Is it possible to plaster walls after waterproofing? Is it possible to apply plaster to waterproofing? Construction mixer price
The operational life of construction projects depends on many factors. Excess moisture has a significant impact on the condition of the building. Anyone can protect the walls of a house from moisture, which leads to destruction, with their own hands. And we will tell you about the most effective way to protect your home from excess humidity in this article.
Types of waterproofing plasters and their features
Plaster waterproofing is the optimal solution. It can prevent moisture from penetrating into the thickness of load-bearing walls. This finishing can be used on low-rise residential construction projects. At the same time, with the same success - and on large buildings public type. ().
At the moment, two types of waterproofing finishing materials are widely used:
- asphalt plaster;
- cement-sand plaster.
Cement-sand waterproofing mortars
Waterproofing plaster based on cement and sand is a durable coating. It is resistant to negative influences external environment. Unlike conventional cement-sand coatings, waterproofing finishes have a high density. It is also characterized by an extremely small number of pores in the thickness of the finishing layer.
A cement-sand waterproofing solution is prepared by mixing non-shrink Portland cement, washed river or quarry sand and water. All of the above components are used subject to certain dosages. This is done to achieve optimal performance of the plaster mixture.
The most popular mixtures are waterproofing cement-sand mortars. But only those produced with the addition of ferric chloride. (In proportions 1:16, 1:22, 1:26 relative to the mass of cement.)
This type of plaster mortar is characterized by short setting times. This occurs due to the addition of sulfate-yeast mash in an amount of 0.2% of the total mass of the material. In order to prevent the possibility of unauthorized setting, the solution is stored in hermetically sealed polyethylene containers.
To treat plinths and buried structures, solutions with ferric chloride additives can be used. This plaster is advantageous due to its increased degree of hydrophobicity.
Cement-colloidal plaster mortar is prepared in special mixers using dry, finely ground sand and cement. Water with sulfate-alcohol mash is added to the prepared mixture. Such modifications of plaster are suitable for finishing structures that are not subject to uneven shrinkage. (Whose foundation is laid on solid ground.)
Application of cement-sand waterproofing
Cement-sand waterproofing for gypsum plaster applied with a layer of solution no more than 25–30 cm thick.
As an example, let's look at the instructions for self-plastering.
- Preparing the surface for plastering. Before applying plaster, clean the walls from dust, dirt and grease stains.
If the surface is not rough enough, we make notches with an ax to ensure greater adhesion. If you have sandblasting equipment, the work is greatly simplified. After all, it is possible to cover an entire wall with small notches not only quickly, but also with minimal labor costs.
Important: Cement-sand waterproofing can only be used on hard surfaces that are not subject to vibration. In addition, the application of enclosing plaster is allowed only after the construction site has completely settled.
When expansion joints (sedimentation and temperature) are formed during sedimentary processes, we fill their cavity with bitumen elastic mastic.
- Stuffing the reinforcing mesh. After the surface to be insulated is prepared, we attach a metal corrosion-resistant mesh chain-link to it. The main purpose of the mesh is to compensate for sedimentary processes and maintain the integrity of the plaster layer.
The mesh is selected with a wire diameter of 2-4 mm with a cage side from 10 to 40 mm. Roll out the mesh roll along the wall, lift it and fix it construction nails or dowels. We attach the mesh in increments of no more than 40 cm.
- Preparing the solution. At this stage, it is necessary to prepare a solution that, when applied, will provide not only the required adhesion, but also demonstrate optimal strength properties.
The guarantee of the quality of the plaster mortar is compliance with the proportions. For example, the combination of cement and sand should be one to two. (As opposed to preparing regular plaster). Water and other components are added with the expectation that the consistency of the material is uniform. And in density it resembled thick sour cream.
Important: Mixing of all components must be done mechanically. That is, you will need a concrete mixer. For insulation work on the walls of a low-rise building, a mixer with a drum volume of 100 to 200 liters will be sufficient. Such equipment can be purchased or rented.
In the photo - a sketch of cement
- Applying the solution to the surface. To carry out waterproofing work using plaster, you will need a medium-sized trowel and a plaster rule.
Before finishing work, spray the surface to be insulated with water from a spray bottle. Then we stand against the wall with our left side. And, taking the solution from the container in medium portions, pour it on with force. The movements of the trowel should resemble the movements of a ping pong racket.
Periodically spray the wall surface with water. This is done to ensure better adhesion of the outline. We spread the solution from bottom to top over a strip width of up to 1 meter. Then we take the rule into our hands. Smooth out the sketch using smooth movements from side to side.
Important: After the plaster is applied, the surface must be kept moist to prevent cracking. To do this, periodically water the surface of the wall with water from a hose with a sprayer over the course of a week.
Composition of cement-sand insulation
The photo shows an example of manual application of insulation
Over a long period of use of plasters, considerable experience has been accumulated in the use of waterproofing coatings. As already mentioned, modern insulating plaster is prepared from dense cement-sand mortars in a 1:2 ratio.
In the manufacture of waterproofing plaster mortars, various chemical additives are used:
- responsible for filling pores and voids in the solution;
- responsible for the formation of neoplasms of a colloidal or crystalline nature in the process of chemical reactions with cement.
- ensuring the waterproofness of the solution (plasticizing additives);
- giving the plaster mortar additional resistance to mechanical loads;
- providing additional adhesion to the wall surface.
Various components are used as sealing additives. Such as ground sand, cerolite, ceresite, ground coal, stone flour, bitumen emulsions, pure bitumen, etc. In addition, plasticizers are necessarily integrated into the solution. Namely - soap naft, abietic and rosin soap, oleates or saponified wood pitch.
Waterproof plasters with a layer thickness of 250 mm or more, applied from the side where water enters, are characterized by the greatest reliability. Water pressure and its tearing effect are characteristics that must be taken into account when making plaster and when selecting chemical additives.
Gunite as waterproofing
Shotcrete can be called another method of protecting concrete pavements.
Statistics and repeated studies show the following advantages of using shotcrete:
- high mechanical strength;
- increased adhesion and, as a result, reliable adhesion to the concrete surface;
- high water resistance of the finished coating;
- resistance to sudden temperature changes during operation of the finished coating;
- Possibility of use on mechanically laid surfaces.
The disadvantages of using shotcrete on insulated coatings include the high probability of crack formation during uneven settlement.
Asphalt waterproofing
Asphalt waterproofing is protective covering, consisting of several layers of hot asphalt mastic or a solution of emulsion mastic and viscosity-enhancing paste.
This type of waterproofing is applied with equal success to both vertical and horizontal surfaces. Asphalt plaster is recognized as the optimal solution for waterproofing basements and basements.
Methods for applying such plaster depend on the type of composition used. For example, hot plaster asphalt insulation is heated to a temperature of +180°C before application.
This method of application guarantees a high degree of hydrophobicity of the treated surface. But it is not always convenient due to the need to use special heaters. In order to simplify the application of waterproofing, cold mixtures prepared in the form of mastic are used. (Or emulsion paste.) This finish can be used for its intended purpose only after complete drying.
Asphalt plaster is applied to vertical surfaces using two methods: manually and mechanized. In the first case, special coating brushes are used.
In the second case, a special device is used - an asphalt thrower. The mechanized method of applying asphalt allows you to process large sections of walls in a short time, evenly distributing the plaster material.
Application of asphalt plasters
The preparation of hot asphalt plaster is carried out using mixtures of high viscosity. As a result, they can be applied to horizontal, vertical and inclined surfaces.
The mixture is supplied to the asphalt thrower using compressed air. Asphalt throwers on the market, in addition to a blower and working tools, are equipped with a mastic heater. As a result, the application of insulating material can be carried out both in warm and cold seasons.
Bitumen mastic is applied in layers up to 7 mm thick. The movement of the nozzle is arbitrary, that is, the coating can be sprayed both from bottom to top and from side to side.
During operation, the asphalt thrower nozzle is held perpendicular to the surface being processed at a distance of 50 cm from it. The total thickness of asphalt plaster is usually between 10 and 20 mm. Plastering work is carried out exclusively in dry weather. Or when using weather protection.
Cold asphalt waterproofing is a bitumen emulsion mastic. It is applied in several layers. Cold mastic is made directly on site or shortly before application. During the preparation process, bitumen paste is mixed with mineral powder with the addition of a small amount of water. Up to obtaining a single-consistency mass.
On large covers, cold asphalt mastic is applied using a diaphragm pump in combination with a compressor, mixer, hoses and nozzles.
The advantage of mechanized application of plaster is the ability to treat the surface of construction sites at a height of up to 15 meters. Laying of cold mastic is carried out at a general temperature of at least +15°C.
Conclusion
Now you know what waterproofing plaster is and how it is applied. It remains to figure out whether waterproofing is needed for low-rise residential buildings. Or should such finishing be used exclusively on large public or industrial facilities?
Of course, high-quality waterproofing is necessary for most structural elements. Regardless of the purpose of the building. Despite the fact that the price of professionally carried out waterproofing work is high, it is fully justified by the durability of the protected structural elements. (
In most modern domestic houses, the walls do not protect against moisture. It is believed that traditional surface covering with ceramic tiles or a cheap analogue - painting with oil paint is sufficient. How to waterproof walls and whether it is really needed in the bathroom, whether money is being wasted - this is what our article is about.
Everyone knows that it is necessary to insulate the floor in order to prevent moisture from entering the building structures and, as a result, to the neighbors living below. Regarding walls, building codes are silent. However, we recommend doing so. In areas where water flows will fall directly on the wall, we strongly recommend that the walls be properly waterproofed. These are places behind the bathtub and shower stall, if it does not have sealed rear walls.
Bathroom areas that need waterproofing
In most cases, there is no need to specially protect walls from water that remain dry or those where only occasional splashes will reach (for example, behind a washbasin). It is enough to tile it, paint it with waterproof paint and even stick waterproof wallpaper with the appropriate glue. But this is provided that the walls and partitions are built from materials that are resistant to moisture: concrete, brick, effective wall blocks. There is one more condition - good ventilation. If your bathroom is small enough and the ventilation is poor, then not only drops of water, but also steam will settle on the walls and ceiling. As a result, this will lead to the formation of fungus and, at a minimum, damage to everything in the bathroom.
WATERPROOFING FLOWER BEDS.
Which mixture is best for waterproofing?
This issue cannot be resolved right away. There are many manufacturers and each may have several types in stock. So, only “Ceresit” has three of them - Ceresit CR 166 (CR 66), Ceresit CR 65 and Ceresit CL 51 mastic. Not to be confused with the water repellent for the facade “ST 13”. The latter composition does not have waterproofing properties.
Water repellent “s13”
The main thing is to understand the principle (idea) of applying waterproofing mixtures. This can be done using the example of Cerosite products. All manufacturers of construction chemicals adhere to approximately the same technologies based on common physical phenomena.
All mixtures can be divided into hard and elastic. Hard can be applied to fixed surfaces - foundation walls, wells, indoor small pools, showers, bathrooms. From Henkel it is a dry waterproofing mixture “CR 65”.
Terraces, balconies, outdoor swimming pools, heated floor screeds, and plasterboard walls are subject to temperature and mechanical fluctuations, therefore, to protect such objects, an elastic waterproofing mass is needed. This is “CR 166” - a two-component polymer-cement waterproofing mass and elastic polymer mastic Ceresit CL 51. Or hard “CR 65″ + elasticizer “CC 83”.
Rigid and plastic waterproofing mixtures.
Also, mixtures are divided into those that can be applied to the gypsum surface and those that react with gypsum and cannot be used. The chemical reaction is accompanied by crystal growth. Then these neoplasms provoke detachment.
Characteristic differences between various waterproofing materials.
And there is one more important difference between “Ceresit” waterproofings - some are suitable only indoors, others can be applied both inside and outside the building.
What else do you need to know about the technology of using waterproofing mixtures?
You cannot make self-leveling floors on the waterproofing layer. It becomes a separating layer and the thickness of the screed, in this case, must be at least 32 mm. Therefore, it is better to apply waterproofing after screeds and self-leveling floors, taking into account the composition of the floor mixture. Some contain gypsum. The screeds must be completely dry (28 days). For concrete this period is 3 months.
Waterproofing on self-leveling floor
How to apply waterproofing.
For dry waterproofing mixtures (“cr 166” and “cr 65”) there is no need to prime the surface. It is enough to moisten it until it is saturated with water. Much like applying plaster to a brick wall. The wall (or floor) should be damp, but not wet, along which the mixture will flow. Can be applied with a brush and spatula.
For elastic polymer “cl 51”, preliminary priming of the surface is required.
For 3 days, the treated surface must be protected from drying out, wind, direct sun rays and frost.
Waterproofing thickness.
The thickness of the waterproofing depends on the conditions in which it will work. It could just be a damp environment, or it could be pressurized water. Based on this, one or more layers are applied. The final thickness can vary from 1 mm to 3 mm (CR 166) and up to 5 mm in CR 65.
The recommendations state that the first layer must be applied with a brush. Second brush or spatula. The thickness of the layer applied in one pass should not exceed 1 mm. This rule applies to two-component Ceresit CR 166 (CR 66) and Ceresit CL 51 mastic.
The thinner the layer, the greater the likelihood of making gaps or creating poor-quality insulation. The greater the water pressure, the thicker the insulation layer should be. Application with a spatula gives an increased layer (consumption is correspondingly greater). But this method has a drawback - waves and irregularities appear that interfere with subsequent tiling. And there remains a danger of missing areas when smoothing.
All this can be eliminated if, immediately after the spatula, you coat the protruding ridges with a brush soaked in the solution. The surface is leveled and the pores are guaranteed to be blocked.
Consumption of dry mixes and mastics.
Consumption depends not only on the method of application, but also on the condition of the coating. So, if there are a large number of sinks on the floor, the consumption may double. Even when applied with a brush. A layer of mixture will accumulate in the recesses. With a significant depth of such pits, the waterproofing may not harden inside the layer for a long time. The crust around the edges will prevent water from evaporating.
Therefore, in such cases, it is necessary to first seal all sinks with CT 24 or CT 29. Bases with a non-uniform structure (brick and stone masonry) should be plastered with a mixture of CT 24 or CT 29. When applied sparingly with a spatula, on a flat plane (plaster on beacons and without sinks) consumption is about 3 kg / m2.
Waterproofing under tiles.
The tiles should be glued to a surface treated with hydraulic mixture CL 51 and CR 166, it is necessary only with plastic compounds SM 16, SM 117, SM17 or with glue of a lower class, but with the addition of an elasticizer. And over a layer of CR 65 you can use CM 11 Plus, CM 12 and CM 14 Extra glue (but not earlier than 3 days after applying the waterproofing mass, and no later than 7 days). In this case, priming the surface is not necessary in both cases. Large porcelain tiles, with or without narrow joints, can cause problems on an insulated wall or floor due to poor water evaporation.
15.05.2008, 21:45
There is a concrete one ground floor(with windows, semi-basement). Where the wall comes into contact with the ground, white spots appear (like frost, apparently fungus or efflorescence), and dark spots (moisture). We cleaned the metal. brush and coat with Pufas anti-mold solution.
The walls are all uneven, the sea waves sometimes move forward 3 cm, sometimes they go inward 3 cm. This is how our little brothers made plaster for us!
Now you need to waterproof and level the walls for the tiles.
Please advise how to level out such differences. Some recommend using Rotbant (but gypsum, and it’s humid here), some using a cement-sand mixture, and some using plasterboard (which will reduce the area).
And what is better - first waterproofing or first final plaster, and then waterproofing.
Does anyone have experience with waterproofing? Three years ago we waterproofed it with a mixture of HYDROTEX, there was no effect and the layer gradually fell off.
21.05.2008, 16:32
It is best to waterproof the outside of the house. Dig it up, coat it, dry it, cover it with extruded polystyrene foam and bury it. It will be warm and dry in the basement. :D
21.05.2008, 19:33
Agree. The problem is that they also waterproofed the outside with HYDROTEX, but the result was zero. In addition, there is a blind area around the house that is quite wide, up to 3 m. In this case, it will have to be destroyed.
So far we have started doing waterproofing inside with a two-component component GIDROLAST. Then we placed the beacons under the plaster, and after the plaster we will coat it again with waterproofing, just in case.
My concern is: the layer of plaster will in some places reach 5-7 cm. Will it fall off over time? It's on the walls.
There is a special song about the ceiling. There are also differences of up to 5 cm. To keep everything in place and not fall on your head, we decided to do this: beacons, cement plaster, mesh, Fugenfühler, Vetonit VH putty.
Can any of the plasterers advise whether this is the right decision?
AnatolyK
22.05.2008, 16:08
The best waterproofing is rolled - you have already seen the effectiveness of tacks, now it’s the turn of the fin. For thick plaster: it is advisable to apply it to a reinforcing mesh screwed to the wall, even if it peels off in some place, it will stick to the mesh. Look in stores for a hardening accelerator for concrete; it will work faster because you have to wait for the previous layer to set. Expanded mesh will also work on the walls, but welded mesh is better for the ceiling - it will be more reliable
---- first the grid then the rest.
23.05.2008, 11:34
What can be the thickness of the plaster layer (not overall, but layer by layer)? I probably have several layers at 5 cm and each one should set before applying the next one?
They also recommended that I use a strengthening primer before plastering the ceiling.
AnatolyK
23.05.2008, 22:37
The thickness of the layer depends more on the skill of the plasterer - it will be determined by eye that he will throw the mortar again and the entire layer will slide off. looks something like this: throw a medium-thick solution onto the entire wall with a ladle - you’ll get uneven surface, according to the beacons, remove the excess solution in thin places and wait for it to set. 5cm - 3-4 times, approximately a layer in the morning, a second in the evening, a third for grouting.
Strengthening primer before plastering the ceiling.
IN the latest technologies and I’m not very good with materials: D (Soviet training), so on the forum I try to pick up something useful from modern materials (it’s better to learn from other people’s mistakes), if this is just another impregnation, then write the name - maybe someone has used it.
23.05.2008, 23:00
It’s clear, now all that’s left is to find plasterers. The teams living in St. Petersburg are looking for large volumes, but I have 60 meters of plaster and 150 meters of screeds. I can’t lure anyone to the site!
AnatolyK
24.05.2008, 12:45
The volume is only suitable for “repair work” and you need to look for them. For those for whom construction is their “main bread,” of course, a small project is certainly not profitable. As a part-time job, just give me these, less volume, higher cost per sq.m.
24.05.2008, 19:10
Yes, it’s a pity that you are far from St. Petersburg.
28.05.2008, 22:13
I brought a plasterer to my site. At the base they advised to use plaster for ceilings in damp rooms. cement mixture KNAUF-UNTERPUTS, which is also used for building facades. Have taken. Today the plasterer calls and is almost crying, saying he sprayed four bags and everything fell on the floor! It turns out that the base did not warn that before UNTERPUTTS it is necessary to apply another mixture of VP 332 of the same KNAUF! We lost more than 2,000 rubles from this experience.
It seems that we should settle on gypsum ROTBANT, which at first they did not want to do because of the humidity of the room. Everyone seems to be praising this mixture.
AnatolyK
28.05.2008, 22:41
and everything fell to the floor. He immediately collected it and put it back on the ceiling in a thinner layer. Gypsum can be made more or less moisture resistant, but in our country where all the mixtures are prepared in one concrete mixer: cry:, and super technology 2e is not possible until you buy 1e. :D
28.05.2008, 22:46
But in general, a concrete ceiling can be plastered the old fashioned way: cement, sand, plastering, for example?
AnatolyK
29.05.2008, 12:34
So I wrote about “Soviet hardening”, i.e. you yourself compose what you need for a given place, using additives - which you know, or which you find. Buying ready-made dry mixtures simply turns out to be more expensive and you have to overpay only for the promoted name. That’s why I mentioned the hardening accelerator: cement-sand 1-3 (4) and the addition of a bit of plasticizer to the cement. Gartsovka is a simple lime-sand solution that has been used since ancient times for interior plastering of walls and ceilings, and for masonry. But before, the lime was kept in a pit for three years, so the quality was different. For the basement, it is better to add cement, or ask for quick-setting ready-made for wet areas.
If the worker has not found where to use the solution, then take off the last of his pants, shame on the jungle.
29.05.2008, 15:33
I called KNAUF today (manufacturer cement plaster UNTERPUTTS). I say, so and so, your product falls from the ceiling and does not dry for a day. They thought for a long time, then they made a verdict: that my room was poorly ventilated and therefore the solution did not dry, and secondly, that we used soil not produced by them, but by the PLITONIT company.
We decided to try ROTBANT on the ceilings (although KNAUFT technologists discouraged it, saying it would only last a year in a damp room), and on the walls cement-sand and plasticizer. Let's see what happens.
02.06.2008, 22:20
I came from the village. In general, it turned out fine on the walls. The ceilings haven't been done yet.
We decided to use a prance. We make the solution like this: 1 tsp cement + 2 tsp. prancing + 2 hours of sand. I refused the plasticizer because... it is for faster drying of the solution, and the solution is stronger when it dries for a long time. It even seems like it needs to be moistened.
Here’s the question: in the next room, to prepare previously plastered (smooth) walls for additional plastering (the walls themselves were plastered about three years ago, but not leveled), what needs to be done?
1. Do I need to coat it with a primer? And which one is better?
2. Place a thin metal grid? Will there be air cushions underneath?
3. Make notches?
AnatolyK
02.06.2008, 22:55
previously plastered (smooth) walls, depending on how much you need to level:?:, maybe just putty will be enough. If you need a layer of plaster, then cut it with a grinder every 5-10 centimeters with a diamond.
For those who are familiar with this chemistry, we don’t use a primer; for me, the primer is the first layer of the solution: oops:
02.06.2008, 22:58
It is necessary to level in places up to 7 cm. Horror, of course, but it is necessary under the tiles. And if you install a mesh, maybe the notches are not needed then?
My plasterer doesn't want to work with an angle grinder.
AnatolyK
03.06.2008, 07:25
amazingly smooth wall - 7cm brick thickness per edge. It is necessary to make some kind of notch, the solution will be held in it “as if with your fingers”, and the mesh, of course, will also be stronger. The wall is simply leveled under the tiles.
03.06.2008, 13:11
Yes, in some places you will have to put bricks on the corners.
What’s worse is that there are still places where the old plaster is crumbling. They will recapture it, of course, but they may not even notice something and cover the weak base with a new one...
