Facade finishing is one of the most important building operations. Exterior wall coverings are exposed to atmospheric precipitation, cyclical freezing / thawing and exposure to harsh ultraviolet rays. Such difficult operating conditions put forward increased demands on the quality of the finish. It is very expensive and time-consuming to eliminate faulty façade walls. We'll have to mount scaffolding, wait for good weather, remove construction waste.
To exclude the occurrence of unpleasant situations, you need to take all measures to prevent them.
Facade reinforcing mesh
Facade wall decoration performed by various materials and technologies. A reinforcing stack is used in two cases.
To improve the performance of the plaster layer. For such purposes, it is better to use a galvanized wire mesh.
Welded galvanized mesh
Reinforcement is recommended to be used on facade walls made of foam concrete blocks, for brick walls additional measures are not required ...
The fact is that among the many advantages of foam blocks, one must definitely pay attention to one very significant drawback - low physical strength. Another problem is that concrete blocks begin to crumble during freezing / thawing in conditions of high specific humidity.
As a result, cement plaster begins to flake off with all the negative consequences.
Foam block plaster
Reinforcing mesh allows the plaster to adhere to the wall surface. Conversations that such a mesh should be used with a large thickness of plaster, which due to this, does not appear on the plaster of cracks, have only partial confirmation. Firstly, there are simpler and cheaper methods of eliminating the appearance of cracks in thick plaster. The easiest way is to cover the solution in a thin layer in several steps.
Secondly, it is possible to increase the adhesion of the solution to the facade wall due to a slight increase in the amount of cement in the solution. If this is not enough, then spray with cement milk is done.
To protect front wall heaters from destruction. Reinforcing facade mesh is used during the finishing of foam insulation boards.
Not to improve the adhesion of the adhesive to the expanded polystyrene surface and to prevent cracks, as some "sofa" builders write , namely for mechanical protection.
Why do we say so? The surface of expanded polystyrene is protected from the negative effects of ultraviolet rays and, oddly enough, damage from birds. For some unknown reason, birds are very fond of pecking on styrofoam, if you leave it unprotected, then soon many large and small depressions will appear on the surface. Conclusion - polystyrene foam needs to be closed.The cheapest and most reliable method is to use glue.
By the way, advertising characteristics of manufacturers of plastic reinforcing nets "they are not afraid of UV" do not affect their actual performance in any way.
The fact is that even the thinnest layer of glue or other cement-sand mixture does not completely transmit ultraviolet rays. Why should a consumer pay for properties that he doesn't need? And one more nuance. Most often, builders fix the reinforcing mesh on the entire wall. We think that this is done either out of ignorance of physical properties, or by a desire to earn more. We recommend using a reinforcing mesh with a height of 1.
5-2.0 meters, there is no need above. No one will damage the finishing screed so high on the foam. Mechanical damage occurs due to various shocks, careless chores near the front wall, etc.
Facade reinforcing nets are made of galvanized wire or polymers.
The former are used for facade plastering, and the latter are for universal use.
|Name||Mesh sizes, mm||Coil sizes, m||Brief characteristic||Approximate cost, rubles|
|Safety||2 * 2||1 * 50||Material of manufacture - fiberglass, used to reinforce the plaster near door and window openings, to align the joints of insulation boards||900|
|OXISS||5 * 5||1 * 50||The mesh has enhanced protection against alkalis, can withstand significant dynamic and static forces for a long period of action.||1050|
|Front glass mesh||5 * 5||1 * 50||For holding plaster on concrete facades and insulation boards. Withstands a breaking load of at least 1400 N / cm.||1400|
|STREN S5||22 * 35||2 * 25 2 * 50|| Withstands roughing and fine facade plaster up to 5 cm thick.
|CREPIX Facade 1300||4 * 4||1*50||Glass cloth, there is protection against alkalis and ultraviolet radiation.||1560|
|CREPIX Facade 1500||5 * 5||1 * 50||Reduces the likelihood of cracking due to linear thermal expansion||1970|
|CREPIX Facade 2000||4 * 4||1 * 50||For the reinforcement of finishing plasters during the finishing of the insulation layer of the facade||2300|
|Welded galvanized mesh||6 * 6, Ø 0.6 mm||1 * 15||Increased strength, resistant to atmospheric precipitation and sunlight||1110|
|Welded galvanized mesh||10 * 10, Ø 0.8 mm||1 * 15||For rough facade plasters 3-5 cm thick||1330|
|Galvanized welded mesh||25 * 25, Ø 1.0 mm||1 * 25|| For strengthening facade walls, universal use. |
Hot-dip galvanized wire, minimum coating thickness 20 μm
|Mesh CPVS||20 * 20, Ø 0.5 mm||1 * 25||Full metal expanded metal. Has an increased contact area with the facade plaster solution.||580|
CREPIX 1800 5х4mm
Plaster mesh CPVS
Modern facade mesh
Construction reinforcing mesh
Metal mesh is used only for cement-sand facade plasters, foam insulation do not get off with them. The reason is the small thickness of the screed on the foam plates.
And the metal mesh cannot be aligned with such precision; it must be pressed with a thick layer of mortar. The metal facade reinforcing mesh is able to withstand great efforts, it is used if it is necessary to apply a thick layer of plaster on an uneven base.
Metal facade reinforcing mesh
The algorithm of its fixation has several features, the implementation of which guarantees the expected effect. The mesh can be laid in both vertical and horizontal stripes. For the strength of the plaster, this does not matter, decide for yourself how it is more convenient for you to work.
How to fix the metal mesh to the front wall correctly?
Plaster metal mesh
Step 1 . Take the dimensions of the wall, cut the metal mesh along them. Select the cutting tool according to the wire diameter. Universal tool - metal scissors.
If they are not available, then a thin mesh with a wire diameter of up to 0.
8 mm can be cut with ordinary scissors. True, after that, these scissors will have to be sharpened, they will no longer cut the paper.
Scissors for metal
Step 2. Metal mesh can be fixed with dowels, the length of the hardware must provide a strong fixation.For facade walls made of foam blocks, ordinary nails 80-90 mm long can be used.
They are easily driven into blocks with an ordinary hammer, working with them is much faster and easier. Nails are much cheaper than dowels, and the quality of fixation is no different. Use dowels only on brick or concrete facade walls.
Fastening to masonry using a self-tapping screw with a widened washer
Step 3. Electric drill with a perforator drill the first hole for the mesh.
The depth of the holes should be several centimeters deeper than the length of the plastic part. Otherwise, it is impossible to insert the dowel to the required depth - the hole is slightly filled with brick chips during drilling and reduces its effective depth. It is difficult to remove it from there, it is better to drill more.
Important. The height of the protruding part of the dowels should not exceed the thickness of the plaster mortar.
Keep track of this parameter throughout the entire area of the facade wall so that you do not have to adjust the dowels during plastering.
Step 4. Drill holes in one line at a distance of about fifty centimeters, hang a mesh on each dowel. Pull it a little, do not allow large irregularities. The position of the line does not matter, it can be vertical or horizontal, depending on the method of fastening the reinforcing metal mesh.
Step 5. Check the position of the opposite edge of the grid, if it lies unevenly, then move the grid to the adjacent cells.
Fixing the plaster mesh - scheme
Step 6. Everything is normal - continue to fix the mesh, dowels install in a checkerboard pattern. Most metal meshes are one meter wide, so you need three rows of hardware to fix it.
Attaching metal plaster mesh to a brick wall
Attaching a metal mesh to wall
Important. In places where two rolls overlap, install the dowels at a distance of approximately 10 cm from the edge. On these dowels, two strips of reinforcing mesh will be hung simultaneously.
Step 7. At the places of window and door openings, the mesh is cut to size.
But it's okay if you don't cut it off, but just bend it. Just make sure that the edges of the folded sections do not protrude beyond the thickness of the plaster layer.
During the plastering of such a facade wall, the mortar must be cast in several stages. For the first time, the mass should be slightly thicker than for the final leveling. Specific values depend on several indicators and are determined individually, taking into account the practical experience of the master.
The consistency of the mortar is influenced by the weather, the ability of the facade walls to absorb moisture, the linearity of the wall, the maximum parameters of irregularities, etc.
The process of plastering the wall on a fixed metal mesh
The durability of its operation largely depends on the correct implementation of the recommendations for the installation of a plastic reinforcing mesh on a foam insulation. In all cases, do not rush, work carefully. We have already mentioned that there is no need to reinforce the entire wall in height, it is enough to protect only the lower vulnerable area. But these are our recommendations, if in doubt - protect the entire surface of the facade wall.
Any brand of glue is suitable for gluing the mesh. Read the instructions, it must have high adhesion to plastic materials. In most cases, a finishing layer of glue with a thickness of several millimeters is applied over the plastic reinforcing mesh. The topcoat is done with facade paints or a thin layer of decorative plaster.
Adhesive for gluing fiberglass mesh on the facade
Inspect the surface of the slabs. If they were fixed with dowels, then completely sink the caps and seal the indentations. You can close the slots at the same time, but this is not necessary. The fact is that the slots will automatically close during the application of the first layer.
Fastening sheets with umbrella dowels
Draw a horizontal line along the height on the wall reinforcing layer. It will help you keep track of the height of the adhesive. A thin layer of material dries quickly, and this not only causes an increase in material consumption, but also negatively affects the final leveling of the layer for painting.
Step 3. Prepare the adhesive according to the manufacturer's instructions.
Always pour water into the container first, and then add the dry mixture. This technology will greatly simplify the mixing process. You can mix it manually with a trowel or using a mixer attachment to an electric drill.
The second method is not only easier, but also more effective. Stir for a few minutes, and then leave the mixture to stand for another 5-6 minutes.
During this time, moisture will be evenly distributed throughout the entire volume, the smallest dry lumps of glue will completely disappear.
Step 4. Glue is applied to the wall with a spatula; the longer it is, the smoother the surface is. Professionals work with spatulas up to 70 cm in size, beginners can use shorter ones at first.
If you are just learning to apply glue to the surface, then it is better to immediately get used to working with both hands. One gets tired - connect the other hand. Believe me, it's not that difficult, you just need to show a little endurance and patience.
Apply adhesive to the trowel with a trowel in the center of the tool. The number will be determined empirically.
While applying the layer, hold the trowel at an angle to the foam boards, press with medium pressure. Aim for a layer thickness of about 2-3 millimeters.Do not prepare a large amount of surface at once, for beginners, two meters in dyne is enough. If you do not have time to fix the mesh, the glue will harden, you will have to remove the old layer and make a new one.
Try on the location of the plastic mesh reinforcement. If it doesn't fit into the window opening, trim the material.
Step 6. Glue one end of the mesh, align it horizontally to the length of the prepared wall section. Make sure that the mesh lies flat without distortions and bends, focus on the previously drawn line on the foam.
Practical advice. The mesh should overlap about ten centimeters. You can find recommendations to not smear the place of overlap of one line with glue, but to do it simultaneously for two rows. We do not recommend doing this, it only complicates the work. Glue the first row of mesh over the entire width at once, including the overlap.
The second line will be glued on top of the freshly applied glue. This method simplifies mesh fixation and has a positive effect on quality.
Fasten the mesh with overlapping fabrics
Step 7. Press the mesh against the fresh glue with your hand in several places, check its position again.
Cut off the excess
How the fiberglass mesh is attached to the foam
With a spatula, begin to press the mesh to the surface of the insulation. Make sure that the glue of the first layer protrudes over the entire surface and evenly covers the mesh cells from the front side. If there are places with insufficient adhesive thickness, reapply it over the mesh. Such passes may appear for inexperienced craftsmen. Over time, you will learn to determine the optimal thickness of glue by eye and there will be no more gaps.
Smear excess solution on free surfaces. You should not try to immediately make the surface perfectly flat, but you need to strive for such a result.
Mesh bonding with a trowel
Step 9. Allow the glue to dry. It is better to leave it overnight, it is recommended to finish grouting the surfaces the next day.
That's all the technology, the surface of the front wall is prepared for painting or finishing with other materials. We remind you once again that the plastic reinforcement mesh on insulated facades is used not to prevent cracks on the glue surface, but from mechanical damage to the foam. Keep this in mind when making your decision.
Compliance with safety measures during construction work on multi-storey buildings is one of the main requirements for all developers. This is especially true for objects being built within cities.
The facade mesh is fixed on the scaffolding and prevents debris and tools from falling onto pedestrian walkways. For such purposes, the cheapest of the plastic reinforcing nets is used; after dismantling, it is suitable for direct use.
Mesh for construction
Facade mesh (half-sleeve mesh)
"Emerald" - new scaffolding mesh
Is it possible to repair peeling areas with mesh reinforcement? It is possible, but it is better not to allow such situations. Unfortunately, in most cases, delaminations appear several months or years after the finishing of the insulated facade walls.
Repairing the delamination
How is the repair done?
Use your hand to check that the mesh is firmly attached next to the delaminated area. Prepare materials: glue and a piece of plastic reinforcement mesh. If the facade walls are painted, then you need to have the appropriate paint.
If the sect continues to flake off during cutting, great. You remove the entire problem area in this way, it would peel off over time anyway.
Apply the first layer of glue, sink the mesh into it and apply the second layer of glue.
Repair of the exfoliated area
How does the quality of a plastic mesh depend on its price? Almost nothing.
When choosing a mesh, pay attention to the thickness of the canvas and the size of the mesh of the mesh. All other characteristics are nothing more than advertising gimmicks of manufacturers.
Why is the plastic anti-corrosion coating of the metal reinforced mesh better from galvanizing? In addition, the price of such a mesh is higher than with galvanized wire. You need to know that the adhesion of all cement mortars to plastics is much lower than to galvanized surfaces. With regard to the service life and bearing capacity, these indicators are absolutely identical.
Metal mesh with polymer coating
Is it possible to do without a reinforcing mesh when plastering uneven facade walls? It is not only possible, but also necessary. We have already talked about simpler and more efficient methods of working with such surfaces.Reinforcement with metal meshes is used not to prevent cracks, but to increase the bearing capacity of cement-sand mortars. It is needed during floor screed. One more nuance.
The indicators of linear thermal expansion of metal and solution differ significantly. This means that microcracks will surely appear in the places where the cement and metal mesh are in contact, because outside temperatures fluctuate within significant limits. In closed rooms, there are no such fluctuations.
Should a reinforcement mesh be used on the basement surfaces of the facade walls? Use this technology only for base / plinths insulated with foam. In all other cases, it is not needed.
Photo - a pie made of insulation and mesh for reinforcement
How much does the cost of finishing facade walls increase due to the use of reinforcing mesh? The cost of finishing increases by no more than 3-5%. But if we take into account possible repairs due to mechanical damage to the foam, then a slight increase in cost is fully justified.
Posted By: Work Style |06, Nov 2020
Posted By: Work Style |04, Nov 2020
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Posted By: Work Style |04, Nov 2020