Do-it-yourself balcony insulation: step-by-step instructions

Recommendation points

By insulating the balcony, we create a buffer zone on the path of cold air to the living quarters, add a few square meters to create a storage room, or even a small room – but this is if you connect a heater. In our step-by-step instructions, we will tell you how to properly insulate a balcony with your own hands and what materials are used for this.

Do-it-yourself balcony insulation: step-by-step instructions

Balcony insulation begins with checking the supporting structures. To do this, it is advisable to look at the balcony slab from the balcony of the neighbors below: if the beginning destruction is visible with the naked eye, then you can strengthen the concrete and reinforcing layer as shown in the figure. If you doubt the strength of the slab and the ability to carry an increased load of glazing, insulation, floors, it is better to seek expertise. Although, as practice shows, balconies can easily withstand increased load and collapse – fortunately, this is an extremely rare exception to the rule..

Balcony slab repair a – concrete is knocked down in damaged places. b – the surface is cleaned and repair compounds are applied: 1 – contact layer; 2 – anti-corrosion protection; 3 – repair mortar; 4 – leveling putty

Before starting work, you need to remove the old finish and frames (if any), clean all surfaces from decaying elements, if necessary, make a small concrete screed or fill up the cracks in the slab with concrete mortar.

Insulation works can be divided into:

  • outer skin;
  • glazing;
  • internal insulation;
  • finishing.

Outside parapet siding

The easiest way to make external balcony cladding is vinyl siding..

Outside the parapet, a vertical sheathing is assembled so that it forms a single flat area (check with a stretched thread). The bars or metal profile of the battens are fixed at a distance of about 40 cm from each other. Further, along the lower and upper perimeter, guides for siding (closing profile) are mounted, and the corners are made out with a special vinyl profile – “outer corner”.

Installing lathing for siding

The siding starter bar is attached with the long side to the lower rail using self-tapping screws. Better to start from the side wall – and the panel is shorter and less visible from the street – you can practice. Soft mineral wool slabs can be placed between the siding and the balcony grating. At the top of the parapet, you need to mount a drainage.

Finishing the balcony with siding outside

A very short video about the main stages of cladding:

Balcony glazing

Glazing is an obligatory stage of balcony insulation. In this case, you can independently make frames from wood, aluminum or steel profiles (corner, profile pipe) and glaze, or you can purchase ready-made double-glazed windows. The first option will be cheaper, but it is more time consuming and, most importantly, it will only slightly increase the temperature on the balcony in winter. You are unlikely to succeed in sealed windows without the use of insulating glass technology; they will have to be insulated for the winter or not, and leave the balcony, in principle, cold, which will only reduce the wind load. So it is better to order ready-made double-glazed windows for glazing.

If the balcony was not glazed, and you are not insulating the loggia, then the parapet for installing the frames is most likely missing or insufficient. You can create a retaining wall in the form of a reinforcement cage with concreting or brick. To lighten the structure, expanded clay can be poured into concrete, reducing the overall load. The top of the parapet must also be reinforced with a metal profile..

Strengthening the balcony parapet

If the protective grill of the balcony is strong enough, and the double-glazed windows are single-chamber, aluminum are very light, then wooden boards under the window sill, which are attached to the upper part of the grill, can act as a support.

If the balcony has a small area, then you can weld a frame on brackets that protrudes beyond the concrete slab. In this case, the window sill will not “eat” the valuable volume of the balcony. Such a balcony device is called a takeout..

Removing the balcony

After that, the window sills and the frame of the future glazing are installed – without frames and sashes, which will be mounted later. For this, the metal structure is welded to the metal profile of the parapet and supports fixed to the neighbor’s balcony slab from above. If you live on the upper floor, the structure will be more complex, since you will have to make a canopy-roof, for example, from corrugated board, polycarbonate, etc. In this case, the racks should be more durable.

Balcony glazing

After the frame is fixed, the upper drainage (visor) is mounted and the double-glazed windows are installed according to the instructions.

Installation of double-glazed windows

For the features of glazing small balconies without increasing the area, see the video:

Insulation of the balcony from the inside

From the inside, the balcony is insulated from the walls, floor and ceiling. For this, you can use various thermal insulation materials..

Balcony insulation materials

Thermal conductivity of building heat-insulating materials differs within wide limits, therefore it is impossible to name the recommended thickness unambiguously. For information, see how the optimal thicknesses differ to achieve the same thermal resistance when using popular materials.

Thermal conductivity of various building materials

The basic requirements for materials also include:

  • long-term strength;
  • non-hygroscopicity;
  • fire safety.

Most often used:

  • mineral or stone wool – fiber insulation;
  • lightweight polystyrene and Penoplex (different types of expanded polystyrene) – plate materials;
  • polyurethane foam or “Penoflex” – polyurethane foam.


Sometimes a composition of these materials is used..

Fiber insulation is easy to install when it is made in the form of soft slabs or blankets with a foil surface.

Minvata in slabs

Polyurethane foam is applied using special, preferably professional equipment.

Thermal insulation of a balcony with polyurethane foam

To compare the consumer properties of materials, we have summarized their main characteristics in a table.

Thermal conductivity coefficient, W / mK Water absorption coefficient,% by weight Density, kg / m3 Flammability group according to GOST 30244-94
Glass wool 0.037-0.041 up to 70 11-100 NG (non-combustible material)
Minvata (basalt) 0.041-0.044 up to 7 20-200 NG (non-combustible material)
Expanded polystyrene (foam) 0.033-0.037 1.5-3.5 11–35 G1 – G4 (depending on the brand)
Extruded polystyrene foam (“Penoplex”) 0.028-0.032 0.1-0.4 30–45 G1 – G4 (depending on the brand)
Polyurethane foam 0.023-0.04 1-4 20-100 G1 – G4 (depending on the brand)

Stages of insulating a balcony from the inside

Now that we know the main properties of heat-insulating building materials, we will consider the order of work..

Advice!If lighting or connecting heating devices is supposed to be on the balcony, make the wiring to the lamp, switch and outlet in advance by placing the cables in plastic boxes. So the wiring will be hidden, which is much more attractive than open wiring..

Before work, make sure that dust, small particles of insulation or mortar do not pollute the apartment – cover the openings with film.

Floor insulation

Insulation should start from the floor. First, a layer of waterproofing should be laid on the balcony slab. It can be ordinary polyethylene or foil insulation. At this stage, the waterproofing material can also be fixed to the walls..

The use of foil insulation

Further, logs are mounted from wooden beams 100×60, and thermal insulation is laid between them – fibrous or slab. Make sure there are no voids that form bridges of cold.

Balcony floor insulation

To protect against condensation, a vapor barrier is laid on top. If you purchase an embossed film, then you need to lay it with the embossed side up.

The subfloor is completed with 10 mm plywood in two layers. It is attached to the lags with screws. Instead of plywood, you can use sheets of fiberboard or chipboard.

Ceiling insulation

Apply a layer of antiseptic to the cleaned ceiling. For thermal insulation, you can take foil-clad mineral wool or foam. A good solution would be to use penofol – a foam material covered with aluminum foil, which is glued to PVA, and nailed on top with a crate for attaching the finishing layer of finishing – a type-setting ceiling, drywall or siding.

Penofol on the balcony ceiling

Styrofoam can be fixed to the ceiling with foam.

Insulation of the balcony ceiling with penoplex

Minvata is laid on a plasterboard false ceiling, which is fixed on a frame made of an aluminum profile or a wooden bar 40×40 mm.

Insulation of the balcony ceiling with mineral wool

If required, fix the lamps.

Wall insulation

The waterproofing was already performed at the first stage, therefore, a vertical or horizontal lathing from a bar is immediately mounted on top of it. The distance between the bars is equal to the width of the insulating material. For walls, it is better to use expanded polystyrene or mineral wool plates.

Insulation of balcony walls with foam

PPP can be glued to special glue or foam, be sure to blow it out all joints and cracks.

A vapor barrier film is fixed on top of the insulation.

Finishing work

There are many materials that can be used to decorate a balcony. This is drywall, which can be plastered or covered with wallpaper, and tiles, and vinyl siding, and lining.

Finishing the balcony with plastic panels

Most balconies are equipped with stationary or mobile clothes dryers that can rise to the ceiling.

Ceiling dryer on the balcony

If the space allows, compact furniture or transforming furniture can be installed on the balcony: folding tables and seats, and some lucky owners of wide balconies even equip a sleeping place. The window sill can be made wider and turned into a table top – for morning coffee or doing chores.

If desired, you can install a fan heater on the balcony, which will allow you to use additional space in spring and autumn, or install an electric convector, which will make the balcony all-season for equipping an office or a winter garden there..

Heating the balcony with a convector

In conclusion, we invite you to see photos of the design finishes of the balcony space – for inspiration and a source of ideas.

Balcony interior design

Balcony interior design

Balcony interior design

Balcony interior design

Balcony interior design

Kitchen on the balcony

Balcony interior design

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