Polyurethane foam for PVC windows: which is better

Properly selected and correctly applied polyurethane foam for windows is an important component of their high-quality installation. It is difficult to imagine installing modern PVC window structures without this easy-to-use and reliable material. A novice master will have to understand the differences and features of foam in order to choose a composition from the wide range offered by stores.

Properties and scope of material

Polyurethane foam is a liquid polyurethane solution pumped into a container under pressure. When exposed to air, it quickly hardens and at the same time increases significantly in volume.

There are 2 types of foam expansion:

Primary (when the composition leaves the cylinder). Provides ease of use: the solution can effortlessly fill any shaped recesses.
Secondary. Among the disadvantages: an increase in the volume of sealant during final polymerization can deform the window elements. Therefore, it must be taken into account when carrying out work.

Completely hardened material acquires unique useful qualities:

Low thermal conductivity is achieved due to air bubbles located in the thickness of the frozen material. If not for the price, foam could well be considered as an alternative to conventional insulation materials.
The presence of air voids increases the sound insulation of the entire window structure: vibrations transmitted to the window are damped by foam. Thus, it complements the installed rubber seals, enhancing soundproofing.
Cured foam does not transmit electric current, has water-repellent properties, and is not susceptible to rotting or mold.

High adhesion rates make it possible to use foam as a fixing material: it securely fixes window or door frames, as well as other elements, in place.
Depending on the brand, the composition does not support combustion or is completely resistant to fire.

Thanks to its special properties, the foam is ideal for exterior and interior use. But, like any material, it has disadvantages:

After hardening, the excess composition is cut off. And if the cut surface is not treated appropriately, then water will get into the open pores. Over time, this causes the material to deteriorate.

The frozen composition does not withstand exposure to ultraviolet radiation, so it must be protected from direct sunlight.
You have to follow the rules for storing cylinders: strictly in a vertical position at a temperature range from +5 ˚С to +25 ˚С.

The high adhesion of the foam allows it to reliably adhere to surfaces made of different materials. Therefore, you should work with the composition very carefully: if it gets on your hands or other parts of the body, you can only wipe it off with the top layer of skin, which will take at least several days. When pouring, be sure to use gloves. You should also securely cover all surfaces on which the solution may drip.

If foam does get on the floor, furniture or other surfaces, it can be removed in several ways, which are described here.

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Advantages

What makes polyurethane foam an indispensable material when working with plastic windows and balcony blocks?

Fast hardening time and ease of use. The full continuation of installation can begin after 12 hours. In a dry, hardened state, the material is easily cut and adjusted to the required dimensions.
Good thermal insulation. Small air bubbles in the frozen mass greatly increase the degree of heat retention.
Noise insulation. Due to their design, plastic window frames capture sound vibrations, which are softened by a polyurethane seal.
Has water-repellent characteristics.
Prevents the spread of mold.

Professional or household?

Based on the design features of the cylinders and other indicators, household and professional foam are distinguished.

The compounds that the masters work with are used only with a special gun. To secure it in the cylinder, a special valve is provided.

The use of this design provides the following advantages:

The ergonomics of the gun allows the master to fill cracks with one hand. The second remains free, due to which you can work alone at certain stages.
The gun makes it possible to accurately dose the volume of solution released. This reduces consumption by reducing unnecessary waste.
A thin, long nozzle will easily deliver the solution into hard-to-reach cracks and holes.
The cylinder can be used in any position.
The reusable valve ensures the safety of the solution between repairs.

When choosing professional cylinders, you do not need to solve the frequently asked question: where can the remaining solution be usefully used?

Professional compositions have better performance characteristics than household ones. For example, they have a lower secondary expansion coefficient, which makes their use more convenient.

Techniques for pouring foam using a professional gun are shown in the following video.

Mr. Build strongly recommends: to install plastic windows, use only professional foam. Secondary expansion will not create unnecessary load on the structure or displace frame elements. The density of the professional compositions is maximum, and this will ensure the best quality of fastening, insulation and sealing of the seam.
Choose a gun based on budget, ergonomics and service life. For a single procedure, the cheapest one with plastic parts will do, but for professional use, give preference to dismountable high-quality models.

Household foam has less outstanding performance characteristics: worse adhesion, a higher coefficient of secondary expansion, and less material yield from the cylinder. It is sold in containers equipped with a plastic tube for supplying the solution. It is screwed onto the valve before blowing begins. It is recommended to use the entire bottle at once.

Working with household foam is less convenient: both hands are used, and the can must be placed bottom up. This will ensure a more complete release of the solution. Use it with extreme caution, in the least important places. Fill the seam to no more than 50% depth!

Classification

Before purchasing, the consumer needs to know how to choose foam for installing plastic windows.

If you pay attention to the design of the cylinder and the properties of the active substance, the sealant is divided into professional and household. At first glance, the difference between them may seem insignificant, but there is one.

The design of any cylinder includes a spray mechanism (adapter tube). Also, when working with polymer, a special gun is used.

It allows you to deliver material in portions to all recesses, crevices, and cracks. In this way, the master controls the amount of sealant supplied and reduces its consumption.

Professional

The first option is used in places where there is a need to fill large spaces. This foam for installation of plastic windows is packaged in cylinders with an internal partition. It separates the components. They mix only at the outlet of the sprayer.

This cylinder cannot be used all at once. When reusing, just shake the packaging and blow out the outlet nozzle.

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Domestic

A cylinder of mounting polymer for domestic use does not differ in appearance from a professional one. The difference lies in the internal design of the packaging. There are no partitions inside, all substances are mixed.

Soundproofing foam

If the windows themselves do not transmit noise, then the polyurethane foam on which they are mounted is an excellent conductor of noise, since it is light, hard, and has a closed cellular structure, which facilitates the unhindered passage of sound waves.

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Therefore, when installing windows or doors, it is necessary to use special soundproofing foam, which, unlike conventional polyurethane foam, has properties important for sound insulation:

high density to reflect sound waves;
elasticity to reduce vibration transmission;
high-quality filling of cavities and cracks to prevent sound from “leaking” into the room.

MAXFORTE SaundFLEX foam has these characteristics

Compared to conventional construction foams, the use of MAXFORTE SoundFLEX foam adds more than 10 dB to sound insulation, which is equivalent to a noise reduction of 2-3 times.

The difference between regular mounting foam and soundproofing foam can be seen in the video:

If you squeeze a piece of polyurethane foam in your hand, it will simply collapse, unlike specialized soundproofing foam. Like a sponge, it will return to its shape. It does not harden and thus does not become a sound bridge.

Why is it important to choose the right one?

Choosing polyurethane foam for installing windows is a responsible procedure, since this material is responsible for the following properties of enclosing structures :

Resistance to heat transfer, which affects the energy efficiency indicator.
Soundproofing the room from noise pollution and vibrations from the street.
Additional fastening of the window block frame in the opening, which guarantees the geometric immutability of the entire structure under the influence of the pulsating component of the wind load.
Sealing the installation gap from atmospheric moisture, drafts, dust and other contaminants.
When choosing fire-resistant foam, compliance with fire safety standards applicable to the space being used is guaranteed.

The foam must be selected in such a way that the service life of the installation gap is no less than that of the window unit itself.

Winter or summer?

Foam is divided according to the seasonality of its use. It happens:

Summer, suitable for work at temperatures above +5 ˚С.
Winter, allowing you to seal cracks at temperatures down to -18˚ C.
All-season. Seen and used less frequently. Professionals advise using it during transition periods in autumn and winter or getting by with the first two varieties.

What to look for when purchasing

High quality is indicated by:

the condition of the packaging, the absence of mechanical and chemical damage demonstrates that the storage was carried out under proper conditions;
shelf life, the “fresh” the foam, the higher the characteristics it has;
The uniformity of the composition can be determined before use; it is necessary to turn the container over several times and shake it; if the contents of the container flow smoothly, then the material is of high quality;
color, high-quality products have a light yellow color, darkening indicates the beginning of the polymerization process; however, companies offer compositions in other colors.

Flammability of foam

The compositions also differ in flammability parameters:

B1 – the highest fire safety class, does not ignite even upon contact with open fire.
B2 – does not burn on its own, without an additional heating source. Such compositions are called self-extinguishing.
B3 – lowest flammability class. This material is not recommended for use, especially in residential areas.

Compound

Most of the consumables used contain substances to impart elasticity (plasticizers) and surfactants. To activate the polymerization process, a reaction of 2 components is needed.

Prepolymer diisocyanate. The substance is in a liquid aggregate state. When sprayed, it absorbs moisture from the air, forming a polyurethane mass.
The propellant responsible for the aerosol properties is propane. The gas is inside the cylinder and is involved in the atomization of the diisocyanate.

After spraying the balloon in the open air, polymerization occurs. Under the influence of air and a humid environment, the mass hardens. A porous material is formed that fills all the cracks.

Rules for choosing foam for installing PVC windows

For high-quality installation of window blocks, the composition most suitable for a particular case is selected. What to look for when choosing?

The temperature at which the cracks will be sealed. It is used to choose winter, summer or all-season foam.
On the secondary expansion coefficient. The lower the value, the better. It is recommended not to use formulations with an indicator of more than 15–20%. Professional foam easily fits into such a framework, but with household foam the choice should be made carefully.
For expiration date. No one can predict how the behavior of the solution will change after storage time. It's better not to take risks.
To the fullness of the cylinder. Underfilling is a common occurrence. It’s easy to check: to do this, weigh the canister. A full container of 750 ml weighs about 900 g.

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Calculating the required number of cylinders causes many problems. It is believed that per linear meter when installing windows in a panel high-rise, 300 ml of foam will be required, for brick the volume of material is 400–450 ml, for houses built in Stalin - 500 ml. But on the bottle the manufacturer indicates the yield of the sealant under ideal conditions; this cannot be achieved in reality. Therefore, an extra cylinder in reserve will not hurt.

Survey

Ratings of the best polyurethane foams are compiled by various experts, whose opinions are subjective. This article analyzes those brands that Internet users are interested in. But the demand for individual brands and formulation options does not demonstrate the high quality of the products. Therefore, we will try to find out which brands of polyurethane foam are really the best. To do this, below is a survey in which any visitor to our website can take part. You can explain your choice in the comments.

Rating of polyurethane foam brands

Professionals prefer proven brands. The following mounting compositions have proven themselves on the Russian market:

"Moment-Montazh" - foam from a domestic manufacturer. Most often all-season, presented in professional and household containers. Dense, homogeneous with good adhesion, it can be painted. The material is characterized by secondary expansion, so you need to work with it carefully, fixing the window elements with spacers.
Soudal - compositions with a fine-porous structure without an unpleasant odor. Three modifications - summer, winter, fire-resistant. Shrinkage and secondary swelling are minimal, the material is characterized by high adhesion and uniform hardening. For delicate installation work, a composition with minimal re-expansion is suitable: SOUDAFOAM GUN LOW EXPANSION.
Makroflex is a sealant with good adhesion and a uniform structure. With primary expansion it increases 2 times, secondary expansion is insignificant. It can be summer or earthy. It is allowed to trim the excess after 3-4 hours.
Penosil is a non-shrinking composition with low secondary expansion and a dense structure, odorless. Gives a record high yield.
Tytan. It does not emit toxic fumes during operation and has a weak, non-caustic odor. The expansion of the second type is practically absent. Available in household and professional, winter and fire-resistant versions. Hardens quickly, excess can be cut off within an hour.

Video description

In this video, the master shares his experience of working with Makroflex polyurethane foam and talks about the advantages of using a gun:

TechnoNIKOL 65 Constant is considered a universal material with increased yield. The expansion here is average, the secondary expansion is minimal. It is used for insulating roofs, plumbing communications, installing wall panels, doors and windows. There is only one drawback - it is rarely sold outside the urban sector.