around the nail and then snapping the string to leave a line the full length of the ceiling. For convenience, let’s refer to this line as the “main center line.”
3.4 - Divide the number of ceiling tiles that will cover the width of the room by two, but excluding the border tiles.
a) If your result gives a whole number of tiles for each half of the ceiling, multiply the number by 12-in. and make a mark on the ceiling at that distance from the “main center line.” Make another similar mark at the other end of the room.
A chalk line traced between those two marks will provide the starting point for tracing all the subsequent parallel guidelines for installing every furring strip needed to build up your ceiling grid. We’ll refer to this line as the “side starting line.”
b) If, on the other hand, your result ends up with a half, multiply the number of whole tiles by 12-in. and add 6-in. for the half tile. This will give you the distance of the “side starting line” where you need to mark the ceiling, measured from the “main center line.”
Add a similar mark at the other end of the room and join them together with a chalk line. This will be your “side starting line” in this situation.
3.5 - From the “side starting line,” trace the “furring strip center line” 1/2-in. over towards the center of the ceiling to ensure the centering of the ceiling tile’s stapling flange at the center of the furring strip.
All the subsequent furring strip center guidelines will be chalk lined from this “furring strip center line.” The “furring strip center line” also gives the overall width (including the flange) at which to cut the border tiles when you begin the installation.
3.6 - Since the furring strips will have to be installed on a 12-in. center from each other to accommodate the 12-in wide tiles, you now need to add a series of chalk line marks parallel to the “furring strip center line” and 12-in. apart over the whole ceiling, keeping the margin of error at no more than 1/4-in. overall.
Step 4 - Squaring off Your Ceiling Area
As mentioned previously, not all rooms are built perfectly square, and adjacent walls can sometimes be slightly more or less than 90° from each other, causing irregular cuts at the border tiles.
You could also have discrepancies with both opposite walls making it that much more challenging to deal with. Adding tiles to the ceiling will not make the room any more square than it already is, but if done properly, it will help to average out all the differences around the whole perimeter of the border tiles thus making them much less obvious.
You’ve already accomplished half the job with the side walls borders figured out in steps 3.3 and 3.4. It is a somewhat different process with the end borders as the room may present you with a trapezoid shape. The only way to do this is to find the exact center of the room first.
4.1 - Find and mark the center of your ceiling grid by finding the center of the “main center line,” measured from one end wall to the other end wall.
4.2 - Next, you have to trace a line perpendicular to the “side starting line” right across the ceiling while intersecting the center mark of the “main center line.” The easiest way to do that without resorting to formulas is probably by using a carpenter’s square or, even better, a 4-foot drywall square.
This will represent the “perpendicular line” as we will refer to for hereon.
4.3 - Repeat step 3.4a or 3.4b to find your end wall border line measured this time from the “perpendicular line.” This line will represent the joint where the border tile and the 1st full tile will meet, and at the same time, will provide you with the length at which the border tile should be cut (adding 1/2-in. for the flange) for that particular row of tiles.
Step 5 - Installing the Furring Grid
5.1 - With the perimeter of the ceiling already covered with furring strips, you can now proceed to build the rest of the grid with furring strips running perpendicular to the joists and each one centered on their respective “furring strip center line” traced in steps 3.5 and 3.6, with each line 12-in. apart.
Before permanently attaching them to the joists, check with a 4-ft level to make sure they all remain level throughout the installation, and use spacers and wedges to correct the dips in the structure before nailing or screwing everything together.
5.2 - With the perimeter covered, the rest of the furring strips can be added to the grid, each one positioned to be centered over the “furring strip center lines.” They should be secured at each joist with two nails or screws.
5.3 - Wherever you need to join two or more furring strips to cover a full row, the butt joint should always be at the center of a joist where both of the strips can be solidly secured, and should never be allowed to fall between joists where they can’t be nailed.
5.4 - Always keep the furring strip joints staggered so that successive joints don’t fall on the same joist
Step 6 - Installing the Ceiling Tiles
6.1 - The first tile to go on will necessarily have to be at the corner covering two borders. This means that it will have to be cut in width for the side border and in the length for the end border.
So as you face that corner, you should be working from your left to your right, with one of the corner tile flanges over the furring strip while the other is on the right side, waiting to accept the next side border tile.
Note: The tiles should be cut face up with a sharp utility knife, and to prevent excessive gaps from uneven walls, each border tile should be measured and cut individually as you get to them. Cutting these tiles 1/4-inch shy of the actual measurement will make them fit better, and the gap can later be covered with molding.
6.2 - Keep cutting and installing side border tiles—installing two or three—then move to the first row of full tiles. When stapling 24-inch tiles to furring strips, make sure that the tiles run lengthwise along the furring strips and secure the tiles with at least six staples in each one.
6.3 - Cut and install the end border tile, then continue to install until you’re one tile away from the previous row, then move another row over and keep going until you’re down to only one end border tile. Your tiles should now form somewhat of a triangular shape on the ceiling.
6.4 - Return to the first side border row and add two or three more tiles, then keep moving to the next rows, always staying one tile offset from the previous row and gradually increasing the triangular shape on the ceiling as you keep following the process over and over until you reach one of the two opposing walls.
6.5 - When you reach the opposing walls and have to start cutting the border tiles, you will find yourself without a flange to attach the tile to the furring strip. Considering the width of the molding you’ll use to finish the job, you can nail down the tiles within that molding width that will cover them later.
Adding crown molding and other wood trim pieces to a plain ceiling creates dimension and architectural interest.
There are many more uses you can get from using furring strips. Much more information can be found on how and where they can be used and is readily available online. These are a few links easily accessible and aimed at DIYers:
Installing Furring Strips on Basement Walls