Sewer pipe connection options: materials, methods and main steps


One of the impor­tant com­mu­ni­ca­tion sys­tems is the design of water dis­pos­al, on the reli­able func­tion­ing of which the qual­i­ty and com­fort of liv­ing in the house depends. Thanks to a wide selec­tion of mate­ri­als and fit­tings for con­nect­ing var­i­ous sew­er pipes, you can assem­ble the sys­tem your­self.

Sew­er­age is need­ed to remove dirty water and human waste prod­ucts from the home. With­out such a sys­tem, the oper­a­tion of a res­i­den­tial build­ing is impos­si­ble.

Con­clu­sion of the sew­er sys­tem under the toi­let

Material selection

The assem­bly of the drainage struc­ture begins with the choice of mate­r­i­al. At the moment, most pipelines are assem­bled from plas­tic ele­ments, which have a num­ber of advan­tages:

  • Light weight. Thanks to this, the mate­r­i­al is con­ve­nient­ly deliv­ered to the assem­bly site.
  • Vari­ety of sizes and diam­e­ters of pre­fab­ri­cat­ed ele­ments.
  • A lot of con­nect­ing parts and fit­tings, which, if nec­es­sary, can be found in any store and replace a dam­aged part.
  • Resis­tance to cor­ro­sive process­es.
  • Due to the low­er fric­tion force inside, com­pared to cast iron, the like­li­hood of block­ages is reduced.
Plas­tic com­mu­ni­ca­tions

Despite the pop­u­lar­i­ty of plas­tic struc­tures, met­al ones also remain in use. Types of met­al sew­er pipes and their con­nec­tions can be divid­ed:

  • Steel. Prod­ucts made from this mate­r­i­al are dis­tin­guished by strength and dura­bil­i­ty, low cost and ease of pro­cess­ing.
  • Cast iron. Com­pared to steel, it is not so afraid of cor­ro­sion, although this option will cost more. They have high rates of strength and reli­a­bil­i­ty, the longest ser­vice life is up to 80 years.
Cast iron duc­tile iron


There are a num­ber of pipe mate­ri­als that are used to cre­ate drainage:

  • ceram­ic;
  • asbestos,
  • PVC;
  • con­crete.

Each of them has its own pos­i­tive char­ac­ter­is­tics, but are used much less often than met­al or plas­tic ones.

Connection types

All plumb­ing meth­ods of con­nect­ing sew­er pipes are divid­ed into detach­able and one-piece.

Detachable connection methods

They are flanged and cou­pling. I use them to con­nect all types of plas­tic sew­er pipes. Dur­ing assem­bly by the flange method, cast-iron fas­ten­ers with a rub­ber gas­ket are used. The action plan will be as fol­lows:

  • In the place where the dock­ing will be car­ried out, a per­fect­ly even cut is made.
  • A flange is mount­ed on the cut.
  • The gas­ket is installed at a dis­tance of 10 cm from the ledge.
  • The flange is mount­ed on top of the gas­ket using bolts with mat­ing flanges.
  • Bolts con­nect eas­i­ly.
Pipe Flange Weld­ing


To col­lect a water pipe that does not pro­vide for high pres­sure or to repair it, use the cou­pling assem­bly method. Cou­pling assem­bly is car­ried out in the fol­low­ing order:

  • Pre­pare the ends of the con­nect­ed ele­ments. They are stripped and cut at an angle of 180 degrees.
  • A cou­pling is laid at the junc­tion so that its cen­tral part lies exact­ly at the junc­tion.
  • Marks are left on the sur­face with the loca­tion of the cou­pling.
  • In the indi­cat­ed place, the walls are treat­ed with lubri­cant for a bet­ter con­nec­tion of the cou­pling.
  • The end of the pipe is insert­ed into the cou­pling until it stops.
  • On the oth­er hand, a pipe of the same size is installed so that the lon­gi­tu­di­nal axis becomes one.
Con­nect­ing the pipeline with cou­plings

All work is car­ried out man­u­al­ly. If work is car­ried out at sub-zero tem­per­a­tures, sil­i­cone grease should be used.

Integral Methods

This con­nec­tion method is per­formed in sev­er­al ways: by sol­der­ing, weld­ing, press­ing, glu­ing using cement mor­tar.

Pipe welding

The sock­et method of con­nec­tion is car­ried out by glu­ing or weld­ing. This is one of the pop­u­lar ways to cre­ate per­ma­nent con­nec­tions. They con­nect met­al and plas­tic prod­ucts. Weld­ing is car­ried out by the method of melt­ing or pres­sure. Fusion weld­ing is car­ried out using spe­cial sol­der­ing equip­ment, which is select­ed depend­ing on the pipe mate­r­i­al: met­al, met­al-plas­tic, plas­tic.

There are two ways to car­ry out weld­ing work: butt and sock­et. When using sock­et weld­ing, one end is melt­ed on the inside, the oth­er on the out­side. Then they quick­ly con­nect with each oth­er.

Sock­et sys­tem con­nec­tion

Butt weld­ing is car­ried out using a sol­der­ing machine for plas­tic pipes. The ends of the two con­nect­ing parts are melt­ed and imme­di­ate­ly con­nect­ed with the pres­sure applied to them.

Weld­ing met­al struc­tures requires spe­cial skills and equip­ment. It’s worth under­stand­ing. That it is impos­si­ble to weld a gal­va­nized pipe with a met­al one. This may dam­age the gal­va­nized lay­er. The cop­per struc­ture is weld­ed using a gas burn­er with a spe­cial sil­ver-bronze sol­der.



For the adhe­sive method, a con­nect­ing mate­r­i­al is required — epoxy or BF‑2 glue. This method is only suit­able for plas­tic struc­tures.

The glu­ing method is car­ried out accord­ing to the fol­low­ing instruc­tions:

  • Two ends of the pipe are con­nect­ed, on one side of which there is a sock­et with a rub­ber end, and the oth­er is smooth. The gas­ket must have a cor­rect­ly posi­tioned and smooth sur­face with­out defects.
  • The ends to be joined are lubri­cat­ed with put­ty or sil­i­cone glue, and imme­di­ate­ly con­nect­ed, since dust set­tling on the mount­ing part is not rec­om­mend­ed.
  • The posi­tion of the ends of the join­ing ele­ments must have one axis.
  • The depth of advance­ment of one end into the sock­et is reg­u­lat­ed by a mark on the sur­face. It is not worth going beyond it.
Apply­ing sil­i­cone adhe­sive to the inner sur­face

If all work is car­ried out cor­rect­ly, it is pos­si­ble to oper­ate the sew­er sys­tem in a few hours, while the ser­vice life will be long.

How to connect pipes from different materials

To con­nect ele­ments of dif­fer­ent com­po­si­tion and diam­e­ters, use:

  • Fit­tings are fix­ing parts with a thread­ed tran­si­tion. With their help, they con­nect dif­fer­ent parts of the parts, rotate the struc­ture, install a meter or a crane.
  • Adapters — parts that allow you to vary the direc­tion of the sys­tem, equal­ize the diam­e­ter of the sew­er sys­tem.
  • Seal­ing ele­ments. Used to seal sys­tem joints.
Tran­si­tion from cast iron to plas­tic drain sys­tem


In old hous­es, where cast-iron sew­ers were wide­ly used, the out­dat­ed drainage sys­tem is being replaced with mod­ern mate­ri­als. At the same time, it is nec­es­sary to apply meth­ods of join­ing two mate­ri­als of dif­fer­ent com­po­si­tion: met­al and plas­tic. You can con­nect them in sev­er­al ways:

  • Use of rub­ber gas­ket.
  • With a plas­tic adapter.
  • With a press fit­ting.
  • Linen wind­ing insu­la­tion.
  • Sil­i­cone seal­ing.
  • Flange appli­ca­tion.

The use of a rub­ber gas­ket is jus­ti­fied if the sock­et of the cast-iron pipe is in sat­is­fac­to­ry con­di­tion. The pro­ce­dure for con­nect­ing two ele­ments will be as fol­lows:

  • The sock­et is cleaned of dust, dirt and rust, dried, and the sur­face is degreased. A lay­er of sealant is applied on the inside.
  • The adapter is also treat­ed with a sealed com­pound and insert­ed into the pipe.
  • Then the free end is insert­ed into the plas­tic drain until it stops.
  • From above, the joints are once again processed with a sealed com­po­si­tion.
Installing the rub­ber gas­ket

The con­nec­tion is con­sid­ered reli­able, and in case of repair it is eas­i­ly dis­as­sem­bled.

The use of a plas­tic adapter with a rub­ber seal is effec­tive when the sys­tem is left with­out a bell. In this case, when con­nect­ing, the edge of the cut­ting pipe should be as even as pos­si­ble. A rub­ber gas­ket with a sur­face pre-treat­ed with a sealant is put on the cast-iron ele­ment. A rub­ber cuff with an adapter is put on top. A plas­tic ele­ment of the appro­pri­ate diam­e­ter is mount­ed to it.

The use of a press fit­ting is due to the spe­cial reli­a­bil­i­ty of the con­nec­tion for the sew­er sys­tem, equipped indoors. The press fit­ting is equipped with a thread on both sides for con­nec­tion with a sock­et of a cast-iron and plas­tic con­struc­tion. Con­nec­tion reli­a­bil­i­ty is high, but dif­fi­cult to assem­ble.

Fit­tings for the instal­la­tion of plas­tic sew­er­age

Linen wind­ing was used by mas­ter plumbers long before the advent of sealants. For many years it served as a reli­able insu­lat­ing mate­r­i­al in the cre­ation of sew­ers and is still in demand. I use it this way:

  • At the junc­tion, linen thread is wound in sev­er­al lay­ers.
  • Insert the sew­er pipe into the sew­er until it stops.
  • Using a flat screw­driv­er, the wind­ing is mint­ed into the gaps between the edges of the junc­tion of the ele­ments.
  • Next, a mix­ture is applied to the junc­tion, which includes PVA glue, cement mor­tar and water.
  • After com­plete solid­i­fi­ca­tion, usu­al­ly it takes at least 24 hours, the sew­er sys­tem can be used.

Con­nect­ing pipes with sealant is sim­i­lar to the pre­vi­ous tech­nique, only sil­i­cone sealant is used here. Try to put it as deep as pos­si­ble into the slot. Use a con­struc­tion gun for this.

Apply­ing sealant to fix the joint

Flange con­nec­tion is used to con­nect cast iron and plas­tic pipes of large diam­e­ter. This is a tech­ni­cal­ly com­plex method that requires skill and spe­cial fas­ten­ing mate­ri­als — flanges. The sequence of actions tak­en is as fol­lows:

  • The end of the cast iron ele­ment is cut off and cleaned of dirt and for­eign par­ti­cles.
  • A flange is mount­ed to it by weld­ing.
  • A crimp sleeve is applied on top of the assem­bled struc­ture.
  • A sealant is placed between the con­nect­ing parts, and fixed with bolts.

Now you have a com­plete under­stand­ing of how to con­nect pipes from dif­fer­ent mate­ri­als.

Connection of plastic pipes of different diameters


The col­lec­tion of the sew­er sys­tem includes the instal­la­tion of san­i­tary equip­ment: toi­let bowl, bath­tub, sink.

The way the toi­let is con­nect­ed to the sew­er pipe will depend on the loca­tion of the pipe and the diam­e­ter. You can use sev­er­al options:

  • Sock­et con­nec­tion. The toi­let is con­nect­ed to the sew­er sys­tem through a cor­ru­gat­ed pipe. If the dis­tance from the drain to the con­nect­ing node on the toi­let is less than 1 meter, you can use an eccen­tric to con­nect. It is put on the toi­let pipe from one end, and on the oth­er side to the dis­tri­b­u­tion part of the sew­er.
Instal­la­tion of cor­ru­ga­tions on the toi­let
  • By weld­ing. To con­nect a plas­tic sys­tem to plumb­ing in this way, you will need a sol­der­ing iron with a disk heater. The seams in the end part are heat­ed and sol­dered togeth­er. You can con­nect PVC pipes using cold weld­ing. This is the eas­i­est and most effec­tive way to glue struc­tur­al ele­ments from pipes of dif­fer­ent diam­e­ters to orga­nize drains from plumb­ing fix­tures.

When installing a bath­tub and sink, an over­flow device is required. To con­nect the siphon to the sew­er, you will need a cor­ru­gat­ed pipe made of hard plas­tic, suit­able in size. It is impor­tant to con­sid­er the height of the drain hole and the dis­tance from it to the sew­er inlet.

Requirements for the joints of sewer pipes and the angle of the connection

When cre­at­ing a sew­er sys­tem on your own, you should remem­ber the rules for lay­ing the pipeline. It is placed under a slight slope. This is nec­es­sary so that water does not stag­nate in the sys­tem. The slope must be at least 2 cm per meter laid. The cor­rect­ness of the lay­ing of pipes is checked by lev­el.

Mount­ed sew­er­age in the floor with a slope

The weak point when lay­ing the sew­er sys­tem are the joints. There­fore, their seal­ing is of par­tic­u­lar impor­tance. After the assem­bly of the struc­ture is com­plet­ed, the sys­tem is checked for leaks. To do this, the drain is com­plete­ly filled with water. Dur­ing test­ing, tem­po­rary plugs are placed in the revi­sion. There should­n’t be any leak­age.


In order to qual­i­ta­tive­ly assem­ble the drainage sys­tem in the house, it is nec­es­sary to choose a method for con­nect­ing pipes, based on the mate­ri­als of their man­u­fac­ture. All work on con­nect­ing and seal­ing joints should be car­ried out accord­ing to the instruc­tions in order to avoid prob­lems dur­ing the fur­ther oper­a­tion of the sys­tem.


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