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It is difficult to intervene on a PVC evacuation already in place, especially to add an additional flow, on the occasion of an enlargement.
Transplanting is however possible thanks to a special connection saddle to be glued.

Install a saddle

Practical advice

This bonding connection must be perfect for a good seal. Check the expiry date of your glue and do not skimp on the quantity, without exaggerating however!
Before drilling the pipe, carry out tests on a Ø 100 mm PVC chute to judge the behavior of the saw. The finish of the hole can be done with the half-round file.

In a PVC installation, all connections are glued, making disassembly impossible. To insert an inlet into a line of fittings, cut the pipe at the desired location and, after placing the joint, rebuild the entire downstream installation with pipes and fittings.
The saddle branch, which takes its name from its shape, is a shell with side entrance. She comes to ride on the main pipe. The waterproof connection is made by gluing. It allows to connect, by transplanting, a PVC pipe Ø 40 or 50 mm on a pipe of Ø 80 or 100 mm, this without any disassembly.


The goal is to connect an evacuation (sink, shower, washbasin, washing machine...) on a large diameter pipe carrying sewage or sewage to the sewer. The exact position of the fitting must first be determined. A shower or a bathtub often requires an exit close to the ground, with a certain slope.
Position the saddle blank on the pipe, in the exact extension of the future evacuation. Then mark the location of the hole and the right and left limits of the fitting. Use a hole saw with centering drill, setting the drill to medium speed. The diameter of the saw should be 34 mm, which is the inside diameter of a 40 mm pipe. In fact, the models of saws available, derived from English measurements, lead to fall back on a ø 32 mm.
Lightly sand the 120-grit sandpaper around the hole and the inside of the saddle to make them rough. Clean surfaces with acetone to degrease and dust. After coating the two parts with special rigid PVC glue, quickly clip the part onto the pipe, centering the lateral outlet well on the hole. Attention, the setting time is short! Immediately put two large clamps type "Serflex". Tighten them reasonably, without forcing too much, and wait at least an hour before removing them.
Now, the female side outlet can receive Ø 40 or 50 mm pipe, fixed with the same PVC glue, and connected to the siphon of the sink, another sanitary appliance or the washing machine.

Install a saddle: pipe

The necessary material: the seat, a Ø 32 mm hole saw, two Ø 100-120 mm collars, good quality PVC glue, a 7 mm wrench or a screwdriver, 120 grit sandpaper.

Install a saddle: install

On this pipe, mounting the saddle will allow to connect the drain of a sink. After positioning the fitting, mark the inside of the external ø 40 mm lateral entry with felt.

Install a saddle: pipe

Temporarily position the saddle on the main pipe by centering the outlet with the hole. Mark the outline of the soleplate with the felt to make it easier to position the fitting.

Install a saddle: hole

In the center of the marking, drill the pipe with a Ø 32 mm hole saw equipped with a centering drill rotating at moderate speed. If necessary, retouch the burrs with the soft half-round file.

Install a saddle: pipe

Carefully sand the relevant part of the main pipe and the inside of the seat with sandpaper. Clean with a cloth soaked in acetone or special thinner.

Install a saddle: hole

On the main line, smear PVC adhesive evenly and evenly inside the fitting boundaries. Do the same for the underside of the saddle.

Install a saddle: pipe

Clip the saddle on the pipe centering it well. Quickly place the collars on each side of the side exit and tighten securely with the wrench or screwdriver.

Install a saddle: hole

A few hours later, remove the collars and glue the sink drain prepared previously. Perform positioning tests and draw benchmarks before
definitive collage.

Video Instruction: How to Install or Replace a Bicycle Saddle