The best ways to attach polycarbonate to a metal frame

The choice of step is the most important stage in the construction of the frame.

When installing the frame under the panels, it is necessary to more accurately select the pitch of the lathing, which depends on the magnitude of the bending of the material, its thickness and the angle of the roof slope. The roof slope angle cannot be less than 30 °. Knowing all the nuances of the construction of the frame, you can quickly set the step of the lathing (it is equal to a hundred times the thickness of the material).

For example, for a sheet with a thickness of 4 mm, the step will be 40 cm, for 8 mm - 80 cm. In other words, the greater the thickness of the material, the less often the lathing step. It should be noted that thick cellular polycarbonate is fastened faster, because the step of the fasteners is smaller and the material bends less. For regions with snowy winters, the crate pitch is reduced by 10-15%. When a frame with such a step is expensive, it is better to do otherwise: design the structure in such a way that the snow from the roof quickly disappears. To do this, use a roof slope of 30 - 50 °. At such degrees, the cellular panels are securely attached, and the snow melts well.

During the installation process, they are especially careful with the fastening, which is performed using washers. If there are few of them, then the sheet material will not be securely fixed.

Given its large windage, there is a possibility that the leaf will be torn off by a strong wind. But it is also not necessary to install many washers, because this will increase the load on the panels, and they may not withstand hot weather and deform. The same can happen in a snowy winter, when wet snow freezes on the sheets of material and the load on the frame exceeds the maximum permissible, as a result, the sheet material breaks. But in any case, you need to use washers so that the fastening is reliable.

On the merits of cellular material

Cellular polycarbonate is quite lightweight. Compared to glass, it is about ten times lighter than the latter.

The walls of the cells act as stiffeners, thanks to which the material is strong in bending and can withstand external loads.

Other advantages of polycarbonate include:

1. Transparency, light transmission and light scattering, which have a beneficial effect on plants (if a greenhouse is built from the material).
2. Resistant to moisture and some chemicals.
3. Easy to transport. Before loading into the car, you can roll the sheet into a roll.
4. Fire resistance. The material does not burn, but melts without emitting toxic substances.
5. Ease of dismantling. One or more sheets can be easily replaced if necessary.
6. Long service life (8-10 years). If you cover the material with a UV protective compound, it will last up to 25 years.

General installation rules

Storage before installation

1. laying is carried out with UV protection upward (see the marking on the protective film), on a flat pallet, avoiding overhanging of the edges and deformation;
2. stack height - up to 2.5 meters;
3. the room is selected dry, ventilated, shaded;
4. there should be no heating appliances nearby;
5. do not cover with plastic wrap.

Protective coatings

They are not removed during transportation, storage, cutting, drilling and installation. They are removed immediately after completion of work.

Immediately after cutting, the film is removed from the edges, the chips are removed and the sealing is carried out.

Frame

When developing a frame project, take into account:

• wind and snow loads;
• thermal deformation of panels;
• direction of rainwater flow;
• permissible bending radii;
• the size of the sheets used, taking into account the economical cutting;
• the edges of the sheet along the long side are best supported by supporting supports;
• installation pitch of longitudinal supports - 700 mm, 1050 mm plus thermal gap between the panels;
• the thickness of the supporting beams must be at least 30 mm for attaching the connecting profiles;
• before installation, the frame is painted white or very light. It is advisable not to allow direct contact of polycarbonate with metal, using rubber gaskets with a diameter of 30 mm and a thickness of 3 mm.

The approximate pitch of the lathing for a flat structure (without taking into account the angle of inclination and climate features):

The approximate pitch of the lathing for an arched structure (excluding geographic location):

Temperature accounting for installation work

In the temperature range from +10 to +20 degrees, polycarbonate does not undergo thermal expansion. This is the best mode for editing.

In hot weather, the gaps between panels and connecting profiles are reduced to a minimum, in cool weather, they are increased to a maximum.

Cleaning polycarbonate after installation

If, after removing the protective film from the honeycomb or molded polycarbonate, it becomes necessary to clean, use a mild neutral detergent, warm water and a cotton cloth. Rinse with cold water and remove water droplets with a dry soft cloth.

For large areas of processing, a machine washing method is used. Stubborn dirt can be removed with isopropyl alcohol.

Basic properties of polycarbonate

Diagram of a polycarbonate greenhouse frame.

Polycarbonate has properties that are taken into account during fastening work. Polycarbonate in a greenhouse can shrink in the cold and expand during high temperatures. This fact should be taken into account during installation. I take into account this feature of polycarbonate, the hole for self-tapping screws is always made 2.5 mm larger than its diameter. When fastening, you need to ensure that the sheets and honeycombs are not squeezed during the tightening of the self-tapping screw.

Polycarbonate sheets are easily connected to each other and to other materials using gluing, welding, bolts and rivets. It is sawn, drilled, polished, cut with a cutter. When drilling, use standard well-sharpened drills. Drilling is carried out between the stiffeners.

Use a circular or band saw to cut the sheet. Can be cut with a wide, sharp knife.

All polycarbonate sheets are covered with foil on both sides. White or transparent goes along the inner side of the sheet, which will face the interior of the room. This protective film is removed before use. All polycarbonate is covered from the outside with a film that protects greenhouse plants from ultraviolet rays of the sun. It is easily injured, and therefore another, removable film is applied on top of it, which is not removed until the end of the work. It is easy to distinguish it because it has a color, usually blue or any other color, but not white.

Necessary distances that are observed when attaching polycarbonate

1. The hole for self-tapping screws must be at least 4 cm from the edge of the sheet.
2. The distance between the holes is 50 cm for panels with a thickness of 10 mm. For sheets with a thickness of 16 mm, 80 cm is enough.
3. On a sheet with a thickness of 4 mm, fastening is done every 40-50 cm from each other, on a sheet with a thickness of 6 mm, the distance should not exceed 60-70 cm either vertically or horizontally.
4. In order for the screw not to damage the sheet, it is necessary to make holes in it in advance, which will be 2-3 mm larger than the screw. Then, during fastening work, the sheet will not be damaged.

Thermal washer and its device

Installation diagram of cellular polycarbonate.

The most correct way to attach polycarbonate sheets is to use the thermal washers that are usually included in the kit. They are put on the roofing screws and screwed in as usual.

The thermal washer consists of:

• a cover that protects the screw from moisture and rust;
• plastic washer;
• sealing washer.

This whole structure is put on a screw.

The thermal washer is sensitive to temperature changes, protects polycarbonate during temperature changes. This property of the thermal washer extends the life of the polycarbonate. A 4-meter greenhouse will need 150 of them. If the length of the greenhouse is 6 meters, then 170 pieces will be needed. If the price of thermal washers is not included in the kit, then they are bought separately, at an average price of 10 rubles. a piece. This increases the cost of the greenhouse and at the same time increases its service life. Therefore, spending on a thermal washer turns into a benefit for the purchaser.

Galvanized tape as a method of fixing polycarbonate

The use of galvanized tape is a new fastening method that allows polycarbonate to be fastened without perforating the sheet. It is pressed with a tape, and then several of them are pulled together at certain points. There are advantages and disadvantages to using this method. Installation time is reduced, and the greenhouse looks original. Among the disadvantages is easy dismantling, which allows intruders to quickly remove the cover from the greenhouse and take it away from the site. The second disadvantage of fastening with galvanized tape is the reduction in operating time. After a couple of years, the tape will weaken and the sheets will begin to dangle in the wind. Then the owner of the greenhouse will have to strengthen everything using roofing screws with rubber seals.

Using roofing screws

Roofing screws must have a sealing rubber press washer. Self-tapping screws are chosen whose diameter is 6 mm or more. If you need to fasten long solid sheets, then the holes are made oval. The long semiaxis of the oval should be located along the length of the sheet, in the middle of the inner channel of the panel. The use of roofing screws with a press washer provides additional structural rigidity. The press washer, which comes with the roofing screw, makes it possible to evenly distribute the pressure on the covering sheet. This fastening is reliable. It will not weaken over time and does not require maintenance. There is a guarantee that the sheets will not go away under the weight of snow and will not fly away from strong winds.

Basic fixing rules

It is impossible to fasten polycarbonate to a wooden frame if the latter has not been given proper stability. The mass of polycarbonate is small due to its cellular structure - a person can easily lift one or several sheets and carry them to the place of work. Weight gain makes it possible to increase the massiveness of the supporting structure, which will stand for decades.

To securely fix cellular polycarbonate on a tree, you must adhere to a number of rules.

1. Moisture condensed from the temperature drop on the inner surface (ceiling and walls of the greenhouse) should drain through the cells inside the sheet and evaporate into the atmosphere.
2. The direction of the stiffeners and the retaining elements is the same. Sheets mounted horizontally are placed only on horizontal supports. Likewise with vertical polycarbonate decking. Diagonal, arched structures also have a stiffener unidirectional with the elements of the supporting base.
3. As with siding, wood flooring, etc., thermal expansion / contraction gaps are required - both for the profiled corners and for the sheets themselves. Without leaving them, the owner of the structure dooms the polycarbonate to swelling in the heat and cracking (from excessive tension of the sheets) in the cold.
4. Sheets are not cut along the stiffening edges, but between them.
5. When cutting polycarbonate sheets, you need a sharpened tool. If this is a construction and assembly blade, it is not inferior in sharpness to a razor blade, and in strength - to a medical scalpel.If it is a saw, its teeth should be located in the same plane, and not "split" and be coated with a reinforcing spraying (pobeditovy alloy, high-speed steel of special strength, etc.).
6. To avoid skewing, the sheet turned out to be of a given shape, they use guide rails and clamps for reliable fixation of both the sheet and the rails themselves.
7. The thread diameter of the self-tapping screw is chosen at least 1-2 mm less than the hole itself. An attempt to clamp the sheet with self-tapping screws without reaming at the attachment point will immediately lead to cracks in the polycarbonate structure. This will not only spoil the appearance of the floor being assembled, but also worsen its strength and waterproofness.
8. Bolts (or self-tapping screws) cannot be overtightened, and also not screwed at a right angle to the supporting support and the plane in which the sheets are located. This will lead to cracking of the polycarbonate due to significant temperature fluctuations. Both honeycomb and monolithic types of polycarbonate are susceptible to cracking, no matter how flexible and elastic they may seem.

In places where the wooden structure is adjacent to the sheets, it is covered with an agent against germs, mold and mildew. Then a non-combustible impregnation is applied - if necessary, in several layers. On top of it, a waterproof varnish is applied (for example, parquet). If these recommendations are followed, the greenhouse will stand for more than a dozen years.

What role do thermal washers play?

Correct fastening of polycarbonate sheets to the greenhouse frame necessarily implies the use of thermal washers.

Thermal washer TSh-6

These elements are made of rubberized plastic and usually consist of three structural elements:

• rubber seal;
• covers;
• washers with a through hole for the passage of the self-tapping screw.

Thermal washer for polycarbonate photo

Typically, thermal washers come complete with self-tapping screws and there is no need to select them separately. Nevertheless, it is worth considering some peculiarities. So, if it was decided to use thick polymer sheets for the construction of a greenhouse, it would be more correct to use a special thermal washer with a leg. Such a washer is recessed deeper into the body of the sheet, providing reliable fastening and allowing to significantly reduce the pressure of the fastening structure on the sheet.

Thermal washers with fixing foot

The use of self-tapping screws with thermal washers allows you to give the structure several important advantages at once.

1. Reliability. When outdoors, polycarbonate (however, like any other material) is subject to temperature deformations - expansion in the hot season and narrowing in cold weather. Thermal washers allow you to leave the necessary gap, which does not interfere with the slight "walking" of the material. This helps to avoid deformation of the walls of the greenhouse and to increase its service life.
2. Thermal protection. A very important indicator especially for greenhouses, the main task of which is to prevent the plants from freezing before the onset of the warm season. Thermal washers provide an almost tight contact at the point of fastening of self-tapping screws, preventing the penetration of cold air into the structure.
3. Tightness. Provides protection against moisture ingress. The thermal washer helps to protect the polymer sheet from premature destruction, as well as the wooden or metal frame at the point of contact from corrosion or deterioration.

Universal thermo washer with EPDM-seal

If you take care of the aesthetic side of the issue, then it is best to choose the color of the thermal washer that is closest to the color of the polycarbonate itself. A huge selection in modern hardware stores makes this easy. As a rule, the price does not depend on the coloring of plastic elements.

Polycarbonate fixing scheme using a self-tapping screw and a thermal washer

Types of self-tapping screws

Depending on the material from which the supporting frame of the structure is made, self-tapping screws are used to fasten various types of polycarbonate.Self-tapping screws can differ in steel grade, have a different head shape, diameter and thread pitch.

Self-tapping screws for a wooden frame

The main distinguishing feature of self-tapping wood screws is a wide thread pitch and the ability to use low-strength steel. The low density index and fibrous structure of wood allow screws with such technical characteristics to be reliably fixed in the body of wooden structures.

For such self-tapping screws for polycarbonate, the price is much lower than for hardware made of high-alloy steel grades. It is desirable that the surface of the self-tapping screws be galvanized, since the anti-corrosion coating of the metal is guaranteed to prevent the occurrence of rust streaks on the surface of the polycarbonate sheets.

The length of the self-tapping screw should take into account the height of the leg of the thermal washer and ensure its penetration into the body of the frame structure by an amount equal to 2/3 of the thickness of the wooden beam. In the case of attaching a split profile to the frame, which serves to connect polycarbonate sheets to each other, the length of the self-tapping screw must also take into account the thickness of this element.

The screw diameter should be 6-8 mm. Self-tapping screws with a smaller diameter can deform when screwed in, and an overestimated diameter can cause cracks in the wooden supporting structure. The screw head can be either a circular cross-notched head or a hexagon shape. The latter is considered more reliable, but when working with wooden structures, this feature can be neglected, saving money.

Self-tapping screws for metal structures

As a rule, square steel pipes with a wall thickness of 2-3 mm are used as a metal frame for fixing polycarbonate sheets. Such structures remain stable against seasonal fluctuations in temperature and humidity. When working with this material, it is necessary to apply much greater efforts than when working with wood, therefore, higher requirements are imposed on the fasteners.

Hardware with a tip with a special drill is used as fasteners. This design allows you to screw the self-tapping screw into the metal without a pre-drilled hole.

Self-tapping screws are made of high quality steel and have a hexagonal head shape. The thread pitch of the hardware is smaller in comparison with the pitch of the wood screws and may have additional fixing notches along its entire length. The length of the self-tapping screw is selected taking into account the fact that it must enter the wall of the metal pipe by half and ensure the possibility of installing a thermal washer with a gasket. Illustrates how self-tapping screws for polycarbonate are screwed into metal in the photo below.

Panel fixing materials

The stiffeners of the polycarbonate sheets are distributed along the length. To achieve maximum structural strength, the hollow channels must be correctly positioned:

• If the panel is installed vertically, then the channels are located vertically.
• In arcuate structures, the channels should be parallel to the bend line.
• In structures of an inclined type - in the direction of the slope.

In the manufacture of external structures, polycarbonate should be used, which on the outside has protection from ultraviolet rays in the form of a film of special substances. The manufacturer indicates all the necessary information on it. For the correct positioning of the polycarbonate sheets, the film is not removed during the installation process.

To solve the problem of how to attach polycarbonate to metal, you need to use the following:

• Various types of profile, including end, corner, connecting, wall and ridge.
• Fasteners in the form of thermal washers and mini-washers.
• Different types of plugs.
• Adhesive tape for ends, including perforated tape for bottom edges.
• Profile seals.

End profiles are used to protect the edges of the polycarbonate, and the short shelf is always located outside. Connecting profiles can be detachable universal or solid H-shaped. They are designed to join the edges of the panels.

It is important to remember that only split profiles can be attached to the frame. Corner profile allows you to connect elements at right angles

The wall profile makes it possible to tightly adhere the panel to the wall. Can be used as an end profile. A ridge profile is required to connect the panels on the ridge of the roof, provided that the elements are connected at an angle greater than 90.

Fastening polycarbonate to metal is carried out with different types of thermal washers. These fasteners can differ in the following ways:

• Design features make it possible to highlight individual and universal thermo washers. In the first case, the element has a length in accordance with the thickness of the sheet, which prevents the polycarbonate from being pinched or deformed. The second option does not have a leg, therefore, it can be used for material of any thickness.
• Depending on the material of manufacture, the fasteners can be made of stainless steel (for covering large areas), polycarbonate (ensure tightness of the connection without damaging the panel), polypropylene (for working indoors or in the shade).
• Mini washers are used for lightweight panels.

Plugs

To make the structure attractive, and to protect the ends of the profiles from the ingress of water, dust and insects, it is necessary to use plugs.

Under the influence of high temperature, some change in polycarbonate may be observed, therefore, certain installation rules must be observed:

• Mandatory presence of gaps.
• Enlarged mounting holes.
• The use of thermal washers.
• Application of special types of profiles.

To perform a high-quality panel installation, you need to take care of the correct storage of the purchased material:

• Lay the sheets on a flat surface with a protective film facing up.
• The stack height should not exceed 2.5 meters.
• Store the material in a dry ventilated area away from heating appliances.
• It is not recommended to cover the material with polyethylene.

In addition, it should be remembered that the protective coating is removed from the panel only at the end of the installation work.

The quality of work largely depends on the compatibility of the materials used. Therefore, it is not allowed to use polyurethane, PVC, amine and acrylic based sealant with polycarbonate.

When drafting a frame, one should take into account various types of load, temperature effects, dimensions of the material used, permissible bending radius, direction of wastewater

It is very important to know through what distance to fix polycarbonate

The optimum temperature for working with polycarbonate is in the range from 10 to 200C.

If it is necessary to move on the surface of the material, support should be used, the length of which is about 3 meters, and the width is 0.4 meters. It is best to cover them with a soft cloth.

If you want to remove any glue residue after removing the protective film, you can use a neutral detergent. After cleaning, you can wipe the surface with a soft cloth.

Classification by head design

Complete with sheet polycarbonate, self-tapping screws are most often used, which can be fixed with a screwdriver. They can have a flat or convex cap. It is also permissible to use hex options. The most commonly used hardware is with the following hats.

1. With cruciform slot for the bit. Such splines are marked as Ph ("phillips"), PZ ("pozidriv"). They are the most common.
2. With faces for a head or open-end wrench. They can additionally have cross-type slots on the head.
3. With a hexagonal recess.Self-tapping screws of this type are considered vandal-proof; when dismantling them, a special tool is used. You cannot simply unscrew the hardware with a screwdriver.

The choice of the shape and type of the cap remains solely with the master. It depends on the tool used. The type of head does not affect the density of the polycarbonate sheets too much.

Fastening devices

In order to attach the polycarbonate to the metal frame, self-tapping screws and various types of sealing washers are used. They help to securely fix the material on the frame, and you can buy them in specialized stores. Washers look nice on the greenhouse surface and protect it from excessive deformation. In addition, they prevent moisture and dust from penetrating into the material in the place where it is pierced with a self-tapping screw. We will tell you more about the best way to fix the cladding on the metal frames of the greenhouse.

Thermal washers made of polycarbonate

This type of fastener is made of transparent polycarbonate and can be produced in various colors. The thermal washer fits tightly into the hole made and expands under thermal load, preventing deformation of the greenhouse cover.

Important! Thermal washers made of polycarbonate are universal fastening materials and can be used for covering greenhouses with both metal and wooden frames. The main characteristics of this type of washer:

The main characteristics of this type of washer:

1. The main part of the fastener is a volumetric washer with a hole for a self-tapping screw in the center and a wide leg, the length of which is equal to the thickness of the polycarbonate sheet.
2. In addition to the washer, the kit includes an O-ring made of polyurethane foam and a plastic plug that fits on top. The self-tapping screw for fixing the washer is purchased separately.
3. The diameter of the fastener is 33 mm, and its thickness is 8 mm.
4. The service life of such a thermal washer is about 20 years. Fasteners are selected individually, depending on the thickness of the sheets of the cladding material.
5. Thermal washer made of polycarbonate helps to achieve a tight fit of the greenhouse sheathing to the frame and gives the outer surface of the structure a decorative look.

Polypropylene washers

This type of fastener has a lower cost compared to thermal washers and is also available in various colors, but has a short service life.

In addition, you need to be careful when screwing polycarbonate to the frame using polypropylene washers - they do not have a limiting leg, so there is a risk of pulling the greenhouse lining too tight and deforming the sheets.

Characteristics of polypropylene washers:

1. The key element of the washer is a polymer cover, in the center of which there is a hole for a self-tapping screw. It comes with a polyurethane foam O-ring and a plug.
2. It has a relatively large size - the diameter is 35 mm, and the thickness is 12 mm.
3. For fixing such washers, screws with a thickness of 6 mm must be used.
4. There is no UV protective coating on the plugs, so they quickly fade in the sun and begin to deteriorate.
5. Average service life is no more than 4 years.
6. They are universal and can be used for fixing polycarbonate sheets of any thickness.

To prolong the life of polypropylene washers, it is recommended to use them only indoors or for cladding structures located in partial shade.

Stainless washers

This type of fastener is used primarily for cladding large structures. Washers made of stainless material are durable and securely fix polycarbonate to the metal frame, even in strong winds.

Specifications:

1. The kit includes a round plate-shaped metal piece with a self-tapping hole in the center, and an umbrella gasket made of EMDP rubber, flexible plastic or polyurethane foam.
2. The diameter of the fastener is 22 mm and the thickness is only 2 mm.
3. Can be used to fix panels of any thickness.
4. The material of the umbrella gasket remains elastic even at an air temperature of –15 ° C. It tightly presses the polycarbonate sheet to the frame, preventing moisture from entering the skin cells and does not loosen over time.
5. This type of fastener does not have a plug that covers the head of the fastener from the outside, therefore, the screws and bolts used for covering the greenhouse, in this case, must be made of corrosion-resistant materials.