Specifications for Coursed Rubble Stone (CRS) Masonry
Posted by BenzuJK in Building Construction on September 3, 2010
Coursed Rubble Masonry
Masonry is affected by the use of low grade materials that is in case of stone masonry, use of low grade stones, improperly cut stones, chipped off stones etc. The mortar mix should follow a specific standard for the proper bonding between the joints of Course Rubble Masonry. Therefore, specifications have to be given for the materials used, the laying technique, Bond or Through stones, Quoins and curing – for the ultimate strengthening of the final masonry work.
Coursed Rubble Masonry
In our earlier articles, we studied different types of specifications, purpose of specifications, RCC specifications, Specifications for Brick Masonry in Cement Mortar. We are yet to discuss Specifications for Plain cement concrete in our further articles. In this article, we are going to discuss in detail all the necessary specifications that are to be given for the construction of Coursed Rubble Masonry.
Specifications for Coursed Rubble Stone (CRS) Masonry
Materials Specifications
Stone shall be hard, sound, free from decay and weathering. Stones with porous matter or with boulder skin shall be rejected. The size of stones shall not be less than 15cm in any direction.
Cement and sand for cement mortar or lime and surkhi for lime mortar shall be of standard specification.
Specifications for Brick masonry in Cement Mortar
Posted by BenzuJK in Building Construction on September 1, 2010
Brick Masonry with Cement Mortar
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone such as marble, granite, travertine, limestone, concrete block, glass block and tile. Masonry is generally a highly durable form of construction. Brick masonry construction involves use of high quality materials in construction. Use of low grade materials in construction or mortar mix in inappropriate ratio can affect the quality of construction.
In our earlier articles, we discussed different types of specifications and purpose of specifications, RCC specifications in detail. We will be discussing specifications for Coursed Rubble Masonry (CRS) and Specifications for Plain Cement Concrete (PCC) in our further articles. In this article, we are going discuss or rather list out all the specifications that are to be given for “Brick Masonry in Cement Mortar”.
Brick Masonry in Cement Mortar
Specifications for Brick masonry in Cement Mortar
- The bricks shall be of first class, regular in shape, size and colour.
- The bricks should be free from flaws, cracks and lumps of any kind.
- Shall have minimum crushing strength 10.5N/mm2.
- The bricks shall not absorb the water more than one sixth of the weight of the brick.
Specifications for RCC Construction | Building Estimating and Costing
Posted by BenzuJK in Building Construction on August 30, 2010
In my earlier articles, I have discussed types of specifications and various purposes for which specifications are to be given. Most of the constructions of various types of buildings are RCC constructions. In this article, we are going to discuss in detail about the specifications that are to be necessarily given for carrying out RCC (reinforced Cement Concrete) constructions.
RCC specifications
RCC Specifications
- Shuttering shall be done using seasoned wooden boards of thickness not less than 30mm.
- Surface contact with concrete shall be free from adhering grout, nails, splits and other defects.
- All the joints are perfectly closed and lined up.
- The shuttering and framing is sufficiently braced.
- Nowadays timber shuttering is replaced by steel plates.
- All the props of approved sizes are supported on double wedges and when taken out, these wedges are eased and not knocked out.
- All the framework is removed after 21 days of curing without any shocks or vibrations.
- All reinforcement bars conform IS specifications and are free from rust, grease oil etc.
- The steel grills are perfectly as per detailed specifications.
- The covers to concrete are perfectly maintained as per code.
- Bars of diameter beyond 25mm diameter are bent when red hot.
- The materials proportion should be as per the specifications of the concrete.
Purpose of Specifications and types of Specifications
Posted by BenzuJK in Civil Projects on August 28, 2010
What are Specifications?
Specifications describe the nature and the class of the work, materials to be used in the work, workmanship etc. and is very important for the execution of the work. The cost of a work depends much on the specifications. Specifications should be clear.
Types of Specifications
Purpose of giving Specifications
- The cost of an unit quantity of work is governed by its specifications.
- Specification of a work is required to describe the quality and quantity of different materials required for a construction work and is one of the essential contract documents.
- This also specifies the workmanship and the method of doing the work. Thus specification of a work serves as a guide to a supervising staff of a contractor as well as to the owner to execute the work to their satisfaction.
- A work is carried out according to its specification and the contractor is paid for the same. Any change in specification changes the tendered rate.
- As the rate of work is based on the specification, a contractor can calculate the rates of various items of works in tender with his procurement rates of materials and labour. Thus tender rate without specification of works is baseless, incomplete and invalid.
Methods of Valuation of a Building | Building Estimation and Costing
Posted by BenzuJK in Civil Projects on August 26, 2010
Valuation of Building
Valuation of a building depends on the type of the building, its structure and durability, on the situation, size, shape, frontage, width of roadways, the quality of materials used in the construction and present day prices of materials. Valuation also depends on the height of the building, height of the plinth, thickness of the wall, nature of the floor, roof, doors, windows etc.
The valuation of a building is determined on working out its cost of construction at present day rate and allowing a suitable depreciation.
Six Methods of Valuation
Six Methods of Valuation
- Rental Method of Valuation
- Direct Comparisons of the capital value
- Valuation based on the profit
- Valuation based on the cost
- Development method of Valuation
- Depreciation method of Valuation
Rental Method of Valuation
In this method, the net income by way of rent is found out by deducting all outgoing from the gross rent. A suitable rate of interest as prevailing in the market is assumed and Year’s purchase is calculated. This net income multiplied by Year’s Purchase gives the capitalized value or valuation of the property. This method is applicable only when the rent is known or probable rent is determined by enquiries.
Methods to calculate Property Depreciation | Building Costing and Estimation
Posted by BenzuJK in Building Construction on August 24, 2010
Depreciation is the gradual exhaustion of the usefulness of a property. This may be defined as the decrease or loss in the value of a property due to structural deterioration, life wear and tear, decay and obsolescence.
Methods of Depreciation
Four Methods for calculating depreciation
- Straight line Method
- Constant percentage method
- Sinking Fund Method
- Quantity Survey Method
Straight Line Method
In this method, it is assumed that the property losses its value by the same amount every year. A fixed amount of the original cost is deducted every year, so that at the end of the utility period, only the scrap value is left.
Annual Depreciation, D = (original cost of the asset – Scrap Value)/life in years
For example, a vehicle that depreciates over 5 years, is purchased at a cost of US$17,000, and will have a salvage value of US$2000, will depreciate at US$3,000 per year: ($17,000 ? $2,000)/ 5 years = $3,000 annual straight-line depreciation expense. In other words, it is the depreciable cost of the asset divided by the number of years of its useful life.
Major causes of Cracks in Buildings | Building Construction
Posted by BenzuJK in Building Construction on August 22, 2010
Causes of cracks in Buildings
In the previous article, we discussed the occurrence of cracks in buildings due to climatic factors and cracks occurred due to problem at the time of construction of the building. These fall under the category of Minor causes of Cracks in Buildings.
Now we will go ahead with our discussion on “Major causes of Cracks in a Building”.
Major causes of cracks in a building
- Movements of the ground
- Over loading
- Effect of gases, liquids and solids
- Effect of changes of temperature
- General causes such as vibrations etc
Unrestrained Movement of Building Materials
Movements of the ground
Mining subsidence, land slips, earthquakes, moisture changes due to clay shrinkable soils (for example, Black cotton soil).
Cracks occur because a part of the building is displaced from the rest without any change in the actual size of the material.
Overloading
- Overloading of the ground
- Overloading of the building itself
- Overloading of the building parts result in cracks
For example; Cracks under a floor due to overloading of slab.