Not more than several decades ago, builders rarely bothered about the insulation of external utility spaces such as balconies and terraces. These days, with modern, energy-efficient construction, nobody would dare underestimate the importance of the thermal insulation and waterproofing of these element. Which waterproof membrane for a balcony is the best? How do you make waterproofing on a terrace, and what does heat insulation for a balcony involve, step by step? Here are the answers!
Why is it worth installing heat insulation for a balcony?
What is the benefit of a proper balcony insulation? It translates into lower energy losses generated by the building, as thermal bridges are not formed within the façade, doors or windows. A precise thermal insulation on a balcony means lower heating bills and achieve greater comfort in summer and winter. Both thermal insulation of a balcony and waterproofing of terraces and balconies positively affect the parameters of the air inside the building. It’s much easier to control the temperature and level of humidity in a room that’s well-insulated.
What is the importance of external waterproofing?
Balconies and terraces are structures that protrude from the exterior of the building and are particularly exposed to moisture. If the balcony waterproofing does not work properly, or does not exist at all, the walls and floors can quickly become damaged. The concrete corrodes, and as time passes, the balcony tiles start to fall off. There is a higher risk of pathogenic fungi forming in the interiors. A properly selected insulating mortar for a terrace or balcony is therefore extremely important: it protects the structural and finishing materials against the destructive effects of water.
How to insulate a balcony: the most popular materials
Due to the proliferation of new and highly efficient materials, the insulation market is enjoying a vigorous expansion, and investors, developers, and homebuilders can choose between a variety of materials designed to insulate and waterproof external structures. These include:
- Styrofoam,
- insulating mortars for balconies,
- liquid membranes, slurries,
- sealing compounds, polymer-based sealing mortars for balconies,
- polyurethane foamboards for insulating terraces and balconies.
Insulating a balcony with Styrofoam (extruded polystyrene): pros and cons
Styrofoam remains the undisputed number one choice among thermal insulation materials for insulating balconies. Which Styrofoam is the best for balconies? Insulation installers most often use XPS, which is also referred to as extruded Styrofoam. This is because it is cheap and well-proven. It also stands out by the fact that it isn’t absorbent, is lightweight, resists physical damage and withstands changes in the weather. Additionally, working with Styrofoam for insulating a balcony is quite easy; it can be successfully done even by beginner installers.
In Poland, Styrofoam is very common on balconies. However, we should note that insulating a balcony with Styrofoam, such as EPS, will not always provide the desired protection against cold and moisture. Low-quality, improperly insulated Styrofoam does not withstand prolonged exposure to high temperatures or moisture, resulting in the formation of thermal bridges. In old buildings, if we install extruded polystyrene on a balcony without a levelling screed, this will also reduce the material’s thermal insulation qualities and make the installation of other finishing materials more difficult.
Insulating a balcony with a PIR board or foam
If we don’t want to insulate our terrace with Styrofoam, we can use other materials, such as PIR foams or boards. They are more expensive than Styrofoam but are extremely durable, lightweight, and resistant to moisture and biological and chemical factors. The market offers various types of polyurethane insulation materials that enable a balcony to be insulated from the bottom, from the top and from the side of the façade. Examples include:
- EUROPIR®SL, sloped boards for insulating terraces and balconies, customised on the basis of the balcony slope, and
- a two-component spray polyurethane system called Crossin® Wall Foam, designed for sealing balconies and façades.
Waterproofing compound for balconies and terraces
How to arrest water and protect the tiles and insulation layer from damage? Which balcony insulation will protect the materials from moisture? For this purpose, we should use a special insulating compound intended for terraces and balconies. It is usually a resin-cement mortar or a liquid polyurethane rubber. How to make a waterproofing membrane on a terrace or balcony with the use of such compounds? See below for guidance.
How to use a balcony sealing compound?
How to lay down a waterproofing membrane on a balcony? The sealing compound is applied as one or two layers, as recommended by the manufacturer and with the appropriate technical gaps. A proper sealing of your balcony should obviously be preceded by adequate preparatory work, that is to say, the cleaning, degreasing and levelling of the base.
Some sealing compounds for balconies and terraces can be laid directly on a wetted floor, others are only intended for primed surfaces. We should also pay special attention to the areas of contact between the substrate, door joinery and railing. The waterproofing of a terrace or balcony should also be made with the use of sealing tapes in order to prevent the floor materials from cracking.
Insulating a balcony step by step
How to properly insulate a balcony within the area of its flooring? You should begin with levelling and cleaning the base (a level surface will allow you to insulate the balcony without a levelling screed). Then install the wall protection tapes, drip, waterproofing layer, and expansion joint.
Remember that your balcony should be insulated from the top and from the bottom. Such a double-sided insulation of the balcony slab can be made with Styrofoam or a PIR board (perform measurements to determine the thickness of the Styrofoam appropriate for your balcony: it is usually offered in sheets from 2 cm to 10 cm thick; PIR boards have a similar thickness and are also available with slopes). How to install insulation on the underside of a balcony? The material can be attached to concrete with appropriate installation adhesives. You will find detailed instructions in the manuals issued by the manufacturers of thermal insulation and waterproofing materials.
All balcony insulation layers have their specific functions. So don’t skip any of them; follow them all if you want to ensure thermal comfort and have the protection of a solid moisture barrier for many years.