How to protect polyurethane foam from the street: 4 methods of protection

When carrying out construction and repair work, polyurethane foam is widely used. The material has good sealing properties, improves the thermal insulation characteristics of structures, and is used for fixing products indoors and outdoors. The product has a long service life, resistance to moisture and temperature. To prevent the composition from losing its beneficial properties, it is necessary to prevent exposure of the treated surface to ultraviolet rays. There are several ways to protect polyurethane foam from the street and protect the sealant from the negative effects of sunlight.

Introduction to the topic

After installing windows and doors, the resulting gaps are sealed with installation sealant. The composition, which is in a cylinder under pressure, expands as the substance interacts with atmospheric moisture. Therefore, excess foam remains on the inside and outside of the structure. They are carefully trimmed with a construction knife, after which the polyurethane foam needs to be protected from the sun.

Ultraviolet rays destroy the structure of the mounting sealant if the surface is not treated with anything. The use of different methods of protection allows not only to preserve the properties of the porous mass, but also to give the installed structure a decoratively attractive appearance. For finishing treatment, painting, puttying, plastering, and priming are used.

Properties and varieties

Polyurethane foam has important technical characteristics that allow the material to be used for a wide range of repair work. Long service life, convenient application and good adhesion to different surfaces are the main advantages of the composition. The product also has other useful properties:

Primary expansion - the sealant increases in volume up to 50 times in a few minutes.
Secondary compaction continues for some time; high-quality sealants do not shrink or form gaps.
The substance firmly adheres to surfaces of different nature and structure - concrete, wood, cement, cinder block, brick.

Foam is used to seal cracks, seal gaps, install doors and windows, seal joints and joints. After final hardening, the polyurethane substance acquires optimal strength, density and a uniform porous structure.

How to cover foam on windows from the street

To find out how to protect polyurethane foam, the first thing you need to consider is its operating conditions. The popularity of polyurethane sealants has spread not only to facade work, but also to interior decoration - accordingly, the methods for protecting hardened foam are quite diverse

Polyurethane foam - properties of the material and its varieties

The consumer characteristics of polyurethane foam for sealing long linear gaps make one sincerely perplexed as to how they managed without it before, before the era of developed chemistry. Basic properties of foam sealants include:

Excellent adhesion, and selective in nature. With the main building materials (concrete, brick, cinder blocks, cement, plaster, etc.), polyurethane foam forms a very strong, virtually permanent connection. But it sticks much worse to moisture, ice, polyethylene, silicone and oiled surfaces. This eliminates accidental sealing of foreign elements;
The volumetric primary expansion when the composition “leaves” the cylinder reaches 50 times, and for the most modest manufacturers - no less than 20 times. The process takes only a few minutes and proceeds quickly, with a characteristic hissing and violent filling of the sealed openings. Just one spray is enough to fill deep and long joints. This is very convenient when working at heights, in hard-to-reach places, when plastering slopes with your own hands, when sealing ventilation pipes, when repairing balconies, etc.
Solid secondary seal. It is not enough to know how to seal the foam - it is important to consider that it changes in volume for several hours after application. For cheap manufacturers, this change is of a shrinkage nature - as a result, gaps may form between the door jamb and the dried foam. High-quality sealants are not characterized by the formation of “slot gaps” after hardening;
The viscosity and full installation volume of polyurethane sealants strongly depend on application conditions - temperature and humidity, the presence of wind, etc. There are “all-season” modifications of foam compositions, but they are optimally used at air temperatures from +5 ˚C to +35 ˚C, moderate humidity and in calm weather.

In addition to direct installation tasks - that is, sealing gaps, filling seams, insulating dissimilar joints, etc. – hardened foam has good thermal insulation and acoustic protection.

When installing window frames made of wood and plastic, pay attention to the flammability class of the sealing mixtures used; it can be fire-resistant, flammable and self-extinguishing.

When labeling the flammable properties of dried polyurethane foam, some manufacturers show a certain cunning. They write on packages, cans and adapter tubes only the numerical name of the flammability class, without verbal explanation. The average consumer may not know that:

B3 is a flammable composition that ignites even better than a wooden frame;
B2 is a self-extinguishing foam, and it can smolder for quite a long time;
B1 – non-flammable mounting composition. Of course, the non-flammable property will affect the price of the sealant in the direction of a significant increase.

The greatest damage to polyurethane sealants is caused by direct sunlight. The influence of atmospheric precipitation and mechanical vibrations also adversely affects the durability of the treated joint, but to a lesser extent. Before sealing the polyurethane foam, you need to make sure that the additional protection is resistant to ultraviolet radiation.

How to seal polyurethane foam - preliminary preparation

Some repair tips seem obvious, but the truth does not fade with repetition. Before you putty the polyurethane foam or tint its top layer, wait until the composition has completely dried.

Make sure that it tightly fills the entire installation opening, that there are no cracks or delaminations, irregularities in uniformity, etc. Deep lacunae and cracks should not be protected from the sun, but re-sealed.

Most polyurethane sealants dry yellow or yellowish, this is normal.

Further, protecting the polyurethane foam from sunlight and atmospheric adversities begins at the preliminary preparation stage, namely:

First you need to decide how to protect the polyurethane foam - putty, special tape or paint. The fact is that for putty or other “volumetric protection” you will need to cut a recess in the sealant; if you are not used to it, this is difficult. Paints, tape and varnishes are applied to a flat surface;
Using a sharp knife, cut off any excess material protruding beyond the dimensions of the slope or jamb. It is most convenient to take a special shoe knife with an oblique triangular blade - then it is easier to maintain an even cut line. And don’t rush to quickly cut off the sagging. This is dangerous due to accidental cuts to hands, feet and damage to hardened foam or a brand new frame;
After the cutting stage, the grinding procedure begins (it is not needed when puttying seams). The dried foam is cleaned with fine sandpaper. You will have to act manually and carefully - grinding mechanical devices can damage the frame, slope, door jamb, etc.

How to protect polyurethane foam - basic repair methods

Any polyurethane foam will decompose when exposed to sunlight. Initially, this looks like a darkening of the material, after which it becomes brittle and falls out of the cracks, like leaves in the wind.

Sealant protection options

Despite the excellent characteristics and properties of polyurethane foam, all products in this category are destroyed when exposed to sunlight. First, the material acquires a brown tint, decreases in volume, and then gradually spills out of the joints and gaps. Polyurethane foam in the sun is destroyed by sunlight. Negative processes can last from a year to several years. This depends on the quality of the sealant, the angle of exposure to ultraviolet radiation, the thickness of the applied layer and other factors. How to protect mounting foam from the street from UV rays:

Treatment with putty compounds. These include liquid plastic, finishing plaster with the inclusion of frost-resistant additives, window putty with the addition of liquid glass. The mixture is applied with a spatula from bottom to top along horizontal and vertical seams.

2.You can paint the installation sealant with paint or treat it with varnishes for exterior use. The best way to protect a polyurethane product is an acrylate composition, which has high adhesion to installation sealants. To obtain long-term protection, the foam is first treated with putty, and then with acrylate paint.

3. Mounting tape. This is a temporary measure, since the material will be constantly exposed to precipitation and temperature changes. In a hardware store, you can choose adhesive tape to match the color of the window frames or the frame of the front door. But every few months the tape needs to be re-glued.

Fire-resistant foam can be protected with a layer of plaster 8 cm thick. But the best option is to prime and paint the surface. To prevent the destruction of the polyurethane foam, a cement-sand mortar is sometimes used, to which a small amount of white grout is added to improve decorative characteristics.

On video: Protecting foam from ultraviolet radiation.

How to plaster polyurethane foam after installing windows - PVC windows, balconies, glazing, accessories

Plastic and metal-plastic windows are becoming more and more common today, although some twenty years ago they could be called a real curiosity, accessible only to wealthy people.

Everything is changing, and in the modern world new technologies are being introduced more and more, and mastering them, learning how to correctly perform certain actions, correctly install, and then care for structures, is already our direct task, if the laurels of a true home craftsman give no rest.

In fact, there is nothing complicated, and, for example, how and with what to cover the foam after installing plastic windows can be figured out by anyone if necessary. Let's clarify a few nuances and present some options that will greatly simplify the task and allow you to cope without the outside help of a professional craftsman, whose services, as you know, are not cheap at all.

Causes and consequences: how to seal foam after installing plastic windows

Everyone knows that when installing any plastic structure, and now similar technologies are used when installing wooden window frames, a material such as polyurethane foam is used.

It is quite convenient, sold in special packaging, from which, using a special gun, through a narrow spout, it is applied to the surface where it is required.

However, the question of how to putty foam around a window sometimes confuses many, since it tends to expand and crawl far beyond the limits that are allotted to it. But in fact, this is not a problem at all, because even a child can cope with the task.

It is important to know

When thinking about how to cover the polyurethane foam on the outside of the window, as well as on the inside of the structure, it is worth knowing that in fact, polyurethane foam is also a sealant, from the subgroup of polyurethane foams.

However, it also contains stabilizers, foaming agents, and other additives, such as catalysts, which give it unique properties.

The main indicators by which foam for installation is evaluated are its viscosity, primary as well as secondary expansion, viscosity, adhesion, that is, adhesion to surfaces, as well as the final output volume.

It turns out that in order to figure out how to seal the foam on the outside of the window, you will first have to figure out what this very foam is, and most importantly, what risks and threats can be dangerous to its functionality.

Moreover, the foam can be in the form of a mixture with one component, but two-component compositions also exist on the market.

For a better understanding, it is also worth saying that polyurethane foam can also be summer and winter, professional and household, and so on.

When thinking about how to cover foam on plastic windows, you first need to pay attention to why this is done, whether it is for purely decorative purposes or whether it needs to be done for some other reason.

It is clear that nothing ideal has yet been invented by mankind, therefore polyurethane foam needs protection from environmental influences.
It does not tolerate regular and constant exposure to moisture very well, and from ultraviolet radiation, that is, direct sunlight, it can generally crumble into dust and ashes.
If you need to understand how to close the polyurethane foam on windows, especially from the outside, you should think about ensuring that precipitation does not fall on it.
Flowing into the large pores of the frozen foam, under the influence of frost, the water will inevitably freeze and, consequently, expand, tearing your insulating material. Therefore, it is advisable to use waterproofing.
It is also important to protect the foam from penetration of moisture from the inside, which is especially dangerous in winter, in the form of condensation. That is, it is definitely worth installing a vapor barrier from the inside of the window, since the market is full of a wide variety of materials.

The appearance of the window, with the installation seam open to all winds, also simply does not look aesthetically pleasing, the window will be sloppy and untidy, and the whole design will go to hell, and this is another reason to look for and figure out how to seal the mounting foam on the windows inside and outside .

How and with what to remove polyurethane foam from a plastic window: starting from the beginning

True, you need to start with something slightly different, because first you will have to figure out how to wash the mounting foam from plastic windows, since it holds quite tightly, sticking to the double-glazed window itself, and even more tenaciously, to the plastic profile of the window frame. It is clear that it would be optimal to remove the foam before it completely dries, but if the moment is missed, then you should not be upset either, since a true craftsman will always find a way out of a difficult situation.

The easiest way to answer the question of how to clean plastic windows from polyurethane foam is before it hardens. The simplest remedy is a simple cloth slightly moistened with a regular paint solvent, for example, acetone. Simply remove the foam with a scraper, if possible, and wash off the rest with a cloth.
Another simple option for removing polyurethane foam from plastic windows is the use of special solutions that are intended for washing mounting guns. However, you need to act carefully here, since these compounds can damage the glossy surface of the window block frame profile.
A product with the surprising name “Cosmofen” will do the job well, but it is not sold in small quantities. That is, you will have to spend quite a large amount on a substance that you may no longer need.

There are also a wide variety of special-purpose removers on the market, for example, Macroflex, which do their job perfectly.

However, even here there are a wide variety of nuances, which is why real professionals recommend first making sure that the product will not damage the plastic. Simply wipe an inconspicuous area of the window frame with the solution and wait a few minutes.

If everything is in order, then you can start cleaning; otherwise, it is better to abandon the idea.

It will be somewhat more difficult to cope if the foam has already hardened significantly and become hard. However, even in such circumstances there is no need to be upset, because there is always a way out.

You can try to soften the material using some solvents, and only then try to wipe it off. In addition, true masters use generally simple methods, purely mechanically scrubbing off the foam using a cut piece of plastic.

Due to its hardness, it will not be able to damage the frame profile, but the foam will be cleaned off quite easily.

You can also simply cut off the remaining foam with a knife, if possible, so as not to damage the surface, and then wipe with vegetable oil or the notorious pharmaceutical remedy for joint pain, called “Dimexide”.

Also, as an option, you can remove polyurethane foam from wooden surfaces using regular sandpaper, but then it will take a long time and you need to restore the coating, so you should think a dozen times before starting work.

How to cover construction foam on windows: how to achieve optimal results

In view of all of the above, since everyone wants to maximize the service life of window units, the question of how to hide the mounting foam on PVC windows so that neither moisture, nor the sun's rays, nor frost or heat can damage it becomes very relevant.

Why do we need protection?

The use of foam helps solve various construction and repair issues. The composition penetrates deeply into the surface being treated and adheres reliably to it. The connection can withstand significant mechanical and deformation loads. Under the influence of external factors, the installation product loses its qualities. The structure of the sealed composition is influenced to a certain extent by precipitation, but most of all the foam needs protection from ultraviolet radiation. Using a protective layer allows you to:

Extend the service life of the sealant.
Prevent moisture from getting on the foam.
Maintain the integrity of the structure of the substance.
Prevent the formation of mold and mildew.
Give the surface a decorative look.

To effectively protect the foam from precipitation, primers and impregnations are used. The substances penetrate deeply into the porous structure of the foam substance and, after treatment, do not allow water to pass through. The sun coloring composition is better placed on the primer layer. A primer alone cannot provide UV protection, but it will prevent moisture penetration.

Puttying process

After choosing a protective agent, the foamed surface should be prepared for processing. Even with the most careful foaming, the installation sealant does not apply evenly as a result of the composition increasing in volume. Excess foam must be cut off with a knife. This can be done half a day after applying the product. The puttying process is easy to perform:

1. It is convenient to cut the foam with a knife with a triangular-shaped oblique blade.

2. Remove excess installation that extends beyond the boundaries of the slope.

3. It is necessary to go deeper into the thickness of the layer - a place for putty.

4. Foam for painting should be sanded with sandpaper.

5. If the surface is treated with putty, sanding is not necessary.

6. The surface is impregnated with a primer and allowed to dry.

7. Cover the polyurethane foam on the outside of the window along the joint with masking tape.

8. Apply the putty in a thin layer - first the starting layer, then the finishing layer.

For more reliable protection, after the putty has dried, the mounting foam can be painted with acrylate paint. The work must be done carefully so as not to stain the frames, double-glazed windows, or the front door; it is convenient to cover the gaps with masking tape. The tape is removed after the putty has dried or painted, depending on the chosen method of protection.

Use of plastic panels

Sealing foam after installing plastic windows can also be done using other materials. One of the popular finishing materials is plastic. Panels made from it are sold ready-made. All that is required is to saw off the part to the required length and attach it to the wall. Such work will take much less time than using plaster and will not cause any difficulties for an amateur. To complete the task you will need to do the following:

Cut out the pieces to the required size, which will be secured using a plastic strip.
Install side panels. They are fixed at an angle of 90 degrees with respect to the window, you can make 110 degrees. For better insulation, the cracks can be filled with foam. The remaining foam must be cut off after it has dried.
The gap between the slopes and the wall is closed using an f-shaped batten.

Installation of plastic slopes outside

Find out on our website about prices for different types of slopes and consumer reviews. This will make it easier for you to choose slopes. An integral attribute of window construction is window sills. Read more about them in our article “Installing ebb tides for plastic windows.”

You can also read about other options for finishing slopes about their insulation, sealing and vapor barrier of seams between the window and the wall.

Protection Features

To increase the service life of the sealant, you need to choose a high-quality putty. The working mixture is prepared according to the manufacturer's instructions - the proportions of the solution with water are indicated on the packaging. The solution should have a thick, uniform consistency. The mixture must be applied perpendicular to the seam - this ensures a more dense filling of voids and cracks.

The putty is distributed not level with the height of the joint, but with a slight excess. Before painting, the excess compound is sanded with sandpaper or construction mesh for finishing work. The putty should be rubbed down after it has completely dried so that the solution does not “smear.” The result is a smooth base on which the paint lies smoothly. It must be resistant to low temperature and moisture, suitable for external processing of products and structures.

Other methods of protection

If you need to process a large number of seams filled with polyurethane sealants, using putty is not always appropriate. This requires a lot of consumables and time. A simple option to protect the polyurethane foam from sunlight is to make a cement mortar. To ensure that the seams do not stand out against the general background of the wall, white grout is added to the mixture. After the cement has dried, the surface is painted in a suitable color.

How else to protect the foam:

Trim off excess mounting sealant.
Rub in the dense substance evenly.
Apply light paint in several layers.

In this case, it is not necessary to use putty. A thick layer of paint will protect the foam from ultraviolet radiation for a long time. If the decorative component is not important, and the foamed area is constantly in the shade, the mass is only trimmed and not treated with anything else. Also, UV rays do not affect sealant covered with metal sheets, plasterboard, boards or roofing felt.

Basic recommendations

If you are not sure that the foam will not be exposed to sunlight outside, the sealant must be puttied and painted. Experienced craftsmen advise adhering to some rules in their work:

The putty mixture must be thoroughly mixed until a homogeneous thick consistency is obtained.
To speed up the process, you can use an electric drill with an attachment or a construction mixer.
A small depression is made in the foam under the protective layer. And the mixture itself is applied with a slight excess.
For external work to protect polyurethane foam, use frost-resistant putty in a layer of at least 5 mm.
The tool must be cleaned immediately after work - dried putty is difficult to remove.

According to its technical characteristics, polyurethane foam is ideal for filling joints and gaps. The service life of the material increases significantly when a protective layer is applied against UV rays. Surfaces can be treated with putty and acrylate paint, which is “not afraid” of frost and moisture.

UV protection of foam (2 videos)

Methods for protecting polyurethane foam (15 photos)

What if you need to finish the slopes from the inside?

The same technologies can be used for interior work, however, in addition to plastic and plaster, you can also use drywall: it will hide the foam from view, it can be painted or covered with wallpaper. The only disadvantage of the material is that it is susceptible to moisture, so it cannot be used outdoors. Drywall is easily attached using self-tapping screws or dowels, helps create a perfectly flat surface, and is inexpensive. After the panels are installed, they must be coated with a primer for better adhesion to the future finishing.

Installation of plasterboard slopes inside the building

Please note that a wooden profile will be required to install the panels. If you have smooth walls, you don't need to use lathing. It is enough to glue the panels with special glue. This greatly simplifies the installation task.