Membrane roof waterproofing. Waterproofing films and membranes for roofing. Types of waterproofing films for roofing
When building a house special attention need to be paid to the roof. The durability of the building depends on the roof, since if moisture gets in from the outside, the building will be destroyed. Big role This is where the waterproofing membrane plays a role, which acts as a vapor barrier.
Waterproofing is an essential element of any roof. It is located under the roof. Protects the structures below, as well as the insulation, from moisture penetration. Waterproofing promotes effective air exchange and prevents the formation of condensation on the inner surface of the waterproofing roll material. The main task of waterproofing is to prevent roof leaks. Humidity leads to the appearance of mold, rotting of wooden structures, and wetness of the insulation, which becomes the reason for its multiple weighting and the risk of roof collapse. Therefore, the waterproofing material must comply following requirements:
- 100% waterproof;
- high tensile strength;
- good elasticity;
- long service life;
- minimum weight.
Depending on the type and design of the roof, they are used different types moisture protection.
- films - a covering made of thin canvas, rolled into a roll for ease of transportation and storage;
- membrane - manufacturing technology involves the use of elastic and UV-resistant polymers;
- mastics - intended for internal and external work, can be used as a finishing coating.
The main advantages of waterproofing film for roofing:
1. The polymer is reliable in strength and does not crumble over time.
2. Increased elasticity and strength.
3. According to its characteristics, the waterproofing film is an excellent water barrier that prevents moisture from penetrating under the roof.
4. Waterproofing film promotes ventilation. This is very important for wooden beams.
5. Prevents dust and debris from getting into joints and joints.
6. Increases the thermal insulation performance of insulation and significantly increases its service life.
7. Environmentally friendly material.
8. Counteracts ultraviolet radiation.
1. The waterproofing membrane is mounted horizontally from the eaves to the roof ridge on the rafters with the edges overlapping by at least 15 cm so that there are no gaps and the joints are taped with adhesive tape.
2. Then the film is laid with an overlap in accordance with the table:
3. The final fastening of the film is carried out using cornet bars with minimum cross-section 40x25 mm every 10-15 cm.
4. Then the sheathing is installed.
5. Installation of counter-lattice.
6. The lower edge of the film is attached to the dropper to last board flooring using polyurethane foam.
The roof is one of the main elements of any structure, and is designed to protect the walls and premises of the building from precipitation and wind, maintain a comfortable environment for people living in the house or favorable conditions for items placed inside. Waterproofing film for roofing, selection and installation - such aspects always raise many questions, since the creation reliable barrier from moisture penetration will always be one of the the most important stages at
In stock today construction stores You can find a considerable variety of rolled waterproofing materials, and it can be very difficult to immediately understand the features of a particular film. Therefore, in order to decide which type is optimal for the planned roofing, there is a need to take a closer look at the characteristics, as well as the features of installation work.
The main purpose of roof waterproofing
Let us first recall that earlier, when constructing private houses, waterproofing pitched roofs was not always installed - this process was mainly carried out on flat or low-slope roofs of multi-storey buildings, and for these purposes, as a rule, roofing felt was used. The technology for mandatory waterproofing of roofs came from abroad, along with materials intended for this purpose, and it must be said that it has taken root well in the Russian construction industry.
Nowadays, the construction of a private house no longer requires the inclusion of such a stage of work in the project, since it is one of the most important for the overall protection of the structure from moisture penetration. Waterproofing rafter system helps to avoid frequent repairs and extends the life of the building as a whole.
Of particular importance is protective film, if the under-roof space is insulated with one of the types of thermal insulation materials that are capable of absorbing moisture - the same condensation that forms during temperature changes. Waterproofing material is able to reliably protect the insulation, create conditions for its free evaporation into the atmosphere or for removal from under the roof - into a properly equipped gutter, fixed along the slope on the eaves board.
In addition, no one is completely insured against leaks of the roofing covering, due to its aging, accidental mechanical damage, or even from trivial errors during installation. The waterproofing barrier will not allow atmospheric moisture to immediately, directly enter the attic and spread further, and the owners will have the opportunity to take adequate measures to eliminate the emergency situation.
Waterproofing membranes are usually sold in 50 m rolls with a width of 1500 mm, and the weight of the roll can vary depending on the thickness and type of film.
Glassine
Glassine is roofing cardboard impregnated with a composition of refractory bitumen with the addition of plasticizers. Glassine is sold in rolls and is used for hydro- and vapor barrier of various building elements.
Many owners of private houses, wanting to purchase glassine, wonder what it is, a hydro- or vapor barrier material? For roofing, glassine is used in one or another capacity - it is used to vaporize the insulation on the side of the premises and to form additional waterproofing for the roofing “pie”, laying it under the roofing material.
Several types of roofing glassine are produced with different markings:
- P-300 GOST and P-300 TU - the material has average density, waterproof, is characterized as a reliable waterproofing material, but is inferior to the P-350 brand.
- P-250 is an economy class material, as it is made from low quality raw materials. However, despite this, it has high strength properties, is water and frost resistant, and is also quite elastic.
- P-350 GOST and P-350 TU - this material is of the highest quality of all brands of glassine, as it is richly impregnated with bitumen. In addition, the advantage of this material is its ability to “breathe”, therefore, when used, a ventilated roofing “pie” is created.
These diagrams present three ways to use glassine in roofing, where it is used as a waterproofing and vapor barrier layer.
- The first diagram shows the installation of glassine on a flat roof as a vapor barrier layer.
1 – Roofing material.
2 – Concrete screed.
3 – Insulation mats.
4 – Glassine.
5 – Concrete floor.
- Second scheme. Here glassine acts as a waterproofing layer for a pitched cold roof:
1 – Roof covering.
2 – Glassine.
3 – Solid plank sheathing.
- The third diagram represents the location of glassine in the roofing “pie” of insulated gable roof, in which it plays two roles at once - waterproofing and vapor barrier:
1 – Roofing material.
2 – Glassine (as under-roof waterproofing).
3 – Counter-lattice.
4 – Insulation.
5 – Glassine (vapor barrier on the room side).
6 – Rafters.
7 – Drywall (internal lining attic space).
Breathable perforated or diffuse membranes
This type of waterproofing material provides decent protection for roofing system from direct penetration of atmospheric precipitation, and at the same time does not prevent the evaporation of water vapor coming out from the inside, from the layers of the roofing “pie”.
High vapor permeability can be achieved due to the perforation of the material. The film is a non-woven fabric made from synthetic fibers, and is used as a wind and waterproof layer. This material can be laid directly on the insulation, which saves on the installation of counter-battens. In order for the material to function “correctly”, it is necessary to secure it with the correct side to the insulation. However, it should be noted that on construction market You can find both one-sided and double-sided membranes, which, accordingly, can be laid on the insulation on either side. Therefore, when purchasing film, you need to pay special attention to this factor.
The advantage of “breathing” membranes is that they meet all the requirements for roof waterproofing and heat conservation. Well, the disadvantages, it must be said - conditional, include their high price, compared to other similar materials.
Otherwise, they can be called the most the best option for arranging roof waterproofing.
According to the level of vapor permeability, “breathable” films are divided into three categories:
- Diffuse, having average vapor permeability.
- Superdiffuse membranes have the maximum degree of vapor permeability.
- Pseudo-diffuse films with low vapor permeability, requiring mandatory arrangement of a ventilation gap between them and the insulation.
Overview of commercially available waterproofing materials
On Russian market There is a fairly wide range of materials for roof waterproofing. Some brands can be highlighted in a separate line, since they have managed to establish themselves exclusively with positive side when used in various climatic conditions- these are Ondutis, Technonikol, Yutakon, Folder Dorken Delta-Roof, DuPont, Izospan and others.
The technical and operational characteristics of some of them are presented in the table, but they also have common parameters. For example, the size of the rolls - the total area of the material is 75 m², with a coating width of 1500 mm and a film length per roll of 50 m.
Material name Main technical and operational characteristics Price, rub./roll as of May 2016 "Ondutis RV100" This is an environmentally friendly material made from polymers that are inert to bacterial influences.
- weight 90±10% g/m²;
- vapor permeability (24 hours) - 10 g/m²;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 650/500.1200÷1500 "Ondutis RS" This is a reinforced film with good performance characteristics, which can provide wind and waterproofing protection. The membrane is resistant to ultraviolet radiation.
– weight: 100±5% g/m²;
- vapor permeability (24 hours): 10 g/m²;
- operating temperature range: from -40 to +80°C;
- UV stability without coating: 1 month;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 250/200.1850 "Ondutis RVM" This is a non-woven fabric equipped with a heat-reflecting surface, so it is winter period protects the insulation from atmospheric humidity, and in summer - from overheating, reflecting ultraviolet rays. Thanks to this layer, ice does not form on the roof.
– weight: 125±10% g/m²;
- vapor permeability (24 hours): ÷10 g/m²;
- operating temperature range: from -40 to +80°C;
- UV stability without coating: 2 months;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 250/130.2500 "Folder Minima D98" This material can be used if there are ventilation gaps in the structure.
- vapor permeability (24 hours): 30 g/m²;
- operating temperature range: from -40 to +80°C;
- UV stability without coating: 2 months;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 550/650.1500-1700 "Anticondensat Folder" This is an anti-condensation film, which also requires the formation of ventilation gaps.
- vapor permeability (24 hours): zero;
- operating temperature range: from -40 to +90°C;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 400/450.1500-1700 "Yutafol D 96 Silver" Waterproofing two-layer laminated perforated polypropylene film.
– weight: 96±5% g/m²;
- vapor permeability (24 hours): 18 g/m²;
- UV stability without coating: 3 months;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 600/4001395 "Yutafol D 110 Standard" Three-layer reinforced, laminated on both sides, waterproofing film.
– weight: 110 ±5% g/m²;
- vapor permeability (24 hours): 41 g/m²;
- UV stability without coating: 3 months;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 600/400.2590 "Yutavek 115" Super diffuse three-layer film.
– weight: 115 ±5% g/m²; - vapor permeability (24 hours): 1200 g/m²;
- strip breaking load 50 mm, N, (lengthwise/crosswise): 260/145.4950 "Tyvek Soft" Single-layer polyethylene waterproofing material with high vapor permeability.
– weight: 60 ±10% g/m²;
- vapor permeability (24 hours): 1375 g/m²;
- UV stability without coating: 4 months;
- strip breaking load 50 mm, N: 140.5650 "Tyvek Solid" Single-layer polyethylene vapor-permeable membrane of increased strength.
– weight: 80 ±5% g/m²;
- temperature range: from -73°C to + 100°C;
- vapor permeability (24 hours): 1300 g/m²;
- UV stability without coating: 4 months;
- strip breaking load 50 mm, N: 250.6950 Video: a brief overview of roofing film materials of the Ondutis brand
Installation of waterproofing film
The main difficulty in installing waterproofing of rafter systems, as well as laying any roofing materials, is that the work is carried out at height, that is, increased safety measures must be observed. Otherwise, it is not particularly difficult. To secure the film, you only need a construction stapler and staples.
Prices for glassine
Glassine
General rules for laying a waterproofing roof barrier
The waterproofing film is laid on top of the insulation laid between the rafters. If a “breathable” membrane is chosen for the flooring, then there is no need to provide a gap between it and the insulating material. When choosing a polyethylene film, before fixing it, to create a ventilation gap, counter-battens with a thickness of approximately 30 ÷ 50 mm are fixed to the rafters, and the waterproofing material will already be fixed to them. This is especially important to consider if one of the following is used for the roof. metal coatings- or
The presented diagram shows a “roofing pie” using vapor-permeable “breathable” super-diffuse waterproofing “Izospan”. It consists of the following elements:
1 – Metal tiles.
2 – Wind-hydroprotective superdiffuse membrane.
3 – Counter rails.
4 – Layer of thermal insulation (mineral wool).
5 – Vapor barrier film.
6 – Rafters.
7 – Sheathing the attic.
8 – Lathing on which the roofing covering is attached.
- If a waterproofing film with a width of 1500 m is purchased, then its installation on the pitched rafter system is carried out from the eaves. The film is spread across the rafters, that is, along the eaves line, evenly, without folds, and secured to each of the rafter legs using stapler brackets.
- If an anti-condensation film is selected, then it is not stretched, but, on the contrary, it is laid in such a way that it sags by 10–20 mm in the space between the rafters.
This type of membrane should be located at a distance of about 40÷60 mm from the insulation, therefore, when choosing it, it is necessary to provide the appropriate width rafter board and the thickness of the insulation. After laying, the anti-condensation film sheets must be glued together with special moisture-resistant tape.
The second waterproofing sheet is laid above the first and overlapped on it. The size of the overlap will depend on the slope of the roof. Recommended material overlap parameters can be found in the table below:
In some cases, for example, on short sections of the roof, where the distance between the rafters allows it, the waterproofing can be fixed vertically, but at the same time the overlap size indicated in the table is also observed, depending on the roof slope angle.
- The canvases are laid according to the described principle to the top of the roof, and a canvas is laid on the ridge, which will be placed on both slopes at once. Since the canvas must be laid overlapped on the sheets fixed below, the ridge part of the roof is waterproofed last.
Very important nuance! Completely covering the ridge with film is only permissible if a super-diffuse membrane is used, with vapor permeability of at least 1000 ÷ 1200 g/m² per day.
When using any other film material, a gap of about 200 mm must be made between the waterproofing sheets in the ridge area - this is necessary to ensure normal ventilation and evaporation of condensate.
- After the membrane is fixed, a counter-lattice, which consists of 30×20 or 40×25 mm slats, is attached to the rafters on top of it. They are attached to the rafters using self-tapping screws.
- Sheathing boards are secured on top of the counter-lattice for installation of the roof covering. The pitch of the lathing depends on the choice of roofing; it can be sparse, frequent or continuous.
For example, if a soft bitumen shingles, then a continuous sheathing of boards or plywood with a thickness of 10–15 mm is installed. In this case, another layer of waterproofing is additionally laid on top of it, and for this, materials such as glassine or TechnoNIKOL are often used. If bitumen-based waterproofing is used, for example, glassine, then the edges of the canvases are laid on a continuous sheathing, which will protect against moisture penetration under the waterproofing.
- For rigid roofing material, depending on the size of its sheets, boards of rare or frequent lathing are attached to the counter-lattice. The most common step size for installing sheathing elements is 350÷400 mm.
- The selected roofing material is laid and secured on top of the sheathing.
Organization of condensed moisture removal
Separately, it is necessary to say about fixing the waterproofing film on the eaves board, since the condensate formed under the roofing and not evaporated into the atmosphere must be discharged into the gutter. If this is not provided for, moisture may get under the eaves board, where fungus can form, which will lead to the destruction of the wood.
This diagram shows the design of a system for draining condensate from under the roof using waterproofing material placed on a metal eaves strip, along which water will flow into the gutter.
If the gutter design has a continuous attachment to the eaves board, then the waterproofing material can be attached directly to it and passed under the metal strip.
Another option for draining condensate is formed by installing a special metal element - a drip line, which is attached to the waterproofing material and discharged under the gutter.
Valley waterproofing
Problem area roofs can be called a valley - a fracture of the slope, that is, the junction of two planes under a certain one, which is carried out under a certain internal corner. The lathing that forms the valley is two or four boards fastened together at the angle where the roof slopes meet.
Before installing the general waterproofing on the sheathing of the roof slopes, a single sheet of waterproofing material is laid on the valley boards from the ridge to cornice strips. It should be evenly distributed on both sides of the valley and securely fixed to them using bitumen, brackets or waterproof construction tape.
Only after the installation of the film on the valley is completed, the waterproofing sheets begin to be fixed to the rafters of the roof slopes from the eaves. Horizontal sheets are laid on top of a vertical water barrier fixed to the valley, so a double layer of waterproofing is necessarily formed here. Only after this is it placed in the gutter between the slopes metal element valley, through which the water will flow.
Installation of vapor barrier films
Vapor-tight waterproofing films can also be used as a vapor barrier, but the principle of their installation is completely different. To understand the difference, the main technological methods for vapor barrier of a roof from the inside will be given.
There are two main ways to install a vapor barrier membrane - from the attic side and from the outside. The first method is more technologically advanced and is used more often, since when performing work, the master sees the entire rafter system, which practically eliminates making mistakes.
Installing a vapor barrier on the roof side
The work is carried out in the following order:
Illustration Brief description of the operation performed This diagram represents the location of all elements of the roofing “pie”. If the first option for fixing the vapor barrier is chosen, then you need to start by sheathing the slopes of the rafter system from the attic side.
They can be covered with clapboard, plywood or plasterboard. Finishing material fixed on the rafters, or on the sheathing attached to them.
Exactly interior decoration will become the basis for laying vapor barrier on the outside of the roof frame and insulation material.So, on the outside, a thin layer of insulation is laid on the prepared base; its thickness can be 15÷20 mm. This layer will protect vapor barrier film from punctures and damage by self-tapping screws that secured the interior trim.
If there are no sharp elements, then a layer of insulation is not necessary.
Next, starting from the cornice, film sheets are laid on all surfaces of the base and rafters.
Secure the material using a stapler and staples.In order for the film to fit snugly at the joints of the rafters and the internal cladding, it is first carefully pressed in the corner with the help of a beam, which will help to straighten it well. Then, the film is secured with staples to the rafters.
Thus, the first vapor barrier sheet is laid.The next step is to lay the second sheet of material, overlapping the bottom one.
The size of the overlap, just like when installing waterproofing, depends on the angle of the roof, and you can be guided by the parameters indicated in the table above.After laying the sheets, their overlaps are securely sealed together using special waterproof tape. After installing the film, insulation is laid between the rafters, which is then covered with waterproofing, sheathed with lathing, on top of which the roofing covering is laid.
This approach also has its significant drawback. It lies in the fact that by choosing this installation option, the work will have to be completed in one day, or you can choose a period during which it is guaranteed that it will not rain.
Installing a vapor barrier from the attic side
In the second option, the vapor barrier is secured from inside the attic, and this work is carried out after the installation of roofing materials is completed. In this case, the process takes place in the following order:
- The first step is to lay a waterproofing membrane on the rafters.
- Then, the material is secured to the rafters with counter-lattice slats.
- Next, the sheathing boards are fixed to the slats.
- The roofing covering is mounted on them and the ridge is closed.
Now that the rafter system is closed from atmospheric influences, you can safely insulate it from the attic side.
- Mats of insulating material are installed between the rafters, they are pressed against the sheets of waterproofing film fixed outside.
- Then, the insulation is covered with a vapor barrier membrane. It can be mounted horizontally or vertically to the rafters. If the fixation will be done horizontally, then you need to start attaching the film from the bottom. The second canvas is stretched and secured with an overlap of 150÷200 mm over the first, and so the process is repeated until the top.
- After the vapor barrier is secured, the panels are glued together with tape.
- Then, a timber sheathing is installed on top of the film, onto which the attic lining will be secured.
This option is more comfortable to implement than the first one, since half of the work is carried out in safe conditions, under a finished roof.
In conclusion, I would like to remind you once again that you should not indiscriminately purchase any material called waterproofing. It is necessary to approach the choice responsibly, having studied the characteristics in advance and decided which film is more suitable for a particular coating.
Video: a clear example of waterproofing a roof with a vapor-permeable membrane “FAKRO EUROTOP”
The problem of roof leaks during rain or melting snow has always worried and continues to worry owners of private houses and apartments on the top floors of high-rise buildings. But among them, few people think that along with the perceived inconveniences and troubles, there are other, invisible aspects of the issue. They relate to the appearance of condensation due to the difference between internal and external temperatures, as well as to vapor formation resulting from human activity. These factors lead to wetting of the thermal insulation layer and a decrease in its protective properties. Get rid of similar situations A waterproofing membrane for the roof, which is a more advanced analogue of traditional roofing film, will help.
Specifics of waterproofing membranes
Although membranes belong to film waterproofing materials, their structural structure has significant differences that determine the principle of operation of the protective layer. Quite often there is confusion in the concepts of film and membrane, because both protect the insulation from getting wet. But the secret is that the first material is vapor barrier, and the second is vapor permeable.
The waterproofing membrane has microscopic pores designed to remove moisture that accumulates in the insulation layer as a result of the penetration of water vapor into it. Of course, a vapor-proof film laid on the underside of the roofing pie can prevent the natural process, but at the same time it can cause condensation to appear on the ceiling, and subsequently mold. The film is relevant only in rooms where high humidity is the norm. Above living rooms and attics, the best option when installing roof waterproofing is considered to be laying a membrane. It does not allow water to pass through from the outside, but does not prevent steam from escaping from the inside.
Waterproofing membranes for roofingsuggest natural ventilation insulation.
In addition to the fact that the membranes “breathe,” most of them have another significant advantage. Unlike films, they can be laid directly on the insulation, without any gap. This means that the thickness of the heat-insulating layer can be increased to the full height rafter beam. In addition, the absence of the need for a lower ventilation gap implies a refusal to install additional sheathing, which affects the savings in material resources when installing the roof.
Pros and cons
Roofing waterproofing membranes have such positive qualities How:
- high strength;
- elasticity;
- endurance to temperature changes;
- lack of reactions to oxidation and decay;
- durability;
- environmental friendliness;
- UV resistance.
Under-roof waterproofing membranes can be intended for pitched or flat roofs. Before installing the main roofing covering, they are able to independently protect the structure from precipitation for 1.5 months. For more long term leave them open under straight lines sun rays not recommended.
The disadvantages of the material in question include the inadmissibility of using certain types of membranes in tandem with roofing coverings that have high thermal conductivity. In particular, this applies to metal tiles and profiled sheets that do not have inside a layer of special primer that protects the metal from moisture. Another problem faced by inexperienced craftsmen is the incorrect determination of the outer and inner sides of the canvas, which leads to laying the membrane “inside out”. As a result, the opposite effect occurs, since moisture and steam begin to move in the wrong direction. Manufacturers themselves help to avoid such mistakes by painting the bottom and top layers in different color. But, unfortunately, not all companies adhere to this rule for various reasons.
Waterproofing vapor-permeable membrane films can consist of one or several layers, which affects the thickness of the material, its additional characteristics and, of course, cost. Membrane film for roofing, the price of a roll of which reaches 15-20 thousand rubles, has maximum quantity layers and high quality. For comparison, the average price tag is in the range of 5-8 thousand rubles.
Manufacturing companies produce waterproofing membranes of three main types:
- diffusion - the cheapest, but not the worst;
- superdiffusive - remove moisture much faster;
- anti-condensation – inhibit the direct release of wet steam to avoid the appearance of condensation on the back side of the roof covering, which is dangerous, for example, for metal tiles.
The shape of the membrane can be flat or profiled (volumetric). The former are made of high and low density polyethylene, as well as polyolefin and polyvinyl chloride. The second type of waterproofing membranes is made exclusively from polyethylene high density. Such canvases can have round or square protrusions that rise above the main plane up to 7-8mm.
Diffusion and superdiffusion membranes are recommended to be used only with roofing materials, having low thermal conductivity.
Volumetric membranes are used for waterproofing metal roofs. They are available in one- and two-layer, while flat ones can also have a middle layer. Its functions include the accumulation of moisture and its gradual, measured release into the ventilation gap space. In this case, any condensation formation is excluded.
The most popular brands today are waterproofing membranes:
- COROTOP (Poland);
- ELBTAL (Germany);
- JUTA (Czech Republic);
- TYVEK (Luxembourg);
- ONDUTIS (Poland);
- ISOSPAN (Russia).
Selection of waterproofing membranes
When purchasing material, you should pay attention to several technical parameters.
Vapor permeability according to European standards, takes into account the thickness of the resistance to water vapor diffusion. It can be within 0.02-0.4 meters. Here you should focus on a smaller value. According to Russian standards, vapor permeability is considered optimal at a level of 500-1000 grams per m2 per day. Moreover, the higher the number, the better the quality of the membrane.
Water resistance is not less than important indicator, indicating the efficiency of water retention. Must be within more than 250mm water column.
Breaking capacity ensures the strength of the membrane in the longitudinal direction (more than 140N) and in the transverse direction (more than 110N). In both cases, the higher the number, the better.
Membrane price per square meter. You should not focus on the cost of the roll. When comparing materials, it would be wiser to use the first option.
General rules for installing waterproofing
Work on laying the canvas should begin in the direction from bottom to top. In this case, they need to be spread parallel to the roof overhang with an overlap of 12-15 cm. The film does not reach the longitudinal ridge by 5-7 cm in order to ensure natural under-roof ventilation.
The membrane must be laid with a vapor barrier layer next to the insulation. It can be determined according to the instructions in the manufacturer’s instructions in one of the following ways:
- by color;
- according to the inscriptions;
- by embossing;
- by larger perforation diameter, etc.
Seams are sealed using special glue or soldering. The option depends on the type of material. Fixation to wooden structures performed with staples using a construction stapler. The fastening technology is prescribed in the attached documentation.
Particular care should be taken to waterproof the areas where the roof meets structural elements passing through the roof. These could be chimneys, drainpipes, ventilation pipes, antennas, etc. Much attention is paid to valleys, inclined skates, dormer windows, ends and overhangs.
To provide a ventilation gap between the membrane and roofing sheeting the sheathing is installed. The thickness of the air gap should be maintained within 8-12 cm.
The work of laying a waterproofing membrane is not particularly difficult. If the requirements are met, the canvas can be laid independently. Although, you will still have to hire a couple of people as assistants.
Her Majesty waterproofing film. Let's try to find the answer to the logical question: “Which material should I prefer?”
What is waterproofing film
By definition this is polymer material with a waterproof structure, designed to protect buildings from moisture. Previously, builders generally ignored this stage of roofing, or used roofing felt.
In the modern construction market, insulating material is conventionally divided into two categories:
Films
Membranes
Both categories perform protective function, but the membranes have a multilayer structure and provide an important factor: vapor permeability. This feature is that the membrane is capable of allowing air to pass through, but does not allow water to leak through. As a result, condensation does not form on the internal surfaces and insulation.
Types of films
Proven material for vapor and waterproofing. The material is made from cellulose impregnated with a bitumen composition. In essence, we are talking about multi-layer cardboard that is resistant to moisture.
This insulation is easy to install and does not emit toxic or other hazardous substances.
Reliable material, where high strength indicators are achieved due to an additional reinforcing layer. Products are presented on the market in three categories:
Non-perforated
Perforated
Reinforced
Perforated films have a surface covered with microscopic pores; the reinforced version has a layer of foil, which makes it indispensable for insulating rooms with increased level humidity.
Resistant to ultraviolet radiation. The upper surface of such films is usually smooth, the lower surface consists of cellulose-viscose fiber. Due to its structure, the bottom layer has increased absorbent properties and accumulates moisture, which evaporates under the influence of high temperatures.
Optimally suitable for roofing made of metal tiles or corrugated sheets.
Their properties resemble leather. This is a non-woven material that has the ability to allow air to pass freely, but prevent moisture from entering the under-roof space. The advantage of membranes is that they can be mounted directly on the insulating layer.
The material is ideal for cold attics and insulated attics.
What does the market offer?
In terms of its structure, it is a multilayer material produced on a reinforced base. The outer surface forms a waterproof layer, the bottom - a vapor barrier, which prevents the appearance of condensation.
Products are presented on the market in three main categories:
Multilayer waterproofing fabric, which is often used for arranging ventilated roofs.
Utahflex D
A two-layer film made of a non-woven base and a laminating surface. This insulation is suitable for gable roofs.
Yutawek
Consists of 4 layers, used when installing unventilated roofs, can be laid on thermal insulation.
These are diffuse roofing membranes, presented on the market in 3 main groups:
This type of insulation has the following advantages:
Absolutely waterproof.
High strength structure.
Excellent compatibility with any type of thermal insulation.
Easy to install: install using staples or glue.
In addition, the membrane is mounted on thermal insulation without the need for sheathing.
Delta
The products are manufactured by the German company Dorken and are presented on the market in the following options:
Diffusion membranes- three-layer fabric made of non-woven polypropylene.
Films with anti-condensation layer- polyester base with polyurethane coating, characterized by high tensile strength.
Films for installation on continuous flooring- three-layer vapor-permeable membrane.
For lower roof- a water-repellent dispersion coating is provided.
For seam roofing- a film whose surface is covered with a grid of polypropylene thread.
It is a high-quality, but expensive material.
Among the roofing waterproofing from this manufacturer, two types of materials can be distinguished:
Bikrost
This is an insulating sheet consisting of a durable fiberglass base with a double-sided application of bitumen mixture and fillers. The protective surface layer consists of coarse-grained and fine-grained topping.
In the first case, shale is used, in the second, sand. It is used for arranging all types of roofing and performing repair work.
Uniflex
Rolled waterproofing, which is made on a polyester base with the addition of a bitumen-polymer solution. Dolomite or talc are used as modifying additives to improve technical characteristics.
Coarse and fine-grained sprinkles are also used here, and a polymer film or foil is applied as additional protection.
Waterproofing film that meets sanitary and fire safety, suitable for protecting any buildings and structures from moisture. Specifics of use are indicated by the manufacturer's markings.
A- protection from wind and moisture.
B- vapor barrier, placed under insulation.
C- auxiliary waterproofing layer.
D- laminated film for non-insulated roofs.
In total, the company produces over 10 types of waterproofing with multi-purpose applications.
High-strength waterproofing films with high moisture resistance. The product shows good tensile strength, is neutral to temperature changes and exposure ultraviolet rays. Presented on the market in three options:
Reinforced.
Diffusion.
Reflective.
Good waterproofing, which is widely used in multi-storey and private construction, has managed to prove itself on the positive side. Three groups can be distinguished here:
R.S.- reliable protection from wind and moisture, resistant to any weather conditions.
RV 100- fabric material with high tensile strength, an excellent option for arranging a temporary roof.
RVM- non-woven film with a heat-reflecting surface.
Waterproofing polypropylene film with laminated coating. Due to its high strength indicators, the material can be used for the construction of main and temporary roofs, and is used when performing repair work.
To insulate with maximum efficiency coped with its function, the sheets are laid overlapping with the approach 10 cm, be sure to leave a ventilation gap of at least 15 centimeters.
Checking the quality of installed waterproofing
The correct installation of roofing waterproofing is determined by three criteria:
Covers the entire area, including gables, overhangs and cornices.
The lower insulating layer is extended beyond the eaves strip.
The insulation adheres tightly to wall structures and pipes.
If the work is carried out in accordance with these points, there will be no problems with protecting the building from moisture.
How long will film waterproofing last?
The material contains no components capable of biodegradation. Based on this, all manufacturers claim that waterproofing membranes will last at least 50 years without loss of original properties. With the caveat that no technological miscalculations or errors were made during installation.
Waterproofing mastics - an alternative to films and membranes
In terms of their structure, such mastics are a multicomponent material with high adhesive and penetrating properties. The composition of such a substance usually consists of bitumen, supplemented with various fillers and modifying plasticizers. The key advantage is the affordable price and ease of application.
Mastic is applied mechanically, which allows processing in the shortest possible time large plots. Average labor productivity: 1,000 m2 for 8 -hour shift.
Liquid waterproofing reliably adheres to any base, filling all microcracks. Thanks to this feature, the material can be used to protect any building elements from moisture: roofing, floors, walls and foundation.
The article was prepared with the participation of Tyvek® specialists
Modern roofs are a complex system in which the reliability and durability of the structure as a whole depends on each layer. And if the decorative effect of the “fifth facade” is largely determined by the type of roofing, and reliability is determined by the compliance of the rafter system with the expected loads, then the under-roof waterproofing is responsible for the tightness and safety of the insulation and rafters, and, consequently, for the service life of the roof. However, some still have doubts about the need for its use, and difficulties often arise with the choice. Specialists from DuPont, the manufacturer of Tyvek® building membranes, will help to finally dispel doubts regarding the advisability of using the material. Together with them, we will consider the main aspects relating to under-roof waterproofing.
- Why do you need a waterproofing membrane?
- Raw material base and production technology.
- Features of choosing membranes in questions and answers.
Functions of a waterproofing membrane
Membranes are “breathable” films that are permeable to vapor, but impervious to moisture - they protect structures from moisture penetration, but freely allow steam to pass through. It is the vapor permeability, that is, diffusion, of membranes that distinguishes them from impermeable waterproofing (anti-condensation) films.
Although vapor barriers are used when constructing roofs, it is impossible to completely prevent the entry of vapors into the insulation, and a certain amount one way or another it penetrates into it, but is brought out through the diffusion membrane, and does not settle on the surface in the form of condensate. Also, moisture enters the under-roof space both from the atmosphere, through leaky zones in the final roofing, and forms in the form of condensation due to the temperature difference. But, regardless of the source of moisture, its presence in the roofing “pie” is fraught with a number of problems:
- moistening the insulation - when the humidity increases thermal insulation materials The thermal resistance characteristics deteriorate significantly;
- humidification wooden elements rafter system - the appearance of mold, mildew, rotting, loss of strength, reduced service life.
The waterproofing membrane prevents the insulation and rafter system elements from getting wet due to steam, atmospheric moisture, and the formation of condensation on the roofing.
In addition, the membrane protects the insulation from wind, preventing convective heat transfer (convective heat loss). Membranes are used as waterproofing and windproofing in pitched and flat areas. metal roofs mainly in low-rise and private construction.
The main characteristics of high-quality membranes include high vapor permeability, strength, water resistance, wide temperature range, resistance to ultraviolet radiation.
- Vapor permeability – from 600 g/m² in 24 hours (Sd< 0,03 м).
- Strength – from 117 N/5 cm.
- Water resistance – from 1 m water column.
- Operating temperature– from -40 to +100⁰С.
- Resistance to UV radiation – from 4 months.
In addition to outstanding technical characteristics, one of the advantages of diffusion membranes is simplified installation and significant space savings due to the elimination of the lower ventilation gap.
Apple Lover FORUMHOUSE Member
Tell me what films to use for the insulated residential attic. On rafters 50x200 mm with a pitch of 630 mm, the waterproofing membrane is overlapped on top, the joints are glued together. On it, along the rafters, there is a counter-lattice 50x50 mm block, on it there is a lathing in increments of 25 cm, a board 25x100 mm or 25x150 mm (along the wavelength of the MC 35 cm). From inside in the rafters stone wool, vapor barrier, lining. I think I heard that there should be a gap between the waterproofing and the insulation, but I don’t provide for it. This is bad? The gap will be along the counter-lattice and the exit will be through the ridge.
Dmitry BelozerovDuPont Technical Specialist
When using impermeable (convective) films as waterproofing, to remove condensation from the surface of the insulation, they are installed with an additional ventilation gap. But modern concepts energy-efficient construction involves the creation of a sealed thermal circuit, and this is possible when installing waterproofing directly on the insulation. You have done everything correctly, there is no need for a ventilation gap between the insulation and the wind-water protection diffusion-open film.
Raw material base, production technology, features
Diffusion membrane market presented several varieties, the differences in the characteristics of which are due to both raw material base, and production technology.
Microperforated membranes are made from non-woven polypropylene, vapor permeability is ensured by chipped cone-shaped holes (pores). They are characterized by relatively low diffusion (about 40 g/m² per day), which is why they belong to the type of pseudo-diffusion membranes and are installed only with a ventilation gap. And according to modern SNiP, microperforated membranes are not allowed to be used as waterproofing, since due to the size of their pores they are not able to effectively retain water.
Microporous membranes made of polypropylene fibers - permeability is achieved by a large number of interfiber pores. Due to the characteristics of polypropylene and the peculiarities of the production cycle, such films are produced in multilayers to protect the working layer (the part of the membrane that allows steam to pass through but retains water) from mechanical damage.
High-density polyethylene (HDPE) membranes are produced from the finest continuous fibers using ultra-high-speed molding at high temperatures.
Dmitry Belozerov
High-tech diffusion membranes made of heat-stabilized polyethylene have a unique structure that is stably vapor-permeable and waterproofing. This material is characterized by a working layer thickness that is 6-8 times greater than that of multilayer analogues. This thickness, coupled with high resistance to ultraviolet radiation, guarantees the membranes durability and maintenance of performance characteristics throughout their entire service life, which is about fifty years according to laboratory tests. Also, membranes made of high-density polyethylene are superior to their analogues in water resistance, as the following table illustrates.
How to choose a suitable membrane
So, waterproofing membranes in roofing pie needed - we decide on the selection criteria. The functionality of the membrane consists of a set of characteristics and an optimal ratio of density, vapor permeability and waterproofing properties.
First of all, these parameters must correspond to or exceed those given, since the lower limits allowed by the standards are indicated.
Also, in addition to vapor permeability and strength, the thickness of the working layer is important.
Dmitry Belozerov
The thicker the working layer of the membrane, the longer its service life, therefore, you will not have to overhaul the roof in a few years due to a leak, after the thin membrane becomes unusable. For comparison, the thickness of a human hair is about 80 microns, while the thickness of the working layer of a standard roofing substrate is about 30 microns, and the rest is made up of protective layers.
The specificity of the application is also of great importance - specialized membranes are produced for cold and insulated roofs, and there are also universal ones. If you have not finally decided on the status of the attic or attic, you should not choose specialized waterproofing.
