How to gradually insulate the facade of a house with polystyrene foam from the outside with your own hands. External insulation of a house with polystyrene foam - the rule of a thrifty owner Insulation of walls with polystyrene foam technology
In order for the house to be warm, it needs to be insulated correctly, you should take into account not only the thickness of the foam, but also the technology itself, following which you can achieve the best results in insulating the external walls of your facade. We invite you to read the detailed step-by-step instructions complete with photos.
Before starting insulation work, it is necessary to carefully check and prepare the base. Walls intended for gluing foam plastic must be stable, dry, free of dirt, dust, old peeling paint and other contaminants that reduce the adhesion of the adhesive solution. The ideal way to clean walls is to clean them with pressurized water or mechanically (for example, using wire brushes or sanders). In case of large accumulations of moss and algae, the use of biocides is recommended.
Leveling the base
When assessing the foundation, monitoring its condition is very important. Using a hammer, you can find a dull sound indicating peeling of the plaster. You must remove such a fragment and plaster the resulting cavity. It is also recommended to beat off the plaster from the outside of the slopes of window and door openings, thus allowing the slopes to be insulated with polystyrene foam 3 to 5 centimeters thick. If there are coatings on the base, such as paint, you should check its load-bearing capacity by scratching it with a sharp tool or gluing it with tape. If partial peeling of old paint occurs, the substrate should be considered weak and must be thoroughly cleaned. If unevenness or depressions larger than 10 mm occur, they must be leveled using a leveling solution.
Surface primer
Dusty walls should be primed with a deep penetration primer before gluing the foam.
Checking the strength of the base
If you doubt the strength of the wall surface, you should conduct an adhesion test. For this purpose, we glue 8-10 samples of polystyrene foam measuring 10 x 10 cm in different places onto a properly prepared surface. To glue foam samples, a solution of a 10 mm thick layer of glue is used. Foam samples with the applied solution should be pressed to specially designated areas on the wall surface. After a minimum of 3 days, an attempt should be made to manually tear off the glued foam. If a rupture occurs in polystyrene foam, this indicates sufficient strength of the base and adhesion of the adhesive. If samples of polystyrene foam come off the wall surface along with a layer of adhesive mass, this means that the walls were not properly prepared or that the top layer does not have sufficient strength.
Installation of the base profile
Before gluing the foam boards, it is necessary to secure the base profiles. To do this, you need to determine the height of the base using a tapping cord and make marks on the base. Then secure the profiles with dowels - on average 3 pieces are used. per linear meter. If the wall is uneven, pads should be used. It is recommended to connect profiles using special mounting clips. Plinth profiles, in addition to determining the level and facilitating the installation of thermal insulation materials, are responsible for protecting thermal insulation from open fire, dampness and destruction, insects, birds or rodents.
When installing base profiles on the internal or external corner of a building, you should pay special attention to the correct installation (see photo). It is also possible to use special connectors.
Preparation of the adhesive solution
Before gluing the foam, you should properly prepare the adhesive solution. To glue the foam, use an appropriate adhesive solution. Mix the contents of the bag thoroughly with about 5.5 liters of clean, cold water using a low-speed drill with an appropriate stirrer. After obtaining a homogeneous mass without lumps, wait about 10 minutes and mix again before using. The prepared solution is suitable for use for a period of 2.5 to 3 hours. During work, it is necessary to periodically stir the solution approximately every 30 minutes. It is not allowed to add water to the prepared solution in order to “improve” its consistency.
Applying the solution to polystyrene foam
Depending on the type of base, the adhesive solution can be applied to the foam in several ways. In the case of insulation of a flat surface, the adhesive solution is applied to the slabs using a notched grater with a tooth size of 10-12 mm. In other cases, the solution should be applied using the “circumference-point” method, i.e., using a trowel along the contour of the slab in a strip about . 3-4 cm and additional cakes in the amount of 3-8 pieces. The size of the cakes should depend on their quantity. The amount of glue located on the edge should be enough so that after pressing the slab, the adhesive solution does not go beyond its boundaries. It is necessary to ensure that the adhesive solution covers at least 40% of the surface of the slab (see the photo for the correct application of glue to the foam).
Bonding foam boards around window and door openings
Near window and door openings, slabs should be selected (cut) so that the horizontal and vertical seams between the slabs do not coincide with the edges of the holes (see photo). This arrangement will prevent cracks in the finish in the future.
Control of the plane of glued foam plastic
Please note that during the process of gluing the foam, the level and evenness of the entire surface is maintained using a plumb line or level.
Filling gaps between slabs of thermal insulation material
Gaps between the boards of more than 2 mm should be filled with strips cut from foam boards. In case of gaps smaller than 4 mm in systems using polystyrene foam boards, it is also possible to fill them with polyurethane foam. It is not allowed to fill the joints with mortar, which is used for gluing slabs, due to the occurrence of cold bridges, as well as the risk of cracks appearing along the joints of the slabs.
Leveling the surface of glued foam plastic
Foam boards after gluing must present a flat surface. Protruding irregularities (bumps) should be sanded with a special grater or sandpaper. The surface of the slabs can be sanded no earlier than 72 hours from the moment they are glued.
Fastening foam plastic using a dowel umbrella
If it is necessary to use additional protection of the foam from tearing, i.e. when the tensile strength of the base is less than 0.08 MPa or the height of the building exceeds 20 m, mechanical connections, a dowel with a plastic or metal umbrella, should be used.
Drilling holes and installing dowel umbrella
Installation of dowels can begin no earlier than 3 days after gluing the polystyrene foam boards, that is, after the adhesive solution has set.
It is believed that the depth of penetration of the rod deep into the wall should be:
- minimum 5-6 cm - dense base (concrete, brick, sand-lime brick or stone);
- minimum 8-9 cm - porous base (aerated concrete, hollow brick and shell rock).
The number of dowels for foam plastic is from 4 to 6 pcs/m². When determining the length of the dowels, you need to take into account the thickness of the old plaster, the adhesive layer and the thickness of the thermal insulation material. It should be borne in mind that, despite the load-bearing capacity of the foundation, in the case of buildings with a height of more than 20 m, mechanical connections must be used. The edge zones of the building, where the greatest forces caused by the wind occur, i.e., from 1 to 2 m from the edge, the insulation project should provide for an increased number of dowels in these places.
Installation of dowel umbrellas
The dowel rods should not protrude beyond the plane of the umbrella. The ideal option to prevent the formation of cold bridges is to mill holes to a depth of 2 cm, into which the umbrella dowel is recessed. Then the space above it should be covered with the remaining foam. The wrong thing to do is to sink the umbrella with a hammer. Excessive deepening of the umbrella in the material can lead to the appearance of cracks (rupture) of the umbrellas, which as a result weakens the load-bearing capacity of the system.
Preparation of glue for foam reinforcement
To create a layer reinforced with fiberglass mesh in a polystyrene foam system, it is necessary to use an adhesive solution designed for reinforcing foam boards. The entire contents of the bag should be thoroughly mixed with an appropriate amount of clean water using a low-speed drill equipped with a stirrer. Then the mass should be kept for about 10 minutes and mixed again. It is recommended to periodically stir the solution every 30 minutes. Depending on the temperature, the solution is usable for approximately 2.5 to 3 hours. You cannot add water to the prepared solution in order to “improve” its consistency.
The glue is applied to the foam in a continuous layer about 3mm thick. To apply the solution, use a notched trowel with a tooth size of 10-12 mm. The adhesive solution is applied in vertical strips the width of a fiberglass mesh.
Embedding fiberglass reinforcement mesh
After applying the adhesive solution to the mesh, it is necessary to carefully press it down, starting from the top, pressing it along its entire width. The mesh should be evenly stretched over the entire surface, without waves, humps or bulges. To ensure proper functioning of the layer, the reinforcing mesh must be recessed in the middle of the thickness of the solution. It is not allowed to attach reinforcing mesh directly to umbrellas or glue applied with a trowel. Immersion of the mesh too deep or too shallow can lead to cracking and the formation of humps in the reinforcement layer. The thickness of the solution layer when using one mesh should be from 3 to 5 mm.
When embedding the mesh into the mortar layer, you should pay attention to ensure that the vertical and horizontal edges of the mesh overlap each other by at least 10 cm. It is necessary to strictly follow the rules for wrapping the mesh on slopes and window sills and on wall corners - in the case of using protective corners without mesh - move the mesh to the adjacent wall by about 15 cm. If the walls of the building are subject to impacts and mechanical damage, given their location, it is necessary to apply a double fiberglass mesh along the entire height of the walls of the first floor. After the adhesive solution in which the first layer of fiberglass mesh was immersed has hardened, a second layer of solution should be applied and another layer of mesh should be sunk into it. The thickness of the layer reinforced with a double layer of mesh should be 6-8 mm.
The mesh must be carefully filled, since the leveling of the surface affects the final appearance of the facade. If irregularities occur, they must be sanded with sandpaper - otherwise they will be visible in the structure of the thin-layer plaster. Grinding can be done when the mortar layer is not yet too hard.
Application of paint and primer
After the reinforced layer has dried, no earlier than 3 days from its completion (this period can be extended in case of unfavorable weather conditions) in order to ensure optimal adhesion of the decorative plaster to the base, you can begin to apply primer paint. Work should be carried out at a temperature not lower than +5°C and not higher than +25°C, without precipitation. The primer should be applied using a brush or roller, remembering to apply it evenly over the entire surface. It is not recommended to dilute the primer paint due to the deterioration of its properties.
Application of decorative plaster
After the primer paint has dried, but not earlier than 24 hours after its application, you can begin applying decorative plaster. To prepare it, the entire contents of the package should be thoroughly mixed with approximately 5.0 liters of clean water until a homogeneous consistency is obtained. The prepared solution is left for 10 minutes and mixed again (without adding water). The solution prepared in this way is suitable for use for no longer than 1 hour.
Application of thin layer plasters
During plastering work, the requirements of the appropriate weather conditions must be observed, both during application and while the plaster is drying: avoid rain, strong winds and high sunlight. The optimum air temperature should be between 5°C and 25°C, and the relative humidity should not exceed 75%. Due to large temperature differences between day and night, plastering work is not recommended between November and March. In case of danger due to a temperature drop below 5°C, the drying time of the plaster (at least 48 hours from the moment of its application) should also not be carried out.
If these requirements are met, you can begin applying plaster to the pre-primed wall.
Using a steel float, apply a thin layer of plaster to the thickness of the grain. Then you should smooth the surface, collecting excess material. After some time, depending on the conditions encountered during the application process, we rub the plaster using a plastic float. In order to avoid a visible contact line between the fresh and already hardened layers of plaster, it is necessary to provide a sufficient number of workers and scaffolding. When applying decorative plaster, avoid interruptions during the application of the layer and adhere to the main rule “wet on wet”. Due to the increased absorption of thermal and ultraviolet radiation on facades located to the south and west, it is not recommended to use dark colors; the number of such colors on the surface of the facade should not exceed 10%.
Rubbing plaster
Rubbing the plaster should begin if the plaster mass does not stick to the plastic float. This time depends on the air and soil temperature, relative humidity and thickness of the material. To complete the texture, you need to use a plastic trowel and, depending on the structure of the plaster, we give it a suitable model. One thing to keep in mind is to press the grater with the same force while holding it at a constant angle.
Plaster type "bark beetle"
Plaster with a “bark beetle” type structure depends on the movements of the trowel. You can draw vertical, horizontal, diagonal or circular indentations of a certain width depending on the size of the crumb.
Painting plaster
The paint can be applied by brush, roller or mechanically by spraying, always in two layers. It is allowed to dilute the first layer of paint, especially if work is carried out at temperatures close to the maximum permissible (+25°C). To dilute silicate paints, use a special primer (solvent) in an amount of up to 5%, and other paints can be diluted with clean water in an amount of up to 10%.
In the case of the second layer, the paint should be used undiluted. During work, you should adhere to appropriate weather conditions, i.e. avoid large amounts of sunlight, strong winds and precipitation. The optimum air temperature should be between 5°C and 25°C and the relative humidity should not exceed 75%
Prepare your sleigh in the summer... This proverb perfectly reflects
the fact that it’s never too late to think about insulating your home, or rather, it’s better
early.
According to reviews, among the types of insulation, like
private houses, dachas and cottages, as well as multi-storey (apartment) buildings,
External insulation is in the lead. And among the materials, the absolute favorite is polystyrene foam.
We propose to understand what determines the high efficiency of insulating walls with foam plastic from the outside.
Advantages of external insulation
- The first, and most important, shift of the dew point outside the wall
(see photo). Why is this good? The fact that the house will always have a dry outer wall.
The problem with freezing will disappear by itself. In addition, moisture does not accumulate
in the wall, will not destroy it. This will allow the supporting structure to “age” for
order of magnitude slower.
- Second, the wall will accumulate heat. So after
ventilation of the apartment in winter, it will quickly restore normal
temperature. After all, the walls will release part of the accumulated heat back into the room, and
not on the street.
- Third, work can be done at any time. Their implementation
is not fraught with lengthy and expensive internal repairs and arrangement
additional ventilation.
Advantages of polystyrene foam
- the lowest thermal conductivity among known ones
modern insulation materials; - low price of material;
- low cost of labor of hired professionals;
- the opportunity to insulate yourself;
- ease of installation of foam plastic and much more.
The technology for insulating walls with foam plastic is quite simple. But
You can do the job efficiently only by knowing some of the nuances and features.
Let's look at step by step how to insulate a wall from the outside with polystyrene foam,
and what pitfalls can be encountered at each stage.
Instructions for insulating walls with foam plastic from the outside
Stage 1 – selection of material
Insulation of an external wall with polystyrene foam is a device
multilayer construction. This pie gives additional insulation
properties, in the form of strength and aesthetics. It also helps protect the material.
from the destructive influence of the external environment.
For external insulation, it is better to choose polystyrene foam of the PSB-S-25 brand.
Note: This choice is due to two factors - strength and
thermal insulation properties. Of course, material with a density of 15 will be better
keep warm. Because it has more air. But, polystyrene foam brand PSB-S-15
more fragile.
Disadvantages of PSB-S-15 foam
(when used in external insulation)
- crumbles a lot during operation;
- difficult to trim evenly;
- it is almost impossible to grate the sheet;
- plaster does not adhere well;
- The plastered surface of the wall is easy to push through.
The thickness of the foam sheet depends on:
- desired effect;
- region (the temperature in the cold month, strength
and wind direction); - the material from which the wall is made.
Nuance: insulating a brick wall from the outside with polystyrene foam
puts forward even more requirements for the accuracy of calculating sheet thickness. Because thin
layer will ensure that the dew point does not shift towards the foam, but
will remain in the wall. Then, the moisture that will collect in the brick will increase
the speed of its destruction. And if the foam layer is too thin, then in winter
the moisture will turn into ice. As a result, bubbles form on the wall, and the sheet simply
will vomit.
Advice: if the required sheet thickness is 100 mm, it is better to buy two
50 mm each. and mount them overlapping. This will eliminate cold bridges in places
joint of sheets.
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Material for external wall insulation with foam plastic
- sheets (plates) of foam plastic;
- starting profile;
- construction glue;
- dowels with a wide head (mushrooms, umbrellas).
Tip: If you use foam plastic 50 mm thick, then for
for a concrete base, the length of the dowel must be at least 90 mm, for a brick base -
not less than 120 mm. The dowel must enter the wall at least 50 mm.
- perforated corner with reinforcing mesh;
- polymer reinforcement mesh;
- profile for slopes;
- plaster;
- paint for facade works.
Stage 2 – surface preparation
The wall is inspected for defects (cracks, peeling,
biological formations – moss, fungus). The protruding parts will be further
are covered with foam plastic, and those that are poorly fixed get knocked down. If from the wall
the old plaster is coming off (flaking off), it also needs to be removed.
Sometimes there is moss on the walls - it needs to be scraped off. Paint is also removed if
there is one. And any other layer with zero vapor permeability.
If there are deep cracks in the wall, they need to be repaired. For
This is why they need to be expanded. Prime the resulting V-shaped channel. Then
close up. Sand-cement mortar and foam glue are suitable for sealing.
or construction foam.
Cracks in the walls
Technology for sealing cracks in walls
The prepared wall surface is primed.
Priming the wallsFor priming, use a universal priming solution
deep penetration. This will protect the wall from fungus and other biological
activity and will also increase surface adhesion.
Tip: The suitability of the surface can be checked as follows:
way. A block of foam plastic measuring 10x10x10 mm is glued to the adhesive solution
to Wall. Three days later it is torn off. If the block comes off completely, it means
the wall is unusable and requires further cleaning. If the block breaks but
holds, you can get to work.
Is it possible to insulate the walls of a wooden house with polystyrene foam?
It is better not to insulate wooden walls from the outside with polystyrene foam.
conduct. This is due to the fact that wood has natural moisture. For
In order for it to be able to release moisture to the external environment, it needs
insulation with a porous structure. Ideal in this case would be
mineral wool.
From a practical point of view, insulating wooden walls
polystyrene foam is possible. Provided there are no serious cracks in the tree. IN
otherwise, before starting work you need to seal them with natural
insulation - moss, felt or special acrylic sealant, allowing
seal even the most minor defects and inter-crown seams. Besides,
Installation of polystyrene foam is carried out only using the frame method.
Insulating wooden walls from the outside with polystyrene foam - pros and cons
Stage 3 – marking
In this case, marking does not mean that you need to apply
drawing on the entire wall. Such a grid will only confuse, because... sheet
foam has a tolerance of 10 mm. by 1 m.p.
But it is simply necessary to measure the horizontal and vertical. Because
that it is not always possible to match the angle, because the wall may have
minor deviations.
Stage 4 – installation of foam plastic on the wall and facade
Advice for beginners - start working from the wall that
least noticeable, this will be your training ground.
The installation of foam plastic on the wall begins with installation
starting profile. Its width is equal to the thickness of the foam sheet. Sometimes for these
for purposes, the UW-50 or 100 profile is used. These are the most popular for insulation
sheet sizes.
Nuance: Special starting (base) profile
It is better to use, because it has perforations that allow fastening
securely fix the profile, and at the same time allow its movement due to
thermal expansion.
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The starting profile is mounted according to the previously applied markings.
Its use allows you to lay the first row of sheets absolutely evenly. Except
Moreover, there is a popular opinion that a metal starting profile will allow
protect the leaf from rodents.
To level the thermal expansion of the metal, between
adjacent profiles need to leave a gap of about 5 mm.
Fastening the profile for foam insulation
The arrangement of the corner is shown in the photo
Installing a corner for foam insulation
Methods for attaching foam
The foam installation technology has several
modifications. To fix the sheet on the wall, you can choose one of three
options:
- apply glue to the edge of the sheet and make several sculpts along
leaf area. This method is suitable for uneven walls;
Method of attaching polystyrene foam to an uneven wall
- Apply glue with a notched trowel over the entire sheet. Option for
relatively flat wall;
Method of attaching polystyrene foam to a flat wall
- apply special glue from a bottle. This glue is similar
construction foam. At the same time, it is much easier to work with than with adhesive
solution. Plus, it doesn't require kneading and secures the sheet firmly to the wall.
Fastening polystyrene foam with glue from a can
The second row of sheets is laid offset as shown
below. This scheme makes installation more reliable and reduces the likelihood of
cracks
Offset foam fastening scheme
So all the rows are laid out in order down to the last one.
Tip: In order for the glue to set completely, the wall,
covered with foam plastic, it should last 3-4 days. If you perform insulation
foam plastic with your own hands, then by the end of the work the first section usually has time
stand for the right time.
Particular attention should be paid to the finishing of slopes, because this
also a source of heat loss. The finishing process in the photo.
Installation of slopes when insulating with foam plastic
The window sill will have to be replaced after installing the foam.
In order to ensure that in places where the insulation adjoins the frame
metal-plastic window or door there was no heat loss, you need to install
special window profile. Due to the fact that the profile has a self-adhesive
The strip is easily installed on the window frame. Installation process in the photo.
Installing a window profile with foam insulation
Installation of the profile guarantees the absence of deformation and a finished appearance.
Stage 5 – additional fastening of foam plastic to the wall
Umbrella dowels (fungi) for fastening foam. Reliable fixation can be provided by special plastic umbrella dowels (fungi) for fastening foam, which do not “fall through” into the sheet, but securely fix it.
There are two ways to mount umbrellas, as shown in the figure.
The first option is suitable for smooth joints. If between
There are significant gaps in the sheets, then you need to use the second option.
Note: The first option will save the dowel, but
takes time to adjust sheets to size.
Fixed umbrella dowel When installing the dowel, make sure that it is slightly recessed into the sheet.
It is worth noting that in the classic version the umbrella
mounted as shown in the photo. However, since such installation takes away
a lot of time, and the plastic dowel does not create cold bridges, this rule
neglected even by experienced builders.
Method of fastening foam plastic with “recessing” the head of the dowel-umbrella
The gaps formed at the junction of two sheets are sealed
foam. If the gap is more than 20 mm wide, the gap is sealed with a piece of polystyrene foam.
For greater reliability, the back side of the trim is coated with glue or foam.
For priming, use a universal deep penetration priming solution. This will protect the wall from fungus and other biological activity, and will also increase surface adhesion.
Reliable fixation can be ensured by special plastic umbrella dowels (fungi) for fastening foam plastic, which do not “fall through” into the sheet, but securely fix it.
When installing the dowel, make sure that it is slightly recessed into the sheet.
After sealing all the cracks, begin trimming the protruding parts of the sheet that meet at the corners.
Corners of the house or slopes need additional protection from impacts. In addition, it is difficult to ensure the required mesh overlap here. Yes, and cutting the foam perfectly can be difficult. Therefore, a special perforated corner with reinforcing mesh is provided for them.
The mesh is fixed with glue. The same one on which the foam was attached. There is a special marking on the mesh. The red stripe shows how much fabric should be overlapped. This is approximately 100 mm.
The procedure for attaching the mesh: cut a strip of mesh of the required length, plus 250-200 mm. Glue is applied to the top of the wall. The area of the adhesive strip is approximately 100x10 mm. The mesh is placed on it and pressed. Roughly speaking, the mesh should sink into the glue. 
Tip: make sure that the mesh does not bunch up. Level it with a spatula. But don't overdo it, otherwise you'll pull the entire strip down. At the bottom, the excess mesh is trimmed off. 
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