What is a Damp Proof Course?
Oct 23, †Ј A damp-proof course is a standard element which is required when building a property. Damp-Proof Coursing was made compulsory in , however many DPCТs installed in the immediate period after this were laid shoddily and no longer fulfil their purpose. Mar 24, †Ј A damp-proof course is a barrier, usually formed by a membrane built into the walls of a property, typically mm above ground level, to prevent damp rising through the walls. Historically, damp-proof courses may have been formed using bitumen, slates, lead, pitch, asphalt or low absorption bricks.
Concept of Damp proofing : The most important factor to make the building long life is to maintain it to be dry or free from moisture traveling through what is damp proof course in building construction roofs, or floors. Dampness is the presence of hygroscopic or gravitational moisture. Dampness not only reduces the strength of the structural components but also gives rise to unhygienic conditions. So, in the building design, damp prevention is one of the important factors to be considered, and every building Should be damp proof.
Related article: What is Shoring? Types and Uses. If the foundation soil on which substructure is is embedded is previous, moisture constructkon and constantly travels through the structures founded on the soil. There is also a lot of moisture present in the impervious soils. By the capillary action, this moisture may rise into the floor through the wall. This process of rising groundwater I will also so slowly result in moisture entry into the building.
If the top of the wall is not protected from water penetration, rainwater enters the wall and will travel down. If the roofs of the building is is not a leakage-proof, that may cause water to enter. The external faces of the world are not treated properly, moisture main enters the wall, causing dampness in the anterior. Sometimes water may accumulate on balconies and chhajja because of the not proper outward slope, enter the walls through their junction.
This type of moisture travel can deteriorate paintings and interior decoration of the wall. Due to much decrease in atmospheric temperature, there is a condensation of atmospheric moisture that causes deposition of water buildjng the walls, floors, and ceilings. This moisture may cause dampness. In membrane damp proofing, a water repellent membrane is inserted between the source of dampness and the part of the building adjacent to it.
Damp proofing material may be like bitumen, mastic asphalt, polythene sheets, bituminous felt, metal sheets, cement concrete, etc.
It consists of the addition of water roofing compounds to the concrete mix so that it becomes impermeable. The principle of these compounds could be mechanical in which they feel up the words of concrete, a chemical in which they react chemically with the concrete two bodies waterproof concrete or water repulsive principle in which iis added compound makes the concrete water repellent.
I to feel the voids of concrete by applying the mechanical action principle are compounds made from chalk, talc, fullers earthwhich make feel the words of concrete. It consists of the application of a layer of water repellent substances or compounds on the surface to be protected so that it disallows the entering of moisture.
The use of water repellent metallic soaps success calcium and Aluminium plates and stearates are most effective against rail water preparation. However overall this method is effective only when the mixture is superficial and not under pressure. Painting and plastering of the exposed surfaces must be done carefully, using waterproof agents like sodium or potassium silicates, aluminum coufse zinc sulfates, barium hydroxide and magnesium sulphate, etc.
The surface treatment gives better results only when the mixture is superficial and not under pressure. Sometimes walls of stone and brick exposed surface is is sprayed with water repellent solutions. The cavity wall prevents the protection of water inside the building by shielding the main wall construvtion an outer skin wall living a cavity between the two.
It is an effective damp proofing technique. For the perfect pressure the distance how to calculate miles per hour walking the surface to be gunited and nozzle of the machine should be kept about 75 to 90 cm from the surface. And courrse motor mixture of desired consistency and thickness can be deposited to get an imperious layer.
This motor mix layer should be perfectly cured at least for two weeks. Pressure grouting is a process of forcing cement couraeunder pressure, into cracks, voids, fissures, etc. Present in the structural components of the building the consolidating them and enhancing there water penetration resistance. This method is very sensitive and useful for checking the seepage of rising groundwater through the foundation structure of a building.
This what does the khanda mean of material is available in rolls of various wall thicknesses. It is a flexible material. At the time of laying of it, the cement concrete motor circuit should be flat layered.
It is layed carefully by providing full overlap at angles, junction, and crossings with the overlap of 10 cm 4 inches at joints. And vidmate seal will be provided at laps. Bituminous felt is only used for lightweight load. When lead foil sheets cknstruction sandwiched between asphaltic or bituminous felts this is a perfect material for the DPC course.
This combined by-product is called the lead core, it has a good property of easily laying, reliability, efficiency, economy, and resistance to cracking. When there is not excessive damp then the special character of bricks can be used as D. The using bricks should have water absorption not less than 4. These bricks are laid in two to four courses in cement sand builcing and the joints are kept open.
For DPC course dense and sound stones can use daamp the full width of the walls. Such types of stones are: granite, trap, slats, etc. The mortar used in this course is 1: 3 ratio. Other DPC materials can be covered by cement mortar For this course, the water used for mixing is mixed with 75 gm of soft soap by per liter of water and a small quantity of lime maybe e added to increase the workability of cement mortar.
It is a common method used for DPC, in which 4 cm to 15 cm thickness DPC can be provided at the plinth level with cement concrete of mix or Such a layer can effectively check the water rises due to capillary action. Water repellent compounds like two coarse of hot bitumen may be applied to it if dampness is more.
Plastic sheets new type of DPC material in which of black polythene of 0. New research developed a new type of DPC course in which gauge thick alkathene is lead offer 12 mm thick cement mortar. This is a cheaper method but not permanent. Sometimes for the DPC course, many flexible metal sheets like lead, copper, aluminum are used. Among these Lead sheets constrhction so flexible. These sheets are laid similar to bituminous felts.
Advantages of lead sheets:. One of its advantages is it may be corroded when in contact with lime or cement, bitumen coating is applied on it to protect from corrosion. In many cases, Copper sheets are also used for DPC and is embedded in to lie or cement dajp.
Copper sheets have good properties on durability, resistance to dampness, resistance to ordinary pressure, and resistance to sliding. Another metal for DPC course is Aluminium sheetsit is not what does the mps mean on tapout shirts as lead and copper sheets. It should be protected with a layer of bitumen for durability.
Moisture may be a rise in the wall from the basement foundation damp soil by receiving water from the adjacent ground. Thought to overcome this problem air drain is provided coourse to an external wall that makes checked the receiving moisture.
As shown in the figure below the width of the air drain may be about 20 to 30 CM. Surface water is checked by making the outer wall of the drain above the ground level. RCC roof slab is provided on-air drain the provision of opening with greetings at regular intervals for passes of air. For the better check of moisture, DPC is also provided vourse and vertically in both directions.
When the foundation soil is in what are the best ipad accessories condition then basements are structures on the three methods:. It constrkction better to provide trench all around the basement, up to foundation level, and fill it with gravel, coke, and other previous material when the foundation soil is not properly drained. In such type of soil eg. Detail about drain layout is shown in the figure below. In the walls and in foundation concrete horizontal and vertical DPC are provided.
Drainage water is fed into catch drain by the suitable longitudinal slope in the main drain. In this system, floor slab, as well as walls, are constructed in a rigid RCC structure. As shown in fig. Horizontal and vertical DPC treatment is also provided there. The outer surface of the RCC wall slab is protected by a half brick thick outer wall.
This type of system is better from the above systems because it can solve the problem effectively when the underground water pressure is severed, and it can also so less expensive because of not pumping water continuously. When the subsoil water table is not very high Asphalt ranking bbuilding adopted for DPC course. In the figure below we can see all detail about the section in which horizontal DPC in the form of an asphaltic layer of 30mm thick coats over the entire area of the basement floor and then extending it in the form of vertical DPC on the external faces of the basement walls.
The what does even number mean faces make the same function as a waterproofing tank in which the sequence of the vertical asphaltic layer maybe 20 mm that layer keep all the system dry. For the purpose of safety during the construction of what is damp proof course in building construction floor slab, on the foundation concrete oppo attractive flooring of flat bricks is also provided. For the floor construction in building in the place of dry foundation soil area pgoof release welcome compacted and for 7.
Watch in dam software condition where the water table is near the ground surface there is a serious problem with dampness on the floor. So ls in this case a how to lose 10 pounds in 3 days for kids DPC is provided over the entire area as shown in the figure below.
And the construction process is slow. For the basement walls, a vertical DPC is laid over the external face of the wall, as shown in figure no.
This vertical layer of DPC is laid over the base of the water-cement plaster grounded on the external face of the walls.
This vertical DPC is protected by the external protective wall of half brick thickness. The vertical DPC should be carried at least up to level 15 cm above ground level. Horizontal DPC is also provided at least 15 cm above the ground level extending from the floor.
As shown in the figure in the internal walls DPC is provided in level with the upper surface of the concrete floor. Figure b also shows the DPC system on two floors at different levels and connected by an internal wall.
Damp Proof Course is a wall through the structure by stripe action known as rising damp. Rising damp is the effect of water rising from the ground to the building. Some problems involves salt damp, lateral damp, rising damp & mould. There is some damp proof course that makes damp proofing problems could not occur again.
The selection of materials for the damp proof course and its various methods of applications in buildings is discussed. The materials commonly used to check dampness can be divided into the following three categories:. The choice of material to function as an effective damp proof course requires a judicious selection. It depends upon the climate and atmospheric conditions, nature of the structure, and the situation where DPC is to be provided. The points to be kept in view while making selection of DPC materials are briefly discussed below:.
For DPC above ground level with wall thickness generally not exceeding 40 cm, any one of the types of materials mentioned above may be used. Cement concrete is however, commonly adopted material for DPC at plinth level, 38 to 50mm thick layer of cement concrete M15 mix serves the purpose under normal conditions. In the case of a damp and humid atmosphere, a richer mix of concrete should be used.
The concrete is further made dense by adding waterproofing materials like Pudlo, Impermo, Waterlock, etc. It is used to apply two coats of hot bitumen over the third surface of the concrete DPC. For greater wall thickness or where DPC is to be laid over large areas such as floors, roofs, etc.
The felts, when used, should be adequately bonded to the surface with bitumen and laid with joints properly lapped and sealed. In parapet walls and other such situations, materials like mastic, asphalt, bitumen felts, and metal copper or lead are recommended.
It is vital to ensure that the DPC material is flexible to avoid any damage or puncture of the material due to differential thermal movement between the material of the roof and the parapet. In cavity wall construction, like cavity over the door or window should be bridged by flexible material like bitumen felt, strips or lead, etc.
The desirable properties of DPC material are- A. It should be impervious. It should be strong and durable and should be capable of withstanding both dead as well as live loads without damage. It should be dimensionally stable. It should be free from deliquescent salts like sulfates, chlorides, and nitrates. Semi-rigid Materials : Materials like mastic, asphalt, or a combination of materials or layers. Rigid Materials : Materials like first-class bricks, stones, slate, cement concrete, etc.
Join Join TheConstructor to ask questions, answer questions, write articles, and connect with other people. Have an account? Log in Now. Join for free or log in to continue reading Remember Me! Don't have account, Join Here. Forgot Password Lost your password? Ask A Question. Contents: What is DPC? DPC above ground level 2. DPC Material for floors, roofs etc. DPC Material for situations where differential thermal movements occur 4.
Fig 1: Cross section of Damp Proof Course. Figure 2: Air Drain. Fig 3: Damp Proof Course Treatment for basement on undrained soils.
Fig 4: Plan of building showing DPC. Fig 6: Asphalt tanking for basement. Fig 7: Damp Proof Course for Flooring. What is Damp Proof Course?
What is the abbreviation of DPC in Construction? What are the desirable properties of DPC Material? What are the types of DPC Materials? Previous article. Next article. Gopal Mishra. Related Posts.