The most common option for covering flat roofs today is the use of rolled welded materials. This method of covering the roof is quite simple, let's consider how the built-up roof is mounted with your own hands.
The roof of any building is created to perform a number of protective functions. Among them:
- Protection of premises from the penetration of precipitation and wind;
- Preservation of heat in the winter;
- Protection against overheating during the summer heat.
Thus, very serious requirements are imposed on the roof. It must be strong, airtight and well insulated.Today there is a huge selection of various roofing materials.
Each of them has its own advantages, but there are also disadvantages. Therefore, before you purchase this or that roofing material, you need to carefully familiarize yourself with its characteristics.
Material selection
If we are talking about the materials used to create a soft roof, then they can be classified according to several main features.
So, according to the type of base used for their manufacture, the materials can be divided into:
- Cardboard;
- asbestos,
- fiberglass;
- Polymer.
According to the type of binder used, it is customary to distinguish materials:
- bituminous;
- Polymer;
- Polymer-bitumen.
Previously used roofing roll materials of the first generation (such as roofing material) are used today only as a lining waterproofing material. The undoubted advantage of roofing material is its low cost. For all other characteristics, it does not meet modern requirements.
Today, to create a high-quality coating, materials based on fiberglass or polyester are chosen, and polymer-bitumen compositions are used as impregnation. For these materials there is no single GOST. Each manufacturer produces them according to their own specifications.
The largest manufacturers label their products using a three-letter code.
The first letter of the code characterizes the type of material basis:
- E - polyester:
- X - fiberglass;
- T - fiberglass.
The second letter of the code characterizes the type of outer coating:
- K - mineral coarse dressing;
- M - fine-grained sand;
- P - polymer protective film.
The third letter of the code characterizes the bottom cover:
- F - foil;
- M - fine-grained sand;
- C - suspension;
- P - polymer protective film.
Preparation of the base for laying the built-up roof
Before starting the installation of the built-up roof, it is necessary to prepare the base well. The first layer of the roofing cake is a vapor barrier, which is laid on the floor slabs. As a vapor barrier, film or built-up materials (for example, Bikrost) are used.
At the junction of vertical elements, the vapor barrier material is fixed with a solid sticker, leading it above the level of future thermal insulation. On horizontal surfaces, rolled materials are overlapped with sealed seams.
The next layer of the cake is a heat-insulating material with a cement-sand screed placed on top of it. Insulation plates are recommended to be glued together with hot bitumen.
A cement-sand screed over thermal insulation is performed with the creation of temperature-shrinkage joints, the width of which should be about 5 mm. Such seams divide the screed into squares with a side of 6 by 6 meters.
Advice! 3-4 hours after laying the screed, it is desirable to cover its surface with a primer, which is prepared from bitumen diluted in half with kerosene.
The last layer in the roofing cake, on which the top coating will be laid, is roof waterproofing. It is also necessary to provide funnels for the internal drain, installing them according to the project.
At the points of contact with vertical elements (walls, pipes), 100 mm high sides are made at an angle of inclination of 45 degrees from asphalt concrete or cement-sand mortar.
Before you start laying waterproofing material, you need to check the level of moisture in the base. It is not allowed to perform work if the primer layer is not yet dry enough. The temperature-shrinkage joints of the screed are additionally covered with strips of waterproofing material 150 mm wide.
Advice! To close the temperature-shrinkage seams, it is better to use a roll material having a coarse-grained dressing. Moreover, it must be laid with a sprinkle down.
In the area of the water intake funnels, additional “patches” measuring 70 by 70 centimeters are laid on top of the main layer of waterproofing.
If the old roof is being repaired using welded materials, then the preparation of the base consists of the following operations:
- Cleaning debris from the roof surface;
- The maximum possible elimination of dust on the surface of the old roofing material;
- Inspection of the old coating in order to identify swelling and bubbles;
- Opening the detected bubbles and heating this place with a funnel to melt the material.
What equipment is needed for laying the built-up roof?
You will need the following equipment for built-up roofing:
- Roof gas burner, which is connected to a gas cylinder through a reducer;
- roofing knife;
- Putty knife;
- Brushes for cleaning the base and applying the primer.
- Roller roller.
- Overalls - protective gloves, boots with thick soles, work overalls.
Instructions for laying the deposited material
When planning the behavior of the work yourself, you must first study the instructions describing the execution of the work. For greater clarity, it is better to see how the built-up roof is mounted - a video on this topic can be found on the net.
We offer step-by-step instructions for the work:
- Laying of the deposited material is carried out on a well-prepared, primed and dried base.
- Laying work begins with the lowest sections of the roof.
- Before you start laying the material, it is worth unrolling the roll completely and making sure that it is positioned correctly. Then, using a burner, you need to fix the beginning of the roll, after which, roll the material back.
- The material is attached to the base by heating its lower layer in a burner flame.
- The flame of the burner must be directed in such a way that it heats the base of the roof and the bottom of the roll of roofing material. As a result of such heating, a small "roll" of bitumen is formed in front of the roll, which, as the roll is rolled out, serves to adhere the material to the base. With high-quality performance of work along the edges of the roll, the bitumen protrudes evenly, approximately 2 cm wide.
Advice! To ensure uniform heating of the material, it is necessary to move the burner in the shape of the letter “L”, additionally heating that part of the roll that goes to overlap.
- After one tape of material is glued to the base, you need to immediately check the quality of the seam. If in some place the material leaves, then it must be lifted with a spatula and re-fused using a burner.
- Walking on freshly laid material is undesirable, as this can spoil the appearance of the roof, as dark marks may remain on the topping.
- For better gluing of the material, it should be rolled with a soft-coated roller. In this case, the movements of the roller should be directed from the axis of the roll to its edges diagonally. With special care, you need to smooth the edges of the material.
- In order to achieve the tightness of such a coating as a built-up roof, the installation of material strips is carried out with a certain overlap. So, when laying adjacent panels, the side overlap should be at least 8, and the end overlap should be 15 centimeters.
- When making joints of individual strips of material, care must be taken that they are located in the direction of the roof slope so that water cannot flow under them.
- When installing the material on vertical parapets, a piece of the required length is cut off from the roll and mechanically strengthened along the upper edge of the parapet (self-tapping screws, nails, etc.). Then the material is welded onto the parapet using a burner.
- To lay down roof material on the outer and inner corners of the vertical elements, use two pieces cut from the roll, which are laid with a significant overlap.
- When laying the material in several layers, the rolls should be shifted so that the joints in different layers are not one above the other. Cross-laying of material is not allowed.
The most difficult moment of installation is to ensure the tightness of the junction of the roof to the vertical elements. Therefore, it is advisable to study this issue with special attention and watch a thematic video - built-up roofing and its installation.
As a rule, it is recommended to stick two additional layers of waterproofing material at the junctions. The first layer of reinforcement must be brought to the vertical surface by at least 250 mm, the second (material with powder is used) - by at least 50 mm.
The amplification sticker operation is performed in the following sequence:
- First, the first layer is laid with a 250 mm approach to the vertical surface. The upper part is reinforced with nails, then the material is pasted;
- Further, a piece of length equal to the height of entry on the vertical element plus 150 mm is cut off from the roll of material with sprinkling for gluing to a vertical surface.
- A piece of material is folded across, stepping back from the edge of 150 mm, and set to the junction.
- Holding the bottom of the segment, glue the vertical part. After that, glue the lower part to a horizontal surface.
conclusions
As can be seen from the foregoing, the technology of laying the built-up roof is not particularly complicated, so the work can be done independently. Especially in the event that the built-up roof is laid on the old base, for example, when repairing the old coating.
However, it must be remembered that when working with gas burners, special care should be taken and safety requirements should be carefully observed.
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