How to prevent cracking when decorating walls and ceilings

Recommendation points

• Painting glass mesh
• How mesh reinforcement works
• How to apply fiberglass mesh correctly
• Fiberglass painting
• “Cobweb”
• Flizelin painting (painting canvas)
• Glass fiber

Even the highest quality and most expensive modern materials for finishing the surfaces of the facade and interior tend to deform. In this article, we will talk about painting reinforcement materials that can extend the life of repaired surfaces..

To prevent cracks during the drying of the material, as well as to mask structural cracks, materials based on fiberglass are used – reinforcing mesh, fiberglass (fiberglass) and non-woven.

Painting glass mesh

Mesh reinforcement is an integral part of all “wet” facade works and some interior ones. It is produced in rolls of 20-50 m, width – 1 m. The cost depends on the density of the material and the presence of polymer impregnation. The work of this material in the layers of the “pie” is divided into two stages:

1. The first. Keep the material dry.
2. Second. Keep it during operation during temperature extremes, moistening and drying. Prevent temperature erosion.

The main indicators of this material are fiberglass density and cell size. The higher the density, the stronger the mesh. The smaller the mesh, the softer and more pliable the canvas – this quality is important when finishing bends, circles and wavy surfaces. The thickness of the thread also matters – thick threads for facades, thin ones for interior work.

Application area depending on cell size:

• 2 mm – masking tape 30–70 mm (serpyanka) for gypsum board joints;
• 2–5 mm – planes of walls and ceiling of the interior,
• 4–10 mm – front walls (with polymer impregnation);
• 10 mm – reinforcement of tile adhesive layers and floor coverings.

Application area depending on density:

• 25 – 40 g / m² – thin layers of interior and exterior decoration, reinforcement with paint or varnish;
• 40–90 g / m² – Reinforcement of the adhesive layer for tiling, self-leveling flooring;
• 120-160 g / m² – “wet facade” on mineral wool or PPR insulation;
• 160-220 g / m2² – exterior restoration work;
• 220-330 g / m² – device of anti-vandal shock-resistant coating.

According to the quality, the mesh yarns are divided into:

• painting – thread thickness 0.13 mm, tensile strength after drying of the solution 540 N / cm – for putty;
• plaster – thread thickness 0.13–0.2 mm, tensile strength after mortar drying 900 N / cm – for plaster;
• reinforced – thread thickness 0.32–0.35 mm, impregnation, tensile strength after mortar dries up to 1800 N / cm – for places with possible settlement, facades.

Question.What is the impregnation of fiberglass mesh for??

Answer.Any solution – gypsum or cement – is an aggressive chemical environment that triggers the processes of corrosion, dissolution, decomposition of the material, as a result of which it significantly loses its strength. In the case of fiberglass mesh, this is about 50%. The impregnated mesh is not subject to the aggression of chemically active substances and retains its factory qualities after the layer has dried. For metal meshes, in these cases, anodizing (galvanizing) is used.

How mesh reinforcement works

It acts like reinforcement in reinforced concrete, pulling and holding the finishing layer and withstanding tensile stresses. In the case of use on insulation (mineral wool, expanded polystyrene), together with the adhesive layer, it forms a crust, which remains solid even when the base (wall material) moves.

How to apply fiberglass mesh correctly

First, an adhesive layer is applied, and then the mesh is gently embedded in it. This can be done with any convenient tool – a simple spatula, rubber or wallpaper, plastic scraper.

Council. Use a tool without sharp corners to avoid unpleasant snags during work.

A common mistake is that sometimes the mesh is first glued to the surface with PVA-type glue, and after drying, it is putty with glue *. In this case, the mesh is useless – its threads are already enveloped with PVA glue and the layer that needs to be reinforced will no longer hold onto them. Moreover, the glue becomes an unnecessary layer between the adhesive and the base, and deprives the “cake” of the necessary adhesion to the base.

* – adhesive (starter) composition (layer) – in this case and further – “wet” material, prone to cracks during drying, which must be reinforced. It can be tile adhesive, putty, waterproofing.

Attention! Reinforcing fiberglass mesh is not a binding factor between the adhesive layer and the surface to which it is applied. The mesh exhibits its design qualities only when it is completely inside the adhesive layer..

After embedding into the starting layer, wait until completely dry and putty the surface again. This is necessary to protect the mesh from possible oxidation in contact with air, water. Table of dependence of price on indicators:

Index	Unit rev.	Manufacturer
X-Glass, Belgium	X-Glass, Belgium	X-Glass, Belgium	Ceresit CT-325, Germany	Ceresit CT-327, Germany
Density	g / m2	35	160	115	160	280
Cell	mm	2×2	5×5	10×10	5×5	8×8
Thread thickness	mm	0.13	0.32-0.35	0.32-0.35	0.3	0.3
Depravity *	N / cm	270	840-1000	1400-1600	1200	1800
Impregnation	–	Not	Not	there is	Not	there is
Appointment	–	Inside.	Facade	Reinforced	Facade	Facade, anti-vandal
Price	RUB / m2	8	25	20	18	28

* – flat strength index in solution after drying.

Fiberglass painting

It is a fiberglass cloth. Release form – rolls 1х50 m, tape 30–70 mm. Depending on the density, three subspecies are distinguished: “cobweb”, non-woven and fiberglass.

“Cobweb”

Low-density universal reinforcing fiberglass. It has a chaotic structure of cells and threads, which allows it to be used as a decorative layer for painting. Purpose, scope and application method are the same as for interior paint.

Question.Is there a fundamental difference between “spider web” and fiberglass mesh for interior work?

Answer.Despite the fact that they are made from the same raw material, they are completely different products in terms of functionality. The fiberglass mesh “holds” the adhesive crust from cracking when the base moves. Fibers “spider web” move together with the base, preserving the outer layer due to their chaotic structure and location in the structure of the material.

The density of the “cobweb” – from 25 (ceiling) to 65 (walls) g / m2².

Flizelin painting (painting canvas)

It is an intermediate option between the “cobweb” mesh and fiberglass, both in properties and in price. It is made from the same raw material – fiberglass. Its main advantage and difference from its “fiberglass counterparts” is its ability to withstand significant stretching. It is reasonable to apply it in places with large cracks, where they are likely to develop. Available in rolls 1×25 m.

Advantages:

• stretches better than others
• reasonable price of material
• low price and moderate consumption of glue
• low consumption of painting materials
• smooth texture

Disadvantages:

• less grip
• not suitable for finishing putty
• few paint cycles

Non-woven fabric has a density of 120-160 g / m² and is used for wall and ceiling decoration.

Glass fiber

They are a continuous non-woven fiberglass canvas without cells. Can be smooth or have a variety of textures in a monotonous pattern. It is used for interior work under the finishing putty or painting with water-dispersion and acrylic paints. Release form – rolls 1-1.2×10-20 m.

Application area. Residential and public buildings. Only for interior work in rooms without significant changes in humidity and temperature. Pasting of any leveled surfaces (walls, ceilings), on sealed cracks.

Mechanical properties. Since the material is solid and is not intended for reinforcement, it does not have working indicators of strength, impregnation, and does not differ in the thickness of the thread. The main difference between fiberglass (besides the pattern) is density. Usually this figure lies in the range of 120-190 g / m2².

Note.Like any moving material, glass fiber has its own tensile limit, after which a rupture occurs. The higher the density of the material, the greater the margin of safety before rupture. Thin solid fiberglass (120-150 g / m²) is only suitable for stable surfaces. If a slight mobility (shrinkage, shrinkage) of the base is expected, it is better to choose a denser material (150-190 g / m²) or painting non-woven.

The method of applying glass wallpaper is fundamentally similar to the gluing of paper wallpaper (in the joint). In this case, glue is used on modified starch or polymers. It should be noted that such glue is quite expensive, and this sometimes pushes the owners (on the advice of friends or the “master”) to save money in the wrong place and stick expensive wallpaper using the “putty” method. For the avoidance of misunderstanding, we will not describe this method. The most reliable way to protect yourself from the unhealthy desire for “instant savings” is set out in the instructions on the package..

The rough surface of the fiberglass wallpaper has excellent adhesion to gypsum and acrylic materials. This allows you to apply decorative layers on them, as well as repeatedly paint..

The technology for the production of fiberglass allows us to make canvases of considerable thickness and density, apply texture to them in the form of drawings, patterns, company logos or family coats of arms. Accordingly, the price of such custom wallpaper reaches 1000 rubles per 1 m².

A summary table of the dependence of the price on the density of fiberglass hosts:

Name	Manufacturer, country	Density, g / m2	Price, rub / m2
“Cobweb”
“Gossamer” 25	X-Glass, Belgium	25	nine
“Gossamer” 50	X-Glass, Belgium	50	eleven
“Gossamer” 25	Oscar, Russia	25	15.5
“Gossamer” 50	Oscar, Russia	50	16.5
Non-woven
Non-woven 50	Fliz, Germany	50	thirty
Non-woven 120	Fliz, Germany	120	40
Non-woven 150	Fliz, Germany	150	48
Non-woven 50	Versailles, Ukraine	50	20
Non-woven 100	Versailles, Ukraine	one hundred	thirty
Non-woven 45	Wellton, Finland	45	20
Non-woven 85	Wellton, Finland	85	35
Glass fiber
Glass fiber “Small horns”	X-Glass, Belgium	120	33
Glass fiber “Large horns”	X-Glass, Belgium	190	47
Glass fiber “Rogozha average”	Wellton, Finland	110	43
Glass fiber “Yolka average”	Wellton, Finland	160	66

A material close to fiberglass in properties is non-woven wallpaper (for painting), also called “simplex”. They have a high density and decorative pattern. Combines the properties of fiberglass and glass fiber painting. Such wallpapers can be used in rooms with variable temperatures, they can withstand fluctuations in humidity (hallways, vestibules, corridors, walkways).