Which sand is better for plastering

Selecting the proper plastering sand is essential to getting a smooth, long-lasting finish on your walls. The quality of the plaster can be greatly impacted by the kind of sand you use, which will have an effect on everything from its workability to its finished look.

For plastering purposes, not all sand is created equal. Due to their distinct qualities, various types of sand are more or less appropriate for the task at hand. Knowing these distinctions will enable you to make an informed choice and steer clear of frequent problems like cracks or inadequate adhesion.

This post will examine the different kinds of sand that are available for plastering and discuss the benefits and drawbacks of each. You’ll know more clearly by the end which sand is ideal for plastering applications.

Choosing sand for the desired type of plaster

The properties and place of origin of sand vary. After this is realized, the question of what effect the plaster mortar’s sand filler’s properties have and what kind of sand is best for plastering becomes apparent. The raw materials for sand are a mixture of different shaped and sized grains (from dust to small pebbles up to 5 mm in size) that are formed during the erosion of rocks.

Sand grains serve as a tiny framework in building solution compositions, ensuring plaster solution strength and lowering cost. Crystals of binders created during a chemical reaction bind the otherwise chemically inert sand grains to one another. The roughness and shape of the grains determine the strength of these bonds and, by extension, the strength of the entire artificial stone (hardened solution). The volume of sand filler (in the solution) determines how much binder is needed.

Let’s start by pointing out that sand can be both natural and artificial.

Natural sand deposits can originate from the following sources:

• marine;
• quarry (or ravine);
• river.

Features like the sand grain shape and amount of foreign inclusions are determined by how these deposits form. In contrast to sand grains, foreign inclusions might not be as inert.

The following, for instance, are regarded as undesirable impurities:

• organic substances (reacting with cement, they destroy it);
• sulfur compounds (participating in reactions, they cause metal corrosion and cement decomposition);
• mica particles (fragile, easily weathered, poorly adhere to the base of the solution);
• dust and silt particles, clay formations (having sizes less than 0.15 mm, envelop sand grains and prevent the binding crystals from adhering to them).

GOST controls how much of these particles can be present in raw sand materials as well as the maximum amount that can be present.

By rubbing a handful of wet sand between the palms, one can ascertain the presence of silt and clay if the amount of organic matter and sulfur can be measured in a lab. The palms are not stained by clean sand grains.

The granulometric composition, or the proportion of different-sized grains, is a crucial feature.

Sand raw materials are separated into fractions based on grain size:

• large (grains from 2 to 4 mm);
• medium (particle sizes from 0.5 to 2 mm);
• small (particles within 0.25 to 0.5 mm).

Additionally, sand material can have a very fine fraction (up to 0.25 mm) for decorative compositions.

The rocks that were used to form the raw sand material determine the shade.

The bulk product’s color may also reveal the presence of specific minerals:

• reddish and orange shades are inherent in metal oxides;
• greenish or bluish shades are river sands with aluminum salts;
• quartz grains are distinguished by their white color.

Because quartz sand is a relatively rare material, its cost is higher. It is utilized for primers, such as concrete contact and certain kinds of plaster.

What does the use of river sand for plastering give

You must comprehend the characteristics of the river filler in order to respond to the question. Sand grains and larger stone fragments formed during stone weathering travel a great distance before settling in the riverbed. The grains roll and round when they are drawn to water flows. The workability of the plaster mix is impacted by this aspect of the grain shape since rounded sand grains do not stick to one another with sharp protrusions.

The second characteristic is the rounded shape, which results from the plaster mix’s lack of shrinkage. The rounded grains of the solution lay tightly as soon as it is applied, forming a skeleton that essentially prevents the plaster coating from settling during the drying and hardening process. The shrinkage value of solutions containing river filler is negligible, meaning that the fresh layer and the hardened layer have the same thickness.

This property is useful for mixing masonry mortars, creating foundations, and producing concrete screeds.

The drawback of shrinkage-free is that it necessitates a larger volume of binder. There is no way to minimize the spaces created by ramming or vibration; the spaces between rounded grains are wider than those between angular grains.

One benefit of this kind of raw material is that it contains less silt or clay particles. The drawback of such sand for plastering walls is not only that it requires more binder, but it also costs more (because of the technological aspects of extraction, like the use of hydro-washing). On unprepared bases, plaster mortar with river filler adheres less well.

Bark beetle plaster is one decorative composition that uses river filler. For the cover layer (and generally the upper plaster layers), it is preferred. By combining it with acrylic water-based paint or glue, the small portion of river sand can be utilized to make putty on your own.

Using sand from a quarry

Sand from ravines is often finer. The angular grains in the quarry material cause the solution to shrink. Granules can move when they vibrate, with the smaller ones settling into the spaces left by the larger ones. When the neighboring filler particles are drawn together by the forming crystalline bonds during the setting process, a similar image is created. Shrinkage for a layer height of 1 cm can be 1 mm.

This solution behavior is appropriate for priming and spraying during rough leveling. However, the surface won’t be level after the solution hardens if, when leveling along the beacons, a layer of 5–6 mm is applied to one area of the wall and 3 cm to another.

Quarry sand is better for plastering when it comes to processing facades or finishing utility rooms.

Material from ravines is more accessible, less expensive to mine, and cheaper. It has more clay particles and might have sulfur compounds and mica in it. As a result, buying this type of filler from a reputable manufacturer is preferable.

Gully sand grains settle more quickly in mixed plaster mortar than round river sand grains do, so in order to keep the mass homogeneous, it is advised to mix in more quarry sand filler more frequently.

A portion of the material is filled with water and a small amount of alkali is added if the quality of the quarry raw material is unknown. The sand mass is washed three times or more if it gets darker. Sifting is also required to get rid of big and foreign inclusions.

Sea sand

Natural sea sand is extracted from the Gulf of Finland and Crimea in Russia. The sand material at the bottom is being purified because it contains a variety of organic and inorganic impurities (clay). This sand costs more than other types because it requires costly purification and is available in smaller quantities. Because sea sand has superior qualities to river sand and can be used with less cement, manufacturers gladly incorporate it into their decorative plaster compositions.

Special types of sand for plasters

In construction, artificial sand filler is used in addition to natural sand. It comes from leftover material from crushing rocks. After the stone is ground, the material is separated and cleaned, yielding angular grains. A filler like that can cause significant shrinkage.

Powder-dry adhesives are occasionally applied to artificial grain material in order to improve adhesion. The grains are thermally hardened to increase the surface area and roughness required for plaster compositions. Cost is impacted by all of this.

Additionally, there are unique kinds of filler:

• barite (for X-ray protective plaster), the substance is toxic (!);
• perlite (for heat-insulating plaster).

A smooth and long-lasting finish can only be achieved with the proper sand for plastering, and knowing the differences between types such as river, pit, and crushed sand can help you get the best results for your project.

Which type of sand is suitable for plastering

It’s important for novices to know which sand is best for plastering walls.

Concrete and plaster compositions are different because the plaster material needs to fulfill the following requirements at the same time:

• the plaster layer must be vapor-permeable, for which it must have air pores;
• the solution must create a coating of sufficient strength and at the same time have minimal shrinkage;
• the composition must be both plastic and viscous (so that it does not flow down the walls during installation) at the same time.

Sand and lime are added as modifying additives to control these properties while mixing. Using the best option for sand raw materials for each layer of plaster would be correct.

• it is better to use raw materials mined in a quarry for the layers of splash and soil;
• decorative compositions, cover or top layer of soil (when plastering walls without a cover) – river filler.

Cement mortar

Cement is the binder of choice. Generally, less expensive filler is used in cement plasters; however, both river and quarry material may be used.

Pre-cleaning of ravine filler is required:

• sift through a mesh with a 4-5 mm mesh, removing large debris in advance;
• soak and stir periodically to disperse the lumps of clay (for 4-5 hours.);
• drain the contaminated water, replacing it with clean water;
• vigorously stir the mass and drain the upper part of the container"s contents into a second container;
• drain the water after settling, dry the sand.

Lime mixture

The lime itself breaks down into small particles during slaking, which gives the mortar a high degree of flexibility. Thus, when using lime mortar, even-angular quarry sand works well. It is most frequently applied to fatty limes. River material is used as filler for lean lime dough.

Clay mortar

For clay plaster, both kinds of sand material are used as filler. The mixture is worked on raw materials from unwashed rivers if the clay is lean. Quarry filler is used for highly plastic fatty clays. Samples are mixed to choose proportions.

How to sift sand correctly

Metal woven meshes with a mesh size of up to 5 mm are used to sift large amounts of sandy raw materials (a filler with 2-4 mm granules is usually used for cement mortars). It is possible to fasten the mesh to a side-by-side wooden frame. Stretching tulle or a mosquito net is an option if the volume of the sand mixture is small. For sifting, dry material is taken.

Passing sand via a sieve

Before sifting, sandy raw materials that contain clay inclusions are cleaned and dried.

Typically, sifting takes place outside. Pick a day that is dry and not too windy. Little sand grains will be separated from larger ones on the leeward side by the air flow, which will also blow out light dust particles of unwashed material.

Additionally, there are specialized installations for sifting sand; however, these should not be purchased for one-time use.

GOST standards

Two standards, GOST 8736-2014 and GOST 28013-98, outline the primary qualities that plastering sand must possess. Granular filler, in their opinion, falls into two categories:

• Class I – coarse-grained sand materials;
• Class II – fine-grained fillers, additionally having smaller fractions, for example, very fine (with grains less than 0.16 mm).

The maximum allowable amount of dangerous impurities, components, or dust particles is specified for each class.

Type of Sand	Description
River Sand	River sand is clean and free from impurities, making it ideal for smooth plaster finishes. It provides a good texture and is easy to work with.
Quartz Sand	Quartz sand has a high silica content and is known for its hardness. It is excellent for plaster that requires a durable finish, but it can be more challenging to work with.
Crushed Sand	Crushed sand, also known as manufactured sand, is made by crushing rocks. It has a rougher texture and is suitable for thicker plaster layers, but it may contain dust particles.

For plastering to be smooth and long-lasting, the right sand selection is essential. While coarse sand has a stronger bond and is better suited for external surfaces, fine sand has a smoother texture and is therefore better for interior walls.

It’s critical to take into account the nature of the project and the particular needs of the plastered surface. The quality and durability of the plaster can be greatly impacted by the choice of sand.

In the end, knowing the qualities of various sands enables you to make wise choices and guarantee that the highest standards are met by your plastering work.

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