In modern construction, moisture protection becomes the number one priority, especially when it comes to flat roofs and complex architectural forms. Traditional roll materials often give way to more advanced solutions, among which the leading position is occupied by the company. polyurea. This material is a two-component composition that polymerizes in seconds, forming a seamless, elastic and incredibly durable coating. Unlike classic spraying, which requires expensive high-pressure equipment, hand-held compounds allow you to perform work with a minimum set of tools, making them available to private developers and small teams.
The main advantage of the technology lies in its chemical stability and curing speed. Polyurethane-urea hybridsThe stainless materials used in handheld systems retain their properties at extreme temperatures, without cracking in the cold and without spreading in the sun. You get a monolithic membrane that has no joints and seams - it is in these places that leaks most often occur when using ruberoid or films. In addition, the material is able to stretch up to 400% of the original volume, which allows it to compensate for the temperature deformations of the base without tearing.
However, working with this material requires strict adherence to surface preparation and mixing of components. adhesion polyurea to concrete, metal or wood depends on the quality of the primer and the lack of moisture at the time of application. Errors in the preparation phase can lead to detachment of the coating, so each stage of the process should be treated with the utmost care. Below we will discuss in detail all aspects of the use of this material.
⚠️ Attention: Work on the application of polyurea should be carried out only in means of individual protection of the respiratory and eye organs. The components of the composition are toxic until complete polymerization, and the aerosol cloud when sprayed can irritate the mucous membranes.
Composition and principle of operation of the material
On the basis polymeric is the reaction of isocyanates with amines, which occurs instantly when mixing components. For manual application, special modified formulas are used, which have an increased pot-life of the mixture from 30 seconds to several minutes. This allows the operator to evenly distribute the material over the surface before the curing reaction begins. Unlike industrial systems where mixing occurs in a pistol, static mixers or mechanical drill mixing are often used.
The key element of the system is primerThe first one to be placed on the base. Its task is to bind the residual dust, level the surface’s absorbency and create a chemical bond between the base and the finish layer. Without high-quality priming, even the most expensive polyurea can peel off under the influence of temperature expansions. Modern primers are divided into one-component (wet curing) and two-component, the choice depends on the humidity of the base.
The physical properties of the finished coating depend on the ratio of components and the type of resins used. Aromatic systems are more resistant to mechanical stress, but can turn yellow under ultraviolet light, while aliphatic The versions are stable in color, but are more expensive. For roofs, the combination is most often used: the lower layer of persistent aromatic polyurea and the upper decorative layer of aliphatic, if the roof is not covered with soil or filled with concrete.
Process chemistry
When the isocyanate component (A) and the amine component (B) are combined, an exothermic reaction begins. Heat is released, and molecules begin to line up in long chains, forming a solid body. That is why it is important to work quickly and not leave mixed material in the container - it can boil and ignite due to self-heating.
Advantages and disadvantages of technology
Use of the hand-drawn It offers a number of opportunities that are not available to traditional methods. The main advantage is the creation of a completely seamless coating. Lack of joints – absence of weak points through which water usually penetrates. The material fits perfectly any geometric shape: ventilation pipes, parapets, endovoy and complex adjoining nodes. The speed of work is also high: one operator can process up to 100 square meters per shift, taking into account the drying time of the primer and the coverage itself.
The durability of such a coating is calculated for decades. The polymer does not rot, is not corrosive and is resistant to most chemicals, including salt solutions and acid rain. Elasticity The material allows you to cover cracks in the base with a width of up to 2-3 mm without additional reinforcement (although grid reinforcement is recommended for older roofs). This makes the technology ideal for repairing old roofs where the base already has defects.
However, the technology has its limitations, which you need to know before starting work. The high cost of raw materials compared to bitumen materials may seem like a drawback, but given the service life and the lack of need for frequent repairs, the final savings are obvious. Also an important factor is sensitivity to humidity when applied: if water gets on the concrete or condensate comes out, the coating can swell.
- 🛡️ Absolute tightness: a monolithic layer without seams and joints.
- 🌡️ Heat resistance: retains properties from -60°C to +150°C.
- 🏗️ High adhesion: sticks to concrete, metal, wood and old bitumen waterproofing.
- 💨 Speed: Ready to operate within hours of application.
Tools required and preparation of the basis
Quality coverage of 80% depends on the preparation of the base. The surface must be dry, clean and durable. To work, you will need an industrial vacuum cleaner that will remove the smallest dust that reduces adhesion. If there are bloating of the old coating or flaking areas on the roof, they must be removed mechanically. Cracks and joints of plates are pre-sewn and filled with a repair composition or sealant.
Specialized equipment is used for application of the material. Unlike high-pressure machines, low-voltage units or even simple mechanical sprayers are sufficient for the manual method. The mandatory element is static-mixerThis is where both components pass before reaching the surface. You will also need brushes and rollers for hard-to-reach places and applying a primer.
Before the main stage, a primer is necessarily applied. It can be solvent (solvent) or water-based. Solvent primers penetrate deeper into the pores of concrete and dry faster, but require good ventilation. After drying the primer, the surface should be sticky, but do not get your hands dirty - this is a signal of readiness to apply the main layer.
☑️ Preparation for application
⚠️ Warning: Never apply polyurea to a wet base or during rain. Moisture, caught under the layer of the polymer, when heated by the sun will turn into steam and tear the coating bubbles. The humidity of concrete should not exceed 4-5%.
Application and reinforcement technology
The application process begins with the preparation of the mixture. Components "A" and "B" are mixed in the proportion specified by the manufacturer (usually 1:1 by volume) directly in the sprayer or container. It is important to work at a pace: after mixing, you have a limited time before the reaction becomes irreversible. Apply the material should be fan-facing, covering the previous band by 30-50% to avoid skips.
To strengthen the structure, especially in the corners, around the pipes and at the junctions of the plates, is used reinforcement. For this purpose, a fiberglass or synthetic mesh is used. The technology "wet on wet" suggests that the mesh is drowned into the first not yet dried polyurea layer, after which the second layer is immediately applied, completely hiding reinforcement. This creates the effect of reinforced concrete, where the polymer plays the role of a binder, and the mesh - reinforcement.
The thickness of one passage is usually 0.5-1 mm. Several layers are applied to obtain the desired thickness (often 2-3 mm for the roof). The advantage of polyurea is that interlayer drying is practically not required - the next layer can be applied in 10-20 minutes, when the previous one ceases to be sticky. This allows you to complete the entire cycle of work in one day.
When working with polyurea, change the static mixers every 30-40 minutes or at the first sign of difficulty passing the mixture. The hardening of the material inside the mixer will lead to an increase in pressure and possible rupture of the hoses or equipment breakdown.
Comparison of hand-painting and spraying
Many people ask: why choose a manual method, if there is machine spraying? The answer lies in the scope and conditions of the task. Machine spraying (High Pressure) ideal for large industrial hangars, where the count is thousands of square meters. However, for private homes, complex roof geometry or local repairs, purchasing or renting a high pressure unit is not economically feasible.
Manual systems (Low Pressure) benefit from mobility and ease of service. The equipment is easier to clean, weighs less and does not require a connection to a three-phase network or powerful generators. In addition, manual application allows for more precise control of layer thickness in complex nodes, where a high-pressure jet can simply blow away the material or create an uneven texture.
From the point of view of physical and mechanical properties, modern hand-held compositions are practically not inferior to machine analogues. The difference can only be in the speed of polymerization: machine versions freeze in seconds, manual versions in minutes. But for the roof, this difference is insignificant, as it allows the master to work more accurately and efficiently.
| Parameter | Manual application | Machine spraying |
|---|---|---|
| Equipment | Low blood pressure, mobile | High pressure, stationary |
| Productivity | Up to 150 m2/shift | From 500 m2/shift |
| Entry cost | Low. | Tall. |
| The complexity of geometry | High precision | Requires operator experience |
| The lifetime of the mixture | 30 seconds - 2 minutes | Instant reaction |
Typical errors and security measures
Despite the simplicity of the technology, beginners often make critical mistakes. The most common of these is subheating. The polyol and isocyanate should have a temperature of about 20-25°C. If you work with a cold material in winter, the viscosity will increase, the mixing will be incomplete, and the coating will not gain the declared strength. Always keep the components in a warm room before starting work.
The second mistake is the violation of the mixing proportions. Even a slight deviation can cause the material to remain sticky forever or become too brittle. Use only calibrated equipment and check the output of the mixture before starting the main front of work. It is also important not to save on the primer: its consumption should be sufficient to create a solid film.
Staff safety is a priority. In addition to respirators, protective suits and gloves are also required. The polyurea that gets on the skin hardens quickly, and it can only be removed mechanically or by special washes, which are aggressive in themselves. Work should only be done in well-ventilated areas or outdoors.
⚠️ Warning: Do not try to dilute polyurea with solvents to increase volume! This will disrupt the chemical reaction, resulting in loss of elasticity and adhesion. If the material is too thick, heat it to the manufacturer's recommended temperature.
The main secret of success is not so much the material itself, as careful preparation of the base and compliance with the temperature regime of the components when applied.
Frequently Asked Questions (FAQ)
Can polyurea be applied over an old ruberoid?
Yes, it is possible, but it requires proper preparation. The old ruberoid should be firmly glued to the base. It is necessary to remove all bloating, clean the surface of the crumb (often grinding or applying a special primer for bitumen is required) and be sure to use a reinforcement mesh to compensate for the movements of the old coating.
How long does polyurea dry before the rain?
Due to the high reaction rate, the polymerization of the surface occurs in 10-20 seconds. However, in order for the coating to withstand a heavy rain without damage and the formation of whitish plaque (amine crust), it is recommended to pause at least 1-2 hours after application. Full strength is achieved within 24 hours.
Do I need to reinforce the roof with polyurea?
For new, crackless concrete bases, reinforcement is not strictly mandatory, but desirable to improve reliability. For old roofs, wooden bases or surfaces with cracks use reinforcement I'll be sure. This turns the coating into a high-strength membrane that is resistant to tears.
What is the life of this coverage?
With the observance of the application technology and the correct selection of materials, the service life of polyurea waterproofing is from 30 to 50 years. The material does not age under the influence of ultraviolet light (especially aliphatic species) and withstands thousands of cycles of freezing and defrosting without loss of elasticity.
How to clean the tool after work?
Until the material has frozen (during the first minutes), the tools can be cleaned with special washes for polyurethanes or acetone. After polymerization, polyurea can be removed only by mechanical means or heating. Therefore, static mixers and containers are recommended to be changed or cleaned immediately after completion of work, without waiting for hardening.