But I still feel like writing about this in more detail. Many of you know that paint and other finishing coatings are applied to brick and concrete walls, but first these walls must be leveled with finishing putty. But now the choice is rich and your eyes are simply wide open. In this regard, the question arises: “Which putty is better?” This is what you and I will look at today.

Putty or putty for leveling walls?

The girl holds a spatula and a falcon in her hands

In any Russian language reference book wall leveling mixture may be called either putty or putty. There is no difference here. But applying the mixture to the wall for leveling is called puttying.

Why? Everything is very simple. This work is carried out using a special tool - a spatula. Well, I think now you understand this.

Where does wall puttying begin?

Plaster will help level out large reliefs, but to achieve a mirror-like surface, you need putty, which has a much thinner consistency. In addition to its main purpose - removing defects on the base, it also solves other equally important problems. With its help, for example, you can create complex curved surfaces (arches, columns, domes, etc.), as well as design various complex architectural details (mouldings, cornices, rods, etc.).

Note: as a rule, on properly applied plaster, in order to obtain a mirror-thin surface, it is enough to apply one layer of finishing putty. On relatively flat but porous cement substrates, it is sometimes possible to do without plaster altogether. The technology for leveling walls is quite simple. First, the surface is primed, which strengthens it and makes it evenly absorbent. Next, it is covered with a layer of putty and allowed to dry completely. They sand, remove dust (remove the smallest particles formed from grinding) and apply the finishing layer.

Leveling walls with putty - how to move the spatula

Which putty is better, types

The range of putties available today is quite wide, and deciding which putty is best is very difficult. How then to understand this diversity? Before deciding this, I want to note that according to the type of binder composition, putties are divided into polymer, cement, gypsum etc. For wet rooms (kitchen, bath, swimming pool, etc.) they are more suitable cement finishing putties. For residential ones - polymer or gypsum, the difference is small. Polymer ones are given more preference, since their working condition is slightly higher than that of gypsum ones. Moreover, after mixing with water, they can be suitable for work for another two days.

Selecting putty for its intended purpose

Their classification according to purpose is no less important. Putties are divided into finishing, which are applied in a layer of 1 to 5 mm, and super-finishers, applied in a layer of 0.2 to 1.5 mm.

Puttying walls - smoother

Finishing putties

Finishing putties are dry construction mixtures based on polymers, cement or gypsum, which contain a binder, modified additives and filler. Before use, the powder is diluted with water strictly according to the proportions specified by the manufacturer. They are usually used when preparing a wall for.

The mixture for wall putty makes the surface perfectly uniform and smooth, which improves further painting or wallpapering. The composition includes components that promote setting and hardening, making it elastic. The article will tell you what modern materials can be used for wall putty and how to apply them to the surface.

Putty is an elastic, fine-grained mixture. Intended for cosmetic finishing of surface roughness and irregularities.

The putty goes on sale:

• Dry. This is a special mixture consisting of the required components in certain proportions and prepared immediately before coating the surface. It is the most popular type of putty. Available in bags or bags. Before use, the dry mixture is diluted and thoroughly mixed with clean water, according to the operating instructions (see). Advantages of dry putty:

1. low price;
2. long-term storage in dry form, at any air temperature;
3. ease of transportation and storage.

The disadvantages of the material include the short shelf life of the already prepared mixture.

• Ready to use. This solution is made on the basis of latex (see) or acrylic. Sold in cans, buckets or tanks. The material is easy to use, does not require time for dilution, and is always ready for use. Ready solution can be stored indefinitely. During a break from working with the finished putty, the container is tightly closed, which does not reduce its quality. The disadvantage of the material is its higher cost than dry.

The composition of putty for walls can be:

• Gypsum (see). Made from gypsum, it adheres well to any surface. Gypsum is hygroscopic, which leads to moisture accumulation. This material is only suitable for interior works. The mixture dries quickly and has an affordable price.
• Cement. This group of compounds is widely used for external finishing works. Having high performance properties, cement-based putty is used for finishing the facades of buildings and rooms with increased humidity. Advantages of the material:

1. stable under changes in temperature and humidity;
2. high strength after drying;
3. prevents the appearance of cracks on the surface;
4. made of gray or yellowish cement, which is easily painted over.

The only drawback is the presence of grain.

• Polymer. IN modern world Leveling mixture based on a polymer component is gaining popularity. Acrylic or latex is used for this. Acrylic composition easy to use and versatile. It can be applied outside and inside the building. After drying the polymer:

1. does not deform;
2. does not shrink;
3. does not crack.

Putty with a latex additive is used for interior walls. Main features of the mixture:

1. very elastic and easy to apply in a thin layer, filling the smallest cavities on the surface:
2. the resulting good film is strong and does not crack after drying;
3. wide range of colors;
4. Sold ready for use.

Advice: When purchasing polymer putty, you should pay attention to the date of manufacture and storage conditions - it is afraid of freezing.

The most unpleasant drawback is the very high cost.

Purpose of putty depending on the type

According to the method of application, putty is divided into four groups:

• Starting. The coarse-grained structure of the initial layer is intended for preliminary leveling of walls, ceiling surfaces, door openings, and slopes. The mixture is selected depending on the base material and operating conditions. It has good adhesion to work surface, high strength and durability, as well as the ability to apply a layer from 0 to 25 mm without cracks or peeling.
• Finish. The finishing layer putty has a finer fraction and is applied to the surface before the final finishing, which can be:

1. dye;
2. flock coating;
3. textile wallpaper.

Apply to the starting putty or to the base itself. It evens out the smallest flaws and scratches, forming a layer up to 1 mm thick. The finish is puttied in several steps, with a thickness of 0.1 - 0.2 mm at a time. After drying, a polished, dense and white surface is formed.

• Specialized. This best putty with a special additive, serves to solve a specific problem. This composition is used for:

1. sealing joints of gypsum panels (see) and concrete slabs, without the use of reinforcing mesh;
2. for “breathing” cracks;
3. for emergency repairs.

The material has higher elasticity and strength. It is very easy to choose. Recommendations and methods of using specialized putty are indicated on the packaging.

• Universal. It combines all of the above functions and is used in a range of combinations of any surface base. It is convenient not only for professionals, but is inferior in quality to specialized putty. At the same time, it is not inexpensive.

How to calculate putty consumption

How to calculate putty for walls? The calculator helps to calculate the area of ​​the walls, and then the required amount of material, which depends not only on the size of the room, but also on the condition of the walls, the thickness of the applied layer and the type of putty.

When calculating material consumption, it is necessary to take into account that:

• When using gypsum or decorative putty, the consumption is 9 kg/m2 with a coating layer of 10 millimeters.
• The cement mixture will need up to 17 kilograms per square meter.
• Polymer, in finished form, consumption with a layer thickness of one millimeter is up to 0.5 kg/m 2.

Instructions for calculating the volume of putty:

• The surface is cleaned.
• IN in the right places Key points are determined, special beacons are set and deviations from the plane are measured.
• The deviations are summed up and further divided by the number of measured points. For example, deviations at three points are: 1, 2, 6 centimeters. In this case:

1. are summed together: 1+2+6=9 (centimeters);
2. the sum is divided by the number of points: 9:3 = 3 (centimeters).

The average uniform coating layer is three centimeters.

• Attention is drawn to the manufacturer's recommendation. Using dry gypsum as an example, it will take approximately 8.5 kilograms to finish one square meter with a layer of 10 millimeters.
• The mixture consumption per square meter is calculated for a layer three centimeters thick: 8.5 x 3 = 25.5 (kilogram).

With a surface area of ​​10 square meters you will need: 10 x 25.5 = 255 kilograms of putty.

The number of 30 kilogram bags will be: 255:30=8.5 (bags). Rounding the resulting value, you will need 9 bags of dry mixture. After this, you can calculate how much wall putty costs.

What set of tools will you need for puttying?

Available for purchase necessary tool for puttying walls.

To work you will need:

• Mixer or drill with a special attachment.
• Container for stirring putty.
• Set of spatulas. At least three sizes, from the smallest to 50 centimeters wide. Use a narrow tool to putty in hard-to-reach places.
• Brush and roller for priming. The roller is used for quick and accurate priming. Use a brush to prime problem areas.
• Rule. Only starting putty will be needed to level a thick layer.
• Spirit level or plumb line. Useful for installing beacons when performing starting putty.
• Sanding machine for preparing walls.
• Hand grouting with a set of mesh or sandpaper.

Tip: The putty should be rubbed in by hand. This will give the surface better quality.

How to prepare a wall for putty

Preparing the wall for puttying is carried out in the following sequence:

• The surface is thoroughly cleaned from old paint, putty, wallpaper and other contaminants. A grinding machine fitted with a wire brush will speed up this process.
• A primer is applied to the wall (see), which penetrates deeply into the surface to be treated. Wherein:

1. the base is strengthened using polymer components such as PVA glue or acrylic. The water-based primer is quickly absorbed into the surface, filling all microcracks;
2. all pores are clogged and a durable film is created. It is necessary for gypsum putties, which quickly lose moisture;
3. adhesion increases;
4. The appearance of fungal mold is prevented due to antiseptic properties.

• The walls remain until the coating is completely dry.

Tip: For proper drying of the putty, you need to create a certain temperature regime from (+10°C) to (+ 20°C) and humidity within 30 - 40%. If necessary, these conditions must be created using heating devices.

How to putty walls

Before starting work, it is necessary to determine why the walls are being puttied. Usually, this is necessary before painting or gluing wallpaper, and the video in this article will show you how to do it correctly. If you follow certain rules, it is not difficult to putty walls with your own hands.

Work order:

• Primary. In this case:

1. large bends, “sinks” and potholes are filled;
2. The walls are plastered in one step, that is, work begins and ends on one section of the wall in one day. If the work is postponed to another time, then the dried joints are generously moistened with water;
3. “beacons” are placed on very crooked walls;
4. the putty is distributed using a rule or a wide spatula; the mixture can also be applied along the guides in a thick layer;
5. puttying the walls starts from the far corner, the direction of movement of the spatula with the solution is from top to bottom or from the corner to the side;
6. in the corners the putty is smoothed out with a special spatula or perforated sheets are applied to the putty metal corners, which are closed with a solution.

• Finishing with a special mixture, which makes the surface perfectly smooth. For this:

1. finishing work is performed with a large and small spatula. Putty is applied in small portions onto a wide spatula using a smaller spatula;
2. then quickly and evenly applied finishing putty to the surface, as shown in the photo.

The layer thickness should be no more than 1.5 millimeters. The final coating is applied in two layers after the previous one has dried and processed with a sanding mesh.

Tip: Before applying each subsequent layer of putty, the previous one must be primed.

A carefully executed process of wall putty facilitates subsequent repairs of the premises.

The huge variety of putties often confuses us. On modern market building materials are presented in mixtures that vary in price, composition and purpose. In the selection process, you have to think about what types of putties there are for interior work, for what work this or that composition is intended, and what properties are inherent in this material. Therefore, it is very important to understand the characteristics various types putty to make right choice for high-quality and durable repairs.

The putty mixture is designed to level the surface and correct possible unevenness, cracks, chips and other defects in walls and ceilings. Puttying is important stage internal repair work, therefore, the types of putties need to be known to everyone who plans to do their own finishing and choose materials.

Putty mixtures must be selected not only depending on the composition, but also in accordance with the stage at which they are intended to be used:

1. Leveling mixture. Designed for initial rough-relief processing, elimination of deep unevenness in walls and ceilings, seams and grooves from self-tapping screws on drywall, large cracks and chips. This putty mixture has a coarse structure and is applied to the base in a thick layer of up to 3 cm.
2. Finishing mixture. Used for thin-layer finishing of walls and ceilings for further painting, wallpapering, application decorative plaster
3. and other finishing coatings. The putty mixture for finishing has a fine-grained plastic structure, thanks to which it is possible to achieve an absolutely smooth surface. Universal putty. This composition can be equally effectively used for processing joints plasterboard sheets

, filling volumetric cracks and potholes, as well as for final leveling before finishing.

Universal mixture - can be used both as a starting and finishing putty

Types of putties according to readiness for use

All types of putties are divided into dry and ready-to-use. Each of these varieties has its own advantages and disadvantages.	View	Advantages
Flaws	Dry mix	Can be used in doses and kneaded to the required consistency
	Preparing the mixture requires certain skills from the finisher, as well as the presence of a drill with a “mixer” attachment	More favorable cost compared to ready-made formulations
	The prepared material dries quickly and becomes unsuitable for further work, so the amount for mixing must be calculated in advance	Long shelf life when unpacked
	If the mixture is prepared incorrectly, all the properties of the putty are lost.
Possibility of storage in any temperature conditions	Ready putty	Easy to apply to walls and ceilings
	Relatively high cost
	Does not require preliminary preparation and can be used immediately after purchase
	Can be stored for a long time in an unpacked container

Features high ductility

Differences in putty composition

• Oil-glue. Used primarily for leveling wooden, concrete and plastered surfaces before applying enamel, oil and water-based paints.
• Plaster. This putty mixture is most often used for treating walls and ceilings in dry living rooms and corridors.
• Cement. Designed for finishing unheated or damp rooms, in particular kitchens, bathrooms and toilets.
• Water-dispersed. This putty composition is suitable for partially leveling and eliminating defects on concrete, plastered, brick, aerated concrete, wood, stone, painted and fiberboard substrates.
• Polymer. A universal putty composition that is used for finishing surfaces made of cement, concrete, gypsum and polyurethane.

The most common materials for interior work are cement, gypsum and polymer mixtures - they have all the necessary characteristics to ensure high-quality leveling of walls and extend the service life of the final coating.

Gypsum mixture: characteristics and specifics of use

Gypsum putty is widely popular among builders when interior decoration walls made of cement, plasterboard and gypsum fiber. This composition has many operational advantages at a relatively low price. In addition, even a beginner can putty with gypsum mixture - it is easily mixed and distributed on the surface.

Important! Gypsum has the ability to absorb moisture, as a result of which the coating begins to swell and peel off from the base. Therefore, it is recommended to use this mixture in rooms with normal and stable humidity and temperature.

Gypsum putty is environmentally friendly and safe for health, since it contains natural ingredients. The mixture is supplied in bags that can be stored for a long time even at negative temperature. Another advantage of gypsum is the absence of the risk of shrinkage and cracks, so this composition can be used for. However, this material is afraid of mechanical influences and vibrations and, as a result, can peel off from the surface of the walls.

Cement putty for interior work

The main advantage of cement putty is its high resistance to moisture, but the main disadvantage is shrinkage during the hardening process with subsequent formation of cracks. It is for this reason that such material is not recommended for finishing living rooms, where the aesthetic appearance of the coating is very important. However, for damp and cold rooms you cannot do without this mixture. In addition, cement putty has a low cost, so it is ideal for large areas, for example, for treating walls in entrances or warehouses.

Features of the polymer mixture

The main and, perhaps, the only drawback of polymer putty compositions is their high cost, which makes it inappropriate to use this material for puttying large areas, as well as for the initial treatment of obvious defects. The main purpose of the polymer mixture is finishing before finishing; it is especially indispensable before applying decorative coatings that require ideal smoothness of the base.

Advice! For those who are engaged in repairs for the first time, in particular, puttying work, the polymer mixture will become ideal option– it is sold ready-made and has an optimal consistency for high-quality and convenient finishing.

Polymer-based putty is a multifunctional material that not only levels any surface well, but also increases sound insulation, provides high vapor and moisture resistance, prevents the appearance of fungus and mold and protects the structure from temperature changes. Thanks to these properties, it can be used not only for decorative finishing dry rooms, but also for tiling bathrooms and kitchens.

Any wall finishing work requires comprehensive preparation. At various stages it is necessary to carry out activities that would contribute to the final goal. Often as decorative covering choose wallpaper. But the surface under them must be carefully leveled. Putty is suitable for this. But there are many types of this material on the market. So, which putty will be better for walls under wallpaper?

Today, there are many methods that allow you to prepare almost any solution yourself. It’s just better to abandon such an idea immediately, especially if you don’t have the proper experience in this matter. The point is that you need to create a surface that will hold the wallpaper very well. You also need to take into account that many compositions absorb moisture from the air, which can also have a negative effect on the decorative layer.

Therefore, it is better to immediately opt exclusively for materials that are sold in special construction stores. This is the only way to be sure that the walls will be prepared as needed.

What is putty?

Accordingly, from the existing pasty and dry materials for preparing walls for wallpaper, it would be better to choose the former. They do not require additional manipulations and can be used immediately after opening. But for large volumes of work they are not very suitable in terms of savings.

Thus, drawing a conclusion about which putty is better based solely on its external characteristics will not be entirely correct. A clear understanding of this issue can only be obtained after a detailed study of the compositions of putty mixtures. And how they interact with wallpapering materials.

Differences in putty composition

You can find many different types of putty in hardware stores. They all differ in their composition. You should avoid mixtures that were made on the basis of drying oil (oil-glue). This option has many significant shortcomings, and is also not recommended for use.

Acrylic-based putty (polymer)

This is enough modern material, which has proven itself well at all stages of finishing work. The latex version is also classified as a polymer composition, but it is not so popular, although it has an undeniable advantage. So, acrylic putty has the following characteristics:

• It is very easy to apply to walls and does not require the use of special tools;
• easy to sand;
• protects the wall from destruction;
• prevents moisture penetration.

It is suitable for almost any subsequent finishing work. There is only one drawback - you cannot apply cheap paint that is not intended for it. It will just peel off.

Common material for various works. Has the following properties:

• sold ready-made;
• has excellent viscosity;
• after drying it shrinks slightly;
• creates a durable layer.

Water-dispersed putty

Forms a fairly smooth surface that does not require significant processing.

Compositions based on gypsum and cement

This material is used everywhere. Has very good characteristics:

• used for any type of work;
• creates a fairly durable layer;
• many varieties are characterized by increased moisture resistance;
• does not require special application skills.

This composition is sold in the form of a dry mixture. To prepare it, you need to add the required amount of water and mix everything well. Preferable are solutions in which the main substance is cement. They can be selected for use even outdoors.

So, which putty is better? Of course, wallpaper is not so demanding decorative material, but this question cannot be answered unambiguously. Based on the combination: price + quality + ease of application + interaction with wallpaper glue, then preference can be given to cement-gypsum mixtures.

They practically do not require further processing (if you follow the application rules). They also do not react with wallpaper glue, which is often mixed with water. Therefore, the choice most often falls on them.

Preparation for puttying before wallpapering

Can hide some wall imperfections. Small irregularities that would be visible when applying paint will remain completely invisible. But this does not mean that you can not pay attention to preparing the surface for applying this type of material. Any significant cracks or potholes are repaired. For this, it is better to choose cement mortars.

It is assumed that the putty layer will act as a finishing application. That is, the surface will initially be plastered.

• First of all, you will need to select the following tools and materials:
• the putty mixture itself;
• several types of spatula;
• sandpaper;
• drill with mixer attachment;

bucket with water.

1. After this, the following steps are performed:
2. The walls are completely cleaned of dust and dirt.
3. A primer is applied to the surface.
4. The putty solution is mixed; the preparation time for the dry mixture is no more than ten minutes.
5. Using a small spatula, the composition is transferred to a wide tool and applied in an even, thin layer to the wall.
6. For greater effect and to avoid any unevenness, the surface is glossed. This way you can achieve perfect alignment.
7. The walls are again cleaned of dust and primed.
8. You can apply wallpaper glue.

After completing all these steps, you can be completely sure that the wallpaper will lie smoothly and will serve for many years.

So, which putty is better? It seems that this question has been answered quite clearly. But still, we must proceed from the fact that the choice should be made depending on specific conditions. Only then will it be possible to ensure that the wallpaper does not fall off the next day, taking with you part of the applied solution.

Not everyone has an idea about which putty is best for walls under wallpaper, because there are many varieties of this material.

It is not always easy to understand which putty to choose for walls under wallpaper.

The article will help you decide what types putty mixture there are and how to make the right choice for each specific case.

Type of putty and its purpose

Wall putty is selected according to two criteria: composition and functions. The mixture is selected based on its constituent components, because the quality of the final result depends on them.

So, putty is divided into the following groups:

• gypsum – levels the wall well and does not shrink in the future. The only disadvantage of such a mixture is that the composition is afraid of moisture;
• cement - has a high resistance to moisture, but may shrink over time. The negative aspects can be added to the long drying time;
• acrylic – moisture resistant, does not shrink. Perhaps this is the most suitable finishing option for both wallpaper and painting.

The list shows the three most common types of putty that can be purchased on the construction market.

The main thing is to remember that the purchased materials must be produced by the same company, which will affect the quality of the finished surface.

In order to ultimately get the result you want, you should consult with the seller and choose a putty that is suitable specifically for your purposes.

Regardless of the components present in the mixture, putty is divided into two types:

• starting mixture, which is used to smooth out large flaws and cracks on the wall. This type of composition can correct any errors in the walls, because the thickness of its layer can be five millimeters;
• finishing option - a type of material designed for repeated puttying in order to eliminate minor defects and give a smooth surface to the wall.

Sometimes a third type of putty mixture is used - universal. This product contains both finishing and starting putty at the same time.

The price of such material is much higher, but the quality is better. Which choice will be correct?

It turns out that all types of mixtures are good, and the question of which putty is best for walls under wallpaper remains unclear.

The answer can be obtained directly from the sales consultant, explaining to him for what purposes the putty solution is needed.

Starting and finishing putty

When you plan to hang wallpaper, then you simply need to putty the walls. Walls with severe flaws are first puttied with a starting solution, because it can be applied to brick or concrete walls.

The finished mixture is distributed in a thick layer, up to ten millimeters; if necessary, another layer can be applied.

If there is a need to apply putty in more than one layer, then a reinforcing mesh is used, thus improving adhesion.

The starting solution is excellent for leveling walls, and the structure of the composition allows it to be easily applied to any type of surface.

Starting putty comes in both dry form and in the form ready mixture. Most people prefer dry powder for dilution: the advantages of dry mixes are an affordable price and the ability to prepare the solution yourself, making the putty the consistency necessary for comfortable work.

It is important to know that to use putty both indoors and outdoors, types of mortar with different characteristics are used.

After leveling the walls with the starting mixture, finishing. This should be done only after the first layer has completely dried.

The finishing putty differs from the starting putty in its fine grain, as a result of which the composition is applied in a thin layer, approximately two to three millimeters.

Taking this factor into account, everyone should understand that finishing putty cannot be used to seal seams and rough surface irregularities.

Finishing putty, like starting putty, can be used for facade works and for interior use - do not forget about this when choosing, because mixtures for exterior and interior use have different adhesion and moisture resistance characteristics.

Of course, you can make the putty material yourself, but the quality of the solution will be worse than purchased, so it is better to purchase a good factory-made product.

Instructions for puttying walls

To carry out the work of filling the walls yourself, you must first prepare the tools that will be needed during the work process:

• several spatulas of different sizes;
• electric drill with attachment;
• empty bucket for preparing the solution;
• sandpaper;
• wide brush (broom brush).

After preparing the tool and purchasing the required quantity building material you can begin finishing work.

So, first you need to treat the walls with a primer - to do this, use a paint brush and a primer container. The process is necessary to remove dust from the surface of the walls.

To prepare the solution, use a clean bucket, into which water is poured in the proportions indicated on the packaging, then mixed thoroughly using a mixer. When the solution is ready, you can begin leveling the wall with the starting mixture.

To apply the resulting mixture to the wall, use two spatulas of different sizes.

Using a narrow spatula, scoop up the solution and spread it onto the plane of a wide spatula, after which the mixture is applied to the wall.

When the surface treated with the starting solution has dried, the finishing putty is applied.

Wallpaper putty, regardless of whether it is a starting mixture or a finishing mixture, must be applied in an even layer.

The final layer of putty is cleaned with sandpaper, after which excess dust is removed from the wall. Now you can start priming the wall, using a deep penetration primer.

If each action is performed strictly in accordance with the instructions, then the wallpaper on the wall will lie smoothly and last longer.

Although there are situations in which people putty the wall with only one layer of starting solution. Of course, you can do it this way, but only if the wallpaper is very thick (vinyl or non-woven).

Instead of a conclusion

So, now you know how to putty walls and you can figure out which putty will be best for walls under wallpaper in your particular case.

But for beginners, a few more practical tips will do no harm:

• the bucket for the solution should always be clean, especially for work with finishing putty - this will help prevent debris from getting into the mixture;
• the solution is prepared in small portions so that the contents do not have time to dry out;
• the walls must be primed;
• Rough surfaces are first puttied with a starting solution.

To understand which putty to choose for repairs, first consult with a consultant at a hardware store: tell us for what purpose you need the building material.

Putty can be either liquid or in the form of a dry solution - decide for yourself which form of material release is best to choose for repairs.

To perform exterior work, always purchase façade putty, because this mixture has increased moisture resistance characteristics and has strong adhesion.

Also remember that to apply the starting putty in a thick layer, you should always use a reinforcing mesh, and the second layer can be applied only after the first has completely dried.