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The question of application of soft roof is very relevant for construction of the private sector. The cause is – number of advantages of this modern material before more rigid analogs. Let’s begin with small weight – transportation and laying of easy roofing covering happens much more simply and quicker, than, suppose, heavy metal tile. The roof surface after installation works becomes absolutely hermetic. The soft roof is used even at the device of difficult roofing configurations when other materials are inconvenient or inappropriate for laying.
It is worth to remember also about esthetic attractiveness of this material: thanks to variety of color gamma the roof looks presentably throughout long time. The product price is important for owners of private building – and it is quite available. One more plus – possibility of independent laying even alone.
Features and assignment of soft roof
The generalized name “soft roof” is usually applied to the materials differing in elasticity due to bituminous impregnation. Basis of sheets (or rolls) is the fiber glass from two parties surrounded with rubber-bituminous layers. This structure provides to roofing covering excellent tightness and wear resistance – for this reason soft types of roof are so popular with builders. In order that sheets of material did not stick together among themselves, they have protective layer – the mineral topping which is also doing material to stronger.
Not each roofing material will fit if the tilt angle exceeds 11 degrees. For soft types of covering it is not problem: due to the lightweight they are capable to perform the functions even on the most abrupt roofs and with mounting of special difficulties will not arise. One of the most widespread types of soft roof – bituminous tile which is released in the form of separate elements of different geometrical form. Also often use also rolled materials, for example, roofing membrane.
Rather small set of materials is necessary for mounting of soft roof:
- trowel for putting mastic;
- waterproofing covering;
- levels (edge and eaves);
- ridge and eaves strip;
- roofing nails;
- working gloves.
Mounting is made in dry sunny weather at temperature from +5 °C. The matter is that connection of several elements of tile, has glue layer which under sunshine is better pasted to the basis on inside. For their durability in addition fix nails. During cold weather it will not be possible to lay also strongly and hermetically flexible tile.
Mounting elements, they should be taken from different parties, that is from different boxes. If there is heterogeneity of shades, then thus it will mix up, and during the subsequent repair new products will not be allocated against the background of old.
Ventilation – necessary condition of roofing covering
Knowing laws of physics, it is simple to draw conclusion that without correctly arranged ventilation the lower part of roof will become covered with condensate. As a result the excessive humidity will cause material rotting, and during winter cold weather water to turn into ice, aggravating destructive processes.
The ventilation system includes several inlet and exhaust outlets and also gap not less than 5 mm. Under the line of eaves overhangs arrange air vents which are necessary for natural air circulation.
Upper part of roof – the convenient location for placement of exhaust openings which arrange either in the fad, or by means of aerators – dot ventilating exits. For normal air circulation there is enough width of openings in 60-80 mm.
Lining layer – additional protection
Roofing furring is carried out from tree therefore when mounting metal parts – pediment and hood molds – it needs additional protection in the form of lining. Besides, this laying serves as barrier to leakages in critical places: on eaves overhangs, end faces, valley gutters.
The protective layer can be partial (covering overlappings and sites of exit of windows, pipes) or continuous. It is better to use rolled material on bituminous basis. Sheets mount by means of roofing nails (with interval of 200 mm), stacking them with an overlap from below up, and width of pad has to be not less than 100 mm. For bigger tightness of position of joint of two sheets coat with bituminous mastic.
Preparation of the basis
The soft roof has no necessary rigidity therefore the basis for mounting has to be continuous, without gaps. Insufficiently simple furring, as for mounting of more solid materials (slate, metal tile).
As material for the basis choose:
- plywood of the moisture resistant brand (9 mm and above);
- chip plate;
- eaves board;
- rabbeted board.
Each of the listed materials possesses sufficient degree of fixity. Boards or plates recommend to get in winter time, and to apply in the summer. Separate parts have to have identical thickness – any differences will be noticeable even after mounting of flexible tile. The humidity of boards should not exceed 20%, and width – 100 mm. Plates and boards stack with small gap on seams. Before mounting of soft roof it is necessary to check the basis for dryness and purity.
Production and use of bituminous mastic
Fastening of roof units to the basis is made with use of bituminous and polymeric structure which does roofing covering more elastic and durable. Hot or cold mastics not only serve as means of mounting, but also save soft roof units from thermal and mechanical deformation. Cold solutions (on the basis of bitumen), for external – hot are suitable for inside layers (for example, tar).
Mastic consists of several components:
- bituminous basis;
- powdered mix (ashes, plaster, lime);
- fibrous filler.
For independent preparation of mastic it is necessary to warm bitumen to 180 °C and to maintain, water will not evaporate yet. At the same time diesel fuel mixes up with filler. Two structures unite – we receive cold mix. Hot solution is prepared in a different way: bitumen is heated to 200 °C, gradually adding to it filler. Temperature of solution should not fall to preparation time below 160 °C.
For quality test hot mastic is applied on the surface located at an angle 45 degrees. Correctly prepared solution has two properties: does not flow down and does not burst after hardening.
Mounting of soft roof
Before laying of roofing material the wooden basis is impregnated with composition of bitumen and diesel fuel. Further stack roofing material or paper roof covering on layer of mastic. Works are conducted from the center of eaves to end faces – in the right and left parties. When mounting soft tile it is worth to remember about film on inside which before direct laying needs to be deleted.
When using hot mastic layers put one by one whereas, applying cold solution, it is necessary to make pause lasting 12 hours after each layer. Each roof unit in addition fastens on nail (5-6 pieces).
Stacking rolls, it is necessary to do blousing 80-100 mm wide. The upper leaf has to cover fastenings lower. If material goes beyond edges of roof, excesses need to be cut off, and to glue perimeter with the same mastic. Correctly laid roof will serve 30 years.
The special skill is demanded by mounting of roofing covering in exit points of pipes and antennas. For respect for tightness it is better to use additional component parts – elements through passage.
- plan exit points of pipes;
- cut openings of the necessary sizes;
- paste edges of lining carpet;
- smear edges of opening with mastic;
- from above impose tile and fix by means of nails;
- insert element through passage;
- places of joinings process sealant.
One of advantages of soft roof – opportunity to repair separate segments, without breaking integrity of all covering. Frequency of replacement of roof units depends on degree of wear of material.
At first smooth out the emergency site. By means of oil remove topping and soften the processed material. If the site of damage small – is enough patch put on mastic. If all layers are punched – it is necessary to apply putty which part mastic with addition of sawdust or sand is.
For protection of mastic structure it is necessary to recover topping – to cover the place of repair with sand. The sandy layer protects material from heating and melting.
Having studied properties and way of laying of soft roof, it is possible to use this hermetic and inexpensive material as roofing covering at construction of the new house.