Frame for a shell garage: a complete guide to selection and installation

A shell garage is the optimal solution for protecting a car from precipitation, sun and mechanical damage when the construction of a permanent garage is impractical or prohibited by SNT standards. However, the strength and durability of such a structure depends 80% on the quality frame. Wrong choice of materials, errors in calculations or installation lead to roof deformation, corrosion of supports, or even collapse in strong winds.

In this article we will analyze all the stages - from choosing between metal and wooden frame to step-by-step assembly taking into account climatic loads. We will pay special attention hidden defects of factory kits, which sellers are silent about: thin-walled pipes, lack of anti-corrosion treatment of welds or non-compliance with the declared loads. You will learn how to avoid overpaying for “air” and assemble a structure that will last at least 15 years.

1. Types of frames for shell garages: comparison of materials

The main division of frames is based on the material of manufacture. Each option has pros and critical disadvantages, which appear after 2–3 years of operation.

• 🔹 Metal frame (profile pipe, channel): withstands snow loads of up to 200 kg/m², but requires mandatory treatment against corrosion. Cheap kits are made from pipes 1–1.5 mm thick - they bend under the weight of polycarbonate.
• 🌲 Wooden frame (timber 100×100 mm, board 50×150 mm): environmentally friendly and easy to install, but without impregnation with an antiseptic it rots in 3–4 seasons. A critical mistake is using raw wood, which will dry out.
• 🔄 Combined frame (metal + wood): supports made of pipe 60×60 mm, sheathing made of timber. Optimal for regions with high humidity, but requires proper fastening to avoid galvanic corrosion.

According to research Research Institute of Building Physics, metal frames with zinc coating last 2.5 times longer than painted ones, and wooden structures made of larch are 40% more resistant to rotting than pine ones. However, in coastal areas, even larch without additional treatment is destroyed in 5–7 years.

⚠️ Attention: If you buy a ready-made frame kit, check the certificate of conformity GOST 23118-2019 (for metal) or GOST 8486-86 (for lumber). The absence of a document is a sign of handicraft production with understated characteristics.

2. Calculation of loads: why standard drawings are not suitable

Typical schemes of shell garages from the Internet are designed for average snow load 100 kg/m² (suitable for Central Russia). However, in most regions the standards differ:

Region	Snow load, kg/m²	Wind load, kg/m²	Recommended Frame Material
Moscow region	120	35	Pipe 40×40×2 mm or timber 100×100 mm
Leningrad region	180	42	Pipe 60×60×2.5 mm with reinforcement
Krasnodar region	50	50	Pipe 30×30×1.5 mm or timber 80×80 mm
Siberia (Novosibirsk)	240	30	Pipe 80×80×3 mm with arched structure
Far East (Khabarovsk)	320	60	Channel 100×50 mm or I-beam

For an accurate calculation, use the formula:

Q = S × k, where:

• Q — total load on the frame;
• S — roof area (m²);
• k — safety factor (1.2 for metal, 1.4 for wood).

Example: a 6x3 m garage in the Moscow region (120 kg/m²) with a metal frame:

Q = 18 m² × 120 kg/m² × 1.2 = 2592 kg. This means that the total weight of the structure, including polycarbonate, should not exceed 2.6 tons.

3. Step-by-step instructions for installing a metal frame

The metal frame is assembled in 5 stages. The critical mistake is to start from the roof. First, the supports are fixed, then they are connected with horizontal jumpers, and only after that the arches are mounted.

Remove the fertile soil layer 20–30 cm under the supports|

Check the level of the platform (permissible difference is 1 cm per 1 m) |

Treat the pipes with an anti-corrosion compound (for example, Tsinol or Galvanol)|

Prepare M200 concrete mortar for the foundation |

Mark the installation locations of the supports in increments of 1–1.5 m -->

Stage 1: Installation of support pillars

For a 6x3 m garage you will need 8 supports made of 60x60x2.5 mm pipe. Depth:

• 🏡 For soils with normal bearing capacity (loams, sands) - 50–60 cm;
• 🌊 For heaving soils (clay, peat) - 80–100 cm with a sand cushion of 20 cm.

Algorithm:

1. Drill holes with a drill with a diameter of 200 mm.
2. Install the pipes, leveling them (use laser level or hydraulic level).
3. Fill with concrete, leaving 10 cm to the top for waterproofing (e.g. bitumen mastic).

Stage 2: Bundle of supports with jumpers

Horizontal jumpers made of 40x40 mm pipe are mounted at a height of 2.2 m (standard height of a shell garage). Use:

• 🔧 Welding - for permanent structures (process the seams zinc spray);
• 🔩 Bolted connections — for collapsible garages (M10 bolts with grommets).

4. Typical assembly mistakes and how to avoid them

According to statistics Rosstroykontrol, 65% of collapses of shell garages occur due to errors during the installation of the frame. Here are the most dangerous of them:

1. Ignoring wind load. In coastal and steppe areas, crosswinds create lift that can tear off the roof. Solution: install diagonal braces from a 20x20 mm pipe.
2. Savings on fasteners. Metal screws instead of bolts or nails instead of screws lead to loosening of the units. For a wooden frame use galvanized screws 6x100 mm, for metal - M8 bolts with nuts.
3. No ventilation gaps. Polycarbonate expands when heated, and if it is firmly fixed, the sheets will warp. Leave a gap of 3–5 mm between the sheets and the frame, use thermal washers.

⚠️ Attention: If you are installing a shell garage on an area with a slope of more than 5°, standard drawings will not work. Need to design stepped foundation or use adjustable supports (e.g. screw piles).

What happens if you don’t take into account the heaving of the soil?

When freezing, heaving soils (clay, loams) expand and push the supports upward. In spring, the soil sags and the frame “sags.” After 2-3 freeze/thaw cycles, the geometry of the garage is disrupted, the roof warps, and the polycarbonate cracks. In critical cases, the supports break at the base.

5. Frame cost: ready-made kit vs self-assembly

The price of the frame depends on the material, garage size and region. Average prices for 2026:

Frame type	Garage size (m)	Cost of the set, ₽	Cost of materials for self-assembly, ₽	Savings
Metal (pipe 40×40×2 mm)	6×3	45 000–60 000	28 000–35 000	35–40%
Wooden (timber 100×100 mm)	6×3	35 000–45 000	18 000–22 000	45–50%
Combined	6×3	50 000–70 000	32 000–40 000	30–35%
Metal (pipe 60×60×2.5 mm)	7×4	70 000–90 000	45 000–55 000	25–30%

Self-assembly is 25–50% more profitable, but requires:

• 🛠️ Skills in working with a welding machine (for metal) or a circular saw (for wood);
• 📐 Accurate drawings taking into account climatic loads;
• 🚛 Access to trucks for delivery of materials (6 m pipes will not fit in a passenger car).

Ready-made kits are more expensive, but include:

• 📋 Detailed instructions with photographs;
• 🔩 All fasteners (bolts, screws, washers);
• 🛡️ 1-3 year warranty (subject to installation by certified teams).

6. Anti-corrosion treatment: how to extend the life of the frame

Even galvanized metal without additional protection rusts in places where it is welded and cut. Optimal processing scheme:

1. Cleaning: Remove rust with a metal brush or sandblaster. For hard to reach places use rust converter (for example, Tsinkar).
2. Primer: Apply 2 coats epoxy primer (for example, Dulux Trade) with intermediate drying for 4 hours.
3. Coloring: use acrylic enamel for metal (for example, Hammerite) in 2–3 layers. For a wooden frame - yacht varnish or terrace oil.

Service life of the treated frame:

• 🔹 Without protection: 3–5 years;
• 🔹 With primer and paint: 10–12 years;
• 🔹 With zinc coating + painting: 15–20 years.

⚠️ Warning: Do not use alkyd paints for a metal frame - they are inelastic and crack when temperature changes. Also avoid oil paints for wood: they create a film under which moisture accumulates.

7. Alternative solutions: when the frame is not needed

If you need a temporary car shelter (for a season or while you're building a house), consider the following alternatives:

• 🏠 Inflatable garage (made of PVC): assembled in 1 hour, withstands snow up to 50 kg/m², but is afraid of punctures. Cost: 25,000–40,000 rubles.
• 🧊 Tent garage (on an aluminum frame): weight up to 30 kg, carried manually, but does not protect against hail. Cost: 15,000–25,000 rubles.
• 🚗 Car covers (for open parking): suitable for rare use, but do not protect against vandals. Cost: 5,000–12,000 rubles.

The advantages of such solutions:

• ✅ Does not require a foundation;
• ✅ Can be transported;
• ✅ 2-3 times cheaper.

Disadvantages:

• ❌ Service life - 3-5 years;
• ❌ They do not protect against theft;
• ❌ Requires monthly maintenance (pumping, snow removal).

Frequently Asked Questions

Is it possible to install a shell garage without a foundation?

Yes, but only on hard ground (asphalt, concrete ground) and provided that the supports are buried at least 30 cm. On heaving soils (clay, peat) or with a slope of more than 3°, a foundation is required. Alternative - screw piles (price from 2,500 ₽ per piece).

Which polycarbonate is best for a shell garage roof?

Optimal choice - cellular polycarbonate 8–10 mm thick with UV protection. Cheap monolithic polycarbonate (4 mm) turns yellow after 2–3 years, and sheets thinner than 6 mm sag under the snow. For northern regions use profiled polycarbonate - it is tougher and sheds snow better.

Is it necessary to approve the construction of a shell garage in SNT?

By Art. 51 Civil Code of the Russian Federation, approval is not required if:

• The garage area does not exceed 50 m²;
• Height no more than 3 m;
• The structure is not permanent (without a foundation or on screw piles).

However, some SNT have internal rules prohibiting metal structures for aesthetic reasons. Check with the chairman.

How to insulate a shell garage for winter car storage?

Insulation is possible, but requires modification of the frame:

1. Sheath the interior walls penoplex 30 mm thick;
2. Install second sheathing for fastening interior trim (for example, OSB boards);
3. Close the ends of the garage sandwich panels or professional sheet;
4. Add thermal curtain at the entrance (for example, PVC tapes).

Cost of insulation: 15,000–25,000 rubles. The temperature inside in winter will be 5–8°C higher than outside.

What to do if the frame is already rusting?

Recovery algorithm:

1. Clean off the rust sandblaster or drill attachment;
2. Treat affected areas rust converter;
3. Apply 2 coats zinc-containing primer;
4. Paint hammer enamel (for example, Hammerite).

If the rust is through (holes), cut out the area with a grinder and weld a patch from a pipe of the same thickness.