Horizontal Drywall Installation on Wood or Steel Studs:
the ButtTaper System with a backer board in between the
studs. One can use a 4 to 6" strip of 3/8 or 7/16" OSB
board or � or 5/8" plywood. The wider the backer board,
the better! These have very little shrinkage. 1 x 3 or
2 x 4 are not recommended as they contain too much
moisture and will shrink considerably.
On the backer board, space the 1��
coarse drywall screws every 5" with the first screw from
� to �� from the end of the board and another 1 to 1 ��
inches from the end of the board spaced 9" apart. This
will insure that the backer is well secured to the butt
joint boards and will not flex. This is the key
to the ButtTaper system...firmly securing and splicing
the backer board to the two butt joint boards.
Try to leave a space of 1/16 to ��
between the butt joint boards � the space need not be
On vertical drywall which is fire-rated,
install a strip of the same drywall on the back end of
the 15" steel stud or track, and use that as the backer
board for the horizontal butt joint. A thin bead of
drywall adhesive may be used on the backer board drywall
for superior adhesion to the butt joint boards.
the spray bottle, spray a liberal amount of water into
the butt joint space. Wait about 10 seconds for the
drywall to absorb and soften the drywall before using
the ButtTaper tool on �� drywall. On 5/8� drywall,
spray it once, let the rock absorb the water for 15
seconds and then spray again and use the ButtTaper tool.
Hold the end of the ButtTaper tool in
your left hand. For lower wall butt joints, brace your
left hand against your thigh. For upper wall boards and
ceilings hold the tool against your chest � this will
leverage and apply more force to the rolling process. Always hold the tool directly in front of you. Roll the
ButtTaper tool up and down the space. Gently at first
and apply more pressure until the tapered edge is
Apply setting compound or all purpose
joint compound into the tapered edge. With the end of
the notched knife, wipe the compound from the tapered
edge, hold the notched knife on a 45� angle and
press it against the tapered edge. Apply the compound
into the tapered edge again. Place the �� tape on the
tapered edge and with the �notch� on the notched knife,
embed the tape just beyond the butt joint facepaper, and
wipe the joint clean with a standard finishing knife.
Allow to dry, and apply the 2nd
coat of setting compound.
Allow to dry and 3rd coat with
a joint or setting compound using an 8 or 10" finishing
Allow to dry, and sand with a sanding
Depending on the type of drywall, the rolling action of
the ButtTaper may cause the facepaper to slightly curl at
certain points. To rectify this situation, apply the
compound into the tapered edge and with the corner of your
finishing knife wipe the compound into the space between the
boards with a slight angle of the knife to the drywall, and
then wipe the excess off the face of the drywall. This will
leave the compound at the center of the tapered edge, and
will hold the facepaper down. Allow to dry, and proceed with
another two coats of setting compound prior to applying the
final coat. This occurs mainly on LaFarge and
Georgia-Pacific drywall with very little on National Gypsum,
and none with USG drywall.
Joint compound is not an adhesive, it does bind,
but not to the extent that coarse drywall screws do, and joint
compound is affected by humidity and temperature. The 4" backer
board behind the butt joint in between the studs or joists is the
binder between the two boards, and is stronger than 2-16 tape. Joint compound because of its low
binding characteristic requires a wide tape (surface area) to bind
the boards. With the use of the backer board, the drywall now is
essentially thicker. Look at it this way...you are not doing a butt
joint, you are repairing a fissure in the drywall.
Therefore, the 1/2" wide tape is not required but
should you use it, you may immediately apply the second coat of
setting compound. The use of the setting compound such as Easy-Sand,
Durabond, etc., for the first two coats speeds the finishing
process. As setting compound has minimal shrinkage, apply it well
into the tapered edge, tape it, and then immediately apply the
second coat. Third coat with a finishing compound or a setting
compound once the setting compound has set. Setting compound adheres
better to drywall than joint compound, is stronger, and is not
affected by humidity.
Butt Joints Over Openings
Butt joints should not be placed over window or door
openings as recommended by the drywall manufacturers. Always make
sure that even on a small butt joint, that it is on a backer board
or stud and not on a header. Refer to this study for drywall failure
caused by wood shrinkage:
There is no sagging of the drywall with the use of a
4 to 6" backer board. On walls, the backer board will overhang the
lower board at the top of the board by 3" and 1-1/2" from the upper
board to the lower board. Screw the overhanging board to its
adjacent board on the backer board if you so desire. The backer
board weighs less than the compound with the ButtTaper system. On
ceilings, use a 4 to 6" wide by 48" long backer or longer. If a
longer backer is used, extend it over the adjacent board, and apply
screws to the backer board on the adjacent, or if using a 48" long
backer on a ceiling, next to it affix a 6" backer that extends over
the adjacent board.
RC-1 Channel and Rigid-X
Use the backer board, and end the butt joint boards
in between the RC-1 channel and the Rigid-X grid.
When the butt joint with the second layer is on a
stud, use a thin bead of drywall adhesive with minimal screws.
Alternatively, leave the second layer in between the studs, use
drywall adhesive with 1 5/8" cement board screws. Cement board
screws adhere well in double layer applications, better than
laminating screws as they have a nip that penetrates the drywall,
and sink into the drywall without tearing the drywall paper.
The ButtTaper system permits the drywall
curvature to remain. Be sure to properly attach the drywall butt
joints on the stud, use drywall adhesive with screws or nails,
create the tapered edge, and then finish pressing your 8" finishing
knife into a slight curve on the final coat. The result is that the
curve of the wall remains intact. Using 1/4" "High-Flex drywall in a
double layer application, leave the second layer butt joint in
between the studs, adhering it to the first layer with a thin
coating of drywall adhesive, and secure it with 1-5/8" cement board
Cut a square or rectangle on the repair, apply
backer boards around the repair, leave a small space between the new
drywall patch and the old drywall, and finish as previously
instructed for butt joints. Another method is to use drywall as the
backer board with a thin coating of setting or all purpose joint
compound to hold the drywall backer to the drywall and use 1-5/8"
cement board screws to secure the drywall backer until the setting
or joint compound sets.
Backer Board and Vapor Barrier
Using 1-1/4" coarse drywall screws with 1/2" drywall
and 7/16" backer board will result in the screws penetrating the
backer board, and tearing the vapor barrier. Affix scrap drywall to
the rear of the backer or use 5/8" plywood as the backer board with
1" or 1-1/4" drywall screws.
New Wall Meeting Old Wall
Cut the backer board to the length of the wall,
preferably 6" wide. Use Durabond on the first two coats. The paint
on the old wall will become loose when sprayed with water,
thus scrape it off before applying Durabond. Should you not be able
to produce a backer board the length of the wall, use 48" long
backers, and splice them together at their junction with a 6" long
Types of Drywall
The ButtTaper works on all types of drywall
including Dens-Armor Plus, Dens Shield and Hi-Abuse XP. On the
latter three, presoak the butt joints or repairs, wait one minute,
spray with water again, and then use the ButtTaper to create the
Cutting the Backer Board
Your drywall crew should have a cordless circular
saw to cut the OSB backer board less than 4 feet long when required
on smaller butt joints or score the OSB on both sides with a utility
knife, and then snap it for a clean break. Prior to starting a large
job, rip your backer boards with a circular saw into 4 to 6" wide by
48" long strips. If more than one 4' x 8' sheet of backer is
required for your butt joints strips, clamp a few 4' x 8' sheets
together, and then cut the strips. The time allocated to this will
be saved by the sheetrockers when installing the drywall.
Working With The ButtTaper
On your belt use three hammer holders; one for the ButtTaper
tool, another for the water bottle, and the third for your finishing
knife. This way you can do the butt joints from stilts.
The ButtTaper tool does not require any maintenance as it
contains two sealed stainless steel bearings, and is totally rust
Rips On The Middle Wall
If you have any rips between two boards, and if
one end of the rip board has the factory tapered edge then only
ButtTaper the other side without the factory tapered edge and use
2-1/16" tape on the tapered edge. If the rip does not have a factory
edge then create the tapered edge with the ButtTaper. Be sure in
either case to use a backer board behind the drywall rip.
To gain speed in doing a number of butt joints,
spray all the butt joints with water in one area such as in a room,
then spray each one prior to using the ButtTaper tool. This double
watering will facilitate the pressure required for the ButtTaper
tool. Roll all the butt joints with the ButtTaper, and then begin
the finishing for all your butt joints.
If you are not using the 1/2" tape on the tapered
edge created by the ButtTaper, the tapered edge can be minimal in
depth. All you have to do is create a slight curl on the two edges
of the butt joints.
Similar to Rock Lath
The ButtTaper's tapered edge is similar to the
tapered edge that was used in 1950's and 1960's in the Rock Lath
Plastering System. The Rock Lath was 3/8" thick by 16" wide drywall
with a plaster veneer system without using any tape. The ButtTaper
system is superior because it incorporates a backer board behind the
drywall which the Rock Lath did not.
The ButtTaper's Novelty
The concept of the ButtTaper is novel, and a far departure from
standard drywall practices. For the first time, a tapered edge is
created on drywall. This radical departure from normal drywall
methods is not readily accepted by many. The ButtTaper was invented
by a drywall contractor, and tested by him and other drywallers in
the past four years.