Waterproofing of the bases and cellars

Waterproofing of the bases and cellars

Whether it is necessary to waterproof the base? If it is about the building with basement storey, the base (or its part) at the same time serves as walls of the lower level. In rooms it has to be dry therefore not to do without waterproofing. In case the building has no first floor or cellar, the question of need of waterproofing is ambiguous.

It is extremely important to execute isolation from moisture of walls and design of floor. For this purpose waterproofing course surely have over the base. But urgent need to protect from moisture the base of the house without cellar, no. Concrete, unlike wall materials, is not so subject to destructive influence of frost and water. Of course, the concrete structures which are completely isolated from moisture will serve longer, but the effect will be not so high. And the difference in heat transfer of dry and wet concrete is so small that it in general can be neglected.

It is possible to draw conclusion that the waterproofing of house footings without cellar is desirable, but is optional. It is worth performing these works for solid residential unit, and here expenses on waterproofing of the bases of the budgetary frame giving or farm buildings by no means are not always justified.

Not smaller value, than waterproofing, for water drainage from the house the blind area has. It is desirable not to tighten with its device and to do not already meter. For decrease in water saturation of soil the drainage is also very effective.

General rules

Regardless of the applied technologies and materials, there are general rules which need to be observed during waterproofing works:

  • The surface of the base has to be clean. Before works concrete should be purified with rigid brushes, to wash out dirty surface strong water jet, it is desirable from high-pressure washing (it is possible to take in rolling).
  • All roughnesses should be eliminated previously. For filling of big hollows use cement and sand solution, special repair structures. Small sinks can be covered with frost-resistant tiled glue. In the designs collected from concrete blocks, special attention should be paid to filling of seams. They need to be fullered carefully the solution mixed in proportion 1:2.5.
  • The waterproofing of building constructions has to be full. It should be carried out from below (horizontal, over basic pillow), outside and from within (vertical, on walls). If works are performed carelessly, in certain places water will get inside and to gradually humidify all mass of concrete. Concerning waterproofing ruled fairly: it is necessary to do qualitatively or at all not to do.
  • Any kinds of waterproofing works should be carried out to the period of steady positive temperatures, lower limit +5ºС within at least a week.
  • It is necessary to study attentively application instructions of waterproofing materials and to unobjectionably carry out them in work flow.

Technologies and materials

For isolation of the bases and cellars the greatest distribution was gained by three types of the technologies determined by the applied materials: bituminous, mineral. There are other, rather effective methods applied at construction of underground constructions, but they provide use of the expensive equipment and run into money.

At construction of the building with basement storey waterproofing properties can be given already to the concrete. If the base and walls of socle represent monolithic construction, it is possible to add hydrotechnical additive to concrete mix. On condition of good consolidation of concrete it considerably will reduce material water absorption, will increase frost resistance. In combination with outside waterproofing, use of hydroadditives allows to achieve the guaranteed result even at construction on soil with high level of underground water. At the low cost good results show the domestic medicines “Penetron of Admiks”, “Bixil WA”, “Gidrokhit”.

Bituminous waterproofing

The main lack of bituminous materials — small life cycle. Unprotected from external influences, in the sun and frost they become brittle, crack in one or two years. Underground will serve years 5-10. Protected by heater, plaster or in a different way, can keep the properties longer, up to 15-20 years.

Two types of bituminous waterproofing materials are applied:

  • Liquid: mastics and primers. These are the oil bitumens dissolved in light oil products: gasoline, diesel fuel or their mix. It is possible to buy ready liquid structure or to prepare similar mix independently. The primer is kneaded less dense and used as primer for the first layer. Mastic it is possible to carry out so-called coating waterproofing. After concrete processing by wide brush put with primer 2-3 layers of dense mastic. Coating bituminous waterproofing as it is cheap, it is so unreliable and short-lived.
  • Rolled material — legendary Soviet roofing material. Represents the cardboard impregnated with bitumen. Apply primer on the surface of the base, and then paste on mastic in the hot way 2-3 layers of roofing material. Rolled panels warm up evenly, roofing material has to be not simply pasted on cold mastic, and is welded on the warmed bitumen. If in work flow negligence is allowed, in this place moisture will inevitably get, gradually tearing off cloth from surface. For heating it is better to use blowpipe, it is more difficult to work with blow torch. Unlike coating isolation which “teapot” can execute, qualitatively to paste roofing material without availability of the corresponding skills not easy. The horizontal single-layer waterproofing should not just be rolled on base of foundation, and it is obligatory to paste to it, it is possible on cold mastic. The lower horizontal roll has to be wider than tape or column of the base on 10-15 cm from each of the parties. After construction of base tape it is wrapped up and pasted vertically, then covered with the following layer. Other option — to give stock longwise of vertical panel and to bring him down, on pillow, having welded with horizontal isolation.

For plastering and pasting the surface is prepared a little differently. In the first case more attention is paid to elimination of minor defects and sinks. In the second — eliminate large roughnesses, hollows fill with solution, cambers force down.

It is inadmissible to apply bituminous materials on wet surface. It is possible to perform works only in dry warm weather. Also isolation on the basis of bitumen does not maintain the negative pressure of water. It means that if the waterproofing is executed poor and concrete sufficiently becomes wet, moisture will put upon bituminous mastic pressure from within and to gradually tear off covering. Unfortunately, on the wet, impregnated with oil fats concrete, it will not turn out to put any other covering.

One more lack of bituminous isolation: to it it is impossible to paste mineral materials a little strongly. Tiled glue, plasters, cement structures, polyvinyl acetate emulsions — everything keeps badly. Therefore plaster and facing are carried out only on the metal gauze fixed on dowels that complicates and raises the price of finishing of elevated part. Heater also fix on dowel mushrooms, them has to be twice more normal. Glue is applied only to alignment. The underground surface, with heater and without, can be protected flat asbestos-cement sheets or at least geotextiles.

Bituminous and polymeric waterproofing

At the expense of the stabilizing polymeric additives bituminous and polymeric materials have the best characteristics, do not change the properties much longer and keep plasticity. Life cycle of bituminous and polymeric isolation is 2-3 times higher, than normal bituminous, reaches 30-50 years. It is necessary to pay for serious improvement of durability and quality: bituminous and polymeric materials it is notable more expensively.

The range of bituminous and polymeric waterproofing materials is similar to normal bituminous. These are also primers, mastics and rolls. In the presence of the huge choice on ratio the price/quality/width of the range, perhaps, is in the lead products concern “TechnoNIKOL”. Mastics incorporate “soft” organic solvents: white spirit, nefras. Rolled materials are reinforced by fiber glass or fiber glass fabric, have thickness in 2-3 mm. The built-up rolled isolation, with rare exception, is more reliable coating.

The technology of coating and backing bituminous and polymeric isolation is similar to described in the previous section, but it is worth calling number of features:

  • It is not recommended to combine different types of materials. It is possible to paste bitumo-polymeric roll on bituminous mastic, but properties of covering are not implemented fully. The dried-up mastic should not be diluted with gasoline, it is necessary to use the solvent specified on packaging.
  • Rolled materials it is more reliable than roofing material. Instead of two-three layers it is enough to build up of one-two.
  • It is more difficult to build up bituminous and polymeric panels. First, they more thickly and, respectively, are just bent more difficult. Secondly, bituminous and polymeric materials are strictly forbidden to be overheated. At rise of temperature above directed, polymeric modifiers burn down and evaporate. Material loses the advantages, approaching on characteristics normal roofing material. Marking indication helps to sustain exact temperature condition. For example, on rolled materials of the TechnoNIKOL company specialized coating with the image of snowflakes is put. In the course of fusing it is necessary to watch closely them. At due extent of heating they “float” and disappear, at this moment it is necessary, is dense rolling panel, to stop heating of the site. Not earlier and not later. In work use only special blowpipes.

This type of isolation is also applied only on dry surface and on it no glue structures, except bituminous keep properly.

Let’s mention that there are also rolled polymeric materials without the content of bitumens, so-called membranes. They are extremely reliable, long-lasting and so expensive.

Mineral waterproofing

Mineral isolation is deprived of the shortcomings inherent in materials on bituminous basis. The technology of its drawing is simple, and cost depending on type of structure and solvable tasks fluctuates from low to moderately high. Mineral isolation is, as a rule, made on the basis of the cement knitting, small filler (quartz sand) and the polymeric modifying additives. Cement structures has excellent adhesion to concrete, correctly executed covering cannot be torn off or damaged. It can be applied on the wet basis, there is no need to expect good weather and to dry concrete. On mineral surface glue and plaster structures, paints in the best way keep. Polymer-cement materials are strong, are not afraid of mechanical influences and ultraviolet. They can be not protected on surface, underground. Processing of any, most irregular and uneven shapes is possible. The covering extremely long serves: almost as much, how many and concrete. Before causing structures small sinks in concrete need to be eliminated previously.

The mineral waterproofing structures can be separated into several main types:

  • Structures for not deformed surfaces. These are the single-component dry mixes which are shut water. Are put with brush or the palette in two-three layers, the technology is extremely simple. The only shortcoming — structure is not elastic. At emergence in concrete of cracks moisture will get into them. Single-component structures are very cheap.
  • Structures for the deformed surfaces have high elasticity, at least, not inferior to bitumo-polymeric materials. Consist of two components: dry mix and the shutting water-based liquid. The technology of drawing is more difficult than simple plastering, but it is simpler than fusing. Apply the first layer of structure on the prepared surface, at once pasting in it polymeric plaster grid. After the first layer grabs, the structure is caused repeatedly. Apply the elastic polymeric tapes capable to absorb shifts even in several centimeters to processing of internal corners and other places of possible deformation. The two-component mineral waterproofing is extremely reliable, not without reason it is applied to processing of bowls of pools and responsible reservoirs over five meters in depth. On all characteristics it advances bitumo-polymeric, but also is more expensive, though not much more. Except the high price, shortcomings has no.
  • The special waterproofing structures. As a rule, it is mixes for elimination of leakages, sealing of joints and cracks. They are waterproof, very quickly harden, quite often allow to work directly in water. To seal and repair of hardly accessible cracks and cavities apply mixes on the basis of the self-extending cements, download them inside under pressure.
  • The structures crystallizing in the mass of concrete. Some types of water insoluble salts are capable deeply, on several centimeters to get into structure of concrete. There they gradually, as a result of contact with moisture, involving in slow chemical reaction of molecule of water, form crystal structure which “grows” into concrete, like mycelium. Crystallization closes micropores on which moisture could arrive. Over time crystallization only increases, improving over the years waterproofing properties and strengthening concrete. Structures release in the form of liquids, or enter them into structure different polymer – cement mixes most of which has this property to a greater or lesser extent.

All types of mineral isolation are combined with each other. In difficult conditions according to product sheets apply several types of the materials which are reliably isolating the seams, cracks, designs located below or above level of underground water. Moreover, perhaps combined use of mineral and bituminous and polymeric structures. Only restriction: polymer – cement mixes have to be applied the first, but in any way not on the contrary. Quite often elevated part (or all surface) socle is processed the inexpensive cement structure which does not have restrictions on further finishing. And underground isolate elastic bituminous and polymeric isolation. It is allowed to execute horizontal waterproofing bituminous having pasted roll on cold mastic, and vertical mineral mixes, often so more conveniently.

Use of mineral structures is especially attractive to the private developer who has opportunity and desire to perform some works independently. Unlike the thermal built-up technology where it is necessary to have the expensive equipment and certain skills, it is possible to work with mineral mixes quietly, without hurrying, comprehending technique in work flow. If strictly to follow instructions for what it is necessary to be just accurate, defects in work will not arise. It can execute waterproofing of the base, cellar, cellar or pool the hands quite.

The range of mineral waterproofing mixes is sufficient today. Have perfectly proved the European brands Ceresit, Mapei, Hydrostop. Quite good results are yielded by domestic structures Gidromatik, Kalmatron, the Penetron, Neoteks. This list is incomplete.

What to do if the outside waterproofing of the cellar is hopelessly spoiled?

Quite often after construction or acquisition of the house with the cellar it turns out that walls of the first floor grow damp, water somewhere proceeds. The waterproofing is executed poor, or it is absent at all. Of course, it is possible to dig out perimeter of the building and to repair isolation on cellar walls. But to recover the spoiled horizontal waterproofing theoretically perhaps, but in practice it is unfairly expensive. Therefore, especially if around the house the blind area and improvement is already executed, resort to internal isolation from moisture. It is carried out by exclusively mineral structures, bituminous coating will not keep on constantly moisturized surface.

For isolation of cellars there are several options of technologies, from simple drawing polymer from within – cement mix to multilayer systems with preliminary drilling of openings and drop supply of the crystallizing liquids in thickness of material. Mineral waterproofing structures, stopping the movement of water, are capable to let off gradually from concrete water vapors that positively affects condition of walls.

Question price

Producers offer set of kinds of primers, mastics and rolls for waterproofing of the bases. For descriptive reasons we will give approximate expenses on materials as examples (without the cost of works) for different technologies. Let’s make selection only by some of popular brands. Let’s give also assessment to reliability and durability.

  • Coating (mastic) bituminous coating. The cheapest option — to dissolve normal construction bitumen in mix of diesel fuel and gasoline. Drawing in three layers.
  • Reliability and durability — extremely low, almost any. The backing (built-up) bituminous isolation. Bitumen, diesel fuel and gasoline as solvent and fuel for blow torch. Two layers of RPP-300 roofing material taking into account overlap. Reliability and durability — low.
  • Coating (mastic) bituminous and polymeric isolation. Primer of TECHNONIKOL No. 04, one layer. Mastic waterproofing TECHNONIKOL No. 24, three layers. Reliability and durability — averages.
  • To be fair it should be noted that on sale there are very quality mastics possessing high life cycle and convenient in work. On characteristics they come nearer, and at times and exceed the built-up isolation. However, and the price is quite often much higher than them, than at rolled materials. The backing (built-up) bituminous and polymeric isolation. Primer bituminous emulsion TECHNONIKOL No. 04, mastic hot TECHNONIKOL No. 41, rolled material of TECHNONIKOL of EKOFLEKS EPP, one layer. Reliability and durability — high.
  • Coating polymer – cement waterproofing covering for non-deformable surfaces. CERESIT CR-65, three layers, 2 mm general thickness. Reliability and durability — high.
  • Coating polymer – cement waterproofing covering for deformable surfaces with intermediate reinforcing. CERESIT CR-166, two layers (2 mm general thickness), fibreglass mesh. Reliability and durability — extremely high.


Let’s focus attention on several questions, important for the builder:

  • When performing of the built-up bituminous and polymeric isolation by unskilled workers the defects probability which can nullify all efforts is high. The overlap of cloths up and down cannot be lower than seam, than it is specified in product sheet (as a rule, it is not less than 8 cm lengthways and 12 across). The strict professional control of works is necessary.
  • In the conditions of high level of underground water it is necessary to apply the most reliable technologies to isolation of cellars of buildings, to use the built-up bituminous and polymeric materials, polymeric membranes or elastic polymeric and cement structures.
  • For independent works it is much simpler to “teapot” to work with mineral isolation, besides the dependence on weather patterns is minimized.
  • We do not forget about blind area. In the presence of the cellar it is desirable to execute drainage.
  • If the underground part of the building is not constructed yet, it should be taken into account monolithic construction with use of hydrotechnical additives.
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