Putty on mounting foam: for windows, for external work

When performing construction work, you have to deal with the installation of doorways, windows and roofs. Currently, craftsmen widely use foam for installation functions, which has a number of advantages. The product saves a lot of time and makes repairs easier. The substance is used to fill large voids and cracks. The hardened material firmly holds structures with medium and heavy weight, such as windows, doors and other elements. After polymerization, stable temperature and humidity levels are observed in the room, which is especially important for residential buildings. The mounting tool performs several important qualities. It is simultaneously a sealant, a heat insulator and a fixative. The material based on polyurethane foam serves for many years without losing its properties.

A few words about polyurethane foam

Its operational period lasts at least five years, after which the substance needs to be replaced.

Certain reasons contribute to destructive processes:

exposure to sunlight;
damage by fungus and harmful microorganisms;
non-compliance with building regulations.

To extend the service life of the foam, several conditions must be met:

when carrying out interior work, use sealing tape;
cover the polyurethane foam with a primer mixture or other special means - plaster mortar, cement-sand composition, acrylic coatings, liquid plastic, window putty, sealant, putty.

The putty solution applied to the foam creates protection from sunlight, temperature changes, exposure to a humid environment, hides uneven spots and other defective areas, and forms the basic basis for decorative finishing.

How to foam, how to cut and close, seal

Polyurethane foam has important characteristics that allow it to be used to solve a wide range of problems in construction and repair. Foam is especially in demand for sealing cracks. Some performers find use for it as a means of waterproofing. Long service life, high adhesion and a wide range are the main advantages. Manufacturers offer various types of foam: professional and household, winter, all-season and summer, fire-resistant, self-extinguishing and flammable, with high and low expansion coefficients. The product range of leading enterprises such as Makroflex, Soudal, Tytan and TECHNONICOL includes all types of polyurethane compounds.

Pistol foam Makroflex 750 ml. Photo by Leroy Merlin

An important advantage of polyurethane foam is its ease of use . Strict adherence to manufacturers' instructions and general recommendations for use will allow a contractor who does not have the skills and knowledge in the field of construction to carry out the work efficiently. The process of using foam includes preparing the user, the working surface and the container with a polyurethane composition, installation itself, removing excess with a construction knife and protecting the seams. To complete the final stage, various materials and technologies are used, which are presented below.

What putty mixtures are used?

We found out whether it is possible to apply putty on polyurethane foam. Now let’s figure out which putty is best applied over the foam.

When deciding on the choice of material, certain nuances should be taken into account. If you have to work from the street side, façade compositions based on polymer or cement are suitable. As an example, let's look at the technical parameters of some samples:

NEOMID putty – suitable for facade and interior decoration, applied with a metal spatula at a temperature of at least five degrees Celsius. It is sold in a form prepared for use, under optimal conditions (humidity - about 70%, air temperature - + 20) and dries within two days.

For interior decoration, it is recommended to use gypsum-based compounds:

Knauf Uniflot is a material made using German technologies, used for finishing premises, applied with a spatula. It has increased strength and is sold as a dry mixture in 25 kg packages.

When you have to work in a room with high humidity levels, you should choose a putty for exterior use to seal the polyurethane foam, because the layer of gypsum material will eventually undergo deformation and complete destruction.

Distinctive characteristics of the work

Consideration of the question of how to plaster foam for installation work must begin with the process of selecting materials and preparing tools . Using the right devices makes the job much easier and makes it possible to achieve excellent results, even without repair expertise.

Selection of composition and tools

So, how to plaster the foam for installation work so that the coating is durable and reliable?

Here it is necessary to take into account the following points:

Where the cladding will be carried out, when working in the middle of the premises, quite a few compositions are suitable, while for external putty the solution must have water-repellent qualities, be able to withstand temperature changes well and not be damaged by the sun.
Layer thickness and slot width. As everyone knows, putty must be applied in a thin layer, while plaster can be used to smooth out even significant differences. This nuance is very easy to establish by looking at all the places that require finishing; we remind you that it is often better to use a plaster solution.

Large areas with difficult terrain are subject to only plaster mortar

Distinctive characteristics of the room in which the areas covered with sealant are sealed. For example, in a bathtub, a cement composition is best suited, which is not afraid of moisture and is very reliable; in ordinary rooms, gypsum compositions can also be used.

Advice! The selection of a specific option depends on you, it is only necessary to note that plaster based on Rotband gypsum, Fugenfüller joint compound and other similar solutions with high reliability qualities are quite suitable for finishing foam. For external cladding, cement- or latex-based facade plaster or adhesive for tiles or thermal insulation panels are suitable - it also has great qualities.

What do you need to purchase before starting work?

Everything is very easy here:

The required amount of mixture is purchased (depending on the volume of work, and it is very easy to determine how much composition is needed, even by eye). As noted above, gypsum plasters are perfect for finishing the inside, but on the outside it is better to use weather-resistant compounds, otherwise the repair will not be reliable. Any plaster on top of foam primarily serves as a protective function, and therefore has great needs.

Do not forget that for blocks based on gas silicate there is a special group of compositions

To finish the base you will need a soil composition. The selection of a specific option depends on the properties of the base; you can easily select the required type in every hardware store. In exceptional cases, use a multifunctional acrylic composition that penetrates deeply into the structure of the base and strengthens the surface.
If the slopes are to be faced, the joints between the frame and the plaster need additional protection, since cracks very often appear there. It is best to purchase a paintable sealant - its cost is small, but the benefits are undeniable. It is used simply: after facing, the plaster is removed along the seam with a knife to a distance of approximately 3-4 mm, and this cavity is sealed with sealant.

Material consumption

Having decided how to putty the polyurethane foam, you need to calculate the need for the material. To do this, we specify the area of the surface to be treated, the type of coating, the characteristics of the putty mixture, and the number of mortar layers expected to be applied.

Manufacturers of putty materials put detailed instructions on the packaging container, which indicate the procedure for preparing the mixture for work and the average consumption per unit surface area when applying a layer one millimeter thick. As a rule, the average value of putty requirement per square meter varies from six hundred grams to one kilogram, but experts recommend adding a certain reserve to the total amount of composition.

Tips and recommendations for use

Repairs that include blowing with foam and subsequent finishing of the room are best left to an experienced craftsman. However, you can do the work yourself. To do this, you need to study all the processes, select materials and follow all the steps. There are detailed instructions on the Internet on how to get the desired result. The following tips are highlighted.

If you plan to use putty, the seam is deepened a few millimeters.
It is better to cover deep differences in materials with special tape.
Excess sections of foam must be cut off.
Old polyurethane foam should be removed.
The putty must harden thoroughly, only after this is sanding carried out.
It is necessary to apply primer - the primer additionally protects the putty.
For large volumes of putty, a construction mesh is placed between the layers, which will hold the mixture on the wall.

Applying putty over polyurethane foam is a mandatory stage of repair, which provides a high degree of protection for the sealed material and insulation from external adverse factors.

Preparatory activities

So, is it possible to putty the mounting tape? Quite if you follow certain rules. Let's start with the fact that all work is divided into separate stages - the base is prepared for applying the solution, if necessary, it is leveled, masking tape is applied, putty is applied, and grouting is performed. Let's look at each workflow in more detail.

Work begins after the polyurethane foam has completely polymerized. First of all, using a sharp knife, carefully cut off the protruding sections of the material, leaving the sealant at the same level as the wall surface.

Please note that you need to act after the foam has completely hardened. Typically this time is twelve hours. It will not be superfluous if you take into account the requirements of the instructions for using polyurethane foam.

The remaining cracks and cracks are filled with primer and plaster mixture, and the walls are cleaned of dust and dirty stains. The areas to be puttied are treated with a primer mixture and given time to dry.

In most cases, polyurethane foam is used to fix products of different textures. To prevent destructive processes, craftsmen recommend applying a special sealing tape to the surface before priming and applying the putty mixture.

If finishing is done around old window frames, a membrane strip material with waterproofing properties is used. If it is necessary to protect the surface from contamination, the tape is attached to the window frame and removed after completing the work. This protective measure is convenient and saves time on cleaning up contaminants.

What is it for

Environmental conditions determine the service life of finishing and building materials.

Polyurethane foam is used for various purposes: improves the appearance of structures (fills cavities, cracks, which allows you to level the surface in the future), strengthens it (when installing window blocks, doors), prevents the appearance of drafts, flooding of rooms through leaks.

All these properties are determined by the structure - after hardening, the material becomes dense and porous. This increases the thermal insulation qualities of protected structures.

But under certain conditions, polyurethane foam loses its properties: it becomes brittle, less dense, crumbles, and can crumble even from the slightest mechanical load. Such changes in the structure of the material are a consequence of violating the rules of its use and failure to follow installation recommendations.

The main factors that destroy the foam structure:

moisture (precipitation and condensation);
ultraviolet radiation.

When installation rules are followed, such material retains its properties for a long period.

According to GOST 30971-2002 “Installation seams of junctions of window blocks to wall openings”, the service life of hardened foam, which is characterized by its initial properties, is 20 years.

To protect the installation material from destruction and increase its service life, protective coatings are considered.

The most common and effective include:

silicones;
ribbons;
cement;
decorative panels;
plaster compositions.

The last option is considered universal. It is used indoors and outdoors (provided that the properties correspond to the operating conditions). For comparison, decorative panels are not used outdoors to protect the foam, since they do not ensure the tightness of the base. In this case, the foam continues to be in contact with the air. Taking these features into account, plaster is distinguished.

Its advantages:

vapor permeability;
increased adhesion;
strength;
waterproofing properties;
decorative properties (used to eliminate errors on rough structures).

Application procedure

Now let’s verify in practice whether the putty adheres to the foam. We proceed directly to applying the solution, observing all the requirements of the instructions and recommendations.

Maintaining the proportions established by the manufacturer, combine the dry powdery composition with water and thoroughly mix the components, bringing them to the required consistency.

Using a spatula, carefully apply the mortar mixture onto the dried foam, trying to stretch it into an even layer, the thickness of which varies from 3 to 5 mm. This parameter depends on the type of putty mixture used, so in most cases a base layer is applied, after which it dries, the putty is repeated. At the final stage, the finishing layer is applied.

Sealing the gaps between the structure and the wall involves the use of serpyanka tape, which strengthens the finishing layer. It is sunk into the base solution, after which it is covered with a second putty layer.

Once the finishing material has dried, it must be sanded. For grouting, use fine-grained sandpaper, a sander or an abrasive mesh. The result of the work is to obtain a flat and smooth surface on which decorative material can be applied.