Which polyurethane foam is better: professional, household, how to choose

Fill a seam, a crack, install a window or a door block, glue insulation – for all these works and a dozen others, mounting foam is used. If you go to any hardware store, you will see at least a dozen items. And in large or specialized ones there may be hundreds. Which one to choose? What mounting foam is better? Depends on conditions, tasks and requirements.

What is polyurethane foam and how is it formed

Polyurethane foam is a foamed polymer that quickly hardens (polymerizes) in air. Release form – metal cylinders of various sizes. The cylinder contains a prepolymer in a liquid state and a propellant gas. Substances that are called “propellants” are characterized by having a low boiling point. The balloon is under high pressure. When the outlet valve opens, the compound is pushed into the lower pressure area. When exiting, the propellant boils, forming a large amount of air bubbles and blowing foam.

Further in the air, the resulting foam polymerizes – it becomes rigid and solid. The curing process requires water, so it is recommended to wet surfaces before application. Moisture is also taken from the air. Since there is little moisture in frosty air, there are certain compositions for such conditions.

Materials

Do not confuse mounting foam with glue. By the way, there is glue in similar bottles, which also foams. But there is a completely different composition and nothing can be securely glued to the mounting foam. It can support / hold in a certain position, but none has the strength of an adhesive bond. So don’t get confused. This is not its scope.

To correctly understand where you can use mounting foam, you need to know about its properties. They are pretty good too:

• mounting property. This is the binding, connection, attachment (not gluing) of parts of the structure.
• Soundproofing. It is impossible to call mounting foam soundproofing, but it reduces the noise level.
• Thermal insulation. Due to the large amount of air enclosed in thin polymer bubbles, thermal conductivity decreases.
• Good adhesion to almost all building materials. Cannot be used only with silicone, rubber, and some also with polyethylene.

The main application of building foam is installation. No wonder it is called polyurethane foam. But as a heater and soundproofing, it is also not bad. Not perfect, but not bad. Filling seams, gaps, sealing / thermal insulation of communications inputs – this is its scope. It is difficult for her to find competitors in this. How were those gaps filled in the past? They were stuffed with rags and smeared with mortar. Foam in this regard is much more convenient and has better properties.

Important features

Any type of mounting foam has two important characteristics − primary and secondary expansion. Primary expansion is how much the mass increases in volume before polymerization is completed. There are foams with both high primary expansion and low expansion. Which polyurethane foam is better – with large or small expansion? It’s impossible to say for sure. They are applied in different cases. Low expansion foam is good for filling small cavities, as well as layer-by-layer filling of deep seams, when installing XPS. Large expansion is more beneficial when filling cavities, used as sound insulation, thermal insulation.

Specifically, for the installation of windows and doors, it is better to take foam with a small expansion. And both primary and secondary. Unfortunately, this is professional foam, so you will also need a gun.

Secondary expansion is an increase in the volume of the foam after the end of the polymerization process. What polyurethane foam is better on this basis? Definitely the one with the smaller secondary expansion. Why? Because this process is difficult to predict. And the possible consequences are serious – deformation of flexible or moving parts. For example, the window frame or door jambs can buckle if the foam increases too much. And even the spacers that they put do not always help.

Why then do we need building foam with high secondary expansion? It has its own field of application – filling cavities and gaps in rigid and stable materials and structures. For example, in concrete, as an aggregate with heat-insulating properties between a wall and a brick finish. Foam with high secondary expansion is cheaper. This is important for large volumes.

Foam outlet

Another thing to pay attention to is the foam output. This is the volume that can exit the balloon. It is indicated in liters. Generally, the larger the balloon, the greater the output. But not always. With the same balloon size, the yield difference can be of the order of 20-30%. You can determine by weight. The heavier the balloon (weight indicated), the greater the yield.

What else is worth knowing that the real output of mounting foam is usually less than the declared one (more often household types sin with this). To ensure the required volume, it is necessary to accurately select the proportions of prepolymer and filler gas. And not all brands can boast of this. Here is a list of those who consistently produce the declared volumes:

• Soudal (Soudal) professional lines (not household).
• Penosil Gold and Premium.
• Moment Installation (very inexpensive and widespread).
• Wellfoam (WellFom).
• Hilti (Hilti).
• Kim Teck (Kim Teck).
• Den Braven (Den Braven).
• Illbruck.
• Tytan (Titan) (some parties either do not work at all or give out less than half of the declared).

There are probably other good brands of building foam. But it is these, according to builders, that fail very rarely. When buying, look at production date. After a year, the valve begins to poison, the filler gas leaves, the output decreases accordingly.

Note! It is necessary to work with mounting foam, which has room temperature. In cold weather, it must be preheated. Even winter or all-weather.

Types and application

All cylinders with polyurethane foam can be divided according to the field of application: household and professional. They also differ externally. Professional made for a special gun. It won’t work without it. Household ones have a pressure valve (as in aerosols) and a long thin tube. Of course, these are not all the differences. There is a difference in properties:

• curing speed. Professional ones harden faster. Some brands become hard after 30 minutes. The “normal curing time” is 24 hours. That is how much it is recommended to wait after applying the foam before continuing work.
• The amount of secondary expansion. For professional ones, it is about 30-50% of the primary volume, for household ones it can be 130-250%.
• Cavity sizes. Foam consisting of small bubbles is considered good. This is what distinguishes professional ones, although some household ones also have few large cavities. But they are not cheap either.

Of the entire list, the most annoying is a large secondary expansion. Why is it bad? The fact that when foaming windows, door frames, strongly increasing foam can bend wood or profiles. Well, and the fact that it is growing too actively, it is difficult to dose it, which leads to a large overrun. So the difference in price is, as a result, quite insignificant. If it stays at all.

When and where to use these types of mounting foam? Household foam is also suitable for filling cavities and holes in rigid structures. For example, Boxer, Ultima, Cosmoflex, Wellfom, Well. When installing doors and windows, it is best to work with a professional. These are Ilbrook, Penosil, Soudal, Titan.

Species by season

Mounting foam is also divided according to the temperature regime of application. There are the following types:

• Summer. Apply at positive temperatures, but not lower than +5°C.
• Winter. It can be used in frosts down to -18°C.
• All season. Its range is declared from -10°C to +35°C, but it is optimal to use it somewhere in the region from +10°C to zero. At lower temperatures, winter is better; at higher temperatures, summer is better.

In a heated room we use summer foam, if we foam windows in winter – winter or all-weather – depending on the temperature outside. In general, “specialized” shows itself better – summer or winter. They are adapted to certain conditions, and this is always more reliable than the universal option (all-weather).

When working in winter, do not leave the foam in the cold. Bring in warmth. If it is supercooled, it will be too fluid, will not hold its shape. In general, we always keep the foam warm. And yet – more foam comes out of a warm balloon.

By combustibility

Mounting foam must also be selected according to flammability. It has three classes:

• fuel – on the cylinder is B3;
• self-extinguishing (no fire, it does not burn) is marked B2;
• non-combustible (even in fire retains properties for a certain period of time) is designated by class B1.

In wooden and frame buildings, it is best to use non-combustible construction foam. It should also be used in rooms with increased fire safety requirements. In houses, such a room is a boiler room. Fire / non-combustible polyurethane foam is available from every serious manufacturer. You need to look at the professional line. For example, Tytan B1, Soudal FR, Den Braven (Den Braven), Kim-Tec (Kim Tek).

There are also two-component mounting foams. But they harden very quickly, so they are used by professionals, and even then not all. You need a skill to work, but a two-component foam costs enough.

Special types

There are some types of work that require special properties.

• With increased adhesion to wood. There are different brands, for example, VIK (Vik) professional and household, FOAM 65, AkFix 940.
• Heat resistant. Used for sealing chimney outlets. In general, you can take any with a fire resistance class of class B1. Even if it darkens or turns black, it will not lose its properties. Examples: Penosil Fire Rated B1 (marketed as chimney foam), Tytan Professional B1.
  

• Very fast, almost instant cure (eg Soudal 2K). They are used in works at height, when it is impossible to wait even 30 minutes. They are used by industrial climbers during installation and repair work.
• Remain flexible after curing: AkFix Maximum 65, PROFPUR ELASTICFORCE and others. Such foams are needed in places where there are constant vibrations or tensile loads.

The listed brands are far from the only ones. There are others. Look at serious manufacturers of construction chemicals, read the specifications, look for reviews. We have become accustomed to the fact that the declared characteristics do not always coincide with reality.

Guns for professional polyurethane foam

If you decide to use professional mounting foam, you will need a gun for it. There is a big price difference here. But for a one-time use, you can take an inexpensive one. The price does not affect the amount of foam. It’s just that the more expensive ones control the intensity of the foam output better, serve it over a greater distance.

The ability to adjust the intensity of the feed is in any, that’s just the level of control is different. After work, if the cylinder is not empty, it can remain in the gun for 2 weeks or a month. During this period, you can simply continue to work. But it is necessary to store the “charged” pistol in a warm room, not under the sun’s rays.

When replacing the cylinder, if the foam goes well, no additional manipulations are needed. If the foam has stopped coming out, and the container is not yet empty, the nozzle may be clogged. Then the nozzle can be washed. If the liquid comes out without problems, then the problem is in the cylinder. Usually the propellant ends prematurely, but the copolymer may also end. After the end of work, the cylinder is removed, the gun (nozzle) is washed with a solvent (mounting foam cleaner). Other manipulations are not required.