Roof Repair a vital need ? Roof repair expert!

Roof repair Types and solutions 

A Roof is an important element of a building structure which demands stability as well as safety. The number of existing types of roof and structures is enormous and is rapidly increasing. Concrete and steel is the most common material used in roofs along with wood. Concrete has massive demand for repair and construction work to maintain the quality of the structures. In many cases repair and strengthening of roof constructed by concrete structures must be performed only a few years after their completion, sometimes immediately thereafter. The dramatic growth in the repair and strengthening industry over the past three decade has resulted in the need for many improvements in material, design practice, contracting processes, insulation and installation procedures, quality assurance/quality control procedures, and more. These improvements are needed to enhance service life, reduce costs, and minimize conflicts. Innovative, fiber reinforced, cement-based materials may play an important role in solving existing roof repair problems.

Many repair techniques including lamination can be used in combination with low-pressure spraying seem to be most suitable. Repairs can be made from the outside and inside especially in case of leakage problem to relieve the water pressure. For outside repair of the roof, many techniques are used including plastic sheets, concrete mix, tar, paper and sprays. Plastic Sheeting is a temporary measure which can be spread and fixed by roofing nails. In case of wooden roof, plastic sheet can be wrapped around the wood and nail down the wood.

In reinforced concrete roof, at first crack stress can be considerably improved by using short glass or synthetic fiber as dispersed reinforcement for the matrix. This measure also leads to a finer crack pattern and to an increase in the work-to-fracture. Strain-hardening cement-based composites (SHCCs) reinforced by short polymer fibers constitute a relatively new class of building material, which exhibits hardening behavior by filling multiple cracks when subjected to tensile loading. The high ductility and strain capacity of SHCC give this material high potential for use in applications in which high, and non-elastic deform ability is needed.

In case of steel repair, three measures are required to protect steel reinforcement:

·       Limiting the maximum crack width,

·       Sufficient concrete cover,

·       Appropriate concrete quality as defined by corresponding threshold values.

Researchers investigated the transport mechanisms of water in and through composite concrete of roof structure as a substrate and cover layer for its strengthening and repair. The cover layer was assessed with regard to its efficiency as a protective layer against the entrance of water. Neutron radiography can be used for testing level of repair. In ordinary concrete quick and deep access of water through relatively wide macro-cracks  followed by transport through the capillary pore system, caused saturation of large areas in a rather short time. Application of concrete mix applied to the surface reduced the ingress of water to a large extent. In the cracked surface of roof substrate of ordinary concrete, capillary suction is obviated, and transport through the pore system of the matrix become the prevailing transport mechanism of capillary action. Since cracks in reinforced concrete roof are very fine, self-healing must consequently have a pronounced effect on the transport properties.

Tar is another important material which is easily available in the market and can be applied by trowel to fix the fine cracks. Good quality plastic papers can be applied by overlapping the layers which make an effective measure for roof repair against leakage.

To sum up, roof repair is required to enhance durability and strength by preventing it against leakage. Concrete provides protective cover to steel used in reinforced concrete roof and increase the life span of steel.