Do-it-yourself facade insulation with foam plastic: technology, photo, video

To reduce heating costs, many owners of houses and apartments are thinking about insulation. One of the possible options is to insulate the facade with foam plastic (PPS or EPS). The work is not the easiest, but you can do it yourself. It is important to know the technology. About it in detail, in detail and we will tell further. 

EPS or EPS (styrofoam or extruded polystyrene foam)

Insulation of the facade with foam plastic begins with a solution to the question: what is still better to use, foam plastic (PPS) or extruded polystyrene foam (EPS). Both of these materials are made from the same starting material (polystyrene), but they are used by different technologies. It is hardly worth going into the intricacies of the processes, it is important to know the main differences between these two materials. So, in short:

• Styrofoam is softer, absorbs moisture, insects and rodents like to huddle in it. With good characteristics, it has a low cost.
• XPS is more rigid and dense, practically does not absorb water, insects and rodents do not like it. Its main disadvantage is its high price. In the case of wall insulation from the outside, there is one more minus – its pre-treatment is necessary (it is necessary to scratch the surface), and this is time.

There is one more plus of EPPS – usually plates are made with a quarter, that is, there will be much fewer direct joints during insulation, which means fewer cold bridges. The choice is not easy, especially when you consider that the price difference is substantial – 2 times. To make it easier to decide, several positions at the prices of EPP and PPP are shown in the table.

Having decided on the type of material, you can proceed with the installation.

Preparatory work

Insulation of the facade with foam plastic begins with the preparation of the walls. Let’s say right away when it is better to start work – in the warm period of time. But the most important indicator is the humidity of the walls. They must be dry. After rain, it is advisable to wait a week for dry, preferably windy, weather. After that, you can start.

Exterior wall preparation

Preparation for the insulation of the facade with foam plastic begins with the cleansing of everything that peels off and falls off. If the walls were covered with paint, it is removed, the lime is cleaned off. If there are swollen places of plaster or tiles, they upholster it. Only that which is firmly held should remain.

Then it’s time to level the walls. It is very good if the insulation boards lie on the wall with the entire surface, without voids. But such walls are more an exception than a rule, therefore irregularities of about 1 cm per square meter are acceptable. Large protrusions and pits in depth / height must be leveled – filled with plaster (preliminarily primed) or cut off. The smoother the surface, the easier the job will be.

To prime or not

It is not necessary to prime only those walls, running a hand over which, the palm remains clean. If there are white marks, pieces of plaster, sand, etc., it is better to prime. This will ensure better contact of the adhesive with the wall. The operation takes a little time, is carried out simply, requires little money, and the benefits from it are great. So if you are doing the insulation of the facade with foam plastic or EPS “for yourself”, it is better to prime it.

Any primer is suitable for facade work. Normal firms are Ceresit, Master, Stolit, Chrysel, Tokan, Ekomiks. The primer is diluted or not – depending on the form of release and instructions, applied with a brush or spray. A sprayer is faster and easier, but a brush is better.

EPS preparation

If you decide to insulate the walls from the outside with expanded polystyrene (EPS), its surface must be made not so smooth. Polyfoam has a looser structure and does not need preliminary preparation. On the surface of the EPS, scratches must be made, otherwise it falls off the glue.

They take a spiked roller, which is used to process drywall, and they are well rolled in all directions. The second way is to take a brush with metal bristles and make a groove with it. Softer methods don’t work. The work is not hard, but it takes a lot of time. It must be done before you start installing polystyrene foam on the walls. If the insulation will be laid in two layers, it is necessary to process sheets for both layers.

Finishing window sills, slopes, low tide

All elements – window sills, slopes and ebb (drip) are best installed before the installation of insulation on the walls. When installing, you must remember that you will still have a solid thickness of insulation + finish. If the window sills and slopes have already been installed, they will have to be replaced – they will be too short. To make everything look organic and easily fit into the insulation cake, the elements should have the following dimensions:

• The window sill should protrude 3-4 cm beyond the plane of the wall (more or less is not necessary). If the thickness of the insulation is 60 mm, you will need a window sill with a depth of 100-110 mm (60 mm insulation, 10 mm finish, 30-40 mm ledge). When installing a window sill, all voids must be filled. You can lay thermal insulation plates, fill the gaps with mounting foam and lay a window sill on all this, load it with something heavy and leave it for 3-4 hours.
  

• When separating the slopes, they should protrude beyond the plane of the existing wall (without insulation) by 1 cm. So it will be easier to join it with insulation. They put it on glue (the same one that will be used when insulating the facade with foam). There is another subtlety here: for finishing the slopes, a heater of smaller thickness is required – 20-30 mm maximum. A thicker one will simply “climb” onto the glass (do not forget about the presence of finishing layers, we leave about 10 mm on them).
• Between the base and the insulation, an ebb is installed (also called a “drip”). This is a galvanized steel strip with powder coating. It is mounted on the plinth with self-tapping screws or dowels (depending on the material of the plinth) in increments of 20 cm. It is sold in pieces of two meters, during installation one piece overlaps the other by 10-15 cm. into the house, and merged into the street.
  

As you can see, preparatory work before insulating the facade with polystyrene foam (polystyrene) also takes time. They are not difficult, but significantly affect the overall result.

The technology of mounting foam on the walls

For a normal result, the foam is first glued to the walls, then nailed. Exactly so, and not otherwise. Gluing starts from the bottom, usually from the left corner. If the house is insulated with polystyrene foam, then the first row is supported by an established ebb, if thermal insulation is improved in an apartment building, the starting bar is nailed. Without it, there is a high probability that the foam will crawl down.

Materials and Tools

To stick the foam on the walls, you will need two spatulas. One is about 100 mm wide, the second is 180-200 mm. Narrow pick up glue from the container, wide apply it to the walls. You may also need a saw with a fine-toothed blade to cut the material. Of the tools at this stage, everything. You will still need glue. It requires a special one, the bag should say “for polystyrene boards” or something similar. There are two types of this glue:

• Universal composition for polystyrene and subsequent facade finishing (mesh gluing and leveling layer).
• Composition only for gluing polystyrene on walls. Other layers require universal.

If you approach the issue from an economic point of view, it is more profitable to buy two different compositions – the universal one is decently more expensive. And glue can do a number of operations:

• glue polystyrene to the wall and on the slopes;
• grease the joints of the insulation;
• lubricate mounting fungi;
  

The list of works for which universal glue is needed is as follows:

• gluing the mesh to the corners (and slopes too) and walls;
• applying a leveling layer.

The consumption of both compositions is approximately the same and amounts to 4-6 kg per square meter. Consumption may be less if the walls are initially even and a smaller layer of glue is required (no need to level the depressions). The consumption for the leveling layer (after gluing the mesh) depends on how evenly the polystyrene is fixed, whether its corners stick out or not.

For the second stage – fixing polystyrene on the walls – fungi will be needed. These are specially shaped dowels with a large plastic cap and a long leg. Steel or plastic dowel-nails are inserted into the dowels. When insulating the facade with polystyrene, it is better to use plastic ones. They do not conduct cold, are not subject to corrosion, cost less, and a large insulated facade does not create a load.

To install the fungi, you will need a drill and a hammer. To apply the mesh and leveling layer, you will need another wide spatula – 300-350 mm or even more. To grind the leveling layer, you will need a plastic float and sandpaper with a grain of 400-500.

Technique for gluing polystyrene on walls

The glue is closed with water according to the manufacturer’s recommendations (stir with a drill with a nozzle or a mixer). It is more convenient to work when it is a little thicker than it turns out if you follow the recommendations. Therefore, we do not add a little less water, and there we look at how convenient it is to work.

If the wall is uneven, apply glue to the wall. This makes it easier to correct unevenness – put more in the recesses and less on the humps. If there is too much hump left to reduce the consumption of glue, a notch can be made in the foam. With EPPS, such a trick will not work.

The solution is laid in “flat cakes” up to 9-10 in area, and a roller (may not be continuous) is made approximately along the perimeter of the plate, stepping back 3-4 cm from the edge. The sizes of the cakes are not necessarily the same. It is only important to level the surface as much as possible. Having laid out the glue, we apply the foam, press it down, clap it with the palm of our hand (not hard, so as not to wrinkle). Sausages laid out along the edges can crawl out of the seams or “swim” under other sheets. The fact that they crawl onto other sheets is normal and even good, it will hold on stronger. But the glue that came out is better to pick up. Then there will be less alignment.

There is a second technique – apply glue to the foam, level it with a comb (notched trowel) and glue it like that. But this method is only suitable for flat facades without drops.

When laying the second row, the sheets are positioned so that the seams are not continuous (with an offset, such as brickwork). All subsequent rows also make sure that the seams do not match. We leave the foam glued on the facade for 3 days – the glue dries approximately as much. In the meantime, glue it on the second section.

A few words about how it is more convenient to glue the foam on the facade and what kind of area. If a private house is insulated with polystyrene foam, the areas of work are significant, as is the height. Some of the work will be done from the ground, some will have to be carried out from the scaffolds. To carry them less, it is more convenient to carry out work in sections. One section is done completely – from gluing the foam to the leveling layer, proceed to the next. In this order of work, there is another plus: less polystyrene remains open (it does not react well to ultraviolet light).

We nail foam plastic (EPPS)

So, after the glue has dried (3 days have passed since it was glued), we take plastic fungi (those that are more expensive, they are hard and clog well). Their length depends on the thickness of the insulation. To it (thickness) must be added 4-5 cm, on which the fungus must enter the wall. If you have a foam layer of 50 mm, then the fungi should be no shorter than 9-10 cm.

One plate requires 5-6 fungi. In selected places, holes are drilled (drill 10 mm) 2-3 cm deeper than the length of the legs of the fungus. If the holes are made shorter, they become clogged with material dust and do not fully insert. The location of the fungi is one in the center of the plate and several at the joints. This position allows, when nailing the foam, to level the wall at the same time (pull the coal into the desired position).

A fungus is inserted into the drilled hole, then driven in with a hammer. His hat should lie tightly on the insulation. If it does not lie, we take it out, deepen the hole. Sometimes after a certain amount of installed fungi, they stop clogging. So the drill has worn off – it has become smaller in diameter – and it’s time to change it.

The fungi are hammered so that the hat is slightly recessed in the foam – it goes somewhere by 1 mm. Then the consumption of glue on the leveling layer will be less. Styrofoam is easy to score, with expanded polystyrene (EPS) it is more difficult.

If there are two layers of insulation

If the required insulation thickness is more than 50 mm, but less than 100 mm, two layers are applied. In this case, one layer is glued, as described above, the sheets of the second are positioned so that they do not coincide with the joints of the first. When sticking the second layer, it is more convenient to apply glue to the sheet, and not to the wall. The joints of the first can not be rubbed or foamed – they will overlap.

If there is time, before applying the second layer, it is advisable to wait until the first one dries. If this is not possible, you can immediately glue the second one, but to a height of no more than 2 m, otherwise the sheets may move.

We begin to nail the foam plastic with fungi after the glue has dried (the same 3 days). Just do not make a mistake by calculating the length of the fungus – the total thickness of the insulation + 1 cm for glue + 4-5 cm into the wall. The depth of the hole is another 2-3 cm more, the diameter is the same 10 mm. When the foam is nailed to the facade, you can move on.

Sealing joints and fungi

First, we level the section of the facade pasted over with foam. Often it turns out that the edges of the foam stick out somewhere. They can be cut with a clerical (wallpaper) knife. There are also special graters for foam. They are easy to level the surface. With EPPS, you can also try to do this, but only with a knife, and then it is cut badly. The work is time-consuming, but it is worth spending time on it – this will greatly reduce the consumption of expensive compositions for subsequent layers of finishes.

Then, to prevent the ingress of cold air between the plates, the seams are overwritten. They take on a spatula the same composition with which the foam plastic was glued to the facade, fill the seams. If there are seams larger than 3 mm, we lay a narrow strip of insulation in them, then rub them with glue. You can fill the seam with mounting foam. Leave it for 4-5 hours, then cut off the excess with a knife and rub it with glue on top. The caps of the fungi are recessed, we also cover them, aligning them with the main surface.

When grouting seams and caps, we try to make the surface even – the glue should not protrude. If you looked somewhere, after drying we take a grater, fasten sandpaper (grain 400-500) and level it. You just have to wait until it dries completely – once in wet glue, the emery instantly clogs, it only needs to be changed (the mesh is not suitable for this work).

Reinforcement and plaster foam

Sometimes the insulation of the facade with foam plastic must be stretched for two seasons – left to overwinter at some stage. It can be left without harm to materials only after applying a leveling layer. Simply attached foam (EPS) cannot be left. It is recommended even packed in packs to keep indoors, and not on the street. So you can only stop after plastering.

Reinforcing mesh sticker on the corners

The mesh is used for facade, for outdoor work (the inner one will simply crumble from the glue). Density 140-160 gr/sq. m. First glue the corners. All corners are reinforced – both external and internal, and slopes. Important! From this point on, it is necessary to use a universal composition, and not the one on which the foam was glued. The glue is diluted a little thinner than indicated in the instructions – it should hold well on the spatula, but be easily squeezed through the mesh.

For reinforcement, you can use a ready-made corner with a mesh, you can cut strips from a roll (30 cm wide) and glue them. It is easier to work with a ready-made corner, cheaper – with a piece of mesh. If you make from a roll, cut strips across the roll, you will get pieces of a meter length. Fold them in half lengthwise and press the fold well with a spatula. It is necessary to fold so that the edges of the mesh are wrapped inward (it was also in a roll). If it turns out the other way around, they will stick out of the glue layer, it will be hard to work.

In any case, the work is almost the same. A strip of mortar 6-7 cm wide and 2-3 mm thick is applied to the corner on both sides. If you glue not a finished corner, but bent strips of the grid, then the length of the area filled with mortar should be 5-7 cm shorter than the cut piece (93-95 cm).

An angle or a piece of a bent mesh is attached from above. Passing a spatula along the grid, we slightly press it into the glue. Herringbone movements – from top to bottom and to the side.

Approximately half of the mesh on the sides remains without glue. This is normal – it will be easier to join it with the foam reinforcement in the plane of the wall. Also, a strip at the top remains without glue if you glue from pieces. When sticking the next piece above, apply glue directly to this “empty” grid, cover it with the next piece from above. So the joint is the same thickness as the entire corner.

When forming a corner, we try to make it even. If it doesn’t work with an ordinary spatula, you can take an angular one (pictured above). It will not be difficult – just with one push to lead from top to bottom.

Styrofoam reinforcement on walls

Polyfoam and XPS are reinforced by applying a layer of plastic mesh, which is pressed into the adhesive (universal). The procedure is as follows:

• Apply a layer of glue (universal composition) to the wall with a spatula (width not less than 350 mm). The width of the strip is 5-7 cm narrower than the mesh (the mesh is usually 100 cm wide).
• Roll the mesh from top to bottom, so that 5-7 cm from one edge are free of glue.
• They pass with a spatula along the grid, pressing it into the glue. Trying to make the surface even.
  

  

• The second strip of glue is applied, starting from the “empty” mesh area. A new piece of reinforcement is superimposed close to the already laid one. It turns out at the junction of two layers of stacks, but the thickness of the glue is the same as on the rest of the wall.
  

  

The glued mesh is left to dry. It should take at least half a day, and preferably a day. After they take a grater with emery and smooth out all the bumps.

Styrofoam plaster (applying a leveling layer)

The technique of applying plaster on polystyrene foam is no different from the standard one (see here about wall plastering). The thickness of the leveling layer is determined based on the result of the previous work. If the previous layer was applied evenly, the leveling layer can be very thin – a few millimeters.

There is only a feature – the mixture should be slightly watery. A little thinner than when applying the grid. This consistency is easier to level.

The applied leveling layer is left to dry. Time depends on temperature and layer thickness. Wait until it dries completely, otherwise the emery will clog. By the way, at this stage it is better to use it already shabby – the surface will be smoother. There are some good scratches from the new one. This is critical if you plan to simply paint the facade further, and you can work with a new one under the application of decorative plaster.

This completes the insulation of the facade with foam plastic. Next up is finishing work. What they will be – you choose.

The video shows all the steps. There is only one mistake: when sticking the mesh, it rolls out onto the laid layer of glue, and not onto a dry wall. With this technology, as in the video, there is a high probability that the entire trim will fall along with the mesh.