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One of the least understood, and therefore most often incorrectly installed items is the furring strip. If you do not understand why and how it is used, it usually goes on the wall wrong. In this article I will give easy-to-follow instructions on placing furring strips on a concrete block wall.
In this example, we will be using ½” x 8’ long drywall screwed to 1-1/2” x 3/4” furring strips. Twelve feet is the professional length, but most homeowners use 8’.
No matter where you run furring strips, there will need to be extra perpendicular strips (usually 1 x 4’s) paralleling the floor, held up off the floor about ¾”. This is to nail the baseboard to later. If you are planning on installing crown molding, you will want to also run one of these along the wall a couple of inches down from the ceiling.
A point that will be addressed by KCTermite a few posts below this is to also not forget to run a "fire blocker" furring strip horizontally at the very top - whether you are doing crown molding or not. This strip needs to be held tightly up against the joists or trusses. And it needs to run all the way tight against the adjoining walls at either end, with no gaps between butted pieces. This is an important CODE requirement, so don't forget it. The only time this would not be needed is if, perhaps, you had a full concrete ceiling. Not usually too likely. (Trust me, most drywallers do NOT run the ceiling lofts tight enough to the walls to fulfill the requirements of this code issue.)
When you place the furring strips on the walls, cut them short enough that you will have a gap of about 1” to 1-1/2" at the top and at the bottom. In other words, do not butt your furring strips up against the 1 x 4’s. The electricians and TV guys like to run their wires through those spaces. Don't leave too much of a gap here, though. Some jurisdictions may require that you come back and fill these gaps with Fireproof Foam after the wires have been run. This is rare, but keep it in mind.
Part I. Beginning at a block corner
The first thing to think about is the fact that your sheet of drywall does not run all the way back into the corner. The reason for this is that the other sheet of drywall, the one turning the corner, sits off the wall an inch and a quarter because of how it is also mounted to the block. All ½” drywall sits an inch and a quarter off the block to the face of the drywall. So don’t expect to start your sheet butted up against the adjacent block wall. It will be sitting an inch and a quarter off that wall.
But why even begin at a block corner? Simple. The perimeter of a house is done first so that you can butt your cut ends up against perpendicular walls. This hides those ragged cuts when the board is applied to the intersecting stud walls. And it is a lot easier to just drag a sheet right into the corner as you enter a room.
Let’s start. We’re using an eight foot board, so simply measure 8’-1/2” out from the corner of the block and make a pencil mark on the wall. Yes, if we were using a 12' sheet you would measure 12'-1/2".
· Now draw a plumb line on that mark from floor to ceiling. Yes, use a level to do this.
· Make an “X” to the side of that line farthest away from the corner.
· Nail on a furring strip, right on top of the “X”, with the edge of the furring strip even with your pencil line.
What you just did was place the furring strip “nailer” for the very end of the eight foot board. The end of that eight footer will be placed right in the middle of that strip. This will give you 3/4" to screw the first sheet to, and 3/4" to screw the next sheet to. Now you want to place some more all across the area where the board will soon go so you can have something to screw the board to.
To do this, we will space furring strips every 16” all the way back to the corner. This is most easily accomplished by hooking your tape measure over the furring strip you just nailed on, and pulling it tightly back toward the corner.
Make a pencil mark at every 16 inches... 16... 32... 48... 64... 80... Don’t mark one in the corner yet. That starter strip in the corner is done a little differently than the rest.
· Now draw a plumb line at each of those marks from floor to ceiling. Yes, use a level to do this too.
· Make an “X” next to each of those lines on the side CLOSEST to the corner. No, this is not the same as the first “X” you made. And that’s OK.
· Nail on a furring strip, right on top of the “X”, with the edge of the furring strip even with your pencil line. In this case the pencil line will be on the opposite side of the furring strip than it was on the first strip you nailed. Don’t worry about it. It’s supposed to be this way.
You are now ready to place the “starter” strip. This one is fun. It goes a full furring strip width (1-1/2”) away from the corner. That’s important. Here’s how I like to do this one:
Cut yourself a short length (about 6”) of furring strip. Hold this on the wall as a “spacer” to offset the “starter” strip. Place your furring strip against this “spacer”, and nail it in that spot with one nail. Move the “spacer” up and down as needed to place more nails, holding the furring strip tightly against your “spacer” each time.
Why did we hold that “starter” strip off the wall? When you go to screw on the board you will see. With the furring strip up tight in the corner, you would not be able to cleanly get screws into your second corner run (opposite corner). You’ll see.
All that is left to do now is to continue this layout on across your wall for the rest of the furring strips. Hook your tape on the end strip, and begin your 16... 32... 48... 64... 80... layout again, continuing on across the unmarked portion of your wall. This time, placing the “X” just past each mark you make. To check your work on these “running” strips, you should expect to see 14-1/2” between strips anywhere you check (except the “starter”)
Pull your tape from the center of any strip (except the "starter") and you will find 8' (or any multiple of 16) will fall right in the center of another strip. This keeps you from having to do a lot of unnecessary cutting.
Of course each time you come to a wall intersection, make sure you have an extra strip running alongside the wall stud (about 1/1/2” off the stud)
One final point to mention here could be very important to you. Wall joints tend to crack. Part of the reason for this has been determined to be the tight fastening of the board to that 'starter' strip. Some drywall installers do not fasten to that last furring strip at all. They prefer to leave it floating, allowing only the tape and mud to make the corner connection. This lets the corner flex and move with minute seasonal wall movements. You might find it beneficial to add one more furring strip centered between the starter strip and the beginning strip (#2) of your layout, and let that strip be the last one you nail to as you approach the corner, nailing your drywall. (But simply ending your nailing at #2 strip is just fine.) I do not show this on the drawing because some municipalities frown on this "floating" technique. (There's no accounting for officials who refuse to keep up with progressive innovations.)
BTW, the same 'floating' trick is used at the top of a wall where it meets the ceiling when trusses are used. All trusses tend to move up and down with the seasons. Letting the last section of ceiling board 'float' helps prevent cracking here too.
Go up to your TOOLBAR and click your ZOOM up to 200% (under the PAGE drop-down menu) if these pictures are too small to see.
In this example, we will be using ½” x 8’ long drywall screwed to 1-1/2” x 3/4” furring strips. Twelve feet is the professional length, but most homeowners use 8’.
No matter where you run furring strips, there will need to be extra perpendicular strips (usually 1 x 4’s) paralleling the floor, held up off the floor about ¾”. This is to nail the baseboard to later. If you are planning on installing crown molding, you will want to also run one of these along the wall a couple of inches down from the ceiling.
A point that will be addressed by KCTermite a few posts below this is to also not forget to run a "fire blocker" furring strip horizontally at the very top - whether you are doing crown molding or not. This strip needs to be held tightly up against the joists or trusses. And it needs to run all the way tight against the adjoining walls at either end, with no gaps between butted pieces. This is an important CODE requirement, so don't forget it. The only time this would not be needed is if, perhaps, you had a full concrete ceiling. Not usually too likely. (Trust me, most drywallers do NOT run the ceiling lofts tight enough to the walls to fulfill the requirements of this code issue.)
When you place the furring strips on the walls, cut them short enough that you will have a gap of about 1” to 1-1/2" at the top and at the bottom. In other words, do not butt your furring strips up against the 1 x 4’s. The electricians and TV guys like to run their wires through those spaces. Don't leave too much of a gap here, though. Some jurisdictions may require that you come back and fill these gaps with Fireproof Foam after the wires have been run. This is rare, but keep it in mind.
Part I. Beginning at a block corner
The first thing to think about is the fact that your sheet of drywall does not run all the way back into the corner. The reason for this is that the other sheet of drywall, the one turning the corner, sits off the wall an inch and a quarter because of how it is also mounted to the block. All ½” drywall sits an inch and a quarter off the block to the face of the drywall. So don’t expect to start your sheet butted up against the adjacent block wall. It will be sitting an inch and a quarter off that wall.
But why even begin at a block corner? Simple. The perimeter of a house is done first so that you can butt your cut ends up against perpendicular walls. This hides those ragged cuts when the board is applied to the intersecting stud walls. And it is a lot easier to just drag a sheet right into the corner as you enter a room.
Let’s start. We’re using an eight foot board, so simply measure 8’-1/2” out from the corner of the block and make a pencil mark on the wall. Yes, if we were using a 12' sheet you would measure 12'-1/2".
· Now draw a plumb line on that mark from floor to ceiling. Yes, use a level to do this.
· Make an “X” to the side of that line farthest away from the corner.
· Nail on a furring strip, right on top of the “X”, with the edge of the furring strip even with your pencil line.
What you just did was place the furring strip “nailer” for the very end of the eight foot board. The end of that eight footer will be placed right in the middle of that strip. This will give you 3/4" to screw the first sheet to, and 3/4" to screw the next sheet to. Now you want to place some more all across the area where the board will soon go so you can have something to screw the board to.
To do this, we will space furring strips every 16” all the way back to the corner. This is most easily accomplished by hooking your tape measure over the furring strip you just nailed on, and pulling it tightly back toward the corner.
Make a pencil mark at every 16 inches... 16... 32... 48... 64... 80... Don’t mark one in the corner yet. That starter strip in the corner is done a little differently than the rest.
· Now draw a plumb line at each of those marks from floor to ceiling. Yes, use a level to do this too.
· Make an “X” next to each of those lines on the side CLOSEST to the corner. No, this is not the same as the first “X” you made. And that’s OK.
· Nail on a furring strip, right on top of the “X”, with the edge of the furring strip even with your pencil line. In this case the pencil line will be on the opposite side of the furring strip than it was on the first strip you nailed. Don’t worry about it. It’s supposed to be this way.
You are now ready to place the “starter” strip. This one is fun. It goes a full furring strip width (1-1/2”) away from the corner. That’s important. Here’s how I like to do this one:
Cut yourself a short length (about 6”) of furring strip. Hold this on the wall as a “spacer” to offset the “starter” strip. Place your furring strip against this “spacer”, and nail it in that spot with one nail. Move the “spacer” up and down as needed to place more nails, holding the furring strip tightly against your “spacer” each time.
Why did we hold that “starter” strip off the wall? When you go to screw on the board you will see. With the furring strip up tight in the corner, you would not be able to cleanly get screws into your second corner run (opposite corner). You’ll see.
All that is left to do now is to continue this layout on across your wall for the rest of the furring strips. Hook your tape on the end strip, and begin your 16... 32... 48... 64... 80... layout again, continuing on across the unmarked portion of your wall. This time, placing the “X” just past each mark you make. To check your work on these “running” strips, you should expect to see 14-1/2” between strips anywhere you check (except the “starter”)
Pull your tape from the center of any strip (except the "starter") and you will find 8' (or any multiple of 16) will fall right in the center of another strip. This keeps you from having to do a lot of unnecessary cutting.
Of course each time you come to a wall intersection, make sure you have an extra strip running alongside the wall stud (about 1/1/2” off the stud)
One final point to mention here could be very important to you. Wall joints tend to crack. Part of the reason for this has been determined to be the tight fastening of the board to that 'starter' strip. Some drywall installers do not fasten to that last furring strip at all. They prefer to leave it floating, allowing only the tape and mud to make the corner connection. This lets the corner flex and move with minute seasonal wall movements. You might find it beneficial to add one more furring strip centered between the starter strip and the beginning strip (#2) of your layout, and let that strip be the last one you nail to as you approach the corner, nailing your drywall. (But simply ending your nailing at #2 strip is just fine.) I do not show this on the drawing because some municipalities frown on this "floating" technique. (There's no accounting for officials who refuse to keep up with progressive innovations.)
BTW, the same 'floating' trick is used at the top of a wall where it meets the ceiling when trusses are used. All trusses tend to move up and down with the seasons. Letting the last section of ceiling board 'float' helps prevent cracking here too.
Go up to your TOOLBAR and click your ZOOM up to 200% (under the PAGE drop-down menu) if these pictures are too small to see.
Corrected to reflect the current usage of the term. Yes, my spelling of firring was wrong, and I should be fired for that.
