1. What do you need to think about before you decide to clad your home?

1.1. The most important things to know before you start work on installing or renovating cladding:

• Look for expert information on the best type of insulation for your property.
• Ask about the prices of different types of exterior wall claddings per square metre.
• Decide on the finish you want your cladding to have. Talk to an architect or a colour consultant.
• Plan to carry out the work when weather conditions are the most suitable (the outside temperature, rainfall, sunlight, and heat). 

2. Facade contractors

Cladding your home is a job you’ll only have to tackle once or twice in your life. Many contractors take advantage of this, along with the inexperience of their clients, and provide shoddy workmanship and poor customer relations (failing to meet deadlines, poor communication with the client, etc.). Once the work is finished and they have been paid, it’s often the case that they refuse to answer calls or emails so as not to have to deal with any complaints about the job they’ve done. This is why choosing a reliable contractor is incredibly important. The best idea is to send a list of all the work you want done to several building firms. Once they have sent you a quote, draw up a shortlist and ask these companies for references and the contact details of their previous clients. Select your contractor solely on the basis of references. The contractors you can find on the daibau.ng portal are all tried and tested. This is borne out by previous clients’ ratings and opinions, which are available via their profiles. When you finally do decide upon the right contractor for you, make sure to sign a contract as well.

3. Types of facade systems

3.1. The most common types of facade systems

3.1.1. ETICS (External Thermal Insulation Composite Systems)

Homeowners usually opt for ETICS. This can be thin-layered or thick-layered. ETICS is actually a multi-layered facade system that is applied directly to the exterior walls. The final layer is a render that is applied to the wall directly or over thermal insulation (non-insulated render system or insulated render system).

3.1.2. Rainscreen cladding

Rainscreen cladding is when the external wall and the finishing layer act as separate systems (i.e., there is a substructure between them). If there is an air gap between the primary wall structure and the outer leaf, it is known as a ventilated facade, while one without an air cavity is an unventilated facade.

Ventilated facade

The layers that make up a ventilated facade are the primary wall, insulation panels (waterproofing, thermal insulation, and soundproofing), an air gap with a minimum width of 4 cm, and the external cladding. The air gap between the layers helps moisture evaporate away. In the hot months, it also prevents the interior of the building from becoming too hot.

Non-ventilated facade

A non-ventilated facade consists of the primary wall, insulation, and external cladding. Since the external cladding (brick, stone, wood, aluminium, etc.) is in direct contact with the insulation, it is important to choose cladding that is waterproof and vapour-permeable so that the moisture that condenses is not retained within the insulation.

3.2. The most common types of cladding

3.2.1. Render

Rendered facades are divided into non-insulated and insulated.

The former is most often found on old buildings, including cultural monuments. Such buildings require a facade that is resistant to the elements, but without insulation. The outer walls of such buildings do not even have waterproofing. Any insulation would block ventilation openings, thus preventing capillary moisture from draining away. A standard render consists of three layers: a scratch coat, a brown coat, and a finishing coat, which contains a lime or silicone-based paint and must be breathable. The binding agent must be lime-based because it allows the outer walls to dry from the outside.

An insulated rendered facade is a multilayer facade system where the final layer (the adhesive and render) is applied directly to the insulation panels. Typically, expanded polystyrene or rock mineral wool panels are used for this. Facade systems can be thin-layered or thick-layered.

For a thin-layered system, the insulating panels are glued to the primary wall and a thin layer of mortar (3-6 mm) is applied over them. Then a reinforcing fiberglass mesh is sunk into the mortar. The mortar is sanded and painted with primer before a thin layer of coloured render finish, up to 2 mm in thickness, is applied. This type of system is used for both new builds and the renovation of older buildings constructed from a variety of materials.

A thick-layered facade system is, primarily, used for new builds. For a thick-layered system, the insulating panels are glued to the primary wall with additional anchors that hold a galvanized steel mesh, which is spread out between them. Cement mortar is then applied over the mesh. When this layer is completely dry, the final render is applied.

3.2.2. Wooden facade

Wood is an eco-friendly building material and as such has always been used in european region. As a material for cladding external walls it has numerous advantages: it is an insulator, durable, and sustainable. There are several species that are suitable for cladding. Spruce, pine, larch, and oak are most often used. Wooden cladding provides an array of attractive finishes depending on the type of cladding you choose (solid wood, engineered wood, etc.), the profile, the configuration (overlapping, board on board, with or without grooves, etc.), and the different surface finishes. Wood combines perfectly with other materials (stone, glass, render, etc.). To prevent the growth of fungi and mould, wooden cladding must always be ventilated.

3.2.3. Glass

Glass facades are popular for commercial premises, but are increasingly used for residential buildings, too. The inside of the building naturally heats up in cold season through the glass cladding; however, equally it can get too hot in dry seasons. The glass also means that the building is flooded with natural light with much less need for artificial lighting. Good quality glass cladding adapts dynamically to the varying weather conditions and the amount of light, it balances heat losses, allows ventilation, and so on. It is also vital that the facade allows for the control and management of solar gain and overheating. Choosing the right type of glass, shading, and ventilation lines will ensure optimal functionality is achieved. This type of cladding can be single or double-glazed, whereby there is an air gap between the sheets of glass.

3.2.4. Stone

Stone has been used as a building material in most european cities since ancient times, but it only started to be used in the form of cladding at the beginning of the 20th century. Stone cladding can be applied in two ways: the first is now obsolete - using cement mortar to attach the stone to the primary wall. The second way, most commonly used today, is to attach the stone as a ventilated facade. Between the stone and the primary wall, there is a frame and an air gap that allows the wall to breathe and any unevenness in the primary wall does not affect the cladding. Between the stone slats (usually 3 cm thick), there are movement joints that allow the slats to expand and contract in line with changes in temperature, and thus the supporting substructure also breathes.

3.2.5. Cement fibre board

These panels are made from cement reinforced with cellulose fibres and are available in a variety of colours. They come in different sizes and are either flat or ribbed on the back. There is a whole range of textural finishes for the front of the panels. The boards are fixed to the metal or wooden frame either with galvanized nails or screws. These boards have a number of advantages: they are non-flammable, long-lasting, and easy to maintain.

3.2.6. Panels made from synthetic materials

These panels are usually made of acrylic glass, polycarbonate, polyvinyl chloride, polystyrene, and unsaturated polyester resin. They are transparent and can be any colour. The panels themselves are lighter, thus placing less load on the substructure, which they are easily fitted to. They also offer endless possibilities in terms of shape and size as they can be cut into smaller panels, strips, and boards.

3.2.7. Aluminium

This type of facade system uses aluminium sandwich panels, which are composed of several layers of synthetic materials along with the aluminium. They include several layers of protective film, which protects the facade from external influences such as UV radiation, acid rain, industrial pollution, and various airborne particles. The advantages of aluminium cladding are numerous: it’s durable yet lightweight, it’s strong yet flexible, it’s resistance to external influences, low maintenance and versatile. The panels are fixed to the metal subframe, so they can be combined with other types of cladding, and they can be different colours, too.

3.2.8. Ceramic

Ceramic cladding is incredibly resistant to external factors and is easy to maintain. It is fitted in such a way so that the joints are either visible or invisible. However, it is not very suitable for most climates around the world because it’s prone to crack in cold weather; it’s most commonly used in regions with plenty of rain and milder winters, such as the UK or Nigeria.

4. Procedure for installing external wall insulation

If you want your facade system to last and to look good, the work will need to be done properly. As such, you must bear the following factors in mind:

4.1. Weather conditions

One of the most important factors when it comes to constructing a high quality facade system is the weather conditions when the work is being carried out. Day and night temperatures should not be below 5°C. Extremely high temperatures, precipitation, and strong winds should also be avoided.

4.2. A suitable surface

The surface onto which the facade system will be glued must be smooth. It must not deviate by more than 1 cm over 4 m, nor can it be damp due to the adhesive that needs to be applied. For new builds, it is recommended that the concrete base be left to dry for at least a month before work is started on the facade system. Otherwise, cracks may well appear and the colour won’t be uniform.

4.3. Application of glue

In order to maximise insulation efficiency and prevent the formation of thermal bridges, the adhesive is only applied to the edges of the panels and should be 5 cm wide and less than 2 cm thick when installing the facade system on concrete or brick walls. If the insulation is being stuck to a smooth substrate, the adhesive should be spread across the entire surface of the panel to a thickness of up to 1 cm. As soon as the adhesive has been applied to the panels, they must immediately be pressed against the base so as to ensure that the glue does not dry and adheres properly.

4.4. Installation of insulation panels

It is very important that the gaps between the insulation panels are as small as possible. If there are gaps between them, they must be filled with expanded polystyrene.

4.5. Installation of windows, window boards, and other elements

Windows, doors, and related elements must be installed professionally, adhering to the guidelines so as to avoid the creation of thermal bridges.

4.6. Balconies

Thermal bridges (smaller or larger gaps between the edges of the wall and the frame of the window or door through which air flows) most often occur during installation of a facade system, i.e. around balconies or windows and doors that are not well insulated, if at all. Where warm air meets cold air, condensation, moisture, and mould can form.