Building a garage is a demanding task that requires accurate calculations and an understanding of the physics of materials. A profile tube frame Today it is one of the most popular solutions due to its strength, relative cheapness and speed of construction. Unlike brick or concrete structures, the metal frame allows you to significantly reduce the time of work, while maintaining high performance characteristics.
However, the ease of installation does not mean that the process is devoid of nuances. Incorrect selection of metal cross-section or ignoring wind loads can lead to deformation of the structure in the first winter. That is why the stage of design and procurement of materials should be approached with the utmost care, taking into account all regional features and safety requirements.
In this article, we will discuss in detail how to design a reliable metal-frameWhat tools will be needed for the job and how to avoid the typical mistakes made by beginners. You will learn about the intricacies of welding, ways to strengthen the knots and methods of protecting the metal from rust, which will allow you to build a garage that will last for decades.
Advantages and disadvantages of metal frame
The choice of a profile pipe as the main carrier element is due to a number of objective advantages. First of all, it is high strength with relatively low weight. The design does not require a massive buried foundation, as in the case of brick, which significantly saves the budget on the zero cycle. Profile tube has a rectangular or square cross-section, which simplifies the docking of elements and the installation of the skin.
The speed of building such garages is also amazing. A two-person team can assemble the main circuit in a few days. Metal is easy to process, cut and weld, allowing you to implement projects of any complexity, from simple one-stop canopies to two-storey boxes with an attic. The ability to dismantle and transfer the structure is also a strong argument in favor of metal.
β οΈ Attention: Metal frame requires mandatory and high-quality anticorrosion treatment. Without proper protection, rust can destroy load-bearing elements in 5-7 years, especially in conditions of high humidity or proximity to the sea.
On the other hand, metal has its disadvantages. Low thermal insulation requires additional insulation costs if you plan to use the garage as a workshop all year round. Also, the metal has a high thermal conductivity, which leads to the formation of condensate inside the room at temperature changes. These problems are solvable, but require a competent approach to the choice of insulation and vapor insulation.
Calculation of the pipe cross-section and design of the structure
Designing does not begin with a sketch, but with the definition of loads. The frame will be affected by its own weight, snow weight in winter, wind pressure and possible load from the hanging equipment. For racks is usually used profile-pipe section 100x100 mm or 80x80 mm at a height of up to 3 meters. For farms and runs, a profile of 60x40 mm or 40x20 mm is often used.
It is important to consider the length of the span. If you plan a garage for two cars without a central support, the length of the farm can reach 6 meters or more. In this case, simply increasing the cross section of the pipe is not enough - you need to change the geometry of the farm, making it higher and adding internal slanting. Triangular farm It is the most stable geometric figure in construction.
Formula for calculating snow load
Snow load is calculated by the formula S = Sg * ΞΌ, where Sg is the weight of snow cover per 1 m2 of the horizontal surface of the earth (taken from the SNiP for your region), and ΞΌ is the coefficient depending on the angle of inclination of the roof. For flat roofs ΞΌ = 1, for pitched roofs above 60 degrees, the load is not taken into account.
Below is a table of indicative sections of pipes for a garage of standard sizes (width 3-4 meters, length 6 meters) with an average snow load:
| Frame element | Recommended section (mm) | Wall thickness (mm) | Step of installation (m) |
|---|---|---|---|
| Vertical struts | 100x100 or 80x80 | 3-4 | 3.0 |
| Bottom strap. | 100x100 or 80x80 | 3-4 | - |
| Stroop farms | 60x40 or 50x50 | 2-3 | 1.5 - 2.0 |
| Runs (crate) | 40x20 or 40x40 | 1.5-2 | 0.5 - 1.0 |
When calculating, always lay a margin of safety of about 20-30%. Metal loses its properties over time due to corrosion, and climatic conditions can change. Using a thicker pipe wall is justified if you plan to attach a heavy gate or lifting mechanism to the frame.
Necessary tools and site preparation
The quality of the assembly depends on the preparation. The garage floor should be flat. If you are making a ribbon foundation, the upper edge of the ribbon should be strictly horizontal. For the installation of the frame you will need a welding machine (inverter capacity from 160A), a Bulgarian with metal discs, a building level, roulette and a coal mine.
Pay special attention to personal protection. Welding work involves working with an open arc, so the mask βchameleonβ and tight gloves-stealing are mandatory. Also do not forget about the respirator, as when cutting and welding metal, fine dust and harmful gases are formed.
βοΈ Preparation for the assembling of the frame
Before assembly, all pipes must be cleaned of factory lubrication, rust and scale. This will ensure better grip of the paint with the metal. If you use pipes that have been lying outside for a long time, it is better to treat them with a rust converter. Welding seams They also require cleaning to remove the slag and check the quality of the cooker.
For ease of work, it is recommended to make simple templates or stops (conductors) that will help to withstand right angles when welding the nodes. This is especially true for farms where all elements are symmetrical. An error in the geometry of one farm will lead to problems in the installation of the roof.
Technology of assembly and welding of nodes
The assembly of the frame usually begins with the lower belt - the binding. Pipes are laid on the foundation, exposed to the level and seized by welding. Only after checking the diagonals and horizontality can the seams be cooked completely. The seam should be continuous, without pores and cuts. For pipes with a wall thickness of 3-4 mm, an electrode with a diameter of 3 mm or 4 mm is considered optimal.
Installation of vertical racks is made alternately. First, corner racks are installed, then intermediate ones. It is important to strictly observe verticality, using plumb or laser level. Temporary slanting will help fix the racks until the moment of welding the upper belt. Corner joints It should be cooked on both sides for greater stiffness.
β οΈ Attention: When welding long seams, the metal heats up and can "lead". Cook the seams in a staggered manner in small areas (10-15 cm), allowing the metal to cool down to avoid deformation of the geometry of the frame.
Farms are better to collect on the ground, and then lift ready-made structures. This is safer and allows you to achieve perfect geometry. The lift is carried out with the help of a winch or a crane, after which the farms are fixed on racks and welded. The runs are laid on top of the farms and also welded.
Use magnetic charcoal for welding. They are inexpensive, but allow you to perfectly withstand the angle of 90 degrees when assembling straight knots, freeing the hands of the welder.
Anti-corrosion protection and insulation
Metal garage will last a long time only if you have reliable protection from moisture. After welding and cleaning of the seams, the entire structure must be covered with a primer for rust. It is better to use the compositions "3 in 1" (soil, rust converter, enamel), which are applied directly to the metal.
For insulation, mineral wool or polystyrene foam are most often used. In the case of metal, it is important to properly organize the ventilation gap. The insulation should not (contact) with a cold outer lining, otherwise condensate will accumulate inside, which will quickly lead to rotting (if it is cotton) or corrosion of the frame.
The optimal scheme of the "pie" of the wall: external sheathing (profencing) -> ventilation clearance -> waterproofing membrane -> insulation between the racks -> vapor insulation -> internal sheathing (car, OSB, drywall). This design will keep warm in winter and cool in summer.
The main enemy of a metal garage is not cold, but condensation. Proper steam and waterproofing is more important than the thickness of the insulation.
Common mistakes in construction
One of the most common mistakes is saving on metal. Buying a pipe with the minimum possible wall thickness (1.5-2 mm) for load-bearing pillars often leads to the fact that the frame begins to stagger even when installing the gate. load-bearing capacity Such a pipe is extremely low, and it is not always possible to save the situation with additional ukosins.
The second mistake is poor foundation preparation. If the pillars or the ribbon of the foundation are not brought to the horizon, when assembling the frame, huge stresses occur in the metal. The welder tries to βtightenβ the structure by creating internal stresses that later lead to cracks in the seams. Always use the level or hydro level.
The third mistake is ignoring the wind load. Garage with a large roof sail (for example, gable) should be securely secured. Lightweight structures are often torn down by hurricane winds if they were not anchored to the foundation. Use anchor bolts or embedded parts when pouring concrete.
Can you build a garage frame without welding, only on bolts?
Yes, it is possible, but requires more accurate preparation of holes and the use of high-strength bolts (strength class is not lower than 8.8). Bolt joints allow you to disassemble the structure, but they are less rigid than welded ones and require regular lifting. For the garage, this option is permissible if there is no possibility to use a welding machine.
What is the best foundation to choose for a frame garage?
The best option is a shallowly buried ribbon foundation or a columnary foundation with a roastwerk. If the soils are hollow, preferable pile-screw foundation, which allows you to lean on dense layers of soil below the depth of freezing. Slabbed foundation roads, but gives immediately ready floor.
Do I need to ground a metal garage?
Yes, I will. The metal frame is an excellent conductor of electricity. In the event of lightning or a breakdown of wiring inside the garage, the lack of grounding can lead to tragic consequences. The grounding circuit must be made according to the rules of the PUE.
What is better to paint the frame: brush or spray gun?
Krascopult gives a smoother and thinner coating, penetrating all hard-to-reach places, but requires skill and dilution of paint. A thicker layer can be applied with a brush, which is better for protection, but the surface will have a texture. For a frame that is not visible, high-quality brush processing is enough, paying attention to the corners and joints.
What is the best angle of roof inclination for a garage of flooring?
For profnatsil minimum angle of inclination is 8-12 degrees, but the optimal is considered 15-20 degrees. With less coal, the risk of leaks with heavy rain or snow melt increases, and the snow load increases. With more coal, the sailing of the structure increases.