Expanding foam

Almost every person who is not afraid to tackle some home repairs has had to use mounting foam (also called polyurethane foam, PU foam, or sealing and insulation foam) in their everyday life. It is a modern tool for various repairs such as window and door installation, sealing gaps and joints, and filling holes.

Using mounting foam is quite simple. Special guns are sold for this purpose, but for small household repairs, you can do without one. However, even for these elementary tasks, you need to follow some rules to achieve high quality.

Characteristics

The vast assortment of mounting foam in specialized stores makes you think about the right choice. Everyone wants to choose high-quality yet affordable polyurethane foam. Generally, there are two main types of this material: household and professional.

Additionally, depending on its specific purpose, you can find waterproof mounting foam, non-expanding mounting foam, polyurethane foam for thermal insulation, and so on. Below, we'll look at the characteristics of each type.

Types of Mounting Foam

Household Polyurethane Foam

The main features of household mounting foam are related to the volume of the canister. Manufacturers sell foam for household use in small cylinders (around 800 ml), and accordingly, the price is higher per specific volume.

Household foam cans come with a nozzle for directing the foam (hence it's often called manual mounting foam). In household cans, the pressure level is low, so it's essential to significantly reduce the material consumption when performing repair work. To achieve the correct consumption rate, you can use a special gun.

Professional Mounting Foam

Professionals use professional-grade mounting foam to install doors and windows. Professional cans have a capacity of over 1.5 liters, with the material inside the cylinder under high pressure. Working with professional mounting or insulation foam is recommended to be done with a special gun.

To make using the material more convenient, the canister is additionally equipped with a fastening device for secure attachment inside the gun. This ensures the best ratio for mounting foam price, quantity, and quality.

When choosing polyurethane construction foam, it's essential to consider what purposes it will be used for and where.

Rules for Work

To perform effective repairs or installation work using the sealing agent, you must know some basic rules for using the foam.

• Using a special mounting gun ensures a better result of the work performed.
• It's best to use mounting foam from a reputable manufacturer, which implies lower secondary expansion.
• It is recommended to carry out installation and repair work during the summer season or when it's warm - this will accelerate the curing process and preserve all the technical qualities of the product.
• It is recommended to use sealing foam for small cracks up to approximately 8 cm in width. If the width of the gaps exceeds these values, it is advisable to use other materials (bricks, wood, plastic).
• For filling cracks and fissures with a width smaller than 1 cm, it is more economical and practical to use gypsum filler.
• During work, the foam canister should be held with the opening facing downward.
• Filling the gap with a sealing material requires one-third of the depth.
• After the sealing material has cured, excess polyurethane foam should be removed with a special knife.
• After completing all the work, it is necessary to protect the cured foam layer from the effects of sunlight using special means.
• To work on the ceiling, you should use a special ceiling mounting foam - these cans can be used in any position (the opening doesn't have to be downward).
• To seal deep gaps or cracks, you should use special adapters for the canister or the gun.
• During work, the canister should be periodically shaken and the nozzle of the mounting gun should be cleaned from excessive foam buildup.
• When performing construction and installation activities, personal protective equipment must be used.

The most common cases where polyurethane foam is used include:

- Polyurethane foam for insulation: due to its properties, the foam helps improve acoustic and thermal conditions (quality foams have low thermal conductivity: λ = 0.034 W/m·K in the case of expanded polystyrene). Here, you can include the well-known insulation mounting foam for bonding fiberglass, polystyrene, and other types of non-expanding insulation mounting foam available on the market.

- Mounting: doors, windows, various panels, or frames.

- Sealing and filling gaps: it allows filling irregular joints or large cracks, gaps resulting from surface perforations for installation, sewerage, various damage, roofs, and more.

The most common polyurethane foams on the market can be divided into several categories:

- Depending on the application method: with a straw/tube or gun mounting foam.

- Depending on the temperature resistance during application: summer, winter. There are also innovative high-quality foam models that are suitable for year-round use.

- Depending on the class of fire resistance - non-fire-resistant or fire-resistant (with class B1, B2, B3, etc.).

What is important for beneficiaries of a particular task is to choose the right foam for the desired purpose. Here's how to do it:

Foam with a straw/tube (manual foam) - intended for filling gaps, large joints. They expand a lot, and the volume of foam isn't controlled by the tube used for application, so the foam flow will be significant. It requires filling, but it won't lead to proper insulation. There's also mounting foam that doesn't expand as much as other types.

Since the obtained foam, after curing, will have low density (it will look "large," but inside it is transparent, without sufficient insulating power and with a high degree of compression/crushing over time). Additionally, this construction foam exerts significant pressure on the surrounding surfaces.

That's why this type isn't recommended for installing doors or windows. This doesn't mean it won't "work," it will fix the frames or insulate, but the result won't be good, thermal insulation will be reduced, durability over time will decrease, and the excess foam will exert pressure on the frames.

So, if you need to fill gaps, large joints, then YES, this foam is the right choice.

Gun Foam

Applied with a spray gun. This way, you have the advantage of being able to control the flow of foam in the tube and the speed at which it comes out, so that the obtained foam expands evenly, in a controlled manner, with reduced post-expansion (with less pressure on the surrounding surfaces). In addition, gun foam formulas have excellent technical properties.

Gun foam is the right choice for installing doors or windows or for any sealing where precision, efficiency, and technical performance of the work are required.