What are the pros and cons of ondulin and how to put it on a pitched roof?

For many homeowners, ondulin—also referred to as bitumen corrugated roofing sheets—has become a popular choice for roofing. This affordable and long-lasting material is renowned for being inexpensive and easy to install. Making an informed decision regarding a roofing project can be aided by knowing the advantages and disadvantages of ondulin.

Ondulin’s durability is one of its main benefits. Ondulin sheets, which are made of bitumen and organic fibers, can withstand strong winds, heavy rain, and snowfall. It is therefore a dependable option for a range of climates. Ondulin’s flexibility and ease of cutting to suit any roof shape further streamline the installation procedure.

Ondulin, like any substance, has drawbacks, though. It might not last as long as some other roofing materials, like tile or metal. UV radiation exposure over time may result in the material becoming brittle and the color fading. It needs to have regular maintenance done on it to stay in good shape and take care of any possible problems.

The next step, if you’ve determined that ondulin is the best option for your roof, is to become knowledgeable about how to install it correctly on a pitched roof. You can accomplish a polished appearance with the correct equipment and some advice. From readying the roof surface to fastening the sheets in place, we’ll guide you through all the crucial actions to guarantee the success of your roofing project.

Ondulin is a well-liked roofing material that is excellent for many pitched roofs due to its affordability, simplicity of installation, and durability. Nonetheless, it’s crucial to weigh the advantages and disadvantages before selecting whether it’s the best option for your project. In addition to possible drawbacks like color fading and reduced fire resistance in comparison to other materials, this article will examine the material’s main benefits, such as its lightweight design and weather resistance. Also, in order to guarantee a safe and durable installation, we’ll offer a detailed installation guide for ondulin on pitched roofs.

Advantages and disadvantages

With superior insulating qualities, Ondulin, also known as Euroslate, is a corrugated sheet material based on a bitumen-cellulose base. Each sheet is approximately 1.92 m2 in area and 3 mm thick, weighing between 6 and 10 kg. The resultant coatings essentially do not load the structures and prevent precipitation from passing through. The benefits of ondulin when designing pitched roofs also show up in:

• Good ventilation of the cake thanks to the corrugation with a height of up to 3.6 cm.
• Protecting the house from external noise (which is especially important in houses without an attic).
• Resistance to biological threats (except for mosses on northern slopes with poor lighting of the house), atmospheric influences and aggressive environments. Ondulin coverings do not rot, are used in any climate and are not afraid of "acid" rain or hail.
• Ease of installation. Rectangular sheets of ondulin can be easily laid on simple pitched roofs, in some cases the material does not even have to be cut.
• Attractive appearance. In order to save money, such roofs are laid with a minimum slope, which complicates the choice of external coverings. In this regard, corrugated euroslate compares favorably with profiled or sheet materials, which make a house with one slope look like an outbuilding. At the same time, by analogy with soft roll materials, it can be laid on slopes with a slope of up to 10 °.

Ondulin has a sufficient number of drawbacks. Even high-quality factory brands are only supposed to last for 15 years, despite the fact that counterfeiters frequently attempt to sell this material.

Performance parameters remain unchanged during this time, however Euro slate ages in the sun rapidly (between two and seven years).

Although the material does not spontaneously burn, it does support combustion and ignite at temperatures above 230°C (more for several foreign brands), which restricts its use to some extent.

Ondulin is more expensive than slate and roofing felt, about the same as medium-hard profiled sheets, and marginally less expensive than metal tiles, but still regarded as an affordable material.

It is important to keep in mind the distinction between usable area and sheet sizes when making a purchase, but even with the largest overlap (30 cm), the cost of 1 m 2 does not exceed 250 rubles. It is insufficient to calculate the estimate by simply multiplying this value by the slope’s area; additional components and fasteners (20 pieces per sheet) are needed for the installation of Euro slate.

Pitch roofs’ straightforward design, however, means that owners need only invest in a gable profile (which starts at 200 rubles per month) and films to replace conventional waterproofing.

Roofing pie

The following are differentiated based on their intended use and whether an insulating layer is present:

• Cold attic roofs without waterproofing film (lathing + ondulin). The absence of a tendency to accumulate condensate allows such a design in outbuildings and cottages with seasonal residence.
• Cold roofs with waterproofing, having excellent tightness in comparison with the first group, but not retaining heat. The pie diagram includes a waterproofing film fixed to the rafters, a counter-lattice, lathing and Euro-slate.
• Insulated roofs with one or two ventilated gaps, ideal for permanent residences. In the first version, the cake consists of a vapor barrier film, insulation in the space between the rafters, an adjacent superdiffusion membrane, counter battens, sheathing and ondulin. In the second, the diffusion membrane is replaced by a film with increased moisture resistance (if necessary, used as a temporary roof), a 2 cm ventilation gap is left between it and the insulation.

Minimum tilt angle

On slopes with a slope of 6° or more, manufacturers permit the use of Euro slate. This parameter has a direct impact on the sheets’ usable area as well as how much of them overlap longitudinally and transversely (cm table).

Rafter system and sheathing

Because of the material’s low weight, straightforward rafter structures can be used. The cross-section and pitch of the legs are chosen with the following considerations in mind for homes with pitched roofs:

• Insulation thickness (if the value is insufficient, additional slats are placed on the rafters).
• Slope area (for a length of more than 6 m, the structure is reinforced with an additional vertical support).
• Snow load (snow does not fall off from rough Euro slate even on a steep slope; in regions with heavy rainfall, the roof must be strengthened or cleaned manually).

There are stricter specifications for the base of the fastening sheets. The slope of the slope must be considered when selecting the type and pitch of the sheathing:

• Slope 5-10° – only a solid base made of sheet materials with a thickness of 12 mm and boards from 20 mm is laid under the ondulin.
• Slope 10-15° – toughened with thin lathing with a uniform pitch of up to 45 cm from timber with a cross-section of 50 mm and boards from 20 mm.
• Slope from 15° — it is allowed to increase the lathing pitch to 60 cm with the same requirements for materials.

Important: The values provided may vary from other European slate manufacturers and are pertinent for standard Onduline brand installations. Whatever the situation, the timber needs to be thoroughly dried and treated with fungicides and fire retardants.

Waterproofing and vapor barrier

The purpose of the building determines whether waterproofing is necessary for cold roofs; in particular, this layer is installed initially when planning the roof insulation following commissioning. Using specialized branded films (Ondutis series), laid with slight sagging and required joint protection (overlapping + soldering or taping), yields the best results. It is forbidden to compromise the panels’ integrity.

Superdiffusion membranes or wind- and moisture-proof films, like Ondutis R70 Smart or Ondutis SA115 Smart, shield the insulating layer when installing insulated single-pitch roofs from the exterior (but not roofing felt or similar cheap impermeable materials). It is recommended by the manufacturer to use Ondutis RS films to lay a mandatory vapor barrier.

Selecting the appropriate installation side is the first step in using branded insulating films; deviating from the guidelines is not permitted.

Roof construction instructions

The building process is typical:

1. After choosing the angle of inclination, the rafter system, cake is calculated and materials are prepared (including impregnation with protective equipment).
2. A mauerlat and rafter legs are attached to two load-bearing walls or a monolithic armored belt (depending on the material and height of the walls).
3. In residential buildings, the pitched roof pie is made insulated: a vapor barrier is laid on the underside of the rafters, mineral wool is laid in the space between the rafters, after which the rafters are covered with waterproofing membranes. According to the norms, the pie is always made ventilated.
4. Installation of sheathing and ondulin is in progress.
5. The overhang is being trimmed and additional elements are being installed. At this stage, ventilation ridges and gable elements are nailed to the eaves. The work is completed by laying gutters at the bottom of the overhang, without rigid attachment to the edges of the sheets.

Tools and materials for work

A standard toolkit (carpenter’s ax and hammer, large- and medium-toothed hacksaw, nail, plowmen, screwdriver, key for fastening Mauerlat, and power tools for sawing wood) will be needed to build a rafter structure. Tools for leveling and marking are used continuously throughout the work process. A construction knife and a stapler are used for cutting and fastening film materials.

The following are ready for Ondulin to be installed directly:

• Special fasteners with a PVC cap that closes after driving or branded nails for ondulin with rubber gaskets – when fastening to wood; hardware with a head and self-tapping screws – when fixing to metal. Each sheet of Euro slate requires at least 20 nails.
• Cord – for aligning sheets and monitoring the fastening line.
• carpenter"s hammer.
• A wood hacksaw with a blade length of 35-40 cm and medium teeth – for cutting sheets.
• Additional elements (combs with vents, tongs, gutters, aprons for sealing passage structures or ventilation windows).

Laying scheme and installation of Euro slate

A pre-designed pattern is followed when laying the sheets in a checkerboard pattern, accounting for all horizontal and vertical overlaps. Special consideration is given to the first sheet, which is positioned on the leeward side of the slope in the left or right corner and protrudes no more than 50 mm beyond the edge of the overhang. The lower corners of the sheet, the upper free corner, and the entire lower row are sequentially attached to each wave after the level is carefully checked; the remaining portions are attached through a single ridge.

It is crucial to follow the manufacturer’s instructions for the fastening scheme at this point in the installation, down to the exact nailing order. Until the cap is fully pressed against the material, nails are driven precisely perpendicular to the top point of the wave. Subsequently, each sheet in the first row is nailed individually, and only then are the second and subsequent sheets nailed, with an overlap and offset. Finishing touches include installing extra components and aligning the ends.

Ondulin is arranged as follows on a pitched roof:

Frequent mistakes and recommendations for construction

When utilizing ondulin Following the manufacturer’s instructions is crucial; failing to do so is regarded as a breach of those instructions. This holds true for sheathing spacing, overlaps, and fastener count (keeping or changing the pattern severely diminishes fastening reliability; the sheet is easily ripped off by the wind). Other grave mistakes consist of:

• Carrying out work under unsuitable conditions (strong wind, frost or heat).
• Stretching a sheet by hand.
• Driving nails into the bottom of the ridge or at an angle.
• Sticking or excessive pressing of caps.

Before lifting, sheets should be numbered and aligned with a cord to prevent errors. The coating is shielded from mechanical damage during installation; special ladders must be placed on the ondulin if frequent passage along the roof is required.

Because ondulin roofing is inexpensive and simple to install, it can be a fantastic choice for a lot of homeowners. The roofing process may be made simpler by its lightweight nature, which makes it easier to handle and work with. Ondulin is a resilient option for a variety of climates because it provides good resistance to a range of weather conditions.

But there are a few disadvantages to take into account. Compared to other roofing materials, ondulin might not last as long and might be more prone to damage from strong winds or heavy rains. It’s also important to keep in mind that, despite being low-maintenance by design, ondulin might not be as visually pleasing or valuable as other roofing materials.

To ensure correct application, it’s imperative to carefully follow the manufacturer’s instructions when installing ondulin on a pitched roof. A well-executed installation maximizes its advantages and averts future problems. In general, ondulin can be a sensible option if you’re searching for a reasonably priced, simple-to-install roofing material, but make sure to assess its advantages and disadvantages to determine whether it’s the best option for you.

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