Extruded polystyrene foam: how to insulate a balcony?

The difference between polystyrene foam and polystyrene foam

Polystyrene foam is less dense than expanded polystyrene.
The materials are similar to each other in that expanded polystyrene and polystyrene foam have a polystyrene foam base and are made from polystyrene, but using different technologies.

To make polystyrene foam, polystyrene is steamed under water steam in special molds, and the polystyrene granules are baked to each other, increasing in size. Polystyrene foam has a lower density than polystyrene foam and tends to crumble when the bond between the granules weakens.

Expanded polystyrene is made by extruding polystyrene, it is melted, a foaming composition (soft, hard freon or a freon-free hydrogen-based composition) is introduced into it under pressure, and passed through an extrusion machine.

The output is strong polystyrene foam, consisting of dense cells filled with air. Available with a smooth and stepped edge with a regular and foil surface.

The most environmentally friendly are hydrogen-based foaming compounds without the addition of freon, which tends to destroy the ozone layer.

Advantages of expanded polystyrene

Extruded polystyrene foam is the best option for insulating a balcony and has a number of advantages:

• durable, sufficiently resistant to mechanical stress material;
• has a solid structure and does not crumble;
• does not collapse due to temperature changes, can be used in the range from -50 to + 75 degrees;
• ecologically pure;
• does not lose its qualities when exposed to high humidity;
• the material is not subject to rotting processes;
• has high thermal insulation and sound insulation properties;
• It is light in weight, which is important when insulating a balcony;
• durability 50 years;
• quite low cost.

Advice from professionals

Insulation using wet facade technology is considered less expensive. Professionals often recommend this method. However, polystyrene foam is a soft material. If it is not reliably protected, dents will appear on the walls over time from accidental mechanical impacts.

Reinforcement will protect polystyrene foam from destruction

According to this technology of insulating a balcony from the inside using polystyrene foam, reinforcement is a prerequisite. The general surface is protected with reinforced mesh. In addition, it prevents the formation of microcracks in the plaster. The outer corners are covered with a perforated corner. The metal element is placed on an adhesive solution and embedded in the plaster.

Flaws

Expanded polystyrene is a flammable material.
The disadvantages are flammability, but with the property of self-extinguishing (the material can catch fire, but does not support combustion).

The surface of expanded polystyrene is destroyed when exposed to ultraviolet radiation, contact with coal resin, paint thinners, and polyvinyl chloride.

When insulating a balcony or loggia with polystyrene foam, it is necessary to cover it on top with finishing material: clapboard, MDF panels, etc. We use glue suitable for working with this material.

What to look for when choosing a material

The heat-saving characteristics are affected by the density of the material. The thicker the sheet we choose, the more area it will take up. With a sheet density of 25 kg per cubic meter, a sheet 80 mm thick will be sufficient.

If the density of the extruded material is higher, then a sheet with a thickness of 50 mm can be used.

When choosing a material, pay attention to:

• all slabs are of the same thickness, width, length;
• granules of the same size, evenly distributed;
• no foreign odor;
• packages are marked;

When using polyurethane foam, we take into account that toluene, which is sometimes included in its composition, dissolves polystyrene foam.

Methods for insulating a balcony

Insulation is carried out using the adhesive and frame method.

Glue method

Even an inexperienced craftsman can glue polystyrene foam.
Even a person without construction skills can cope with such work. We treat the surface with adhesive suitable for working with polystyrene foam, glue the insulation, and additionally fix it with self-tapping screws.

A fiberglass reinforcing mesh is attached to the glue on top, then plastered or covered with the selected finishing material.

Frame method

Installation is more complex than insulation using the adhesive method. Preliminary installation of a frame made of wooden beams or metal profiles is required.

The insulation is fixed between the frame so that there is no space left between the frame elements and the polystyrene foam.

We choose insulation of the same thickness as that of the frame slats.

Pouring the floor screed

Before pouring the screed, it is recommended to cover the polystyrene foam with a layer of foil insulating material - penofol, with the metallized side up. Usually 3 mm of penofol is sufficient.

For better adhesion of the concrete screed to the surface. To prevent insulation from cracking during operation, reinforcing plastic or metal mesh can be laid on top of Penofol.

The thickness of the screed should be 20-40 mm. The balcony slab is not designed for heavy loads; you should not overload it with a heavy concrete screed when installing the floor.

Materials and tools for insulating a balcony

Before starting work on insulating the ceiling and walls, it is necessary to prepare tools and prepare materials. We calculate the area of ​​the room, purchase the material with a reserve of 10-20%.

You will need:

1. Extruded polystyrene foam, preferably with a stepped edge, so that the sheets fit better together;
2. Vapor barrier material (foiled polyethylene foam penofol or dense polyethylene film);
3. Special adhesive for polystyrene foam;
4. Polyurethane foam that does not contain toluene;
5. Wood beams or metal profiles for installation of sheathing;
6. Plastic dowels with disc head;
7. Scotch;
8. Construction level, stationery knife;
9. Drill, hammer drill, screwdriver, stapler, electric jigsaw, grinder.

Correct installation of insulation in stages

1. The room should be cleared of unnecessary items before starting the insulation process.

2. The enclosing surfaces are leveled - they should be free of screws and cracks.

3. Using fasteners (dowels), the slabs are fixed (the sheets are cut with a knife if necessary).

A disc-shaped dowel used for mounting sheets on walls (“umbrella” or “mushroom”).

The sheets can also be secured using a special mounting adhesive if the surface is pre-leveled.

5. In order to smooth the joints, you can use tape. The result will be a smooth surface;

6. The high moisture resistance of the material allows for the absence of special vapor barrier. However, if you decide to organize an additional layer, it can be made of polyethylene film covered with foil (penofol). Thus, the balcony room will be protected to the maximum from moisture. The foam layer should be oriented with the foil facing outward.

Polyethylene foam with metal tape operates on the principle of a thermos, additionally insulating the room;

Metallic tape for joining polyethylene foam film.

7. Another way to provide vapor barrier is to cover the surface with special plaster and plasterboard;

Do-it-yourself insulation of a balcony with polystyrene foam

Insulation of a loggia or balcony with polystyrene foam can be easily done with your own hands. Before starting work on insulating the loggia, we install the balcony frame and prepare the surfaces that will be insulated.

Surface preparation

Adhesive for expanded polystyrene
Before insulating a balcony or loggia with expanded polystyrene, it is necessary to repair and prepare all surfaces. Only after this should we begin insulating the loggia with polystyrene foam.

Preparation stages:

1. We carefully inspect all surfaces for smudges and yellow-brown spots.
2. We remove the swollen, peeling layer of building materials.
3. We treat the surface with an antifungal compound and prime it to increase its strength.
4. If the balcony is leaking, we find even the most microscopic cracks and fill them with polyurethane sealant.
5. If the cracks are large, we widen them with a grinder, look at the condition of the reinforcement, remove rust from it, and cover it with an anti-corrosion compound. We wet the cracks (for better adhesion with foam), fill them with polyurethane foam, when the foam dries, cover them with sealant.
6. If desired, you can align the walls and ceiling. If the surface is not leveled, the finishing will hide all defects.

For insulation, you can use types of polystyrene foam:

• Styrofoam;
• penoplex;
• foil polystyrene foam.

Sheathing the ceiling

We begin insulation work from the ceiling. The optimal thickness of the insulation sheet for finishing with clapboard or plastic is 50 mm with a density of 15 kg per square centimeter. Under the putty, insulation with a density of 25 kg per square centimeter is used. On the top floor, you can perform external insulation of the top slab and insert insulation under the roofing material.

Stages of indoor work:

1. We mark the locations of the fasteners, install hangers for fastening metal profiles (when installing wooden sheathing, mark the installation locations of the sheathing).
2. We treat the surface with a special glue, in a dotted manner, and apply a strip of glue along the edges of the sheet. We glue the insulation, pressing it tightly, hold it for several minutes, and strengthen it with self-tapping screws.
3. If plaster is to be applied on top, after the glue has hardened under the polystyrene foam, glue the reinforcing mesh onto it.
4. If the finishing is done with wooden lining, plastic or MDF panels, we attach a vapor barrier layer to the foam plastic.

Materials with a foil surface have good quality characteristics; they simultaneously have thermal insulation and vapor barrier properties, and are attached with the foil side facing out.

Wall insulation

Following the ceiling, we insulate the walls. The internal wall that adjoins the room does not need to be insulated. But if you insulate, then the room will be warmer, and if you do not insulate, then the heat from the radiator in the room will pass to the balcony, and it will be warmer on the balcony. For more information about insulating walls with polystyrene foam, see this video:

We insulate the walls according to the same scheme as the ceiling; we begin to attach the sheets from the bottom level. These works are performed easier and faster due to the fact that the work is not done at height.

We lay the insulation tightly to each other; if a gap has formed between the sheets, blow it out with foam. We cut the outer slabs to the required size with a stationery knife. If the sheets do not fit together in the corners, fill the gap with foam. The last step is to insulate the window slope.

The best option for a vapor barrier material is penofol on an adhesive base, with a top foil layer. The edges of the penofol are glued end to end and insulated with foil tape. If penofol does not have an adhesive base, it is secured with special glue.

We attach the outer trim at a distance of 20 mm from the foam foam to form an air gap between the materials. This distance is optimal for the foil layer to reflect heat into the room.

Floor insulation

We lay expanded polystyrene on a concrete screed or between wooden joists, polystyrene foam only between wooden joists. Before insulation, it is necessary to repair the balcony slab; it can be preventive or major, depending on the degree of its destruction. For more information about floor insulation, watch this useful video:

The floor of the balcony should be either at the same level as the floor of the room, or lower.

Stages of work:

1. We remove the old covering from the floor, remove all loose, swollen building materials, and remove dust using a vacuum cleaner.
2. We inspect the slab. After treating all the cracks (with cement mortar, tile adhesive, sealant), we prime the surface to increase its strength and proceed to insulation.

Insulation using concrete screed

We level the floor using a screed, wait until the screed is completely dry, this can take up to several weeks, depending on the temperature and humidity in the room. On the screed that has dried to the ground, we cover it with a waterproofing layer, lay polystyrene foam on top of it, and a vapor barrier layer.

Then fill the thin screed with a self-leveling mixture or lay an OSB board. We lay the finishing coating on top. This can be laminate (you need to lay a backing underneath), linoleum, parquet, ceramic tiles. For more information about concrete screed, watch this video:

Floor insulation using joists

Wooden logs are attached strictly level to the prepared surface of the slab, and polystyrene foam is laid between them so that there is no gap left at the edges.

All gaps between the floor elements are filled with foam, without toluene in the composition, vapor barrier material, OSB board, floor covering are laid: floorboard, laminate, parquet, linoleum.

Using wooden joists you can raise the floor to the required height.

By insulating the floor, ceiling and walls on the balcony, you can turn it into a full-fledged living space and get a cozy corner for relaxation.

Installation

It’s up to you to choose exactly how to attach polystyrene foam. Installation with glue is much easier, but fastening with screw cutters is several times more reliable. But if we talk about these two methods, then they are both very good for fastening. The main factor in repairs is the sequence of actions; first of all, you should insulate the ceiling, and only after that the walls and floors.

Before you start laying polystyrene foam, attaching it with glue, you must cut out the sheets of the required size. After preparing the glue, as it is written in its instructions, you need to spread it on the tiles you cut. Then you should glue the polystyrene foam to the desired surface, and then wait until the glue has completely set and dried. After all the work done, you need to further strengthen the tiles. This should be done correctly like this: drill the tiles along the dowels, then you need to fix them with self-tapping screws.

Following additional strengthening, all existing seams need to be sealed. Seams that are less than 4 centimeters in size must be sealed with polyurethane foam. If the seams are larger, it is better to seal them with pieces of insulation. Having completed all the previous work, you need to cut the reinforcing mesh and apply it to the polystyrene foam. You will also need to apply a protective layer of glue on top and, after complete drying, thoroughly clean the surface with a sanding knife. Only after insulation with extruded polystyrene can you safely finish your balcony or loggia.

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