How to connect a cast iron sewer pipe with a plastic one. Tunnel to tutel: connecting plastic sewer pipes How to connect a riser to a plastic pipe

If the main element of which your new sewage system will consist is a plastic pipe, the cast iron pipe must be removed. Or at least cut as much as possible.

Why change

Soviet plumbing was simple and monotonous. A tiny toilet with a cast-iron riser in the corner, a bathroom next to it, another riser in the kitchen - that's all. But times change, new ideas appear in the layout, new plumbing and new requirements for it.

All currently released plumbing devices are unified and adapted for attaching plastic pipes to them. Their design does not provide for the use of cast iron sewer pipes... Plastic has many benefits. It is much lighter than cast iron, easy to install and much more economical than steel or cast iron pipe..

Plastic pipes are sold in various lengths, with ready-made branches and corners. Each of them has a socket for tight and reliable entry of one pipe into another. All this allows you to collect the entire sewer system in just a few minutes. Thanks to this simplicity, it is possible to put other plumbing fixtures, while slightly changing its location. But there is one problem that cannot be avoided. Through all multi-storey building from the bottom to the top, a common cast iron riser... And there is a need to make the transition from cast iron to plastic.

How to go

How to connect a cast-iron sewer pipe with a plastic one, while ensuring the reliability of the connection? This can be done in several ways.

The simplest is the connection via a rubber adapter. The size of the pipes is standard, and therefore this transition provides that a plastic pipe will be tightly inserted into it, and it itself will hermetically enter the cast iron pipe. Connect your sewer system to the common house in this way quickly and reliably. Unfortunately, it is not always possible to do this.

Connect cast iron pipe with a plastic one using one adapter is possible only when its seat is in perfect condition, smooth, has no cracks or chips.

And this does not always happen. Pipe joints from time to time burst, become covered with cracks.

Embossing with reel

It may happen that the diameters of the pipes to be joined do not match each other, or the condition of the inner surface of the socket of the cast iron pipe does not allow the use of such a method. In this case, they use the good old method of "chasing", with the help of which cast iron pipes were previously connected. This will require a plumbing linen roll.

The joints are prepared as follows: the inner part of the cast-iron pipe is carefully cleaned, and the end of the plastic pipe is wrapped in several layers of winding. Then we insert one pipe into another. What happened is a weak and unreliable connection.

It is necessary to seal it. The reel is folded into a kind of rope or rope, which is pushed in a circle with a thin spatula into the gap between the pipes. The joints are hammered to about 2/3 of the depth, and care should be taken to ensure that the packing is as tight as possible. The remaining space is filled with a mixture of cement, glue and water.

Difference from old methods

V Soviet times before connecting the cast-iron pipe, the sulfur mass was heated and the cracks were poured into it. But it is very dangerous to health, so now more civilized methods are used.

It will not be possible to immediately connect the resulting connection to work, you will have to wait for the cement to harden, but the joint made using this technology is strong, reliable and simple.

Very often nowadays, to solve the question of how to connect a plastic pipe with a cast iron pipe, they do not even use a reel. Hardware stores are replete with all kinds of sealants. This is a silicone that fills the free space of the joint with high quality, adhering securely to the walls. At the same time, it does not completely harden, remaining moderately plastic. This makes the joint insensitive to vibration and minor bending loads.

Connect pipes from different materials maybe. Sometimes this is done quickly, sometimes you have to tinker, but this work is quite within the power of any skilled owner. Therefore, if you have new ideas for the placement of plumbing, then you should not be stopped by the absence sewer outlet near your chosen location. This is a fixable problem. You just make the transition from cast iron to plastic and make the wiring you want.

There are several ways how to connect a plastic pipe to cast iron sewerage... Next, we will consider the main ones, features of their application, advantages and disadvantages, and the sequence of installation work.

1.Connection with fittings

This connection is necessary not only if necessary to connect cast iron installation with plastic, but even if there are problems in already installed system sewerage.

If you have a leak in the joint of a pipeline made of cast iron and plastic, then it was formed either due to a temperature drop or due to a water hammer. The latter are extremely rare. Temperature drops, however, happen often and are a common problem, as there are often disconnections and switching on. hot water... If such a problem occurs, the reason is a poor-quality fitting, the fastening of which has loosened and cracked. In order to fix this problem, replacing the connection with a crimp will help you. You will need to replace the old fitting with a new one.

You can also connect the sewer system using a press fitting, one end of which has a cast iron thread, the other - a special socket for connecting a plastic pipe. You will need two adjustable keys and a Teflon strap.

Unscrew the coupling from the cast iron pipe where there will be a connection to the plastic system, or cut off a piece of the old pipeline using a grinder.
Use grease to lubricate the edge of the nipple.
Remove dust from threads.
Cut the threads using a thread cutter.
Wipe the threads and wrap Teflon tape around them.
Lubricate the threads with silicone.
Screw the press fitting onto the threads. Be sure to use an adapter sleeve that has a special rubber seal, or use a split brass sleeve from plastic elements.

Tighten the press fitting by hand without a key in order to avoid breaking it.

Another method involves the use of a molded fitting.

Degrease the pipe joint using alcohol.
Treat it with plastic glue.
Sprinkle with sand.
Wait for the glue to dry completely.
Clean the socket from dirt, degrease.
Treat it with a sealant.
Fit the latex O-ring.
Place the narrow part of the fitting into the O-ring.
Insert edge plastic system into the fitting collar or corrugated adapter. Important: Avoid kinking the hose.

2.Rubber pad

Use a special seal - a rubber gasket - if you can easily dismantle the old cast iron system, the inner surface of the cuff of which is even. You will need to insert the plastic nipple 3-8 cm. Benefits this method is that you can immediately use the sewerage system after connecting the pipeline, and it will function for about 8 years.

Clean any debris and rust from the sewer line.
Apply a coat of sealant to the rubber junction with outside cuffs.
Insert a special rubber adapter into the cast iron system.
Insert the plastic drain pipe into the collar.

Use a plastic adapter if there is no special socket in the pipe. Then you will have to cut off part of the cast-iron system with a grinder, put on an adapter made of rubber, coat the edge with sealant, put on an adapter made of plastic, which was previously lubricated with sealant.

3.Silicone sealing

If there is a slight gap in the joint, use a silicone seal at the bottom of the joint.

Dry the docking area with a hair dryer.
Fill the gap with silicone using a construction gun. Important: fill the gap with silicone as deep as possible.
Wait 5 hours for the silicone layer to dry.

4.Splared pipe connection

Prepare a special adapter made of rubber with a diameter of 5 or 11 cm, clean the flare from rust, coat it and the adapter with sealant. Place the socket all the way into the cast iron system. Next, insert the end of the plastic pipe into the adapter. The advantage of the method lies in its simplicity and reliability. Please note: when inserting the plastic pipe, it is important that it slopes towards the riser.

5.Flanged pipe connection

Dismantle the old system using a grinder. Strip the nipple that adjoins the main sewer system... Weld the metal flange to it. Slide a ferrule over the workpiece you previously machined. Connect the flange parts using bolts and nuts, placing a sealing ring between them. Tip: wire sewer installation in the direction from the riser.

When it is necessary to replace cast iron sewer pipes with plastic products Many homeowners are interested in how such work should be done. According to specialists, such a connection can be made using a press fitting or using one of four simple joining methods without it.

All of the above methods provide reliable repair pipeline.

Simple connection of cast iron and plastic sewer pipes

Method one - using a rubber gasket... If the old cast iron pipe can be removed without problems, and the inner surface of its socket (cuff) is even, then you can use in a simple way connections using a special seal. The plastic pipe must be inserted into the cast iron pipe by 3 centimeters, or better - by 8 centimeters.

In both cases, the connection is made using a single technology, for which:

first remove rust and dirt from the cuff;
a sealant is applied to the rubber transition located on the outside of the cuff (read also: "");
a rubber adapter is inserted into the cast-iron bell;
a new plastic tube is placed in the cuff.

In the event that the connection is made to a pipe without a socket, then you need to use a plastic adapter.

In this situation, proceed as follows:

part of the cast iron pipe is cut off with a grinder and the edge is leveled, after which a rubber adapter is put on it;
The "dressed" edge of the pipe is coated with a sealant;
on top of it is placed a plastic adapter, also treated with a sealant (read also: "").

The size of the collars and transitions must correspond to the diameter of the pipes used. The connection of cast-iron and plastic sewer pipes according to the transition technology does not differ for products different diameters.

In this case, the work is performed in the following sequence:

at the junction, a plumbing reel is wound on a plastic pipe in several layers;
using a wide screwdriver or a narrow spatula, push the reel tightly into the gap formed between the pipes (this is the work called stamping);
the place of transition to a cast-iron pipe is coated several times with a polymer-cement mortar consisting of water, PVA glue and cement;
after completion of the work, the sewage system should not be used for at least one day.

The joint, which is made in this way, is quite reliable and was used everywhere before the appearance on the domestic construction market silicone sealants, and now it is still used if you need to connect a plastic pipe to a cast iron pipe in the place under the sink or sink. Using high-quality sewer pipes and fittings, even after several years of using this method, no leaks occur at the junction.

Method three - sealing using sanitary silicone... When connecting a plastic pipe with a cast iron pipe, a slight gap may form, the dimensions of which do not exceed 2 millimeters. Then the replacement of sewer pipes from cast iron to plastic in this way turns out to be very effective (more: ""). When carrying out work, special attention should be paid to maintaining the tightness of the joint in its lowest part.

Docking in accordance with this method must be performed in the following sequence:

before connecting a cast-iron sewer pipe with a plastic one, the junction is thoroughly dried using construction hair dryer;
the gap between the ends of the pipes is filled with silicone using a construction gun. The deeper the sealant penetrates, the stronger and more reliable connection between pipeline elements;
the silicone layer must dry well. As a rule, it takes about 3-5 hours to completely dry, depending on the thickness of the silicone applied. The junction can be coated with it both from the inside and from the outside, as in the photo. Do not use the sewer until the silicone dries.

Method four - a combination of the above three methods... In order to increase the reliability of the joint between plastic and cast iron pipes, it is permissible to combine the methods that were previously described in the article. For example: if available big slit between the pipes at the junction, capping and rubber gaskets can be used.

When connecting the toilet to the sewer system using corrugated pipe use linen coiling with a further overlapping of the joint with sanitary silicone. At the same time, the cast-iron cross and rubber seals located at the docking point are coated with the same material. When capping, the polymer-cement mortar can be replaced silicone sealant.

How to connect cast iron and plastic using a press fitting

Press fitting- this is a transition element for cast-iron pipes with threads for these products at one end, and on the other side there is a socket for sliding joints of plastic elements. When using it, you will need tow or Teflon tape.

Technological process pipe connections using pressfitting:

first of all, with the help of a grinder, they cut off the old pipe or unscrew the coupling on the pipeline in the place where there will be a joint with the plastic element;
lubricate the edge of the pipe with grease or oil to the point where it comes out of the die;
using a thread cutter, a thread is cut, then it is wiped and a FUM tape or tow is wound on it, smearing the winding with silicone;
then the press fitting is screwed onto the thread by hand. Tighten it after turning on the water supply, if a leak occurs at this point.

Before inserting a plastic sewer pipe into a cast iron pipe using a press fitting, you need to take into account the difference between the coefficients of thermal expansion of cast iron and plastic. For this reason, experts do not recommend screwing fittings made of polyvinyl chloride onto a metal base.

Observing all the rules for connecting plastic and metal pipes, you can do this work with high quality on your own, without inviting professionals.

When replacing old sewer, it may be necessary to connect a plastic pipe with a cast iron one. It is desirable that such work be carried out by specialists, but if you wish, you can do everything yourself.

So that after replacing the pipeline there are no leaks or blockages, it is necessary to qualitatively connect the plastic pipes with cast iron. In this article, we will figure out how to properly connect a cast iron pipe with a plastic one.

All work can be divided into several stages:

preparation;
dismantling of cast iron pipes;
installation of plastic;
compound.

Preparatory work

The first step is to carefully measure the area to be replaced in order to know the number of pipes and what diameter you need to buy. Diameter is also an important aspect, for example, when replacing pipes with a diameter of 50 mm are used, and when or a section coming from the toilet bowl -. In addition, you will also have to purchase a certain number of adapters, corners and other fittings.

Before starting work, prepare the material and tool:

plastic pipe of the required diameter;
a coupling with which the transition from cast iron to plastic will be carried out;
wooden or rubber mallet;
grinder or hacksaw for metal.

It is advisable to have time to replace the sewer pipeline in 1 day.

Video: Installation of a transition from a cast-iron sewer pipe to a plastic one.

Removing cast iron pipes

The pipes are connected using press fittings. At one end of such a product there is a thread, and at the other end there is a socket for connecting a plastic pipe. You will also need Teflon tape (FUM tape) or sanitary flax for sealing and two adjustable wrenches.

Installation steps:

We unscrew the coupling or cut off a piece from the cast-iron pipe in the place where it will be carried out
connection with plastic pipe.
We cut the threads, if necessary, in the cut off area.
We clean the threads from dust and wind tape or flax on it, lubricate with silicone grease.
We screw on the press fitting.

Advice!

Tighten the press fitting by hand, without a key, as it can crack with strong force. It will be possible to tighten it after turning on the water.

You can also connect a cast-iron pipe with a plastic one using a cast fitting. For this:

Degrease the joint.
We process the joint with plastic glue and sprinkle with sand, wait for the glue to dry completely.
We clean and degrease the bell.
We treat with a sealant.
We mount sealing ring.
Insert the narrow part of the fitting into the sealing ring.
We insert the edge of the plastic pipe into the fitting collar.

Connection with rubber gaskets

This method is suitable if you managed to remove the old pipe from both its edges and the inner surface remained even. The branch pipe should go into the socket on average by 5 cm. With this method of connection, it will be possible to use the sewage system immediately after the end of all work. Installation steps:

we clean the parts from rust, dirt, etc .;
We coat the rubber adapter with sealant from the outside.
insert the rubber adapter into the cast-iron bell;
insert the pipe into the cuff.

If pipes are connected without a socket, then a plastic adapter is used. Then proceed as follows:

cut off a piece, align the edges;
put on a rubber adapter;
coat the edge with sealant;
put on a plastic adapter greased with sealant from above.

Silicone sealing

The gap formed when connecting the pipes (up to 2 mm) can be sealed with sanitary silicone. This method is quite effective if Special attention pay to the bottom of the seam.

Dry the joint with a construction hair dryer.
We fill the gap with silicone, as deep as possible, for this we use a special construction glue gun.
We are waiting for the silicone to dry, usually in 3 - 5 hours.

Socket connection

For this type of connection, you need to buy a special adapter that is designed to be installed in a socket. Such a part can be purchased at any hardware store, usually products with a diameter of 50 or 110 mm are required. But there are pipes of a different diameter, so it is better to decide in advance with.

The connection process takes place in several stages:

we clean all the connected parts from dirt, dust and other things;
coat them with sealant;
insert the adapter, all the way, into the cast-iron bell;
insert a plastic pipe into the adapter.

This method is the simplest and most reliable, and if necessary, the connection can be disassembled and reassembled.

Flange connection

This method uses special connecting parts... In addition, the use of welding will be required, which does not always allow you to carry out the work yourself.

We clean the branch pipe adjacent to the main pipe.
We weld on the metal flange part.
We put the crimp sleeve on the workpiece.
We connect the flange parts by placing an O-ring between them with bolts.

It is possible to carry out quality work in the event of repair or planned replacement of cast iron pipes with plastic ones only by observing the installation steps. I would also like to note that it is better to carry out these works in advance, and not wait for an accident.

Video: transition from cast iron to plastic pipe, nuances and tricks in replacing plumbing, pvc pipes and sewerage

Old and bulky cast iron pipelines can still be found in many apartments. But no matter how reliable they may seem, sooner or later their service life will come to an end. An excellent solution a complete replacement of cast iron with plastic may become, but, unfortunately, this is not always possible.

Someone is stopped by the financial side of the issue, others fail to come to an agreement with their neighbors. It is in such situations that the need arises to connect the plastic and cast iron sections of the sewer. There are several methods that make it possible to carry out such work quickly, efficiently, and without the involvement of professional help.

The whole complex of works can be conditionally divided into four stages:

Preparation of the place of work and the necessary tools.
Dismantling the old pipeline.
Installation of plastic pipes.
Connection of elements.

In order for the connection of a plastic pipeline to a cast iron pipeline to be reliable and durable, it is worth preparing everything in advance the right tools and materials:

Special hammer with rubber or wooden attachment. An ordinary iron hammer will not work here, as it can easily damage cast iron, which looks so strong, but very sensitive to impacts.
Cutting tool. It can be a grinder or a hacksaw for metal.
Adjustable wrenches.
Depending on the connection method chosen, you may need a hand press, thread cutter or welding machine.
Plastic pipes suitable size... To connect the toilet bowl to the riser, you will need elements with a diameter of 110 mm, for laying pipes to the bathtub and sink the best way plastic with a diameter of 50 mm is suitable.
Necessary adapters, gaskets, couplings, seals, sealing agents.

Note! Installation of plastic piping should include inspection hatches. Neglecting this rule will significantly complicate renovation work, if the need arises to conduct them.

Dismantling the old pipe

Dismantle the cast iron pipeline very carefully in order to prevent the appearance of chips or cracks.