The better way to sheathe a metal frame: comparison of 10 materials with prices and instructions

The metal frame is the basis for hundreds of structures: from garages and hangars to change houses and frame houses. But bare metal does not protect against cold, wind and moisture, and over time it begins to rust. Frame covering solves these problems by turning the skeleton from a profile or pipes into a full-fledged insulated room. The choice of material depends on the budget, climate and purpose of the building: corrugated sheet metal is suitable for a garage, and sandwich panels or OSB with insulation are suitable for a residential building.

In this article we will analyze 10 popular materials for cladding, their pros and cons, and also give step-by-step installation instructions. We will pay special attention typical mistakes, which shorten the service life of the structure, and we will tell you how to avoid corrosion of the frame under the cladding.

If you plan to sheathe the frame with your own hands, it is important to think in advance not only about the material, but also about the method of fastening, the need for insulation and waterproofing. For example, for regions with high humidity it is critical to use vapor barrier membranes, otherwise condensation will destroy the insulation in 2-3 seasons. And in northern latitudes without mineral wool or PPU A thickness of 100 mm or more is not enough - the thin skin will freeze already at −10°C.

1. Profiled sheet: fast, cheap and reliable

Profiled sheets (corrugated sheets) are the leader in popularity for cladding garages, hangars and temporary buildings. Made from galvanized steel with a polymer coating that protects against corrosion. Main advantage — installation speed: a team of 2 people sheathes a 6x4 m frame in 1 day.

There are three types of professional sheets:

• 📏 Wall (marking C) — wave height 8–44 mm, suitable for vertical surfaces.
• 🏗️ Roofing (N) — wave up to 114 mm, withstands snow loads up to 600 kg/m².
• 🔄 Universal (NS) - average option for walls and roofs with moderate loads.

For cladding frames they are often used profiled sheet C20 or S21 — it is optimal in terms of price and rigidity. The color of the coating is chosen not only for aesthetic reasons: dark shades (RAL 8017, RAL 7024) heat up more strongly in the sun, which can lead to deformation of sheets in southern regions.

⚠️ Attention: When attaching corrugated sheets with self-tapping screws, use rubber washers (EPDM). Without them, leaks will appear at the fastening points over time - the metal will begin to rust under the casing.

Average cost of profiled sheet S20 coated Polyester — 450–600 rub/m². More expensive options (Pural, PVDF) last longer (warranty up to 30 years), but the price rises to 800–1200 rub/m².

2. Sandwich panels: insulation + cladding in one

Sandwich panels consist of three layers: two sheets of metal (or OSB) and insulation between them. This the fastest way get a warm room without additional work. The panels are attached directly to the frame, joined using a tongue-and-groove system, and the seams are sealed with polyurethane foam or tape.

Types of insulation in sandwich panels:

• 🔥 Mineral wool - non-flammable, but afraid of moisture. Suitable for residential buildings.
• ❄️ Expanded polystyrene (PPS) - cheap, but flammable (class G3-G4). Used for garages.
• 🧊 PPU (polyurethane foam) - the best in thermal insulation, but expensive (from 2500 rub/m²).

The thickness of the panels varies from 40 to 200 mm. Enough for an unheated garage 50–80 mm, and for a residential building in central Russia you need a layer 150–200 mm.

Panel type	Thickness, mm	Thermal conductivity, W/m K	Price, rub/m²
Metal + mineral wool	100	0.038	1 200–1 800
Metal + PPS	80	0.035	900–1 400
OSB + PPU	150	0.022	2 500–3 500

Installation of sandwich panels requires care: if the top layer is damaged, moisture will penetrate into the insulation. For cutting use jigsaw with fine teeth or circular saw — the grinder overheats the metal, which leads to corrosion of the edges.

3. OSB boards: a budget option for insulated buildings

Oriented strand boards (OSB) are a popular material for cladding frame houses and cabins. They are cheaper than sandwich panels, but require additional insulation and waterproofing. Main advantage — ease of processing: OSB is cut with a hacksaw, it is easy to screw self-tapping screws into it.

OSB classes for cladding:

• 🏗️ OSB-2 — for dry rooms (interior partitions).
• 💧 OSB-3 — moisture resistant, suitable for external cladding.
• 🔥 OSB-4 - reinforced, for load-bearing structures (rarely used).

Standard slab thickness - 9–12 mm for walls and 15–18 mm for roofs Cost OSB-3 9 mm thick - 300–450 rub/m². For external cladding, the slabs must be covered facade paint or vinyl siding, otherwise they will swell from the rain.

⚠️ Attention: When purchasing OSB, check the certificate E1 (low formaldehyde emission). Class slabs E2 toxic and prohibited for residential premises in the EU.

Installation technology:

1. Attached to the frame vapor barrier membrane (for example, Izospan B).
2. Insulation (mineral wool or ecowool) is installed.
3. OSB boards are attached to the top with self-tapping screws 15–20 cm.
4. The seams are sealed acrylic sealant or covered with flashings.

Check the evenness of the racks (deviation no more than 2 mm per 1 m)

Treat the metal with anti-corrosion primer (Tsinkol)

Install horizontal jumpers for rigidity

Secure the vapor barrier with an overlap of 10–15 cm -->

4. Metal siding: durability and aesthetics

Metal siding is steel or aluminum panels with a polymer coating that imitate wood paneling, stone or brick. Main advantage in front of the profiled sheet - a more presentable appearance and the ability to choose a texture. For example, timber siding visually indistinguishable from a wooden house.

Types of metal siding:

• 🏡 "Ship board" - classic horizontal profile.
• 🧱 "Under the brick" - imitation masonry, popular for facades.
• 🌲 "Block House" — imitation of a rounded log.

The cost of metal siding starts from 700 rub/m² (economy class) up to 2000 rub/m² (premium coated Printech). Installation requires a sheathing made of metal profiles or wooden beams (section 40×40 mm). Attach the panels to clamps or self-tapping screws with a press washer.

Coated metal siding Pural or Granit HD guaranteed not to fade for 20+ years even in the southern regions (tests according to the standard EN 10169). This is critical for facades facing south.

5. Wood-polymer composite (WPC): an alternative to wood

WPC is a mixture of wood flour (60–70%) and polymers (polypropylene, PVC). The material imitates wood, but does not rot, does not require painting and serves 25–30 years. Ideal for covering cabins, gazebos and facades of houses in the style eco or scandi.

Advantages of WPC:

• 🌳 Does not crack or deform from moisture (unlike lining).
• 🔥 Flammability class G2 (moderately flammable).
• 🎨 Wide selection of colors: from PAL 8017 (chocolate) to PAL 7016 (anthracite).

Disadvantages:

• ❌ More expensive than metal: price from 1500 rub/m².
• ❌ Heavier than vinyl siding - requires a reinforced frame.

Installation of WPC is similar to siding: the panels are attached to the sheathing with a gap 3–5 mm for thermal expansion. Used for cutting circular saw with carbide teeth - an ordinary hacksaw leaves chips.

How to distinguish high-quality WPC from a fake?

High-quality WPC has uniform texture without voids and delaminations on the cut. Counterfeits often contain too many polymers (less than 50% wood), causing the panels to become brittle at −20°C. Check the certificate by GOST 32971-2014 — it must indicate the composition.

6. Lining and block house: natural wood

Wooden cladding (lining, block house, imitation timber) is an environmentally friendly, but demanding material. Suitable for baths, houses in the style chalet or country, as well as for interior decoration. Main disadvantage - the need for regular care: painting or impregnation with an antiseptic every 2–3 years.

Comparison of wood species:

Breed	Service life, years	Cost, rub/m²	Features
Pine	10–15	400–700	Resinous, rot resistant
Larch	25–30	1 200–1 800	Solid, not afraid of moisture
Oak	50+	3 000–5 000	Elite option, requires impregnation

For external cladding, class lining is used A or Extra (no knots). Board thickness - 16–20 mm. The wood is treated before installation antiseptic (for example, Senezh Ultra) and fire retardant (fire protection).

⚠️ Attention: When covering the frame with wood, leave ventilation gap 2–3 cm between the insulation and the lining. Without it, condensation will lead to wood rotting in 3–5 years.

7. Plastic siding: lightweight and inexpensive

Vinyl siding is the most budget option for cladding (from 250 rub/m²). It does not rot, does not rust and does not require painting, but it has limitations:

• ❌ Withstands temperatures from −50°C to +50°C, but at −30°C it becomes fragile.
• ❌ Flammable (class G4) - not suitable for residential fire codes.
• ❌ Deforms when heated above +60°C (critical for southern regions).

Pros:

• 💰 The cheapest material.
• 🎨 Large selection of colors (more than 20 shades).
• ⚡ Light weight - does not load the frame.

For installation of vinyl siding use galvanized sheathing in increments of 40–60 cm. The panels are mounted on stainless steel screwsleaving a gap 1–2 mm for expansion. Service life - 15–20 years with proper care (wash with water under pressure once a year).

8. Fiber cement boards: for extreme conditions

Fiber cement boards (eg. Cembrit or Eternit) consist of cement, cellulose and mineral additives. They don't light up, do not rot and withstand hurricane winds up to 200 km/h. Ideal for coastal areas or regions with frequent fires.

Specifications:

• 🔥 Flammability class NG (non-flammable).
• 💪 Bending strength - up to 20 MPa.
• ❄️ Frost resistance - 100 cycles freezing/defrosting.

Disadvantages:

• ❌ Weight — 15–20 kg/m² (requires reinforced frame).
• ❌ Fragility when cutting - you need a diamond saw.
• ❌ Price - from 1200 rub/m².

Fiber cement boards are mounted on galvanized profile in increments of 60 cm. For cutting use grinder with diamond blade or jigsaw with concrete saw. When installing, be sure to use respirator — Dust from stoves is harmful to the lungs.

Common mistakes when covering a metal frame

Even high-quality material will not save you from problems if the installation technology is violated. Here 5 critical errors, which lead to corrosion of the frame or destruction of the skin:

1. Lack of waterproofing. Without membrane (eg Tyvek) condensation accumulates on the metal, causing rust. This is especially true for insulated buildings.
2. Tight fit of the sheathing to the frame. Need to leave a gap 1–2 mm for thermal expansion (critical for WPC and vinyl siding).
3. Using black screws. They rust in 2–3 years. Take only galvanized fasteners with a rubber washer.
4. No anti-corrosion treatment. The frame must be covered before covering zinc primer (for example, Zinga).
5. Incorrect sheathing pitch. For corrugated sheets - 50–60 cm, for siding - 40 cm. If you do it less often, the skin will sag.

Another typical problem is cold bridges. They appear if the insulation is not laid tightly or the panel joints are not sealed. As a result, frost forms on the walls and the room becomes damp.

How to check the quality of the cladding after installation?

1. Walk along the walls thermal imager (or with your hand in cold weather) - cold bridges will be noticeable as cold streaks.

2. Tap the trim rubber mallet. A dull sound means moisture has accumulated under the panel.

3. Check seam tightness flashlight: in a dark room, light should not leak out.

FAQ: Answers to frequently asked questions

Is it possible to cover a metal frame with plasterboard?

Drywall is suitable only for interior decoration heated premises. It is not suitable for external cladding - it gets wet from rain and crumbles when it freezes. If you need to sheathe the frame inside, use moisture-resistant plasterboard (GKLV) 12.5 mm thick and prime it before painting.

What insulation is best for a metal frame?

The choice depends on the budget and climate:

• Mineral wool (Rockwool, Isover) - the best option in terms of price/quality ratio. Not flammable, but afraid of moisture.
• Ecowool - environmentally friendly, but requires special equipment for application.
• PPU (polyurethane foam) - the most efficient (thermal conductivity 0.022 W/m K), but expensive and flammable.

Often used for garages polystyrene foam PSB-S-25 (cheap, but rodents eat it).

Do I need to treat the metal frame before covering it?

Definitely! even if the frame is made of galvanized profile. Minimal processing:

1. Clean metal from rust metal brush or sandblasting.
2. Apply anti-corrosion primer (for example, Phosphosoil).
3. Paint alkyd enamel (for the street) or hammer paint (for garages).

Without treatment, a ferrous metal frame will rust in 5–7 years, even under the cladding.

Is it possible to sheathe the frame in winter?

Yes, but with reservations:

• Vinyl siding and WPC are installed at a temperature not lower than −10°C — in the cold they become fragile.
• When using polyurethane foam, choose winter (for example, Tytan Professional −20°C).
• Metal panels (corrugated sheets, sandwiches) can be fastened at −20°C, but your hands get cold and work slows down by 2 times.

The optimal time for sheathing is spring or autumn (temperature +5°C to +25°C).

Which material is the most durable?

The leaders in terms of service life are:

1. Fiber cement boards - 50+ years.
2. Metal siding with PVDF coating - 30–40 years.
3. Larch or oak — 25–50 years (with regular treatment).

The most short-lived: vinyl siding (15–20 years) and OSB without protection (5–10 years).