Seven good reasons for thermal insufflation of walls

Thermal insufflation with granular cork is an excellent choice for easy insulation of perimeter walls with empty cavities.

The choice of a thermal insulation technique must always consider several technical and economic factors: the thermal insufflation of perimeter walls is often easier to implement and less expensive than the most well-known intervention, which is that of the thermal coat. Here are seven good reasons why you should prefer blowing in perimeter walls with granular cork, to the coat.

Blowing in empty perimeter walls of buildings can have several benefits, including:

1. Improved thermal insulation: blowing in walls allows you to increase the thermal insulation of the building, reducing heat loss in winter and heat entry in summer, with a sure advantage in terms of living comfort. Thanks to the low hygroscopicity and excellent breathability of granular cork, the best thermal result will be obtained in every period of the year.

2. Reduction of energy costs: the increase in thermal insulation leads to a reduction in energy costs for heating and cooling the building.

3. Reduction of noise pollution: blowing the walls with granular cork improves the acoustic insulation of the building, reducing the transmission of external noise inside the building. The proven qualities of cork and not least its considerable specific weight, guarantee the maximum result of acoustic absorption of the walls once blown.

4. Improved indoor air quality: insufflating the walls helps improve the indoor air quality of the building, in fact with humidity and mold the bad smells that characterize poorly insulated environments will also go away.

5. Eco-sustainability: cork is a natural and recyclable material, which does not contain chemical substances harmful to the environment and human health. Granular cork is obtained from the bark of the cork oak which is removed periodically without damaging the tree.

6. Durability: granular cork is a very resistant material, which can last for many years without the need for replacements or maintenance. In fact, granular cork does not undergo settling and is not sensitive to changes in internal and external humidity.

7. Ease of installation: granular cork is a easy to install material, which can be blown directly into the empty perimeter walls of buildings through special holes: being a natural material, it does not constitute any danger either during installation or once laid for the (unlimited) time in which it will constitute the thermal insulation of the home.

Expanded granular cork

Granular cork blond

HOW TO UNDERSTAND IF THERE IS A CAVITY IN THE WALL?

Being certain of the existence of the cavity in the wall is essential to be able to carry out thermal insufflation in the most correct way possible. The cavity, in order to be blown, must also be empty: this situation is frequent in homes built in the 70s/80s, when it was thought that the air cavity constituted a valid thermal insulation.

To verify the presence and size of the cavity in the perimeter walls of the building, it is useful to make a small hole thanks to which you can be sure of the presence of the cavity and its width.

Measuring the width of the cavity is essential to estimate the quantity of granular cork necessary for blowing and to be able to precisely calculate the transmittance value once the work has been carried out.

Over the years we have seen a great variety of cavities starting from 3 or 4 cm up to 15 cm and more. Only after having carried out a core sampling can you be sure of the presence of the cavity and the opportunity to carry out thermal insufflation.

To calculate the quantity of granular cork needed, you will have to measure the surface area in square meters of the walls to be insufflated and multiply it by the width of the cavity. For example: if the surface area of ​​the perimeter walls to be insulated is 50 m2 in total and the width of the cavity is 10 cm, 5 cubic meters of granular cork will be needed (50 m2 x 0.1 m = 5 cubic meters)

MATERIALS COMPARED: HERE'S WHY TO CHOOSE GRANULAR CORK!

There are various materials available on the market presented as valid for thermal insufflation of walls, but in our experience granular cork is by far the best insulating material for healthy and long-lasting insulation. In the following list we compare some of the materials used for thermal insufflation.

CELLULOSE FIBER

Cellulose fiber is a common option for thermal insulation of perimeter walls through insufflation, but it has some disadvantages to consider:

It absorbs moisture: cellulose fiber is very sensitive to moisture and can lose some of its efficiency in high humidity conditions. In addition, if a moisture protector is not used, it can also attract insects and rodents. Granular cork does not have this disadvantage because it maintains its insulating power even in high environmental humidity conditions.

It is difficult to install: cellulose fiber is a light and soft material, which makes it difficult to work with and install correctly. In addition, it requires the use of specialized equipment and qualified personnel for installation.

It is flammable: cellulose fiber can burn easily since it is essentially paper obtained from the recycling of old newspapers. In order to make cellulose fiber partially fireproof, boron salts are added, which are however harmful to health if inhaled during the blowing operations and also afterwards.

Not suitable for small thickness cavities: the low density of the material and the physical characteristics of cellulose fiber do not favor easy distribution of the material in narrow spaces.

Cellulose fiber

EXPANDED UREA RESIN FOAM

Expanded urea resin (Urea Formaldehyde Foam Insulation) has been used in the past as a thermal insulator for blowing perimeter walls, but its production and use have been banned or severely limited in many countries due to its toxic components. In fact, expanded urea resin is a reaction product between urea and formaldehyde, two chemical substances used in the production of adhesives, paints and resins. In particular, we point out that formaldehyde was listed in 2004 by the IARC (International Agency for Research on Cancer) among the compounds of group I "certain carcinogens"

The use of expanded urea resin (UFFI) as a thermal insulator has been banned or severely limited in many countries due to its toxic and flammable properties. In particular, in the United States, the Environmental Protection Agency (EPA) banned the use of expanded urea resin in 1982, due to its possible negative effects on health and the environment. In Canada, the use of expanded urea resin has also been banned since 1980.

EU Regulation No. 305/2011 also recommends a "Sustainable use of natural resources" that includes the use of environmentally friendly raw and secondary materials in construction works. The same European regulation also recommends "the durability of construction works": this is also a further element against expanded urea resin which, having been banned in most countries, does not have data on the long-term durability of this product.

In general we can conclude that the use of expanded urea resin as a thermal insulator is no longer recommended due to the possible negative effects on health and the environment.

Expanded urea foam

MINERALISED GLASS WOOL

Mineralised glass wool is another material insulator commonly used for thermal and acoustic insulation of walls: the material has undeniable good qualities being fireproof, stable over time and not very hygroscopic.

However, there are some potential dangers and disadvantages associated with the use of this material:

Low density. The specific weight of about 35 kg per m3 denotes a poor effect for protection from summer heat.

Danger to health. Glass wool is obtained from recycled glass, a natural raw material but which, once reduced to very fine fibers, constitutes a danger if inhaled or in contact with the skin. This results in a danger both during the blowing phase and subsequently in the case of contact with the inhabitants.

Difficult to remove. In the event of subsequent renovation work, the possible removal of glass wool can certainly constitute a problem for the health of the people responsible for this task.

Glass wool also therefore presents dangers that advise against its use and that certainly make it unsuitable for DIY.

Glass wool

ROCK WOOL

The characteristics of flaked rock wool are very similar to those of glass wool. Unlike glass wool, rock wool is produced from natural rocks, such as granite and basalt. The production process of rock wool begins with crushing the rocks into small pieces. These pieces are then heat treated at high temperatures (about 1400 °C) in an induction furnace to create a molten glass mass. The molten glass mass is then spun to create rock wool fibers.

In addition to the positive and negative aspects that it shares with glass wool, we note that unlike glass wool which comes from recycled glass, rock wool consumes finished raw materials and uses a particularly energy-intensive manufacturing process, first for the transport and crushing of the stones and then for their fusion at very high temperatures.

Rock wool

EXPANDED POLYSTYRENE (POLYSTYRENE) BEADS

Expanded polystyrene is perhaps the cheapest material but it is also the worst insulating material both from a technical and environmental point of view. Its nature as a petroleum derivative makes it the most harmful material: for the use of finite energy, for the production of greenhouse gases and finally for the problems of difficult disposal that it entails.

It is also an insulator with poor chemical-physical qualities being sensitive to light and chemical agents, furthermore the low density makes it ineffective for protection from summer heat.

Styrofoam beads

GRANULAR CORK FOR EASY BLOWING, ALSO SUITABLE FOR DIY!

After having highlighted the critical points of some of the blowing materials, it is easier to compare the many advantages in using granular cork: a natural, renewable and harmless material for our health. Here are the main advantages deriving from the use of granular cork in comparison with other materials:

1. Greater effectiveness in winter thermal insulation: the high insulating power and low hygroscopicity (it does not absorb humidity) make it suitable for use even in the most critical situations, in humid locations or in contact with damp walls.

2. Greater effectiveness in summer cooling: thanks to its very high "Specific Heat" value, cork is particularly effective in protecting the home from the "penetration" of summer heat, to a degree approximately double that of other insulating materials. (below is a more in-depth explanation of what the specific heat of an insulating material means)

3. Effectiveness of acoustic insulation: thanks also to its considerable specific weight, granular cork is particularly effective in acoustic insulation, helping to reduce noise outside and inside the building and thus improving living comfort.

4. Ecological aspect: cork is a natural and recyclable material, which does not contain harmful chemicals. Choosing cork means promoting the cultivation of cork oak, a tree typical of the Mediterranean area, important for the protection of the ecosystem and for the reduction of greenhouse gases.

5. Inalterability over time: cork is a resistant and long-lasting material, which does not require any maintenance and can last for an unlimited time. Cork is certainly the insulating material that was first used in homes and that can boast a thousand-year history, in fact there are known findings of cork in the walls of Nuraghi, the ancient Sardinian constructions that date back to 3000/4000 years ago. Coming to the present day, the production of the expanded and self-glued brown cork panel certainly dates back to the early years of the last century thanks to a thermal process without the use of glues that became widespread only after the Second World War. In other words, we can safely say that cork is the only insulating material with a duration proven by time, while the other insulators are based on hypothetical estimates made at the table.

6. Versatility: Granular cork can be used in a variety of applications, including wall, attic and roof insulation, and can be used in both new and existing buildings.

7. Suitable for DIY: Unlike all the other materials examined, granular cork can be safely used even by non-specialists because it is easy to insufflate and harmless to health.

HOW TO BLOW GRANULAR CORK?

After having verified the presence of the cavity and its capacity, you can proceed with the installation of the granular cork, the work can be carried out by a specialized company or even in "do-it-yourself" mode obviously after due information on the subject and with a minimum of equipment.

INSUFFLATION FROM THE OUTSIDE

Carrying out the work from outside the home certainly has the advantage of causing less disturbance to the unfolding of daily life, but on the other hand it requires it to be carried out by a specialized company with the aid of scaffolding or other means to reach the points where the blowing is to be carried out. Even the restoration of the facade can be a non-trivial task that the same specialized company will have to complete.

INSUFFLATION FROM THE INSIDE

This is the most used method due to the fewer difficulties it involves in terms of safety and the absence of special authorizations to request. The equipment can also be smaller in size due to the less effort required and to be able to be moved easily from one room to another.

THE WORKING PHASES:

1. Drill the holes about ten centimeters from the ceiling (or a little lower if the presence of a beam obstructs the hole), the holes can be made with a special cup cutter or with a chisel and mallet, if the granular cork is blown in by means of a 5cm diameter tube the hole will be about 6cm. Drill the holes at a distance of 80/100 cm from each other.

2. At this point you can proceed with blowing the cork to fill the cavity until you see the material coming out of the adjacent holes.

3. Once all the holes have been filled, you can proceed to close them and restore the finish and painting of the wall.

THE EQUIPMENT NEEDED TO BLOW CORK

If a specialized company is carrying out the blowing, it will do so with a professional blower that can be of the fixed type (located in the truck also used to transport the insulating material), or with portable equipment, more convenient for working indoors and when the blowing takes place on the upper floors of a building.

In the absence of a professional tool, it is possible to make a homemade one that can serve the purpose very well: you need a container with a hermetic lid with a capacity of 100/150 liters and a vacuum cleaner that also has a blowing nozzle. The cork container will have an air inlet hole (coming from the vacuum cleaner's blowing mouth) and an outlet tube from which the cork will come out together with the air blown by the vacuum cleaner. As previously mentioned, the diameter of the tubes can be 5 cm, a size generally compatible with normal vacuum cleaners on the market.

A BIT OF THEORY: WHY IS THE SPECIFIC HEAT OF THE INSULATING MATERIAL IMPORTANT?

You have certainly heard about the different behavior that insulating materials have in the winter and summer periods.

In reality, this aspect is normally underestimated and little discussed considering how climate change has suddenly modified the seasons and average temperatures. In fact, in recent years we have seen increasingly milder winters and increasingly longer and hotter summers.

Why then is the summer behavior of insulating materials not given the right importance? The answer is quite simple: because it is convenient for the oil and chemical lobby to "hide" what is a weak point of all synthetic and petroleum-derived insulators.

To understand how much this characteristic is clearly in favor of natural insulators (in particular cork and wood fiber) we must explain what the Heat capacity and the Specific heat of an insulating material are, let's take the definitions from Wikipedia:

"The heat capacity of a body is defined as the ratio between the heat exchanged between the body and the environment and the resulting temperature variation. The heat capacity indicates the quantity of heat to be supplied to a substance to raise its temperature by one degree kelvin (K). Saying that a substance has a high heat capacity means that it can absorb a lot of heat by raising its temperature by a small amount."

Once we have defined what the heat capacity of a body is (in our case of an insulating material) we move on to defining the "specific heat":

The specific heat of a substance is defined as the heat capacity per unit mass of a fixed quantity of substance. It corresponds to the quantity of heat (or energy) necessary to raise, or lower, the temperature of a fixed quantity of substance by one degree.

In summary, we can say that the heat capacity is an intrinsic data of the material, while the specific heat depends on the heat capacity of the material and its mass, ultimately: the value that we find in the technical data sheet of an insulating material is generally the specific heat and is relative to the insulating material at a given density.

In the table below we can see how synthetic materials for blowing have low density and consequently a low value of Specific Heat: confirmation of the poor ability to protect from the summer heat.

CONCLUSIONS

For all the reasons given, there is no doubt that cork granular is the best material when you decide to carry out thermal insufflation in your home.

If you would like more information or a cost estimate, write to: info@biosughero.it