Rust on the surface of the metal and wet spots on the floor of the garage - it's not just a cosmetic defect, but a signal of critical destruction of the protective layer. Renovation of the roof of the iron garage requires immediate intervention, since moisture destroys not only the roofing, but also contributes to the corrosion of the load-bearing beams, threatening the collapse of the entire structure. Ignoring the first signs of leakage leads to a significant increase in the cost of restoration work in the future, when you will have to change not the sheets, but the entire frame.
Owners of metal boxes often face a dilemma: try to patch holes with bitumen or completely cover the roof with modern materials. The choice of strategy depends on the degree of wear flooring or iron sheets, as well as from the budget allocated for maintenance. In this article, we will discuss all stages of restoration, from dismantling the old coating to the finish sealing of the joints, so that your car is dry and safe.
The modern building materials market offers dozens of solutions, from classic ruberoids to polymer membranes, but not all of them are suitable for steep stingrays or flat metal roofs. Stowage technology It must take into account the thermal expansion of the metal, which is much higher than that of brick or concrete. Errors in the selection of fasteners or ignoring temperature gaps will lead to the fact that in a year or two the roofing will again require attention.
Diagnosis of the condition of the roof and identification of hidden defects
Before purchasing materials, a thorough audit of the current state of the design is necessary. Often, external manifestations of corrosion are only the tip of the iceberg, and the real problems lie in the places where the sheets adjoin the frame or in the hidden cavities of the crate. Visual inspection is better to carry out in dry weather, but traces of water on the floor will tell you where to look for the main foci of destruction.
Particular attention should be paid to welded seams and places of fastening of sheets with screws. This is where it most often starts. electrochemicalIt quickly eats through metal. If the metal crumbles or falls when pressed with a mounting knife or screwdriver, such a site requires a complete replacement, not a local patch.
⚠️ Warning: When inspecting the roof, step on areas covered with rust or moss - they may be slippery and can not withstand the weight of a person. Use a safety cable and wide boards to distribute the load when moving along the slope.
An ultrasonic thickness meter can be used to estimate the thickness of the remaining metal, although in garage conditions experience and visual control are often relied upon. If the through holes occupy more than 30% of the slope area, it is more economically feasible to dismantle the old coating completely than to try to patch every hole.
Selection of materials: from proflagging to soft roofing
The market offers three main ways to solve the problem: the use of metal profiled sheet, the laying of soft bitumen materials or the use of sprayed waterproofing. Fresh-natil remains a leader due to its durability, fire safety and ease of installation, but it requires high-quality corrosion treatment of sections and attachment sites.
Soft roofing, such as euroruberoid or asphalt shingles, perfectly seals complex surfaces and does not require frequent maintenance, but it is more sensitive to mechanical damage and ultraviolet light. Sprayed polyurethane formulations create a seamless coating that perfectly fits any bumps, but require special equipment for application, which makes this method expensive for a single garage.
When choosing a material, it is important to consider the angle of slope of the slope. For sloping roofs (less than 10 degrees), a metal sheet is not recommended without a solid crate and additional sealing of the joints, since water can flow under the profile waves in strong wind or oblique rain.
Comparison of material lifespan
Metal flooring with polymer coating serves up to 40-50 years with proper installation. Bitumen materials (ruberoid) require replacement or repair every 10-15 years. Polymer membranes can last up to 30 years, but are sensitive to punctures by sharp objects.
Do not forget about the additional elements: skates, endowments and adjoining bars. The use of cheap analogues or their absence leads to the fact that water penetrates the coating through the ends, causing rotting of the wooden crate or corrosion of the metal frame.
Preparation and dismantling of old coating
The quality of repair depends on the preparation of the base. The old coating should be removed if its restoration does not make sense. This process is often accompanied by the formation of a large amount of metal scrap and construction debris, which must be immediately lowered down to avoid damaging the remaining entire sections of the structure.
If it is decided to leave the old frame, it must be cleaned from loose rust to metal. For this purpose, mechanical brushes, grinding machines (Bulgarians) with petal circles or chemical rust converters. The surface must be dry, defatted and rough to ensure the adhesion of the primer.
☑️ Checklist of preparation of the basis
An important step is to check the bearing capacity of the frame. If the metal beams are rotten in the places of resting on the walls, they must be strengthened or replaced. Sometimes it is necessary to digest the adjoining nodes, which is a difficult task that requires skills. gas-arc welding.
After cleaning the metal, a primer is necessarily applied. Ignoring this stage will negate all repair efforts as the new material will fall on the oxidized surface and corrosion will continue beneath it. The soil must dry completely before the start of the main work.
Technology of laying proflagging on a metal frame
Installation of the profile sheet begins at the bottom of the slope and moves up to the skate. The sheets are stacked with overlap in one or two waves, depending on the angle of the roof and the manufacturer's recommendations. For garages with a small slope, the flooring should be maximum, and the joints should be additionally smeared with a sealant.
Fixing is carried out by special roofing screws with EPDM washers, which prevent moisture from entering the hole. They need to be twisted strictly perpendicular to the surface, not tugging, so as not to damage the sealing washer, but also without leaving gaps. The use of conventional nails or screws without rubber bands is strictly prohibited.
| Parameter | Value/Requirement | Note |
|---|---|---|
| Float of leaves | 150-200 mm | Depends on the angle of the stingray |
| Step of attachment | Through the wave | Perimeter, in every wave. |
| Type of screw-up | Roofing 5.5x19 mm | With an EPDM puck to color the leaf |
| Overhang of the leaf | 50-100 mm | To drain water from the eaves |
Particular attention is paid to the design of the cornice overhang and skate. The cornice bar protects the front board and directs water into the trough, and the skating element covers the upper junction of the ramps, providing ventilation of the underroof space. Between the metal and the skate is often laid sealing tape to prevent blowing snow and dust.
When screwing screws into the flooring, keep the screwdriver strictly vertical. The distortion will lead to the fact that the EPDM washer will not press evenly, and in this place in six months the leak will begin.
Sealing of joints and adjoining walls
The most vulnerable place of any roof is where it meets vertical surfaces, such as the wall of a house or a neighboring building. For sealing of such nodes, a wall bar is used, which one side is wound into a groove (groove) in the wall or is attached to a vertical surface, and the other covers the roofing.
The gap between the bar and the wall is necessarily filled with polyurethane or silicone sealant, resistant to UV radiation and temperature changes. A regular acrylic sealant will crack quickly and lose elasticity, leading to repeated leaks.
⚠️ Note: Do not use mounting foam to seal roofing adjoinments without sun protection. The foam is destroyed under the influence of ultraviolet light in one season and turns into a crumb, ceasing to hold water.
If the wall is brick or concrete, it can be made a small stove at a height of 2-3 cm above the roof level, lay the edge of the bar there and cement. This will create a reliable mechanical lock that will not blow the wind. All metal elements of the adjoining must also be treated with an anti-corrosion composition.
Waterproofing and Insulation: Do You Need a Garage?
The issue of insulation of a metal garage is acute if you plan to use it not only as a parking lot, but also as a workshop. However, from a physics perspective, insulation of a metal roof without proper vapor insulation will result in increased condensation. Warm moist air from the inside will settle on the cold metal, causing corrosion from the inside.
If insulation is necessary, the scheme is used: vapor insulation (from the room) - insulation (minwat or foamplex) - hydro-wind-protective membrane - ventilation gap - roofing. The presence of a ventilation gap is critical to remove moisture from the thickness of the insulation.
For simple unheated garages, they are most often limited to a quality ventilation device to level the temperature inside and out, minimizing condensation. Waterproofing in the form of a roof film under the flooring is always desirable, since it serves as a second barrier in case of leakage in the places of attachment.
The main mistake insulation of the metal roof is the absence of a vapor insulation film on the inside, which leads to wetting of the insulation and rotting of the metal of the frame.
Frequent mistakes in self-repair
Many motorists, trying to save money, make typical mistakes that negate the result of repairs. One of the most common is the use of bitumen mastic over rust without prior cleaning. Mastic creates a film, but the corrosion process under it continues, and after a year the coating swells and peels off.
Another mistake is saving on the fastener. Conventional galvanized screws rust in 2-3 years, leaving rusty streams on the roof and open holes for water. Only specialized fasteners with high-density zinc coating and colored polymer coating should be used.
The temperature expansion of the metal is also often ignored. If you rigidly fix the sheets without taking into account linear expansion, when heated in the sun, the metal will begin to "walk", tearing out screws or deforming the profile. The correct hole in the profnastile should be 1-2 mm larger than the diameter of the screw leg.
How often should I check the roof of the garage?
It is recommended to conduct a visual inspection twice a year: in spring (after snow melting) and in autumn (before the winter season). This will allow you to identify small defects before they turn into serious leaks.
Can I paint a rusty roof without cleaning?
There are rust converters that allow paint to be applied to oxidized metal, but their effectiveness is limited. If the rust is deep and layered, mechanical cleaning is required. Paint without preparation will not hold.
What is the best roof angle for a garage?
For profnatsil minimum angle is 8-12 degrees, but the optimal is considered 20-30 degrees. Such a ramp provides a rapid descent of water and snow, reducing the load on the structure and the risk of leaks.
What to do if the load-bearing beams are rotten?
If the main bearing elements (farms or runs) are rotten, a simple replacement of sheets is not enough. Requires reinforcement of the structure with new metal profiles or complete replacement of the frame, which is often comparable in cost to the construction of a new garage.
Do I need ventilation under the floor?
Yes, a ventilation gap between the insulation (if any) and the roof is necessary to remove moisture. If the garage is not insulated, ventilation is still useful for reducing the temperature inside in summer and removing condensation in winter.