Is it possible to put metal roofing on ruberoid, how to put

The construction of the roof has always been considered one of the key moments of the construction of your own house, an outbuilding or a bath house. From the integrity, strength and durability of this complex structure depends on the comfort of using facilities and the microclimate in it. Recently, metal roofing is increasingly being used as a roofing material, which combines practicality and lightweight sheeting with the aesthetic appearance of traditional ceramic tiles. Many craftsmen do not have enough experience with this relatively new coating, so by their unqualified actions or poor-quality installation they shorten the life of the material. In particular, a common mistake is the wrong choice of waterproofing substrate. In this article we will tell whether it is possible to put roofing material under the metal tile.

Characteristics of the material

The metal tile is a modern roofing material, it is made from thin sheet metal, which with the help of a powerful press is attached to a wavy profile that imitates the shape of a classic ceramic tile. For the manufacture of this coating are used metal blanks of black steel, aluminum or copper, which for corrosion protection are covered with polymer paint based on Pural, polyester, plastisol, polyviniofluoride. The undoubted advantages of this material are light weight, wear resistance, weather resistance and durability. Different brands of metal can be divided by the following parameters:

• The height of the profile, which determines the stiffness and bearing capacity of the material. Usually the crests of the metal tile wave reach 28-52 mm. The higher the coating profile, the stronger and tougher it is.
• Profile form. Visually, the profile of a metal tile is divided into asymmetrical and symmetrical. On the technical and operational characteristics of this indicator does not affect.
• Sheet dimensions. Manufacturers cut products on sheets of standard sizes, whose width is 1.1-1.18 m, and length - 4-7 m. The dimensions of the material are selected based on the area and shape of the slopes.
• Thickness. The thickness of the metal is 0.45-0.6 mm, it depends on the thickness of the metal billet and polymer coating.

Important! The construction market offers about hundreds of different grades of metal tiles, which differ in shape and profile height, feedstock, and type of polymer coating. More expensive products are supplied with gutters, additional stiffening ribs or reservation dressing.

Types of metal roofing

The metal tile is considered to be a fairly affordable roofing coating, suitable for overlapping roofs of any areas and shapes with a slope of 5 to 60 degrees. Depending on the nature of the use of the structure, different requirements are imposed on the roofing cake. Metal roofs can be divided into 2 types:

1. Cold. Roofs of cold type are installed on structures in which heating is not provided. These include household and industrial buildings, sheds, gazebos, seasonally used summer houses. In the roofing cake of a cold roof do not include a heat insulating layer. The temperature inside the attic and outside differ slightly, so the pair is almost not formed, which eliminates the installation of vapor barrier.
2. Warm. Roofs of a warm type are installed on structures that are heated with the help of any heat generating device (stove, fireplace, gas boiler, central heating). They differ from cold in that, in addition to waterproofing, they include a layer of insulation and vapor barrier, which allows warm vapors saturated with moisture, which are formed due to the difference in temperature outside and inside the room.

Note! The composition of the roofing pie of the roof of metal depends on the nature of the use of attic or mansard room. The duration of operation of the structure depends on the correct selection of materials. The lack of vapor barrier in the composition of warm blood leads to intensive condensation, dampening of the insulant and the truss frame, and corrosion of the coating.

Roofing Cake Composition

The composition of the roofing pie with a coating of metal consists of several layers: rafters, insulating material laid between them, waterproofing, kontrreshetki, crates and roofing material. To ensure the long life of the roof, it is necessary to install using materials recommended by the manufacturer of metal tiles. Inexperienced builders often wonder if it is possible to use roofing felt as a waterproofing for economy. There are 2 answers to this question:

• If the roof belongs to the cold type, the metal tile on the roofing felt is laid down quite often, especially in cases when it comes to the reconstruction of the old coating. This technology is allowed, since the difference between the temperature inside the attic and outside is insignificant, as a result of which condensate does not accumulate on the inner surface of the metal tile. This measure saves rubbing time spent on the dismantling of the old roofing material, and reduces costs.
• If the roof is of a warm type, roofing material is strictly prohibited to use as a waterproofing material. Roofing paper, impregnated with petroleum bitumen, does not allow steam, as a result, moisture accumulates in the insulating material and settles on the rafters, leading to dampness and rotting. For the installation of warm blood using diffuse membranes that do not pass water, but do not impede the output of steam.

Experienced roofing masters say that for several seasons the roofing material is so glued to wooden rafters that it becomes simply impossible to dismantle this material. In order for a metal tile with high thermal conductivity, when heated, not to melt roofing material, it is possible to put a second crate between them, which organizes the ventilation gap.

Technology cons

Most manufacturers in the instructions limit the use of roofing material for waterproofing under the metal, instead of recommending diffuse membranes. Professional roofing masters confirm the expediency of such a decision with their experience. When installing metal on an old ruberoid roof, the following problems occur, which cause accelerated wear of the coating:

1. Melting of ruberoid. The metal tile has a high thermal conductivity; therefore, when the roof surface is heated by the sun, the roofing material under it melts frequently. To this process began, the roof enough to heat up to 60 degrees.
2. Extraction of bitumen fumes. The high thermal conductivity of the metal tile provokes the heating of the ruberoid and the release of bituminous pores, which have an unpleasant odor, and also have a negative effect on human health.
3. Condensation. Roofing material is laid down with an almost hermetic layer that does not allow steam, as a result of which moisture accumulates on the surface of the rafters and inside the insulation, leading to dampness of the wood and a decrease in the effectiveness of the thermal insulation material.

Note that the use of roofing material as a substrate for metal roofing as part of a warm roofing pie leads to premature wear of the coating. In addition, these materials have different service life, which makes their sharing meaningless.

Waterproofing roofing material

Despite the lack of vapor permeability, roofing material can be used as a waterproofing material, if the roof of the metal is cold type. It is mounted on rafters to protect the structure from moisture or condensation. Installation of roofing material is performed as follows:

1. A roll of roofing material is rolled out on a flat surface, cutting into strips equal to the length of the roof slope.
2. The strips are left to lie down so that there are no wrinkles or waves on the surface of the material.
3. The first strip is laid perpendicular to the rafters with an overlap of 10-15 cm, fixing with the help of rails to the toe nails.
4. The ridge is also waterproofed with a strip of roofing felt, bending the material through it.
5. The joints between the strips are glued with a special tape or soldered with a torch.
6. A crate of 4-6 cm thick bars is nailed over the roofing material to arrange the ventilation gap.

After laying the waterproofing material, begin laying metal. Experienced roofers note that it is advisable to use roofing felt as a waterproofing only on old reconstructed roofs. If a new roof is being installed, it is better to use a more durable and vapor-permeable diffuse membrane, especially since the price for them is practically the same.

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