Insulating a house with Styrofoam and PIR boards: what you should know

How to insulate a house?

Installing thermal insulation on new and old buildings is never easy. This is because if you intend to do it by yourself, you should first expand your knowledge about the rules of insulating buildings with Styrofoam or PIR boards and learn about the properties of these materials. Improperly installed insulation of the foundations, walls, floors or attic will soon cause the loss of heat. Thermal bridges will form in various areas, through which the heat accumulated in the building will escape outside. Improperly done insulation leads, of course, to higher heating bills and a lower heat comfort of the residents.

How to do thermal insulation with Styrofoam and foam boards? Before you start, you should read the manuals issued by the manufacturers of the chosen insulating materials. Tutorials on the installation technologies can also be found on websites of the companies that sell, install or manufacture Styrofoam and PIR boards.

How to start insulating a house with Styrofoam?

Is it possible to insulate a building by yourself, without help from an installation crew? It turns out that it is possible if you have some free time, the appropriate tools, and sufficient practical and theoretical knowledge. How to insulate a house with Styrofoam by yourself? You should start by gathering all the materials you’ll need, and to do that, you will need to determine the quantity and type of the required boards, mortars, adhesives, etc. Please note that commercially available Styrofoam is classified into several groups, each of which has a number of varieties, based on its intended use:

• façade Styrofoam,
• foundation Styrofoam,
• floor Styrofoam.

Stores offer grey (mainly graphite) and white Styrofoam with different thermal conductivity (lambda) coefficients expressed in W/(m·K). Remember that the lambda coefficients are different for Styrofoam boards intended for foundations, walls and floors. Detailed and up-to-date requirements for the thermal performance of buildings can be found in the annexes to the Regulation of the Minister of Infrastructure of 12 April 2002 on the technical conditions to be met by buildings and the site on which they are located.

How to start insulating a house with Styrofoam? You should always begin with the foundation. The foundation is the element that supports the whole structure; appropriate insulation protects the walls against cracking and keeps the heat inside the building. The next step is to insulate the façades and floors inside. For floors that separate residential rooms from non-usable attics, it is worth insulating the structure from both the top and from the bottom.

How to make a façade from Styrofoam?

In energy-efficient construction, a crucial role is played by the thermal insulation of façades. External walls are particularly exposed to extremes of temperature, moisture, UV radiation, and wind. How to insulate a wall with Styrofoam to keep the heat inside the building? You should always work from the bottom up, starting from the lower storeys and proceeding towards the roof. Prime the walls to improve adhesion of the substrate and then glue the Styrofoam onto the walls with an adhesive mortar.

Insulating a building with Styrofoam improves the thermal performance of walls, provided that you follow the rules of good building practice and apply one layer of material with a specified thickness. Which sheets to choose? It would be best to confer with an architect, who will analyse the design of your building recommend the best solution. It is also worth talking to the manufacturer’s technical advisor, who will suggest how to insulate a house with Styrofoam and which materials have the best lambda parameters.

How to insulate the foundations with Styrofoam?

For many years, Styrofoam has been used for insulating the foundations in single- and multi-family buildings. How to use Styrofoam to insulate a house; how to make an insulation layer that sits directly atop the ground? Before you use Styrofoam boards, protect the structure with a waterproofing layer in the form of a liquid membrane, tar board or bituminous mastic. Then apply the adhesive in adequate proportions on every panel of Styrofoam, attach the panel to the base and secure all of it with plastic sheeting.

Styrofoam insulation technology: pros and cons

Is it worth insulating a house with Styrofoam? It is definitely one of the cheapest and most effective methods of thermal insulation. Extruded polystyrene is lightweight, very tight, water-resistant and friendly to the environment. It’s well worth familiarising yourself with the technique of insulating a house with Styrofoam, because installing Styrofoam boards isn’t complicated and can be done successfully by yourself and without professional help.

Before you decide to choose Styrofoam for insulating your structure, you should know about a few important disadvantages of Styrofoam, such as:

• low resistance to chemicals, especially solvents,
• Styrofoam can deform at high temperatures.

Many people who don’t know how to insulate a house with Styrofoam but still decide to do it by themselves, face a lot of problems. For the most part, these problems involve boards falling off and moisture penetrating into the Styrofoam.

How to properly insulate a house with PIR boards?

Of course, Styrofoam insulation is not the only method of insulating residential buildings. What can we use instead of extruded polystyrene to insulate walls, ceilings, terraces and floors? Let’s focus on one of the most modern thermal insulation materials: polyisocyanurate (PIR) boards. They are specially profiled sheets made of a light polyurethane foam with low water absorption and a low heat transfer coefficient. How to use PIR boards? You should always follow the recommendations of the manufacturers, whose manuals explain step by step in precise detail, how to install polyurethane boards on vertical and horizontal surfaces inside or outside the building.

PIR boards and PIR foam: applications

When you search specialised websites to find the answer to the question how to insulate a house, you will find a lot of information on PIR boards and polyurethane foams. How are they different from one another and what are their applications? PIR boards are made of rigid foam and have a compact, rectangular form. They are mostly used for insulating walls, ceilings of usable or non-usable attics, flat roofs, and balconies. Sprayed polyurethane foams are semi-liquid and are mainly used for protecting roofs, foundations, floors and façades.

Insulating a building with PIR boards: pros and cons

In Poland, PIR boards are a novelty on the market of insulation materials. They stand out with their durability, high thermal performance, excellent strength parameters and low water absorption. Foam boards prove to be good both indoors and outdoors, as a substrate for floor heating systems, or on the walls. Their disadvantage is that they tend to be expensive, which discourages some investors who want cheaper options.

With your building properly insulated, you will have  warmth and comfort for years. Before you start work on installing your thermal insulation, you should check and compare the properties of different materials such as the varieties of Styrofoam or products made of polyurethane.