cast iron; you could use similar
couplings to splice aBS or PVC
drainpipes to cast iron.
338 Chapter 12
Run clear water through the drains before
cutting into them. Flush the toilets several times
and run water in the fixtures for several minutes.
Then shut off the supply-pipe water and post
zzzzzz vent Termination
signs around the house so people don’t use the
fixtures while work is in progress.
splICIng a BranCh
DraIn InTo a sTaCk
12 in. minimum
If you’re adding a toilet, have a plumber calculate
6 in. minimum
the increased flow, size the pipes, recommend fit-
10 ft. minimum
tings, and—perhaps—do the work. Adding a lav,
sink, or tub, on the other hand, is considerably
easier and less risky—mostly a matter of splicing
3 ft. minimum
a 11⁄2-in. branch drain to a 2-in. or 3-in. stack.
The basic steps are clamping the stack before
Roof flashing
cutting it, inserting a tee fitting into the stack,
and joining the branch drain to that fitting.
Windows open.
Let’s look at splicing to a cast-iron stack first.
Start by holding a no-hub fitting (say, a 2 by
11⁄2 sanitary tee) next to the stack and using a
grease pencil to transfer the fitting’s length to the
stack—plus 1⁄2 in. working room on each end.
So vent gases won’t enter the home,
(This gap at each end will be filled by a lip inside
plumbing vents must terminate at
the neoprene sleeve.) Install a stack clamp above
least 3 ft. above an openable window,
and below the proposed cuts. Then use a snap
or a minimum of 10 ft. horizontal
distance from an openable window at
the same level.
A CAST-IRON STACK
AN ABS-PLASTIC STACK
zzzzzz splicing a Branch Drain to a stack
Slip-coupling or
1
Stack clamp
no-hub coupling
2x cleats
Short length of
nailed to studs
plastic pipe glued in
Cast-iron
no-hub fitting
4
1 in. more than
length of fitting
3
5
2
ABS
No-hub coupling
reducing tee
4
Neoprene sleeve
ABS stack
3-in. or 4-in.
cast-iron stack
Stack clamp
1. Using stack clamps, support the stack above and below
Glue two short lengths of ABS pipe to a tee. Mark an equivalent
the cuts. Mark and cut the stack. 2. Slide no-hub couplings
length plus 1/2 in. on both ends onto the ABS stack to indicate
onto cut stack ends (you may need to roll the neoprene
cutlines. (Each ABS slip-coupling has an inner lip that nearly
sleeves on first). Insert a no-hub fitting. 3. Slide couplings
fills the 1/2-in. space). Support and cut the stack. Finally, join
over fitting ends. 4. Tighten. 5. Connect the branch drain
the pipes by slipping the couplings in place.
to the no-hub fitting.
plumbing
339
cutter to make the two cuts. Drill through studs
diameters, to tie the new 11⁄2-in. plastic branch
as needed to run the branch drain. Next, slide no- drain to the cast-iron no-hub coupling.
hub couplings onto both cut pipe ends; in most
Tying into an ABS or PVC stack is essentially
cases, it’s easiest to loosen the couplings, remove
the same, except that you’ll use a wheeled cutter
the neoprene sleeves, roll a sleeve halfway onto
to cut the stack. And, instead of using a no-hub
each pipe end, and then replace the couplings.
coupling, glue short (8-in.) lengths of pipe into
Insert the no-hub fitting, unroll the sleeves
the tee fitting, then use plastic slip couplings to
onto fitting ends, slide the banded clamps over
join the 8-in. stubs to the old pipe. (The slip cou-
the sleeves, orient the fitting takeoff, and tighten
plings also glue on, with an appropriate solvent-
the clamps with a no-hub torque wrench. Finally, based cement.) Use a reducing tee, such as a 2 by
use a transition coupling, which is a special no-
11⁄2. Be sure to support the stack above and below
hub coupling that accepts pipes of different outer before cutting into it.
BuIlDIng ouT
From The maIn DraIn
3-in.
Extending the DWV system out from the end of
zzzzzz extending a Cast-Iron main Drain
soil stack
a cast-iron main drain—where it joins the soil
3-in.
stack—can be the least disruptive way of tying in
main drain
Cleanout
a new drain if there’s a cleanout at the end of the
If you build out from a cleanout,
main drain that you can remove. Before cutting
you must install a new one at
into existing drains, however, support both sides
the end of the extension.
of the section to be cut, using pipe clamps or
strap hangers.
Combo fitting
The exact configuration of the end run will
depend on the size of the main drain, the fitting
currently at the base of the stack, the fixtures
you’re adding, and the size of the drain needed to
Stack
serve them. If you are not adding a toilet, the
3-in. main
3-in. cast iron
drain extension can be 2-in. pipe, which can be
attached with a reducing bushing such as the
3-in. ABS drain
male-threaded adapters shown in “Extending
with 2-in. ABS” at left. If you’re adding a toilet,
however, the extension must be 3-in. pipe, often
inserted with a ribbed bushing to ensure a tight
fit. If it’s not possible to insert the 3-in. pipe into
Transition coupling
an old cleanout leg, you may need to cut out the
existing combo and install a no-hub combo to
EXTENDING WITH 3-IN. ABS
If the present cleanout is a cast-iron inset caulked with oakum,
build out from.
remove the oakum and the inset and replace it with a short section
Note: If you build out from an existing clean-
of 3-in. cast-iron pipe. From there, use a transition (no-hub) coupling
out at the end of the main drain, you’ll need to
to continue with 3-in. ABS plastic.
add a new cleanout at the end of the extension.
TyIng InTo The
Stack
maIn DraIn In mIDrun
2-in.
3-in. main
MIP adapter
Before tying into the main drain in midrun, flush
the drain and support both sides of the section
you’ll cut into. Then install strap hangers to sup-
port both sides of the 3-in. or 4-in. drain. Tying
into a cast-iron or plastic drain is essentially the
same procedure as splicing into a stack, but it
<
br /> requires different fittings. With one hand, hold
Threaded cleanout
2-in. ABS drain
Cleanout
the no-hub combo fitting you’ll add next to the
drain section, and with the other hand, mark cut-
EXTENDING WITH 2-IN. ABS
lines onto the drain using a grease pencil. The cut
If there’s presently a threaded cleanout opening and you are adding a
marks should be 1 in. longer than the length of
tub, lav, or sink—but not a toilet—use a plastic MIP (male iron pipe)
the fitting to accommodate the thickness of the
adapter.
stop lip inside each no-hub coupling’s neoprene
340 Chapter 12
Framing for Toilets
and Tubs
you may need to cut through joists to
accommodate the standard 4 by 3 closet bend
maximum sizes for holes and notches
beneath a toilet or the drain assembly under a
standard tub. In that event, reinforce both
FRamINg eLemeNT
HoLe dIameTeR (in.)
NoTcH dePTH (in.)
ends of severed joists with doubled headers
attached with double-joist hangers. This
Bearing studs
beefed-up framing provides a solid base for the
7
toilet as well. If joists are exposed, you can
24
13⁄8
⁄8
also add joists or blocking to optimize support.
26
23⁄16
13⁄8
Toilets. a minimum 6-in. by 6-in. opening
Nonbearing studs
provides enough room to install a no-hub closet
bend made of cast iron (41⁄2 in. outer diameter)
24
2
13⁄8
or plastic (31⁄2 in. outer diameter). The center
2
of the toilet drain should be 12 in. from a fin-
6
31⁄4
23⁄16
ish wall or 121⁄2 in. from rough framing. If
solid lumber joists
joists are exposed, add blocking between the
26
13⁄
7
4
⁄8
joists to stiffen the floor and better support
the toilet bowl, even if you don’t need to cut
28
21⁄2
11⁄4
joists to position the bend.
2
Bathtubs.
10
31⁄
a 12-in. by 12-in. opening in
8
15⁄8
the subfloor will give you enough room to
212
33⁄4
17⁄8
install the tub’s waste and overflow assembly.
Ideally, there should be blocking or a header
close to the tub’s drain that you can pipe-strap
The toilet drain. After framing the toilet drain
P R O T I P
it to. To support the fittings that attach to the
opening, install the 4 by 3 closet bend, centered
shower arm and spout stub-outs, add cross
12 in. from the finished wall behind the toilet.
braces between the studs in the end wall. To
If the neoprene sleeve inside
Install a piece of 2x4 blocking under the closet
a no-hub coupling won’t slide on
support tub lips on three sides, attach ledgers
bend, and end-nail through the joists on both
easily, it may have a small stop
to the studs, using galvanized screws or nails.
ends. Use plastic plumber’s tape to secure the
lip inside—sort of a depth gauge
Finally, if there’s access under the tub, add
bend to the 2x4. What really anchors the closet
to stop the incoming pipe in the
double joists beneath the tub foot.
bend, however, is the closet flange, which is
middle of the sleeve. soap the
cemented to the closet bend and screwed to
inside of the sleeve to reduce
the subfloor.
friction. you could use a utility
The flange is screwed to the subfloor, yet it
knife to trim off the lip, but that
will sit atop the finish floor when it’s installed. If
would be more time-consuming
sleeve. (If the main drain is cast iron, use a snap
the finish floor is not in yet, place scrap under
and you’re likely to puncture
cutter to cut it; if it’s plastic, use a wheeled cutter.)
the flange so it will be at the correct height. If, on
the sleeve.
After cutting out the drain section, use no-hub the other hand, the flange is below the finish
couplings to attach the new no-hub combo fit-
floor, you can build up the flange by stacking
ting. Slide a neoprene sleeve onto each end of the plastic flange extenders until the assembly is level
cut drain, insert the no-hub combo, and slide a
with the floor. Caulk each extender with silicone
sleeve onto each end of the combo. Align the
as you stack it, and use long closet bolts to rese-
combo takeoff so it is the correct angle to receive cure the toilet bowl. (Check with local codes first
the fixture drain you’re adding. Finally, tighten
because not all allow extenders.)
the stainless-steel clamps onto the couplings.
Once you’ve secured the closet bend, add pipe
sections to the bottom of the bend, back to the
ConneCTIng BranCh
takeoff fitting on the main drain that you
DraIns anD venTs
installed earlier. Maintain a minimum slope of
1
After modifying the framing, assemble branch
⁄4 in. per ft., and support drains at least every
drains and vents. Here, we’ll assume that the new 4 ft. Dry-fit all pieces, and use a grease pencil to
DWV fittings are plastic.
make alignment marks on pipes and fittings.
plumbing
341
Drilling and notching studs and Joists
It’s often necessary to notch or drill
third of the joist’s depth. notches are not
those studs are doubled and holes don’t pass
framing to run supply and waste pipes. If you allowed in the middle third of a joist span.
through more than two adjacent doubled
comply with code guidelines, given in
otherwise, notches are allowed if they don’t
studs; hole diameters must not exceed 60%
“maximum sizes for holes and notches” on
exceed one-sixth of the joist’s depth.
of the width of nonbearing-wall studs. notch
p. 341, you’ll avoid weakening the structure.
width may not exceed 25% of the width of a
although that table is based on the following studs
bearing-wall stud or 40% of the width of a
rules of thumb, remember that local building
Drilled holes must be at least 5⁄8 in. from the
nonbearing-wall stud.
codes have the final say.
stud’s edge. Ideally, holes should be centered
in the stud. If it’s necessary to drill two holes edge protection
; Joists
in close proximity, align the holes vertically,
any pipe or electrical cable less than 11⁄4 in.
you may drill holes at any point in the span
rather than drilling them side by side.
from a stud edge must be protected by steel
of a joist, provided the holes are at least 2 in.
Individual hole diameters must not exceed
nail plates or shoes at least 1⁄16 in. thick to
from the joist’s edge and don’t exceed one-
40% of the width of a bearing-wall stud, if
prevent puncture by drywall nails or screws.
pipe slope
Dwv pipes slope, so before drilling or notch-
ing framing, snap sloping chalklines across
JOISTS
the stud edges, then angle your drill bits
zzzzzz notching and Drilling limits
slightly to match that slope. Drill holes 1⁄4 in.
Holes OK anywhere,
Notches 1/6 joist depth,
larger than the outside dimension of the
2 in. from edge, minimum
maximum
pipe so the pipe feeds through easily. none-
theless, if Dwv pipe runs are lengthy, you
may need to cut pipe into 30-in. sections
(slightly shorter than the distance between
two 16-in. on-center studs) and join pipe
sections with couplings. That is, it may be
No notches,
impossible to feed a single uncut Dwv pipe
middle third
Holes 1/3 joist depth,
through holes cut in a stud wall.
maximum
STUDS
40% of stud
60% of
width, maximum
stud width,
maximum
When hole diameters exceed maximums
allowed by code, reinforce framing with
Multiple holes?
a steel stud shoe.
Stack ‘em!
Notches
25% of stud width,
Notches
maximum
40% of stud width,
maximum
Bearing walls
Nonbearing walls
342 Chapter 12
The toilet flange (orange ring) will sit atop the finish
Support vent stacks in midstory by using plumber’s strap
floor. If the finish floor has not been installed, place scrap
to tie stacks to blocking between studs.
under the flange, elevating it to the correct height. This
assembly is essentially the same as that shown in
“Constricted Spaces” on p. 336.
Other fixture drains. Run the 11⁄4-in., 11⁄2-in.,
at least 42 in. above the floor, or 6 in. above the
and 2-in. fixture drains up from the main drain
flood rim of the highest fixture, and those runs
takeoff. Drains must slope at least 1⁄4 in. per ft.,
typically slope upward at least 1⁄4 in. per ft.
Renovation 4th Edition Page 79