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Surface priming is one of the stages of the technological chain of finishing works. It is needed often, but not always. You first need to know what composition is needed – when a deep penetration primer is needed, and when a filling, adhesive one. This is important, as improper application can cause problems: peeling plaster, bulging tiles, etc.
Types of primers and their purpose
In the description of many types of work it is written: a base primer is required. For this stage, special compositions are used, which are called a primer or primer.
What is a primer (primer) or primer composition? It is a liquid mortar that prepares the surface for the application of the next coat of finish. Moreover, the “next” can be anything, both intermediate and final. Take, for example, wall decoration – from “bare masonry” to painting or wallpaper. First, the wall itself is primed from the building material. After the soil has dried, plaster is applied. When the plaster dries enough, put the primer on it, then putty. The puttied surface is also primed, and then, after the primer layer has dried, paint or paste wallpaper. This number of coats of primer is not necessary, but an option is possible.
The primer is applied at finishing of walls, a floor, a ceiling, a facade. In general, everywhere. There are subspecies for outdoor and indoor work, there are those that are used both there and there.
Types of primers
As seen from the example, the base on which the primer is applied can be different. For example, a concrete wall and a foam block, a concrete floor, a plasterboard or plastered ceiling. They are completely different in characteristics. This means that different preparations are required, covering the problems of a particular material. To solve each problem, there are primer compositions. In general, according to the results of the action, four groups are distinguished:
- Filling. These are compounds that reduce the hygroscopicity of the base, its absorbency. Apply to highly absorbent surfaces. Designed for leveling small irregularities and filling joints in ceramic tiles, plank floors and parquet before filling. They are applied:
- under the paint to reduce its consumption and so that it lies more evenly,
- under the plaster, so that the wall does not draw moisture from the plaster composition and it has enough moisture to gain the required strength,
- on a plastered wall under tile adhesive, in order to slightly extend the “life span” of the adhesive due to the fact that the liquid will be absorbed more slowly,
- on plaster or putty before wallpapering, so that the surface absorbs glue more slowly, etc.
division according to different characteristics. May be useful
- Film-forming or adhesive. These formulations are applied to slightly absorbent substrates to improve adhesion. After drying, a sticky film remains on the surface, on which it is easier to apply, for example, plaster. As you can see, the problem is solved differently. The film-forming primer increases the adhesion ability (materials “adhere” better).
- Deep penetration or penetrating. This type of primer compositions are used for those bases that cannot be dedusted. Gypsum plasters, chalk paints and other surfaces that leave a dusty trail on hands. The task of this type of composition is to bind dust particles and ensure normal adhesion to the next layer.
Of the variety of bases, most of all acrylic primers. They fill about 80% of the market - Firming. This is a special type of primers that are used to bind loose bases. This is a subspecies of deep penetration soils, but they contain more adhesive component, due to which they bind the particles not only in a small surface layer, but also to a decent depth. They are usually used for repairs in old housing or for restoration / restoration of finishes.
There are also universal primers. They are the cheapest. The description usually contains a fairly solid list of properties. In fact, universal primers contain the least active ingredients. This is also soil, but weaker. This type should be used only if there is no urgent need for a primer. For example, under wallpaper or paint.
Problems that primers solve
Primers should ensure good adhesion of the two coats. This is their main purpose. Most often, this requires adjusting the absorbency of the substrate. The fact is that all finishing materials – plasters, putties, paints, glue – are developed for medium absorbent substrates. And there are not so many of them. More often it is necessary to adjust the absorbency. Sometimes it is necessary to reduce the absorbency, sometimes it is necessary to create a sticky film on a surface that is too smooth and / or poorly absorbent. Here are primers and solve this problem.
And yet, compounds that reduce absorbency, at the same time improve waterproofing and fight high humidity. So this is also part of their tasks. And they are also used for this.
Deep penetration primers bind surface particles. The compositions penetrate deep into loose materials to a sufficient depth – 5-7 mm and bind the particles together. Often a “side” effect is a decrease in hygroscopicity and absorbency. Often does not mean always, so check the properties in the description of each composition.
Even on the surface, after the primer dries, an adhesive film may form, since the composition that has not been absorbed leaves a sticky residue after drying. This improves the conditions for applying the next material. That is, some types of primer increase surface strength and adhesion. Some more formulations have antibacterial properties, while others are simply injected with special anti-mold or anti-fungal additives.
Sometimes a primer is used to “make friends” with cement and gypsum-based materials. Without this, there will be no normal adhesion. For example, when a concrete or cement-based block wall is going to be covered with gypsum plaster, the classic and proven solution is Betokontakt from Knauf. It is applied to almost any mineral base under gypsum materials and ensures their high-quality bonding.
Primer types
So, we came to the conclusion that when choosing a primer, it is necessary to focus on the properties of the base. According to their absorbency, they are divided into three groups:
- With low absorbency and non-absorbent. This group includes concrete surfaces, cement plasters, refractory bricks, sand concrete, expanded polystyrene, gypsum tongue-and-groove slabs.
- Medium absorbency. Ordinary brick. An ideal base that does not need to be primed. But only if the brick has not yet begun to crumble.
Wood is a complex base that requires the application of primer - With high absorbency. Gas silicate, foam concrete blocks and any cellular concrete, white silicate brick, gypsum and lime, cement plasters and mixed plaster mixes.
How to determine the absorbency of a surface? Apply drops of water to the surface and track the time for which they are absorbed. If this takes more than 20 minutes, the surface is non-absorbent, if less than 3 minutes have passed, it is highly absorbent. Everything in between is medium absorbent. In this case, you are lucky and you can do without compounds that regulate water absorption.
Now it’s clear how to choose a primer. For surfaces with low absorbency, film formers are suitable, and for those with high absorbency, deep penetration primers or fillers are used. Deep penetration is needed only if the surface is dusty, but not loose and does not crumble.
What is a deep penetration primer and how does it work?
An indicator for the use of a deep penetration primer is a dusty surface. That is, the dust cannot be completely removed. How to check it? A surface is considered “dusty” if a trace remains on the hand after being touched, even after careful and (if possible) wet cleaning. Only in this case it makes sense to use this type of primers. In other cases, it will be cheaper to use film formers or fillers.
So for what surfaces is a deep penetration primer used? For chalk surfaces, gypsum plaster before painting or wallpapering. Do I need to prime gypsum under gypsum putty? No, they get along really well. It will be necessary to process all sheet materials in which gypsum serves as a binder: GVL, GKL, tongue-and-groove plates.
Asbestos is also treated with a deep penetration primer, although it is not on plaster, but it is dusty. And also silicate blocks before applying a layer of plaster. They also leave a layer on the hand. In general, it seems clear.
Note! The surface to be treated must not be loose. There is a special primer for this, which is called strengthening. It also belongs to deep penetration soils, but contains a larger amount of adhesives (and is more expensive). If applied unnecessarily, the absorbency may be too low, leading to problems.
How deep penetrating soil works
How do deep penetration primers work? They are made on the basis of the same polymers, only modified in such a way that the particles are very small. The difference can be appreciated by comparing a soccer ball and a tennis ball. The particles in ordinary and penetrating soils differ by approximately the same factor. It is clear that smaller particles penetrate deeper.
Very small particles of the polymer dissolve, and with the liquid penetrate through the capillaries deep into the surface to be primed. After drying, the polymer particles remain in the capillaries, creating an additional crystal lattice there and reducing the porosity of the material (and its absorbency at the same time), creating additional bonds between the particles of the material. As a result, after processing, the surface ceases to “dust”.
What happens when processing with a conventional soil composition? Moisture is absorbed into the surface, and larger particles of polymers remain on the surface, only slightly penetrating inside. After drying, the polymer is concentrated in the upper small layer. This is sufficient for normal non-dusting substrates. Now, we hope, the difference between a conventional primer and a deep penetrating primer is clear.
Deep penetration primer: which is better
On the market, as usual, there are many different brands. There are Russian and imported. Of the imported ones, German Knauf, Polish Ceresit are often found. These are companies that have been on the market for many years. There are very few complaints about the quality of their products. But there are a lot of fakes and you need to know the distinctive features of authentic products well.
There are also Russian manufacturers who have also been on the market for a long time and who monitor quality – these are Eunice, Prospectors, Volma. Tellingly, the difference in price with the “Europeans” is quite small – no more than 10-15%. There are also cheaper brands, which have a more significant difference – up to 30%, but their reputation is also unstable. Yes, and if you look at the description, the difference can be found.
Deep penetration primers: characteristics, prices, consumption
| Name | appointment | binder type | For what reasons | Under what layers | Drying time | Consumption | Price | Notes |
|---|---|---|---|---|---|---|---|---|
| Ceresit CT 17/st 17 (Ceresit ST 17) | For interior and exterior use | Aqueous dispersion of acrylic copolymer | Concrete, cement-sand and lime plasters and putties, lightweight and cellular concrete, chipboard, fiberboard, GVL, GKL | screed, self-leveling floor, gypsum plaster, all types of putties, tiles, paint, wallpaper | 2 hours | 0,1-0,2 l/m2 | $10 for 10 L | Has a yellow color, paintable or light wallpaper is problematic |
| CT 17 Concentrate | For interior and exterior use | The same, but a concentrate that is diluted with water | 0,1-0,2 l/m2 | |||||
| Deep Penetration Primer Prospectors | For interior and exterior use | Styrene-acrylic dispersion with antiseptic additives | Concrete and concrete screeds, bricks, plasters, putties, GVL, GKL, TsSP | screed, self-leveling floor, gypsum plaster, all types of putties, tiles, paint, wallpaper | 1 hour | 0,1-0,2 l/m2 | Not intended for slightly absorbent surfaces, oil paint and steel | |
| Primer strengthening Vetonit Vetonit.Prim Multi | For interior and exterior use | acrylic dispersion | Concrete, plaster, brick, stone, drywall, cellular concrete, foam block, putty, cement surfaces, CSP, GKL, GLV | for painting, waterproofing, floor leveling, for acrylic, silicate, silicone paints | 1-2 hours | 0,05-0,075 l/m2 | $11,4 for 10 L | On slightly absorbent substrates can be applied twice |
| PRIMER of deep penetration before puttying KSh (10) BIRSS | For interior and exterior use | Acrylate | Concrete walls and ceilings of normal and increased strength (weakly absorbent), gypsum board, gypsum board, plaster (except polymer), | Before puttying or applying water-dispersion paints | 1 hour to touch | 0,2 – 0,25 kg/m2 | $9,5 for 10 L | |
| Firming KNAUF-TIEFENGRUND (Knauf tiefgrund) | For interior and exterior use | Polymers | Gypsum and cement plasters, GKL, GVL, gypsum tongue-and-groove boards, gypsum and cement screeds | Putty, paint, wallpaper, tiles | 3 hours | 0,1 kg/m2; | $12 for 10 L | |
| Priming compound for deep penetration of LNPP | For outdoor work | acrylic dispersion | Foam concrete, aerated concrete, old plaster, concrete and brick surfaces, gas silicate, cinder concrete, plaster | Under subsequent finishing layers | 4 hours | 0,16 kg/sq.m. | 2$ for 1 liter | Do not apply on poorly absorbent substrates, lime plaster and whitewash |
| Bolars | For interior work | Acrylic | All types of cellular concrete, cement-sand screeds, plasters (except polymer), fiberboard, chipboard, brick | For mortars, paints, finishing materials | 1 hour before next coat and 2 hours for other materials | 0,08 kg / m2 | $7 for 10 liters | Use gloves, goggles, respirators |
| VD AK 0301 | For indoor work, for outdoor work (different compositions) | acrylic dispersion | On mineral surfaces | For painting, tile, wallpaper, putty, for applying to concrete floors | 24 hours | 0,08-0,1 kg/m2; | from $7,6 to $12,7 for 10 liters depending on the type | There is antiseptic and old paint |
| Volma Universal | For interior and exterior use | Styrene-acrylate dispersion | Tongue-and-groove slabs, GKL, GVL, cement screed, putty, brick | 2,5 hours | 0,1-0,15 kg/m2; | $9 for 10 liters | On highly absorbent aerated concrete substrates. apply two layers of foam concrete | |
| Glims (Glims-Grunt Prime) with antiseptic additives | For interior and exterior use | Brick, concrete, foam concrete, plaster, putty, drywall, asbestos cement | Plaster, putty, glue, paint | 30 minutes to next coat | 0,08-0,2 kg/m2; | $10 for 10 liters | ||
| Birss primer M (strengthening, stabilizing, frost-resistant) | For interior and exterior use | Acrylic copolymer | For plaster, putty, brickwork | 20 hours | 0,15-0,2 kg/m2; | $9 for 10 L | Not recommended for polymer plasters and putties | |
| Unis (Eunice) with antiseptic | For interior and exterior use | polymer dispersion | Concrete, plaster, aerated concrete, gypsum plasters, bricks. gas silicate, GVL, TsPS, tongue-and-groove plates, | For painting, plaster, wallpaper | 30-40 minutes before the next layer and several hours for subsequent works | 0,15 kg/m2; | $6 for 10 L | Works with wood, does not allow efflorescence on brick |
| 2-in-1 Deep Penetration Primer TEX Universal | For indoor and outdoor use, for walls, floors, facades | Polymer | Wood, concrete, drywall, plaster | For painting, wallpaper | 30-40 minutes | 0,07-0,2 kg/m2; | ||
| Perfect expert | For interior and exterior use | Polymer | Concrete, brick, cellular concrete, cement and gypsum plasters and putties, GKL, GVL, TsSP, paint, wood, tiles | Plasters, putties, tile adhesives, water-based paints and varnishes, self-leveling floors. | 1 hour | 0,15 – 0,2 l / m2 | $7,3 for 10 l | |
| Optimist (anti-bacteria) | For interior work | acrylic latex | Concrete, plasterboard brick, gypsum, cement plaster, mineral and wooden surfaces | Varnishes, paints, including water-dispersion | 30 minutes to the next coat of primer and 2 hours completely dry | 0,1 – 0,25 l / m2 | $6,3 for a 10 l canister | |
| Optimum Leningrad paints | For interior work, for walls | Acrylic | Concrete, plaster, drywall, brick, wood | Water-dispersion paints, tile adhesive, wallpaper | 0,07-0,2 kg/m2; | $4,3 for 5 liters |
As you can see from the table, it will not work to say that there is no difference between more expensive and cheaper brands. Even according to the description of the surfaces on which the composition is applied. There are significantly more surfaces in more expensive formulations. Well, you have to look at the quality. But usually cheaper ones are taken for applying paint (if it is not expensive), for wallpapering, etc. For more critical areas – such as plaster, putty, on complex bases – they prefer not to take risks and take products from trusted companies. A perfectly reasonable approach.
Rules of application
The rules for applying soils of any type are similar. A deep penetration primer is also applied to a dry, clean substrate. Dry is a residual moisture of the order of 3-5%. Clean – no oil and dirt stains, flaking materials. That’s just “dust-free” – this is not for this case. Although all dusty particles must be removed. If dusty work was carried out, we pass the walls with a brush, sweep the floor, wash it if necessary and wait for it to dry.
Next, soils are applied to warm bases. We look at the minimum allowable temperature in the description, but usually it is not lower than 10-15 ° C, but there are frost-resistant compounds. They can be applied to surfaces with a temperature of +3°C. Note. This is the surface temperature.
Compositions can be applied with a brush, roller, spray gun, spray gun. Some of them contain a coloring pigment that allows you to control the application. But in some cases – under paint or light wallpaper – the presence of pigment can interfere, as it can distort colors. Therefore, under the finishing light materials we take a transparent or white primer.