Repair of roofs

Roof repair: What to pay attention to on certain types of roofs

The roof is one of the most important elements of the building that ensure its stability. Due to special meteorological conditions - a sudden large amount of precipitation, hot sun, strong winds and snow, as a result of which a considerable additional load appears - in our country, roofs with a slight slope and with attic space. In addition to pitched roofs, There are also flat roof. Of the many materials used for roofs, the best known are: reeds, wooden shingles, tile, eternite, salonite, steel sheet, boards, ter-paper and plastic materials.

 Roofs

Shapes of roofs

In terms of shape, the simplest solution is a single-pitched (single-pitched) roof (fig. 2, part 1), or a roof with a slight slope to one side. It is especially suitable for buildings that have a rectangular base. Gable roofs - the usual solution - are somewhat more complicated, all can be made from shorter beams and protect the walls better (fig. 2, part 2). The most economical solution for modern family buildings with a square base is tent roofs. The advantage of these roofs is that the roof construction can be made of relatively short beams, that they are good heat insulators, and that the roof enables the formation of an attic for drying laundry (fig. 2, part 3).

Mansard roofs are ineffective and do not provide a modern solution. The construction of mansard roofs is very complicated and their maintenance is difficult. The use of these roofs is only justified if the attic space is to be used for rooms. However, even in these cases it is more economical to build a floor, because the walls are cheaper than the roof structure (Fig. 2, part 4).

In terms of economy, tented roofs are the most suitable for family buildings, while single-roofed roofs are the most suitable for weekend houses, because they require the least amount of material and are the easiest to maintain. 
 
 
 Shapes of roofs
 
Canopy function
 
The most important task of the roof is to protect the building from precipitation. However, in most cases, rain and snow do not just fall vertically. Sometimes, wind and gutter elements cause precipitation to hit the side walls regardless of the roof being in good condition. The main task of the canopy at the eaves is to protect the walls from these side impacts. 
Due to the simplification of construction, the rafters of the roof support and the attic are usually supported on the cornice, which is built on the walls. The canopy at the eaves is solved with cornices that are attached with a smaller slope to the horns in their extension (fig. 2, part 2).
 
You can often see such family buildings or cottages where the walls are raised above the roof structure, so that the roof structure does not cover the walls. This causes a lot of inconvenience, because the roof does not protect the walls, and the insulation between the roof and the walls is never ideal. This solution can only be accepted for gable walls, because in this case the wall above the roof separates the building from the neighboring building (fig. 3, part 1). The length of the canopy is also important. If the length of the eaves is short, the walls will not be protected from precipitation, the lower parts of the walls will be wet and the plaster will fall off them. If, on the other hand, the length of the canopy is too long, it will leave a very bad impression, it will look like a tall man with a big hat (picture 3. part 5). A canopy is good if its depth is one fifth of the height of the side wall. (This information applies only to single-story family buildings and weekend houses.) 
 Elements of the roof
 
Elements of the roof
 
The most important elements of the roof are: the rafters, the ridge and the cornice, which is placed on the walls and is in contact with the attics. The latter can also be wooden beams, but lately they are often made on site from concrete. First, the wedding dresses are placed on the walls, and on these supports that hold the helmet, then the horns are placed on the helmet, and on the horns the slats that are the carriers of the veil (fig. 3, 2, 3rd and 4th part).
When designing roof structures, the aim is to load the beams only by pressure. Tensile stress is avoided, deflections are prevented by bracing, and buckling is prevented by installing shorter elements.
 
Wooden beams, which are loaded in bending, are always placed so that their largest dimension in the cross section is loaded, i.e. to have these dimensions set for them vertically. Also avoid the use of knotted wood and wood where the fibers are not in the longitudinal direction, as well as insufficiently dried wood that is prone to deformation.
One of the materials for roof structures is reinforced concrete. Its disadvantage is its heavy weight, and therefore it is usually installed with a crane. Reinforced concrete rafters are made in cross-sectional dimensions of 10 x 14 cm. Standard lengths and corresponding weights are as follows: 5,26 m = 145 kg, 4,62 m = 136 kg, 3,39 m = 94 kg, 2,14 m = 59 kg. On the back of these beams, steel rods are placed on which battens - cover supports are placed, and at the ends of the beams there are also steel ends for attachment to the crown, that is, to the helmet (fig. 4, part 2).
 
On smaller buildings, narrow gauge rails are often used for rafters. The ends of the rails - which rest on the crown or on each other - are machined at a certain angle, usually autogenously, and then the feet are welded from sheet steel, thickness 4-6 mm. With the help of holes that are drilled in the feet and with the help of screws, the rail horns are very easily attached. The slats are attached using holes, which are drilled in the foot on the upper side of the rails. The weight of narrow gauge spikes per meter of length is 12,5 kg. 
 Roof construction
 
Roof structure (SRB supports)
 
One of the variants of roof structures is made of SRB beams. This abbreviation denotes spatial grid supports made of sheet steel profiles. The constructions of the lattice supports are very strong, light and convenient for assembly and handling. Triangular cross-section supports rest on the cornices using sheet metal plates that are welded to the ends, and are fastened using the holes in these plates and screws. In the upper part at the place of the ridges, they are joined by joints for the horns of the other side, so that the ridges are unnecessary. The supports are placed so that the base of the triangle of their section is on the upper side, and on this surface, at certain distances, sheet metal is welded plates with holes for attaching slats. The rafters of the opposite sides are connected by cables with tension bolts to transfer the lateral pressure of the rafters to the cables so as not to stress the walls. Welded sheet metal is usually sized to fit the roof tiles. Therefore, if you want to install a slate roof, you should first place longitudinal battens on the tin plates and fasten the plate battens to these.
 
Roof constructions of auxiliary rooms such as: terraces, open rooms in gardens, garages, sheds for boats, etc. they can also be made from pipes with a diameter of at least 50 mm and a wall thickness of 3 mm. With these roof constructions, the cover can be made of corrugated asbestos-cement boards. The weight of the pipe per long meter is 3,8 kg and they can be attached with screws M 8 or M 10. 
 
Covers made of tiles and asbestos-cement plates
 
The construction of the roof structure should be adjusted in advance to the selected type of roof covering. In our country, the most widely used roof covering is made of baked tiles. Tiles are produced in two forms: standard slotted tile measuring 40 x 21 x 2 cm and "pepper" tile (pepper-schwantzigl) measuring 36 x 17,5 x 1,5 cm. For standard tiles, battens are placed on the rafters at a distance of 32 cm, and for "pepper" tiles at a distance of 28 cm. In this way, tiles can be installed with an overlap of 8 cm. The most suitable pitch for roofs with tile covering is 32-60 degrees (fig. 4, part 3).
 
Tiles are always laid in rows starting from the eaves and continuing towards the ridge. The tiles on the edges and corners are formed into appropriate shapes using a hammer. The repair of the tile cover is very simple: we pull the damaged tile into the attic space and replace it with a correct tile. The crest and ridge are covered with grooves. The dimensions of the grooves are 33 x 20 x 12 cm and they are connected to each other using grooves. For each square meter of the roof surface, 16 tiles should be calculated, and for each length meter of the ridge and ridge, 3,5 tiles groove. The crest, ridge and ends are fixed with a good quality lime mortar. Many use asbestos-cement boards to make the cover. These panels are made in dimensions of 30 x 30 or 40 x 40 cm in the shape of a square, rhombus or standard shape without corners. In all three forms, halves, diagonal halves, as well as edging pieces are made. Semicircular or triangular shaped pieces for covering ridges and edging with dimensions of 30 or 40 cm are also produced. (s]. VII-15), As asbestos-cement boards are very sensitive to tension and break very quickly, the laths must be placed exactly in the prescribed plane. A length of 8 cm is usually left for the overlap, so when using standard boards, the distance between the slats is 21,5 cm. Each board must be attached to the base with two nails with a clip. Of the standard 40 cm diameter tiles, exactly 1 pieces are required for 2 m10 of roof surface. Repairing a damaged cover made of asbestos-cement tiles is quite complicated. Cracks in individual tiles can be temporarily repaired with epoxy, all finally solvedthe only thing is to change the tile. For the change, it is necessary to tear off all the correct tiles starting from the nearest edge or ridge and go all the way to the damaged one. The minimum slope of the roof with asbestos-cernental boards is 20 degrees. For flatter roofs, the overlap should be increased from 8 to 10 cm, and the distance between the slats should be reduced to 20 cm. 
 
Cover it
 
 
Salonit plates
 
One of the uses of asbestos-cement boards is salonit boards. The width of corrugated pressed plates with a thickness of about 5 mm is 93 cm, and the number of waves is 5. The lengths of the plates are 1250-1600-2500 mm or their integer multiples, or quotients. Corrugated boards can be installed on almost all roof structures without slats. Plates are produced with a thickness of 6 mm, width of 105 cm, number of waves in the plate 7,5, length of 122 cm, increasing by 15 cm to 244 cm.
 
salonit plates
 
Salonit panels are attached, depending on the shape of the roof beam, with screws in the shape of U, J or S. The upper part of the screws is attached to the beam or pipe of the roof. constructions. Holes are drilled in the plates with a drill or punched with a hammer. A rubber seal (to protect against rain), a washer and a nut are placed on the screw. The overlap between individual plates is 4-15 cm, depending on the slope, which can be 50-54 degrees. To cover the ridge of the ridge and for the ends, fashion pieces are also made. A very suitable material for covers is a plate made of artificial materials, lighter in weight, transparent with reinforcement from steel sheet and glass fibers. The dimensions of these plates are 2060 x 800 x 2,5 mm. Their waves are malleable and the material loads ("eats") the tool a lot during processing. The weight of one board is 3 kg. Much cheaper is this type of non-transparent board, which can also be obtained in rolls with a width of 1750 mm. Its weight is 3,5 kg/m. There are corrugated sheets in panels with dimensions of 680 x 870 x 2000 mm, as well as steel sheets with dimensions of 630 x 800 x 2000 mm. Steel sheets should be protected from corrosion, while plates made of aluminum and synthetic materials do not require special maintenance.
 
The slope of roofs covered with flat metal sheets can be as low as 4 degrees. A flat formwork board should be placed under the roof covering material in the direction of the slope, and at the places where the individual boards are joined in the direction of the slope, triangular cross-section battens should be attached. These laths are used to join sheets with overlap and bend. In the transverse direction, a flat overlap of 5-15 cm or an overlap with a bend of 4-8 cm is left, depending on the slope. Similar to tin covers, a cover is also made from roofing felt. It is necessary to cover the roofing plaster well with tar or hard-to-melt bitumen. Since tar and bitumen melt easily under the influence of the hot sun, a layer of finely rounded and completely clean gravel is placed on the surface, which is set while the bitumen is still warm. If this is not possible, then you should at least paint the dark roof surface (picture 6).
 
 Cover
 
A few words about concrete covers 
 
And finally, a few words about concrete covers. For the production of concrete covers requires a lot of board formwork and horns. Only grade 500 cement should be used for the cover. It must not be spared.
 
concrete roofs
 
You should wait until the material is completely ties. It is important that the eaves are placed on the lower surface drips that will prevent water from leaking towards the walls (si. 6, part 1). The roof should first be covered as thickly as possible with a layer of mash of uniform grains that will serve as thermal insulation, and put a layer of concrete on this layer. Irregular a finished concrete roof can be the cause of serious accidents. In the case of smaller buildings, it is important that the entire roof is made at once so that the concrete sets well. The concrete as well as the insulation layer of slurry should be well compacted. Special attention should be paid to edging and drainage around the cornfield.
 
Repairing concrete roofs is an unusually difficult job, so they should be made in such a way that they do not require maintenance later. We do not recommend a concrete roof for covering family buildings, and for weekend houses it is quite economical, although it requires good preparation, and it is quite warm. Therefore, it is best to place buildings with a concrete cover in the shade of other buildings or trees.

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