Warm water floors on wooden floor


For a coun­try house, a wood­en bath, an under­floor heat­ing sys­tem will become con­ve­nient and prac­ti­cal. Under­floor heat­ing, water, the con­tour of which must be hid­den in the under­ground, is able to effi­cient­ly and effi­cient­ly heat quite spa­cious liv­ing quar­ters. This is espe­cial­ly con­ve­nient for you to do to improve the hab­it­abil­i­ty of your dacha, to cre­ate more com­fort­able con­di­tions in the bath­house.

It is not pos­si­ble to solve such an engi­neer­ing and tech­ni­cal prob­lem by lay­ing water pipes under a con­crete screed. This affects the tech­no­log­i­cal fea­tures of the struc­ture itself and the very nature of the tech­nol­o­gy. Not every wood­en floor or logs under­ly­ing the build­ing can with­stand the huge addi­tion­al load in the form of a mono­lith­ic slab. The way out of this sit­u­a­tion is to make warm floors, water, laid on a wood­en floor.

Main idea and practical solution

For quite a long time, it was con­sid­ered that mount­ing water heat­ing cir­cuits direct­ly on wood­en floors was not a very good idea. Main­ly, the rea­son for this opin­ion lay in the char­ac­ter­is­tics of the build­ing mate­r­i­al. Con­struc­tion wood, despite a lot of tech­no­log­i­cal advan­tages, is high­ly sus­cep­ti­ble to the effect of ther­mal defor­ma­tion. In addi­tion, exces­sive expo­sure to mois­ture also adverse­ly affects the wood. The light­ness of wood­en struc­tures and insu­lat­ing prop­er­ties were con­sid­ered dis­ad­van­tages when it came to the instal­la­tion of more com­plex ther­mal and hydraulic struc­tures in the build­ing.


Despite the obvi­ous obsta­cles, attempts to find a rea­son­able way out of this sit­u­a­tion have led to the emer­gence of new tech­nolo­gies that allow you to install a water-heat­ed floor on a wood­en floor, cre­ate heat­ing water sys­tems in wood­en build­ings. The main thing is to choose the right con­sum­ables and adhere to a cer­tain tech­nol­o­gy.

To date, there are two types of under­floor heat­ing used in res­i­den­tial build­ings as a heat­ing ele­ment. We will not talk about the elec­tri­cal cir­cuit, since it has not found its devel­op­ment in com­bi­na­tion with wood­en struc­tures. Let’s pay atten­tion to the water heat­ing sys­tem — a warm water floor, in which hot water runs through the pipes of the heat­ing cir­cuit.

What tech­ni­cal dif­fi­cul­ties await us in this case? The prin­ci­ple of oper­a­tion that under­lies this heat­ing sys­tem is well known and under­stood. It makes no dif­fer­ence whether the water cir­cuit lies in a con­crete screed, or skill­ful­ly hid­den in a wood­en floor. Water cir­cu­lat­ing through the pipeline heats the sur­face of the floor, there­by giv­ing off pre­cious heat to the inte­ri­or of the heat­ed room.

On a note: skep­tics can make a remark — the tree does not con­duct heat well, in addi­tion, the wood­en struc­ture itself can be deformed as a result of heat­ing. There is some­thing to be said for these com­ments. The use of spe­cial heat-con­duct­ing plates allows you to ensure that the ther­mal ener­gy will go in a strict­ly ver­ti­cal direc­tion, heat­ing the floor.


Here we should say a few words about the fact that from a tech­ni­cal point of view, lay­ing heat­ing pipes on a wood­en floor is not dif­fi­cult. If at the ini­tial stage you have a clear idea of ​​​​what your under­floor heat­ing should be, what type of floor­ing you will have, it is quite pos­si­ble to make water floor heat­ing.

Key points

We have already said that it is not always pos­si­ble to solve the prob­lem sim­ply as you would like. For cap­i­tal stone struc­tures with con­crete floors, a con­crete screed for under­floor heat­ing is very con­ve­nient. How­ev­er, in most cas­es, wood­en res­i­den­tial build­ings, in which wood­en floors are not able to with­stand an addi­tion­al weight of 10–15 tons. A tree, even if you are deal­ing with a beam sys­tem of a set, can­not with­stand such a load. It does not make sense to strength­en the sup­port­ing struc­tures dur­ing the con­struc­tion of a coun­try house or a bath­house. This will lead to an increase in cost and to the weight of the entire struc­ture.

For ref­er­ence: any water-heat­ed floor involves the cre­ation of a sub­strate. This ele­ment is manda­to­ry for under­floor heat­ing of any type. With­out under­lay­ment and one floor cov­er­ing will not have suf­fi­cient sup­port.

The key point in this sit­u­a­tion is the new tech­nol­o­gy, thanks to which it was pos­si­ble not only to sig­nif­i­cant­ly reduce the weight of the entire struc­ture of the heat­ing sys­tem, but also to ensure that the heat was trans­ferred direct­ly to the floor cov­er­ing. The sub­strate can be suc­cess­ful­ly cov­ered with linoleum or car­pet. The emer­gence of new prac­ti­cal and high-tech mate­ri­als allows you to cre­ate an entire heat­ing sys­tem based on wood­en floors in a mat­ter of days. When work­ing with a con­crete screed, you will have to strict­ly adhere to the tech­nol­o­gy and wait 25–28 days until the screed reach­es its matu­ri­ty.

Assessment of the condition of wooden structures. Pre-insulation


Before pro­ceed­ing with the design of the “water heat­ed floor” heat­ing sys­tem, it is nec­es­sary to exam­ine wood­en struc­tures, ceil­ings, logs and oth­er load-bear­ing ele­ments. The wood­en base, con­sist­ing of boards, must be sol­id. The cracks exist­ing between the boards are care­ful­ly sealed with heat-insu­lat­ing mate­ri­als. The floor in a wood­en house is usu­al­ly mount­ed on logs, so it is impor­tant to study their con­di­tion and loca­tion.

Con­di­tion assess­ment includes:

  • visu­al inspec­tion of the state of the sur­face of wood­en boards;
  • feel­ing and scrap­ing the sur­face of wood­en boards to assess the struc­ture of the wood;
  • elim­i­na­tion of cracked and sag­ging boards;
  • align­ment of lags in places of deflec­tion;
  • adding lags if the dis­tance between exist­ing ele­ments is too large.

For ref­er­ence: if the con­di­tion of the wood­en floor is unsat­is­fac­to­ry (old cracked or rot­ten boards), it is bet­ter to dis­man­tle such a base. The joists that hold the boards are too far apart. For a warm floor, the logs must be at a dis­tance of at least 60 cm from each oth­er.


There is an instal­la­tion option when a warm floor is laid on wood­en logs. Those. in oth­er words, the whole struc­ture will be on top of the sup­port­ing struc­tures, rep­re­sent­ing an inde­pen­dent struc­ture.

Old boards that do not have a mar­ketable appear­ance must be treat­ed with a join­t­er to make the sur­face of the mate­r­i­al even and uni­form. The max­i­mum allow­able height irreg­u­lar­i­ties for a wood­en floor are no more than 2 mm. Such care and pre­ci­sion is nec­es­sary for a wood­en floor due to the fact that there is no sub­strate in this sys­tem.

Hav­ing fin­ished with the assess­ment of the con­di­tion and prepa­ra­tion of the wood­en floor, you should pro­ceed to the insu­la­tion of the struc­ture. Such a pre­lim­i­nary pro­ce­dure is nec­es­sary due to the fact that all the heat radi­at­ed by the water cir­cuit should not go down into the under­ground, but linger and go up.

Rein­stall the lags at an accept­able dis­tance, install the raised floor. On the logs, ply­wood or used boards are nailed from below. This will serve as the basis for the ther­mal insu­la­tion mate­r­i­al to be laid. Steam and heat-shield­ing film should be laid on the pre­pared base. In the open­ings between the lags, a heater is laid on the film, the thick­ness of which should not exceed 100 mm. On top of the insu­la­tion, a heat-insu­lat­ing film is again fixed. Only after all this, you can start lay­ing the heat­ing water cir­cuit.

On a note: It is strong­ly not rec­om­mend­ed to use ordi­nary poly­eth­yl­ene film as ther­mal insu­la­tion. Neglect of tech­nol­o­gy will lead to the fact that con­den­sate will begin to accu­mu­late in the sub­field. Due to the accu­mu­la­tion of mois­ture, the insu­la­tion may soon become unus­able.

Insu­la­tion in this sit­u­a­tion can be min­er­al wool, the den­si­ty of which is 35–40 kg / 3.

Installation of the floorboard and methods of laying heating pipes

At this stage, it is nec­es­sary to take into account tech­no­log­i­cal sub­tleties. Of course, this will take a lit­tle more time, but in the future the work will already be car­ried out much faster. Should be said right away. The lay­out of the water heat­ing cir­cuit in this case is a “snake”. Instal­la­tion of the pipeline accord­ing to the “spi­ral” or “snail” scheme is unac­cept­able for this tech­nol­o­gy.

On the pre­pared base, we begin lay­ing boards that have a spe­cial con­fig­u­ra­tion, equipped with spe­cial grooves. Between the boards there should be grooves mea­sur­ing 20x20 mm. The edges of the boards are turned in a semi­cir­cle for a con­ve­nient inver­sion of the water pipe. Hav­ing made all the nec­es­sary prepa­ra­tions, you can lay all the boards on the pre­pared base. The pres­ence of grooves and the semi­cir­cu­lar edges of the boards are the route for lay­ing the water cir­cuit. This to some extent facil­i­tates the task in the future when installing the under­floor heat­ing pipeline direct­ly.

Ready-made grooves for mount­ing a water pipe of a water-heat­ed floor under wood­en floors are shown in the pho­to.

Thanks to the grooves, lay­ing the heat­ing cir­cuit is easy and fast. Before work­ing with the pipe, foil is unwound over the grooves. After that, a pipe is laid in the grooves, the diam­e­ter of which should not exceed 16 mm. In order to get max­i­mum heat trans­fer, the pipe is wrapped in foil, attach­ing its edges with sta­ples to wood­en boards.

On top of the pipe, they are attached to the boards with met­al plates. Accord­ing to this scheme, the entire water pipe is laid, there­by cov­er­ing the entire floor area.

On the pre­lim­i­nary plan of the room, marks are made where the con­trol equip­ment (col­lec­tor, man­i­fold cab­i­net) will be installed.

Impor­tant! Pipes should be laid tak­ing into account a cer­tain step. For the cen­tral regions of the coun­try, where the aver­age month­ly tem­per­a­ture in win­ter is ‑15, ‑200C, the opti­mal step for lay­ing is 150–300 mm.

It is bet­ter to use a stain­less cor­ru­gat­ed pipe with a diam­e­ter of 16 mm.

The final stage. Connection to autonomous heating system


After you have laid the water cir­cuit, you can start con­nect­ing it. For man­u­al con­trol, the con­nec­tion is sim­ply made to the main pipeline using a con­ven­tion­al tap. If you want to make the sys­tem adjustable, warm water floors under the wood­en floor are equipped with mix­ing units and a col­lec­tor. In this case, you get a con­ve­nient, effi­cient and adjustable heat­ing sys­tem.

For those who want to impro­vise should remem­ber! Under no cir­cum­stances should under­floor heat­ing be con­nect­ed to a cen­tral heat­ing main. Con­nect­ing addi­tion­al heat­ing devices, includ­ing under­floor heat­ing, to a cen­tral­ized heat­ing sys­tem and hot water sup­ply is not legal.

Based on this, it is imprac­ti­cal and risky to install a water floor in a city apart­ment. For a pri­vate house or for a sum­mer res­i­dence, this option is quite accept­able and effec­tive. After con­nec­tion, the water cir­cuits must be pres­sure test­ed. The pro­ce­dure is manda­to­ry and allows you to iden­ti­fy places of coolant leak­age, iden­ti­fy zones of low heat­ing. Only after that you can start work­ing with floor­ing.

Finish. Floor covering flooring

The cov­er you choose can be any­thing. To date, the trad­ing net­work has a huge selec­tion of a wide vari­ety of mate­ri­als. You will have to choose not so much for man­u­fac­tura­bil­i­ty as for cost. If you pre­fer to use lam­i­nate, then you will need some time for this. The costs will not be so high in this case.

On a note: any mate­r­i­al has its own coef­fi­cient of ther­mal con­duc­tiv­i­ty, so your lev­el of com­fort and heat­ing effi­cien­cy depends on what kind of coat­ing your warm floor will be cov­ered with.

Wood has a low ther­mal con­duc­tiv­i­ty com­pared to ceram­ic tiles. Before start­ing the instal­la­tion of a water heat­ed floor along the logs, ther­mal cal­cu­la­tions should be made to give an idea of ​​the amount of heat that will be on the sur­face. By doing every­thing cor­rect­ly and in accor­dance with the tech­nol­o­gy, you can inde­pen­dent­ly make an effec­tive heat­ing sys­tem in res­i­den­tial premis­es.


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