10 things you should know about plaster

What thickness are plasters applied? Undercoat plasters are generally applied 11mm thick (for walls), or 8mm (for ceilings) and finish coat plasters at 2mm thick. Thistle Universal One Coat plaster is applied at 13mm thickness (for walls), or 10mm (for ceilings). Thistle Magnetic Plaster is applied at a minimum of 3mm. What plaster to apply to sand & cement undercoats? The best finish to apply depends on suction level of the background material. Thistle Multi-Finish or Thistle Durafinish would both be suitable. What plaster to use after DPC installed? Thistle Dri-Coat is cement based plaster for re-plastering after a damp proof course. Please refer to the plaster section of the White Book for further information if required. How to plaster an existing painted wall? If the paint is in very good condition in terms of quality, strength and adhesion etc, it may be possible to wire brush the surface using a suitable detergent and apply ThistleBond-it prior to the application of Thistle Multi-Finish. We suggest carrying out this procedure on a trial area to ascertain the suitability. Where would you use Thistle GypPrime? Thistle GypPrime is a suction control primer used to reduce suction on very dry backgrounds. It is normally diluted (up to 5 parts water to 1 part Thistle GypPrime) or undiluted if severe suction control is required. Plaster is applied after Thistle GyPrime has soaked into the background. How can plaster assist in reducing air leakage of a building? Using Thistle plasters to plug gaps and cracks is a quick and easy way of maintaining airtightness. Gyproc SoundCoat Plus is used as a parge coat when using a dot and dab method with plasterboard. Does plastering help increase thermal mass? Thistle plaster is ideal for use where thermal mass is an integral part of the design of a building. Plaster provides the desired decorative finish whilst also enabling efficient heat transfer between the air and fabric of the building. Can I plaster a damp wall? Not if the wall is subject to rising or penetrating damp. Yes, if there is just residual dampness after successful DPC treatment. The wall needs to treated to eradicate any damp issues such as a damp-proof course. Thistle Dri-Coat could be used following a successful DPC installation. Please refer to the plaster section of the White Book for further information if required. How should salt contamination on a background be dealt with? Any salts brought to the surface of the background during drying should be carefully removed. The background must be clean, sound and free from dust. Heavy salt contamination can cause persistent damp problems, so it is important to establish whether the salts are purely from the drying process or whether a more serious damp problem exists. See the White Book for more information. How much plaster is made in a typical week? Barrow-upon-Soar, the home of Thistle Plasters, produce around 440,000 bags of plaster a week – that’s enough to plaster 29,000 homes.

DEFECTS IN BRICKS

Common defects in brick work and cement mortar Raw materials like brick, sand, cement and water are of sub standard quality without qualifying any test. Bricks are not soaked in water properly. The joints in brick works are thicker, unfilled properly. Raking of mortar is not done when the mortar is green. Bricks bats are used in masonry work. Mortar is not mixed properly on platform. There is improper mixing of cement mortar There is excessive water content in mortar Brick work is not in plumb, level and straight line. Mortar is not according to the structural requirements. There are gaps between door/window frame and masonry. The holes of scaffolding are not filled in with mortar properly. Vertical joints in brick work are hollow. There is high suction of brick and less water retention of mortar There are uneven joints in brick works There are voids in vertical joints There are disturbances of brick works just after the layout Over thick joints reducing the strength of brick work.

Brick work according to cement mortar ratio

1. First class brick work in cement sand mortar 1:4 Brick walls constructed with cement sand mortar 1:4 ratio means 1 part of cement and 4 parts of sand. This mortar is of high strength and is recommended for following construction works. Multi storey buildings Heavy weight /load bearing walls In earth quake zones Brick pillars Where there is more vibration due to heavy traffic or factory. Boundary wall, courtyard wall parapet wall and other free end walls Partition or 4.5 inch thick walls Brick works used for drainage 2. First Class Brick Work in cement sand mortar 1:6 Brick walls constructed with cement sand mortar 1:6 ratio means 1 part of cement and 6 parts of sand. This mortar is of medium strength and is recommended for following construction works. Three storey buildings Load bearing walls Heavy and frequent rainy zones Foundation of multi storey buildings 3. First Class Brick Work 1:7 Brick walls constructed with cement sand mortar in the ratio of 1:7 means 1 part of cement and 7 parts of sand. This mortar is low in strength and is recommended for following works. Toe walls Single storey buildings Temporary structures Light weight walls having no load of beams etc.

Brick work in foundation

Brick work in foundation is done to transfer the load of super structure to the ground. The width of the brick work in foundation is taken according to the load coming on it. The load of super structure is divided into various steps of brick works in foundation below plinth level. Care may be taken that all steps should accommodate in the ground. The foundation should be made according to the drawing and design. Brick work above plinth level is called brick work in super structure. Brick work in super structure transfer the load of RCC beam and slabs to the foundation of the walls. Doors, windows and ventilators are accommodated in this part of brick work. This part of the building is used to divide the space into required room etc. Outer walls may be used for ornamental design of the building.

Mixing ratio to make 1 yard of concrete

To produce a 3000 psi cubic yard of concrete (27 cubic feet) the concrete mixture ratio 1. 517 pounds of cement 2. 1560 pounds of sand 3. 1600 pounds of stone 4. 32 - 34 gallons of water This mixing ratio will give you a concrete mix that is strong, durable, and good for most concrete projects. A cubic yard of concrete will fill an area 8 feet wide by 10 feet long by 4 inches thick, or 80 square feet @ 4 inches thick. At 6 inches thick a cubic yard of concrete will fill an area 52 square feet and at 5 inches thick, it will fill an area that's 65 square feet. To produce a cubic yard of 4000 psi concrete, you have to adjust the concrete mixing ratio to: 1. 611 pounds of cement 2. 1450 pounds of sand 3. 1600 pounds of stone 4. 33- 35 gallons of water As you can see a little more cement and a little less sand is required to produce this stronger concrete mix that is great for driveways, pooldecks, sidewalks, exterior patios, and commercial garages. Knowing the weight of the materials and how much water to use should help you determine how much cement, sand, and stone to purchase to complete your project. For estimating purposes, you can make about 1 cubic yard of concrete with 5 1/2 94-pound bags of cement, 17 cubic feet of sand, and 18 cubic feet of gravel. (It takes about forty 80-pound bags of prepackaged materials to make 1 cubic yard of concrete.) If you need less than 1 cubic yard of concrete (or if ready-mix is not available) you can mix your own on site either by hand or using a concrete mixer. To make smaller batches of concrete, use the same proportions, but with smaller quantities, substituting buckets for cubic feet. (For the mix proportions given previously, you'd use 1 bucket of cement, 3 buckets of sand, 3 buckets of stone, and 1/2 bucket of water.) For any batch size, the most important thing is to keep the proportions of the ingredients the same. You can double or triple the batch size simply by doubling or tripling the number of buckets of each ingredient you add to the mix. For very small projects, such as setting a mailbox post or doing repairs, you may want to purchase a packaged concrete mix. Such a mix combines cement, sand, and gravel in the correct mixing ratios and requires only the addition of water to create fresh concrete. These concrete mixture ratios are designed for the concrete to reach full strength at or around 28 days. Curing the concrete can be done by keeping it wet after the first day until the concrete is 7 days old. This is an important step to take for the concrete to achieve full strength by 28 days.