Is it possible to insulate walls with foam plastic from the inside and in what situations is it better not to do this

Foam plastic insulation applied from the inside of walls can be a tempting way to increase comfort and energy efficiency in your house. Because of its superior thermal insulation qualities, foam plastic can help cut down on heat loss and energy costs. However, not every circumstance calls for the use of this insulation technique.

It is crucial to take into account the unique circumstances of your area before choosing to use foam plastic. The local climate, pre-existing wall structures, and moisture levels are a few examples of the variables that may affect how successful or problematic this insulation technique is. Unsuitable installation techniques or environmental factors may occasionally result in problems like trapped moisture, which over time may harm your walls.

This post will discuss when it makes sense to insulate interior walls with foam plastic and when it might be preferable to use other techniques. Comprehending these factors will facilitate your decision-making process and guarantee that your insulation project efficiently fulfills your requirements.

The advantages and potential disadvantages of using foam plastic for interior wall insulation should be carefully considered. Foam plastic can act as an effective insulator in your home, increasing comfort and energy efficiency. This approach might not be appropriate in every circumstance, though. For instance, foam plastic may result in issues like mold growth or diminished wall integrity in homes where there are moisture problems or wall structure compromises. Knowing these elements will enable you to assess whether this insulation technique is appropriate for your particular requirements.

Foam plastic: characteristics and common misconceptions

The clear answer to the question of whether foam plastic can be used to insulate walls from the inside is that it certainly can. However, a lot of people still maintain that doing this is not desirable. Many of the myths and legends surrounding this substance date back to the turn of the 20th century, when polystyrene foam was primarily utilized to protect goods during transit rather than as insulation.

The name of the foam from earlier has been replaced by many other changes in production technologies. Many people still think in stereotypes, though. Let’s examine the most widespread misunderstandings about this subject.

Stereotypes and myths

• Foam is highly flammable and can cause a fire, and also, it independently supports combustion. This was the case before. Indeed, the old foam easily flared up at the slightest contact with fire, but today fire retardants are added to its composition, which at high temperatures break down the insulation into water and carbon dioxide, due to which foam not only does not contribute to the spread of fire, but also prevents it.
• Foam loses its shape at high temperatures. Nothing of the sort. Modern polystyrene foam has a temperature range from -40 to + 80 degrees, that is, it can be used as insulation in any climatic zones, from the far north to the far south.
• Rodents start up in polystyrene foam. This problem was relevant 20 years ago. Manufacturers also knew about it, and now they add a special substance to the composition that repels mice and rats.
• Polystyrene foam has a persistent chemical smell that is impossible to remove. This is also a relic of the past. Previously, ammonia was used in the production of polystyrene foam, which formed granules after evaporation. It was this that left behind an unpleasant odor. Today, ammonia is included in the list of substances hazardous to health and is prohibited in production. It has been replaced by freon, which leaves no traces after evaporation.

Crucial! There are no restrictions on the internal insulation of walls using polystyrene foam, but only if the product bears the PSB-S marking on the label (the final letter denoting the presence of fire retardants in the composition). Although polystyrene foam without fire retardants is less expensive, it is not safe to use as wall insulation.

As you can see, there are a lot of false beliefs, and none of them are accurate. Naturally, there are many drawbacks to this material, which we will discuss below, but for the time being, let’s focus on its benefits, which are what make polystyrene foam so widely used.

Do you still have concerns about foam made of polystyrene? Then, we recommend that you view the production process video in this article. You’ll see that this content is entirely safe after watching.

Advantages

Since polystyrene foam does not grow mold or mildew, it can be utilized in moist areas.

• Relatively low price. On the market of insulating materials, polystyrene foam is one of the cheapest. Considering its heat capacity.
• Light weight. Polystyrene foam does not create a load on the walls, so it can be used on lightweight partitions.
• High degree of heat capacity. Polyfoam can even be used to insulate the walls of a loggia (see. Do-it-yourself finishing and insulation of balconies and loggias), and if installed correctly, it completely eliminates cold bridges.
• Waterproofing. Styrene insulation materials are not able to absorb moisture, and they are not afraid of even long-term contact with water, not to mention condensation.

• Resistance to mold. Since polyfoam is a product of the chemical industry, fungal and mold spores cannot develop on its surface.
• Durability. Considering all the above characteristics, we can conclude that walls insulated with polyfoam will last for decades.
• Ease of installation. Below will be given detailed instructions for working with this material, but for now we note that it is very easy to install it yourself, and what is important is fast.

If it weren’t for a few drawbacks that must be acknowledged in order to retain objectivity, foam plastic could easily be regarded as the perfect material given the list of advantages.

Disadvantages

• Lack of vapor permeability. Mold cannot grow on foam plastic, but it can find its place on the wall itself. And all because foam plastic will not allow moisture to evaporate from under its surface.
• Need for additional insulation of joints. Foam plastic is produced in the form of simple sheets, without grooves and ridges, therefore, in order to eliminate cold bridges, the joints between the slabs will have to be processed additionally.
• Slab thickness. Due to the porous structure, the thickness of a foam plastic slab is rarely less than 5-10 centimeters, which means that you can insulate the walls with foam plastic from the inside, but only on condition that you are ready to sacrifice 30-50 centimeters of the room area.

As you can see, foam plastic offers far fewer drawbacks than benefits. To be fair, we will provide a small table where we attempt to compare the primary technical attributes of foam plastic and mineral insulation materials:

Counseling! Make sure the walls are mold-free before applying foam insulation to them from the inside. A specific impregnation using an antiseptic in the composition needs to be applied if there is condensation on the surface.

Installation of foam

Installing foam insulation on walls doesn’t require any specialized knowledge or costly tools.

In light of everything mentioned above, it is concluded that the question of whether foam can be used to insulate walls from the inside is closed. It is feasible, yes. Selecting the installation technique is the only thing left to do. First things first: there are two of them, and which one to choose is solely based on the distinctive qualities of the walls.

Method one: with dowels

We witness an example of how to prevent the destruction of polystyrene foam by repairing it with dowels with plastic caps.

Particular plastic dowels with a wide cap are available for fastening insulating materials. Their lower portion expands in a pre-drilled hole when hammered into the wall, pressing the plate firmly against the base. These dowels can be used to fix soft insulation materials like mineral wool in addition to polystyrene foam because of their wide cap.

We recommend watching the video on how to insulate walls from the inside using polystyrene foam with your hands in order to avoid focusing on the simple fixing process. The installation is demonstrated in the video to be completed quickly and without the need for specialized training.

This is the only method of fastening, by the way, if your home has wood walls. Additionally, the wood must be carefully stained with a special impregnation to prolong its service life and stop it from rotting from condensation before insulating wooden walls from the inside with foam.

Method two: on glue

The second way is even easier to use than the first. It is perfect if you need to use foam plastic to insulate brick walls from the inside. After applying glue to the plate, it is pressed against the base.

You will need to hold the sheet pressed for a while because the setting time is approximately five minutes. The installation time will be impacted by this, but other than a trowel and a construction spatula, no other tools are required.

Incidentally, the adhesive used for installation works well for insulating joints as well. Following the fixing of all the plates, glue is applied to the joints and allowed to dry. After that, you can complete the finishing touches.

In some circumstances, insulating walls from the inside using foam plastic can be a useful way to increase thermal comfort and energy efficiency. Many homeowners choose it because of its good insulation qualities and ease of installation.

Nonetheless, there are situations in which this approach might not be the best. For instance, using foam plastic in older buildings with moisture problems could make matters worse by retaining humidity inside the wall, which could result in the growth of mold and structural damage.

Furthermore, using foam plastic for insulation may not solve the root causes of serious problems with your walls, such as poor ventilation or cracking. It’s critical to evaluate the general state of your walls and, if necessary, take professional advice or alternative insulation techniques into consideration.

Video on the topic

Insulation of a house with EPS and PPS. Where it can be used, and where it is PROHIBITED.

Mineral wool or Foam Plastic? When the insulation will pay off? BUILDING FOR OURSELVES

It is impossible to insulate wood with expanded polystyrene or foam plastic. Everything is smart

House insulation. TOP – 10 mistakes.

Is it worth insulating the walls of a frame house with foam plastic .

Insulation of curved walls with foam plastic !!!

Insulation with 50 or 100 mm foam plastic? Which density is better – 25 or 35 kg / m.cube?

Insulation between walls. A thermal imager will show what is better: blowing foam, filling balls, mineral wool crumbs ?