Warm water floor in a wooden house from GVL

A warm water floor is a heat­ing option for wood­en pri­vate hous­es, because the water that is in it all year round even­ly dis­trib­utes heat over the entire area in win­ter and cool­ness in hot weath­er. In addi­tion, wood­en res­i­den­tial build­ings (log cab­ins, frame or pan­el hous­es) do not with­stand a lot of weight con­stant­ly act­ing on floors, and the tech­nol­o­gy for installing a water con­tour floor involves the use of light­weight mate­ri­als.


If you want to fin­ish the floor with a durable and reli­able coat­ing with a long ser­vice life, then pref­er­ence should be giv­en to gyp­sum-fiber sheets (GVL). They are char­ac­ter­ized by increased wear resis­tance, because gyp­sum, fluff pulp and rein­forced addi­tives are used in its man­u­fac­ture.

GVL appearance
GVL appear­ance

The advantages of the material in question

Gyp­sum fiber is a durable and envi­ron­men­tal­ly friend­ly homo­ge­neous mate­r­i­al with refrac­to­ry qual­i­ties. The ver­sa­til­i­ty of the sheets allows them to be used for var­i­ous con­struc­tion pur­pos­es, recent­ly they have gained pop­u­lar­i­ty as an arrange­ment of a warm water floor from GVL in a wood­en house due to their excel­lent char­ac­ter­is­tics.:

  • The front part of the prod­ucts is pol­ished, the edges are fold­ed, which elim­i­nates the chalk­ing of sheets dur­ing oper­a­tion. They are avail­able in sev­er­al sizes, but only small-sized sheets (1500 * 1000 * 10) should be used to work with floors. Their pop­u­lar­i­ty is due to the fact that the instal­la­tion of GVL does not require spe­cial tools and prac­ti­cal skills, there­fore it can be done inde­pen­dent­ly, with­out the involve­ment of con­struc­tion teams. In addi­tion, there is prac­ti­cal­ly no waste in the work­ing process.
  • The mate­r­i­al has a high lev­el of noise and heat insu­la­tion (in the case of lay­ing GVL on a warm water floor, it reduces elec­tric­i­ty costs) and pro­vides an even base, so it is used as a sub­strate for any top­coat.
  • Pressed gyp­sum fiber is elas­tic, there­fore it does not deform dur­ing tem­per­a­ture changes, which is good for use in coun­try wood­en cot­tages in which per­ma­nent res­i­dence is not planned.

They are used for dry screed­ing, base assem­bly and cladding.

Advantages of dry gypsum fiber screed

A water-heat­ed GVL floor in a wood­en house does not imply the use of cement or con­crete pour­ing (the dry screed method is used) and allows you to imme­di­ate­ly lay the fin­ish­ing floor cov­er­ing. Dur­ing instal­la­tion, you can imme­di­ate­ly mount the “warm floor” sys­tem.

laying a water-heated floor in a wooden house
lay­ing a water-heat­ed floor in a wood­en house

Such a screed using gyp­sum fiber sheets allows you to equip:

  • The basic base of the floor with the use of expand­ed clay (lay­er 2 — 3 cm), which reduces the noise lev­el and pre­vents heat loss.
  • Draft floor with insu­la­tion.
  • A pre­fab­ri­cat­ed screed, where, in addi­tion to expand­ed clay, poly­styrene foam plates are used.

In addi­tion, con­struc­tion and repair work of such a plan is car­ried out at any time of the year in a short time, because you do not need to wait more than a month for the screed to dry com­plete­ly.

Features of installing a warm floor on GVL

The sys­tem of water heat­ing of the floor can be laid on GVL. To do this, you need to famil­iar­ize your­self with the tech­ni­cal require­ments:

  • Gyp­sum fiber is not laid direct­ly on the floor beams — instal­la­tion of the crate is nec­es­sary. This will avoid heat loss in the low­er direc­tion. The dis­tance between the lags varies depend­ing on the size of the room and the type of fin­ish (30 — 60 cm).
  • There must be a lay­er of ther­mal insu­la­tion between the under­floor heat­ing sys­tem and the fin­ish coat.
  • Pipes are used polypropy­lene, cop­per or poly­eth­yl­ene. Experts rec­om­mend lay­ing the lat­ter, because they are char­ac­ter­ized by a long ser­vice life, ease of instal­la­tion and low cost. In such sys­tems of a warm water floor, any liq­uids are used — water or antifreeze, because poly­eth­yl­ene pipes are resis­tant to chem­i­cals.

Com­pli­ance with tech­nolo­gies extends the oper­a­tional life of the sys­tem and increas­es its effi­cien­cy.

heat spreading plate
heat spread­ing plate

Steam and thermal insulation

Before lay­ing the first lay­er of mate­r­i­al on the exist­ing pre­pared wood­en base, the lat­ter must be vapor-proofed with poly­eth­yl­ene (den­si­ty 200 microns). An insu­lat­ing film in under­floor heat­ing between pipes and GVL is need­ed to main­tain dry­ness. At the same time, you can­not use a reg­u­lar film — con­den­sa­tion will col­lect on it.

Tip: The film should cov­er all joints and go to the walls, excess poly­eth­yl­ene can be cut off.

Logs are fixed along the perime­ter of the base, with the help of which the insu­la­tion (expand­ed clay) is dis­trib­uted even­ly and on which gyp­sum fiber boards are then attached.

Impor­tant! Expand­ed clay should have frac­tions of dif­fer­ent sizes — this will cre­ate a stronger foun­da­tion.

Par­tic­u­lar atten­tion when falling asleep, uni­form dis­tri­b­u­tion and com­paction of expand­ed clay should be giv­en to areas in the cor­ners of the room, in door­ways and along the perime­ter of the walls.

Marking gypsum fiber boards for laying underfloor heating pipes

The first lay­er of GVL is laid on top, after which mark­ings are made on it for lay­ing pipes (by the snail or snake method), for which it is nec­es­sary to make accu­rate cal­cu­la­tions. Depend­ing on the diam­e­ter of the pipes, divid­ing grooves 5–6 cm wide are cut from the GVL boards, into which the pipes will be laid. The grooves to the lined base are attached with self-tap­ping screws. Some crafts­men pre­fer to lay out the pipes first, and then lay the strips between them.

GVL strip fastening scheme for creating grooves
GVL strip fas­ten­ing scheme for cre­at­ing grooves

On top of the steel plates with heat­ing pipes, two gyp­sum-fiber sheets (GVL) 10 mm thick each are laid, glued with PVA glue and fas­tened with self-tap­ping screws. They cre­ate a rigid and even sur­face nec­es­sary for lay­ing a fin­ish­ing coat­ing. GVL sheets also pro­vide a more even load dis­tri­b­u­tion over the floor sur­face.

The sequence of laying GVL boards

Instal­la­tion of GVL bars for the instal­la­tion of warm water floors does not require spe­cial skills. The most impor­tant thing is to strict­ly fol­low the sequence of actions nec­es­sary to cre­ate a high-qual­i­ty floor that will last for decades:

  • Accord­ing to its phys­i­cal prop­er­ties, GVL does not sig­nif­i­cant­ly expand after instal­la­tion, there­fore, to com­pen­sate, before lay­ing along the perime­ter of the walls, it is nec­es­sary to lay a mount­ing tape of basalt wool.
  • Then you can pro­ceed direct­ly to the lay­ing of gyp­sum fiber sheets in com­pli­ance with the off­set. To do this, you can cut one or more sheets of mate­r­i­al.
  • Floor­ing should start from the cor­ner in which the door­way is locat­ed. For high-qual­i­ty fas­ten­ing of joints, a spe­cial adhe­sive mix­ture is used.
  • After that, the gyp­sum fiber plat­inum is attached to the base using self-tap­ping screws. The dis­tance between them should be 30 — 40 cm.

note! Instal­la­tion of GVL should be car­ried out care­ful­ly, oth­er­wise the com­pact­ed lay­er of expand­ed clay can be dis­placed, which will lead to a sec­ond lev­el­ing pro­ce­dure.

If a lam­i­nate or car­pet will be laid as a fin­ish­ing coat­ing, all con­nect­ing places of the rough mate­r­i­al must be care­ful­ly put­tied.

How many layers of GVL need to be laid?

Most often, sheets of gyp­sum fiber are laid in one lay­er. Dou­ble deck­ing is also allowed to cre­ate a more rigid base. In this case, the sec­ond lay­er is laid out per­pen­dic­u­lar to the first so that the seams do not match.

puttied surface of a warm water floor
put­tied sur­face of a warm water floor

If the lay­er of expand­ed clay is 10 cm or more, then three lay­ers of GVL must be laid on top.

The mod­ern con­struc­tion mar­ket offers to pur­chase two GVL sheets already fac­to­ry-con­nect­ed, which have spe­cial folds with adhe­sive. This sig­nif­i­cant­ly reduces the time of work.

Tip: when lay­ing gyp­sum fiber boards in rooms with a high lev­el of humid­i­ty (for exam­ple, in wood­en baths), addi­tion­al water­proof­ing must be done near the walls and at the joints of the sheets.

After car­ry­ing out all the pre­lim­i­nary work on lay­ing a warm water floor in wood­en res­i­den­tial build­ings and before start­ing work on lay­ing the fin­ish coat­ing, you need to wait a day for all lay­ers of the “pie” to final­ly take their places.

Con­clu­sion. Depend­ing on pref­er­ences, any coat­ing can be laid on GVL — regard­less of its tex­ture or weight. And the dry lay­ing method used in this case allows you not only to man­age on your own and not use spe­cial equip­ment for the prepa­ra­tion of cement mor­tar, but also save time and mon­ey.


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