What is the difference between a membrane and a vapor barrier. What is the difference between vapor barrier and waterproofing

Briefly

vapor barrier- protects the insulation from the effects of steam, which accumulates indoors.

Waterproofing- prevents the ingress of water from outside the room - inside (for example: during precipitation).

The key difference is that waterproofing should not allow water to pass through, but should allow air to pass through, and vapor barrier should not allow water or air to pass through.

Vapor barrier: what is it used for

Vapor barrier protects the insulation of the house from steam that comes from sources located in the house (due to people breathing, cooking, evaporation hot water, from household appliances). Even with good ventilation, it is impossible to completely eliminate the effect of steam on the insulation. During cold snaps, the steam condenses - the insulation gets wet, and its properties deteriorate.

For vapor barrier of premises use: glassine, roofing material, roofing felt, but best material are special vapor barrier films. For the vapor barrier of the bath, it is better to use special heat-reflecting films (for example: Ondutis R Termo).

Waterproofing: Application Features

Finishing materials protect housing well from direct exposure to precipitation, but if moist air gets into the thermal insulation and wets it, then the insulation properties will decrease, and in winter the pores will become clogged with ice. Waterproofing protects the insulation from the harmful effects of moisture that can get in from the outside.

For waterproofing, materials are needed that are capable of passing moist air, since the layer also performs the task of removing excess steam that can seep into the insulation. So upper layer insulation must "breathe" and release accumulated moisture.

For waterproofing, special diffusion and superdiffusion membranes are used. They allow steam to pass through, but water cannot seep through small pores.

Advice: Choose high-quality materials for vapor barrier and waterproofing, then you will maintain the integrity of the insulation for many years.

What is the difference between waterproofing and vapor barrier? This question can be answered by analyzing the structure of both materials.

Structure of vapor barrier films

Vapor barrier differs from waterproofing mainly in that both sides of it are completely waterproof. The vapor barrier should not allow steam or water to pass both outside (into the house) and inside the insulation. Conventional polyethylene can be attributed to a cheap version of such a film. However, it is not recommended to use it as a vapor barrier for a roofing “pie” due to the fact that under the roof, especially in summer, the film will get very hot, which will lead to its stretching and, possibly, damage. And since we cover the roof for more than one year, it is optimal to use a film of several layers with a polymer reinforcing frame, which prevents the film from stretching.

sheathing inner surface mansard roof film, covered with foil on one side, will cost a little more than use different kind vapor barrier materials, however, in addition to creating a reliable vapor barrier, it will also be possible to retain heat in the house. The installation of this film is carried out with a foil surface inside the room, which contributes to reflection from it infrared radiation, with which the main share of heat from the dwelling disappears. Thus, the use of such a vapor barrier allows you to kill two birds with one stone, reducing heat loss through the roof of the house to a minimum, which in turn will allow you to save quite a lot on heating.

Before buying any film, be sure to make sure that it is a vapor barrier, as indicated by the inscription on the package.

Structure and types of waterproofing films

It may well seem to an amateur that if the vapor barrier is completely waterproof, then it may well serve as a replacement for the waterproofing layer. It can be assumed even out of ignorance that vapor barrier is better than waterproofing, which is fundamentally wrong.

Both vapor barrier and waterproof film materials serve a specific purpose, and if you substitute one for the other, this can lead to unpredictable consequences and additional monetary costs.

The main functions of waterproofing are as follows:

• protection against ingress of external moisture into the insulation layer;
• removal of accidentally trapped water vapor from the heater.

But how can steam suddenly appear in a heater? The thing is that not a single film in the world, it would seem, hermetically closing the insulation on both sides, does not have absolute vapor tightness. The proportion of water vapor, albeit insignificant, somehow penetrates through the film insulation from the ventilation gap and from the inside of the room into the insulation, which means that it is necessary to ensure that this moisture can escape to the outside. This purpose is served by waterproofing films, otherwise referred to as membranes.

Waterproofing polymer films have a number of useful properties:

• resistant to ultraviolet radiation;
• resistance to temperature fluctuations;
• high strength properties.

However, this is all secondary. Most important property waterproofing film is porous structure of this material . The meaning of the idea is to enable that part of the water vapor, which somehow got into the insulation, to freely exit it into the under-roof space. This is precisely what contributes to the pores, which are very similar in shape to funnels, through the wide part of which steam exits the insulation. The narrow part of the pores at correct installation should be turned outward, which prevents the penetration of moisture into the pores in the form of a liquid from the atmosphere, since the volume of a water molecule is larger than vapor molecules. When using waterproofing membranes, it is important not to confuse and put the film with the correct side to the insulation.

According to the type of porous structure, membrane films can be:

• diffusion;
• superdiffusion.

These structures differ from each other in the number of pores. In diffusion membranes, there are fewer pores, and, accordingly, the level of vapor removal is significantly lower. Such a vapor barrier cannot be placed directly on the insulation itself, therefore it is necessary to leave a ventilated gap not only between the roofing and waterproofing, but also between the film and the insulation. Otherwise, the contact of the pores of the diffusion membrane with the insulation material will lead to blockage of the “funnel” of the waterproofing with mineral wool and the loss of its functional properties.

Superdiffusion membranes significantly outperform diffusion films in terms of vapor removal, and it is not required to create a ventilation gap between the waterproofing and the insulation.

The organization of a ventilation gap between the roofing and the membrane is mandatory in any case, in order to allow water vapor to escape with the air flow into the atmosphere.

However, it is recommended to use membrane waterproofing films not with any type of roofing, but only with those that are resistant to the damaging effects of condensate accumulating from back side roofs. So, for example, in the case of roofing with metal tiles, it is necessary to use special anti-condensation films. Such waterproofing does not allow steam to escape from the insulation, but accumulates it through a huge number of tiny villi located on its back surface, from where moisture leaves with air flows through the ventilation gap.

Vapor waterproofing is a whole complex finishing works, focused on increasing the hydrophobicity of the protected surface, while maintaining the vapor permeability of the insulated medium.

Moreover, this technology is in demand only in the case of arranging a protective layer for wall or roof insulation. Otherwise, the simultaneous use of steam and waterproofing is simply not in demand. Indeed, to protect ordinary surfaces, it is enough to use only waterproofing.

Therefore, in this article we will describe the process of steam and waterproofing, both inclined and horizontal, and vertical surfaces, along with an overview of the materials used in this technology.

Let's clarify right away: waterproofing and vapor barrier are two completely different technologies. Waterproofing solves external problems, protecting the insulation from "outside" moisture - rain, snow, fog. Vapor barrier is focused on solving "internal" problems. It protects the insulation from "internal" moisture - water vapor seeping through attic floor or a wall.

In a word, the main difference between waterproofing and vapor barrier is the positioning of the protective layer. For waterproofing, it is located outside, and for vapor barrier - from the wrong side.

In addition, vapor barrier can only guarantee "deaf" protection, which does not give a chance to "break through" to the insulation. And waterproofing can cut off moisture and let air through. However, not all are vapor permeable. waterproofing materials. After all, such insulation is much more expensive than the usual option.

How does vapor barrier and waterproofing work?

Waterproofing coatings are laid on top of the heat insulator, on a special crate. The main task of such a coating is to cut off the moisture that has seeped through the roofing or facing material from the insulation.

In addition, the waterproofer protects the insulation from condensate accumulated on the inner surface of the roofing or facing material. At the same time, vapor-permeable universal-purpose waterproofing is able to pass air, being impervious only to moisture. This quality of waterproofing membranes facilitates the process of ventilation of the attic space.

The task of vapor barrier is a little different. With its help, an impenetrable barrier is formed that cuts off the insulation from bearing wall or roof frame. That is, the vapor barrier is laid directly on the wall or roofing shield, and already a crate and a layer of insulation are mounted on it.

Vapor waterproofing for roofs and walls - an overview of materials

Waterproofing and a vapor barrier that protects the insulation from moisture are formed on the basis of roll materials of a membrane or monolithic type.

A good example of such a product is Isospan vapor barrier - in the assortment of this trademark you can find five varieties of steam and water insulators. Therefore, we will consider typical varieties of such materials using the example of Izospan products.

A series of vapor barriers and waterproofers from Izospan consists of the following types of membranes and roll coatings:

• Vapor-permeable films , with which you can build hydro and wind protection of a wall or roof. With the help of such material, it is possible to protect the insulation of a ventilated facade. Moreover, this product has both hydro- and vapor barrier properties: the front side of such a film does not allow moisture to pass through, and the rough underside accumulates water vapor, bringing it out through the capillaries. In the assortment of the company, such a product is called Izospan A.
• Roll waterproofing with zero permeability that mount on the inside roofing cake. The material is laid on the side of the heat insulator facing the interior space (attic or living space). Such a product is called "Izospan V".
• Impervious films with increased thickness on which the roof is laid or finishing material. A product called "Izospan C" is used only for waterproofing. And it solves the problem of insufficient hydrophobicity with 100 percent efficiency.
• Universal vapor-permeable waterproofing , for which it does not matter how the vapor barrier of the roof is arranged - from the outside or from the inside. The Izospan D product works both from the front and from the wrong side of the insulating layer.

As you can see, there are a lot of options. And you can choose the perfect vapor and water insulator for any insulation protection installation scheme. It remains only to deal with the installation technologies.

How is the vapor barrier installed?

Steam and waterproofing are used to solve different problems. The first protects the material from "room" moisture, and the second from precipitation. And differences in functionality have left their mark on the installation process of these materials. Therefore, we will have to consider the vapor barrier technology separately from the waterproofing process.

Arrangement of vapor barrier occurs as follows:

• With inside attic space, a crate is mounted on top of the heat insulator, consisting of a beam laid in increments of 40-50 centimeters.
• A vapor barrier film is attached to the beam using a conventional stapler for this purpose. Moreover, the insulator strips are mounted without interference, with an overlap of at least 100 millimeters. The location of the strips relative to the slope of the roof or wall can be anything - both parallel and perpendicular. And as a vapor barrier, it is best to use a foil film mounted with a reflector in the room.
• After the completion of the "construction" of the vapor barrier in a protected room or in the attic, they equip supply and exhaust system ventilation that removes excess water vapor from the house.

The last point is very important. Without ventilation, vapor barrier will only harm the house, provoking the appearance of mold and fungi.

Waterproofing - how it's done

To waterproof the insulation, you will have to do the following:

• On top of the cards (mats) or rolls of insulation, you need to fill the slats, in increments of 30-40 centimeters. They form a crate to which the waterproofing will be attached.
• Roll material should be laid on top of the crate. Moreover, the vapor-permeable side of the membrane is oriented to the wrong side - the top facing the roof must be completely impermeable.
• The joints of adjacent waterproofing strips are overlapped with a 10 cm overlap. Moreover, the laying is a ladder - the first layer is laid on the crate, the second layer overlaps the first, the third - the second, and so on. In this case, the laying goes from the bottom up in transverse stripes. Although a variant with longitudinal mounting is also possible.
• The final fixation of the film is carried out with the help of a counter-lattice stuffed over the waterproofing. This detail allows you to build a ventilated facade system and is a mandatory element of the roofing pie.

In conclusion of the review of the waterproofing process, we allow ourselves to give you some advice:

Vapor waterproofing of a window: the nuances of the technological process

Waterproofing roofs or walls is still a relatively simple task. But the arrangement of steam and hydroprotection of the window is a completely different task, which can only be solved with the help of special technology.

Well, the process of vapor barrier windows is as follows:

• After installing the window in the wall or roof, there are gaps between its frame and the opening. These gaps are filled with mounting foam.
• A layer of a vapor-permeable waterproofing layer is laid on top of the foam. It should "go" onto the window and fit over the roofing insulator, blocking the access of moisture to the seam between the frame and the opening.
• After that, an elastic material is laid directly on the insulating film, which can expand under the influence of moisture, and pressed against the window with roofing sheets or trim, which are attached to the window opening.

As a result, the window is protected by as many as three insulators - an elastic material under the casing, a waterproofing film and polyurethane foam. And such a sandwich leaves no chance for moisture!

Most people dream of own house. First, they look for a suitable plot, then a project for a house. After that, construction begins. And now the main work is behind, it's time for finishing.

And many people think about how to make their home not just convenient, but comfortable, so that no matter what the weather, it is always pleasant to return to it. How to achieve this? This will require waterproofing.

Insulate your home with the help of special heaters, and today a variety of them are offered. Let's see how to properly insulate the house so that the material used in this capacity does not disappear and does not lose its qualities.

Most often, for the insulation of walls, ceilings and floors, materials based on mineral wool, it has long established itself as an excellent heat insulator. But with all their positive qualities, it also has one negative, and if you do not take it into account, then over time all your efforts to warm the house will be in vain.

Mineral wool perfectly absorbs moisture, and as a result loses all its thermal insulation properties. And here it is important to carry out competent work on vapor barrier and waterproofing of materials based on mineral wool.

Let's start with the roof. When building a house, this structural element is of paramount importance. Because it primarily resists the effects of various natural elements: heavy precipitation in the form of rain, snow, hail, hurricane gusts of wind (wind protection), and also protects the house from the scorching rays of the sun. Both materials have wind protection. The roof stands guard over our comfort and convenience.

In addition to protecting against external influences, the roof also does not allow heat to escape from the house to the outside. After all, it is very well known that warm air currents always tend upwards, therefore it is always necessary to install insulation on the roofs in order to keep internally warm and prevent external cold from penetrating into the premises. But in order for the insulation to last as long as possible and not lose its commercial qualities, it must be protected from any exposure to moisture, both in the form of water and in the form of steam.

By themselves, the materials from which the roof is arranged, of course, do not allow moisture to pass through and protect the insulation from getting wet, but they are not able to protect it from the effects of water vapor. To do this, it is necessary to carry out waterproofing measures that will protect the insulation from excess moisture.

Some builders, in order to save money or due to lack of knowledge, do not waterproof the insulation installed under the roof. Very often cheap materials are bought, and some use even ordinary polyethylene film for greenhouses, others prefer to use materials that protect only from steam, without betraying the fact that these are completely different products with different properties.

As a result, within a short period of time from the installation of the attic roof and insulation with improper waterproofing, suddenly water begins to drip, and the ceiling is covered with stains from stains. In this case, most often the roofing surface is carefully checked for damage, but not finding any, many think what was done wrong.

The explanation in this case is quite simple, if a vapor barrier was installed instead of a waterproofing film, then as a result of this, the insulation has completely accumulated moisture and creates stains and “rain” in the room. It is much worse if the waterproofing was not carried out at all, then in this case the moisture-filled insulation damages both the rafters and the wooden crate and even the entire roof structure, while damaging the interior decoration of the premises.

What is the difference between waterproofing and vapor barrier

What is the difference between vapor barrier and waterproofing? Currently on the market construction goods There are a huge variety of films used as materials for waterproofing work. With so many proposals from various manufacturers it's not hard to get lost.

The main problem arises from a misunderstanding of the difference between the materials that are used for waterproofing or vapor barrier. Some so-called specialists or consultants construction stores and companies, due to the lack of necessary knowledge, do not distinguish between these goods that are completely different in terms of consumer qualities.

Therefore, those who dream of living in comfortable housing and not suffering from unexpected surprises associated with improper waterproofing of the roof should expand their horizons themselves and get necessary knowledge in this matter, even just to control those who will carry out waterproofing work on your roofing. Therefore, let's first clearly understand how waterproofing materials differ from vapor barrier materials in terms of their functional properties.

What is waterproofing?

A waterproofing film is mainly used to prevent moisture that penetrates from the outside from contacting the insulation. One may, of course, ask the question, what is it for? After all, the roof is designed to protect the interior from high level humidity. Of course, if you are installing a roof over an ordinary attic space, then most likely you will not insulate the roof and, as a result, the roof will not be waterproofed. As well as roof insulation.

But when the roof is installed over the attic, then in this case it is expected from it that in addition to its main “duties” of protecting housing from precipitation, it will also protect against the ingress of water vapor generated during warm rains and fogs.

This water vapor, getting into the pores of the mineral wool insulation, clogs them, reducing its performance properties. And in the cold season, the moisture that gets into the insulation freezes and destroys it. In view of this, the thermal insulation cover needs to be protected with waterproofing films.

What is vapor barrier?

The place of application of vapor barrier films is the lower part mineral insulation. This film will protect it from vapors rising to the ceiling from the interior. Some believe that well-ventilated rooms do not produce excessive vaporization. But it's not.

In any living space, water vapor is always formed, which penetrate the roof insulation through the ceiling and can also lead to a decrease in its quality and even getting wet, with subsequent unpleasant consequences. Therefore, the installation of a vapor barrier film is an important component of roof protection.

The difference between waterproofing and vapor barrier

What is the difference between vapor barrier and waterproofing? Films that are used as waterproofing membranes are designed so that they allow moisture to penetrate in only one direction from the inside to the outside, but protect against the ingress of external moisture.

For example, when installing a vapor barrier above the basement, the film is laid under the finished floor, this is done so that the steam that always moves from heat to cold does not penetrate into the insulation. But that part of the moist air that nevertheless gets into it will come out through a film that passes steam from the inside.

Can films differ from each other in appearance? Vapor barrier films are completely impervious to moisture from both sides. For example, polyethylene is such a material. But if you use it as a vapor barrier, then over time, due to its qualities, stretching will occur, and then the film will tear, which will require its replacement. Therefore, it is best to use a reinforced polymer film.

Materials covered with foil have good consumer properties, the installation of such a film is carried out by such a part during interior. Thanks to this, the heat, which also rises with the steam, is reflected from the foil and does not leave the room. The vapor barrier film is marked by the manufacturer in a special way, so when buying, carefully read the product description.

The structure of the waterproofing film

At first glance, it may seem that using a film that is completely impervious to moisture is the way to go, but in fact it is not. Steam and waterproofing have completely different purposes, and replacing one material with another will bring nothing but disappointment.

What is waterproofing used for?

• protect the insulation from the penetration of moisture from the outside;
• remove the moisture that got into the insulation.

The question arises: how can moisture get into the insulation if measures have been taken to protect it?

This is possible because there is no complete sealing of the insulation, moisture enters through the gaps intended for ventilation into the insulation from the room. And our goal is to bring it out, for this a waterproofing film or membrane is used. It is distinguished by the following properties:

• Resistance to UV study.
• Resistant to temperature extremes.
• High strength.
• Porous structure.

Let us dwell on this last and main quality of her. Thanks to this structure, water vapor that has entered the insulation can exit it. On the entire surface of the film there are holes or pores that have a certain shape, in the form of a funnel, its wide part is directed inward to the insulation, and the narrow one is outward, due to which moisture from external environment cannot penetrate the insulation, as it has big size molecules, vapor, on the contrary, can freely escape.

Therefore, when installing such membranes, it is very important not to confuse the corresponding sides, the one that will be directed towards the insulation and the other outside.

According to the structure of the pores, the membranes are divided into:

• diffusion;
• superdiffusion.

AT this moment they differ in the number of pores. There are fewer of them on diffuse, laying it on a heater should make a ventilation gap, since mineral wool villi can clog the pores of the film and lead to a decrease in its quality. The use of super diffuse membranes does not provide for the creation of a ventilation gap.

It is worth remembering that when using any membranes, it is necessary to leave spaces between the roof and the membrane so that water vapor does not accumulate under the roof, but goes into the air space.

It is important to remember that films can not be used with all types of roofing. So the metal tile can be destroyed under the influence of condensate, which will accumulate under its unprotected part. It uses a membrane that accumulates moisture for completely two different material, its inner side and gets rid of it thanks to the ventilation gap.

Vapor barrier and waterproofing differences - we examined them. Waterproofing vapor barrier - materials that have different purposes.

Every building is inevitably exposed to moisture. Nothing is immune from rain and snow that interfere with performance building materials. To protect them from unwanted moisture penetration, vapor barrier and waterproofing are needed. These are two different materials, similar to each other except for the name, and in no case should they be confused.

A little theory first. We all know that the brunt of nature takes on the roof of the house. After all, walls and floors are much better protected from precipitation, aren't they? And the roof must be constructed in such a way as to endure temperature changes, rain, downpour, snow, wind and other weather vagaries. For this, waterproofing with vapor barrier is used.

The roof is a kind of boundary that separates the air inside the building and outside. Warm air rises and cold air sinks. In order for the roof to retain heat well, a heater is used, placing it under the roofing. This material characterized by good thermal insulation. How warm the roof will be depends on the thickness of its layer and high-quality laying.

It would seem that the problem is solved, but you can’t get away from the water. It will still appear in the form of rain, snow or steam. We recall the laws of physics: steam always tends up, that is, towards the roof, and moisture gets inside the building, that is, down. All this passes through the insulation, which is a kind of boundary and an excellent place for the accumulation of water condensate due to steam going up. And from above through roofing moisture seeps in, again concentrating inside the roofing pie. It turns out that such protective coatings, like a vapor barrier from below and a hydro barrier from above, are simply necessary.

In the absence of steam and waterproofing systems, moisture freely penetrates into the insulation and the entire roof structure, condensation appears, mold forms, the rafters and the crate are moistened, and the interior decoration

The main differences between hydro and vapor barrier

Once again, we clearly recall how vapor barrier differs from waterproofing, so that later they are not confused when arranging, for example, an attic:

• Vapor barrier does not allow moist air to penetrate from the room into the insulation;
• Waterproofing does not allow accumulated moisture to pass into the insulation, and also lets out moist warm air that has seeped through the vapor barrier layer.

As you already understood, waterproofing allows only air to pass through, while vapor barrier does nothing at all. In the very name of the vapor barrier film, its main ability is to keep vapors out.

There are also differences in appearance. At a cursory examination, these materials are no different, but if you look closely, then on the waterproofing film you will see many small holes for air to pass through. On the vapor barrier, they are absent.

What happens if you accidentally confuse these two different coatings? Warm air, when it gets up from the room through the holes in the waterproofing, will freely penetrate into the insulation. Having met a vapor barrier layer on its way, it will not be able to go outside. It is known that warm air accumulates moisture much more than cold air, which means that it will condense in a “poor” insulation. Over time, water can be right in the room. As a result, the dismantling of the insulation and all incorrectly installed films is inevitable.

The design of the roofing pie. The diagram clearly indicates where moisture can come from. As you can see, there are many sources

Where else is waterproofing needed?

Moisture can be concentrated not only outside the room, but also inside it. Therefore, waterproofing is required not only during the construction of the roof, but also for the foundation, floor and bathroom, where humidity is often too high. There are quite a lot of materials for these purposes, sometimes you can get confused in them for the uninitiated in construction matters.

Foundation waterproofing methods depend on its type and design. It is performed in vertical or horizontal planes. Vertical waterproofing is done with outer side foundation, to the level of the sidewalk or blind area. The horizontal method is used to protect walls or the building itself from water. Both use a clay hydro-barrier, the difference is that in the vertical waterproofing between the castle and the foundation, it is necessary to install a pressure brick wall.

Bathroom waterproofing scheme

The waterproofing of the tiled foundation is carried out using a rolled roofing material. At least two layers are laid, the overlap should be from 10 to 20 cm. Hot bituminous mastic will be most acceptable for gluing.

Most effective method for a strip foundation - this is a penetrating waterproofing, when sprayed onto a wet surface special composition. It is impossible to exclude rolled materials (roofing material) or bituminous mastic. Penetrating waterproofing is also suitable for pile and column foundations.

Roof protection from water

To protect the roof from moisture, microperforated films or diffuse, that is, breathable membranes, are used, which are most suitable for this purpose. Their obvious advantage is that they allow you to use the entire space between the rafters for protection. Lay the membranes directly on thermal insulation layer. They are single-sided, intended for laying with only one side to the insulation, and double-sided, which does not matter which side to lay.

Micro-perforated film for waterproofing

The most suitable roof vapor barrier

Any vapor barrier layer combines two polymer material- polypropylene and polyethylene. More precisely, it is a reinforced film with a mesh structure based on them. It is available in four types: standard (completely vapor-tight), with a reflex layer (used in residential buildings, bathroom, saunas), with limited and variable vapor tightness.

Standard scheme laying the main layers of the roof. The vapor barrier must be under the insulation, on its inner side

The second type of film has an aluminized or foil layer on one side, which ensures its tightness. Limited vapor barrier is used in houses with non-permanent residence, for example, country houses, and variable - during overhaul roofs.

Vapor barrier materials are produced in the form of rolls with a width of about 1.5 m, a length of 50 to 100 m. The film is laid with a smooth, inner side to the insulation by rolling the roll both perpendicularly and parallel rafter leg. In order to protect the thermal insulation layer from vapors as much as possible, when installing the material, overlaps of 15–20 cm are made, and the joints with building structure sealed with glue and tape. It also uses double sided tape.

Vapor barrier for the attic. In the diagram from top to bottom: the ceiling sheathing of the first floor, the vapor barrier layer, the insulation laid between the joists, the plank floor of the attic

Small Conclusions

We hope this article has given you an idea of ​​the difference between vapor barrier and waterproofing. The materials are different, the ways of laying them are also not the same. Observe simple rules installing them, and then your roof will always be dry and retain heat.