In modern multi-storey buildings, the sewer system is made of polypropylene pipes, which have a lot of advantages. Cast iron risers are still quite common in the buildings of the old fund. Many of them have long lost their original appearance and require replacement.
If you've decided to upgrade your sewer system, but your neighbors aren't planning any repairs any time soon, you'll have to make the switch from cast iron to plastic. Such a connection is performed in several ways, each of them has its own nuances. Read more about this and the entire sewer repair process in our article.
What difficulties can you face in the process of work?
The most difficult stage in the entire sewer repair is the dismantling of the cast-iron pipe. Over time, all joints look like a single whole, which makes them very difficult to stamp.
When making the transition from cast iron to plastic, please note that the standard polypropylenethe pipe is slightly narrower than its metal counterpart, which leaves a gap in the floor slab.
The complexity of dismantling lies in the fact that in Soviet times the pipes were connected using cement mortar and sulfur. Over the years, this fixation becomes much more reliable and durable.
Cement compositions have to be knocked out. To loosen the sulfur compound, craftsmen use a gas burner. As a result of its work, rather unpleasant odors are released into the air, which makes it necessary to use protective masks.
If your neighbors have an old sewer, you need to knock out your pipe very carefully, as cast iron is prone to cracking. Any unsuccessful hit can lead to the fact that the neighbors will have to change the riser.
Preparation for work
If you are going to replace the pipe, specify the terms and date of the work with the neighbors. Ask them not to use the sewer during this period, or rather, turn off the water throughout the riser.
To bring as little inconvenience as possible to the residents of the house, prepare the necessary tool in advance. This list includes:
- grinder with a disk for metal (or a pipe cutter);
- scrap;
- chisel;
- hammer;
- screwdriver;
- grinder (or just paper);
- nail puller;
- drill or punch.
When equipping the sewer transition from cast iron to plastic, cover the floor and plumbing with plastic wrap. Prepare an old workingclothing, gloves, protective mask. Find a place in the apartment in advance where you will put the old sewage elements.
Purchase materials
When shopping for new pipes, pay attention to the diameter of the old riser. The standard parameters for the transition from cast iron to plastic are 110 mm, but thicker options are also available.
If you want to reduce the size of your sewer pipe, you will need special rubber couplings with which the transition is made. In cases where the pipe is absolutely flat (without a special flange), a plastic sleeve is used. It allows you to make different transitions from cast iron to plastic (160 to 110; 180 to 110; 110 to 100; 110 to 50 mm).
Also for work you will need:
- plastic pipe of appropriate diameter;
- fasteners for fixing the new pipe to the wall;
- compensation pipe, with the help of which the transition between two pipes is equipped.
- sanitary sealant;
- tee with pipe bends;
- level;
- FUM tape.
Also get a bottle of detergent or liquid soap. Soapy solution will come in handy in the process of docking new sewer elements.
Dismantling process
The dismantling of the pipe should be carried out in such a way as to prevent the destruction of parts of the pipes located in the ceilings between floors, since in these places the transition from cast iron to plastic will be carried out.
Work to remove the oldpipes are made in the following sequence:
- Disconnect pipes from riser.
- Dismantling small sewer sections.
- Performing the top notch on the pipe. To cut the pipe, you need to step back from the ceiling of about 10 cm.
- Making an incision from the bottom of the pipe. The file should be done with an indent of 80 cm from the tee.
When you cut the pipe, wrap the upper edge of the sewer with a film, as liquid may drip from there during work. Next, using a puncher, grinder, hammer and crowbar, disassemble the lower tee with bends and fittings.
If the seams between the pipes are practically invisible, embroider all the joints with a cloth for metal. When the old pipes are removed, sand the metal edges of the top and bottom pipes with a grinder. Next, join the pipes in one of the following ways.
Transition with rubber pad
If an even socket is located at the junction of the pipes, it is possible to perform the transition of cast iron to plastic with a cuff (110 mm). With this connection, the polypropylene pipe is inserted into the cast iron pipe, deepening 30-80 mm in it.
This method is considered simpler, but the service life of such a system does not exceed 8 years.
Work is done as follows:
- The bell is cleaned of rust, dust and dirt.
- The outer side of the rubber cuff is covered with sanitary sealant.
- Inside the cast-iron socket is installedrubber adapter;
- A new tube is installed in the cuff.
If there is no socket in the pipe, you can install in a similar way using a plastic adapter.
Docking using linen winding
Quite a reliable and popular method of connecting pipes is considered to be caulking using natural winding. This method can be used in cases where a special sealant was not at hand.
The transition from cast iron to plastic is arranged as follows:
- Wrap several layers of plumbing winding into a plastic pipe (in the area where it meets cast iron).
- Insert the pipe into the cast-iron end of the riser sticking out of the ceiling, using a narrow spatula, push the take-up into the space between the two pipes.
- For greater reliability, the junction can be treated with a reinforcing compound. It is made from a mixture of cement, water and regular PVA glue.
The question of the durability of this docking method causes different opinions of experts. Someone safely uses it in everyday work, and someone claims that with such a fixation, periodic leaks cannot be avoided.
In any case, if you decide to use this particular method, please note that it will be possible to use the sewer only after a day, when the cement mortar hardens enough.
Combination connection
If you want to improve the reliability of the pipe joint and make a quality transitionsewer from plastic to cast iron, use several methods at the same time.
For example, if there is a large gap between a cast-iron and a plastic pipe, a standard caulking should be used and supplemented with a rubber cuff.
If you leave the bottom tee intact, the toilet will have to be connected to a cast iron pipe. To do this, the sewer corrugation can be inserted into a rubber cuff and additionally treated with silicone or filled with linen winding.
The sewer lines entering the riser will have to be joined in a similar way. They are mounted using a special plastic adapter and a 50 mm cuff.
If you understand the question of what is better: linen winding or silicone, then it should be noted that linen is used only if there are large gaps at the junction. If the seam does not exceed 2 mm in width, then it is best to use silicone.
Docking using special press fittings
Facilitate the work of arranging the transition from cast iron to plastic cuff and special adapters designed for joining a plastic and metal riser. Their peculiarity lies in the fact that one side of such an adapter has a thread, and the other side has a socket designed to fix the plastic sleeve.
Such fixation is considered the most reliable, but also time-consuming. Works are performed in the following sequence:
- The end of the cast-iron pipe is cleaned and cut intothread (5 cm deep).
- FUM tape or linen winding is wound on the thread of the fitting. Also for this purpose, you can use special plumbing paste compositions.
- The adapter is screwed to the pipe by hand. You shouldn't overtighten it right away.
- Insert a plastic pipe into the other end of the coupling, on which a clamping collar is put on.
When the pipe is installed, the cuff is crimped using a hand press. The plumbing wrench tightens the nut on the thread of the fitting.
Advice from experts on arranging a new sewer riser
When equipping a plastic riser in your apartment, pay attention to the fact that such pipes are characterized by low soundproofing properties. To make the installed system emit less noise, securely fasten the pipe with special clamps with rubber gaskets. Pull the riser to the nearest wall, which will allow you to avoid additional vibrations.
If you want to ensure absolute silence in the bathroom, sew up the pipes with a GVL box, but first fill the free space with mineral wool.
Often, in order to reduce noise, homeowners use machine soundproofing. It is convenient in that it has one adhesive side, due to which the pipe can be covered with it without much difficulty.
Summing up
In the process of sewer repair: transition from cast iron to plastic (100 mm and wider joints) - strictly follow the technology for such work. Usingthreaded press fittings, be sure to process the joints with additional materials, since such seams are more prone to leakage than others.
If you chose the option of arranging the joint using transitional couplings, do not forget to cover the rubber element with a layer of sealant. Direct connections of sewer pipes are equipped with tight rubber gaskets. So that the elements of the system fit well into each other, pre-lubricate them with soapy water.
