Before carrying out plastic rendering, it is important to know the basic concepts involved, that is, how to prepare the surface area, choose the mix, use the correct ratio for elements and apply the plaster.
The ratios of concrete, lime, and sand to apply depend upon the purpose of the plaster and the pattern of the building surface to which it is to provide. A fine lime plaster is slow setting, so it is usually measured with cement to increase its durability and hardness and to reduce the time of hardening of solidifying, especially for plaster wall repairs. The durability improves and the time of hardening reduces the quantity of cement improves compared to the quantity of lime, until with a cement plaster with no lime, the durability is an optimum and the hardening times the least. However, as the ratio of concrete is improved the plaster becomes less usable and more difficult to apply. The ratio of sand should not surpass three times the mixed ratio of cement and lime. The strong plaster should not apply to poorly permeable support or a strong finish coat to a poor first coat. On bigger projects, before even starting, we recommend hiring a commercial cleaner and then starting on a smooth clean surface.
For external building rendering on a heavy material such as cement, heavy concrete blocks and hard clay-based bricks of low porosity, the best ratios to use are 1 part hydrated lime, 1 part cement and 6 parts sand by quantity. On revealed building surfaces susceptible to driving down rains the quantity of lime may be reduced and the cement increased to say 1 ¾:¼: 6 mixes or a 1:4 cement plaster to which up to 10% of lime by weight of the cement is added to make it usable.
If you’re looking for the best plasterer in Melbourne then you’ll want to check out the plastering services by Plaster Wizards, they’re one of the top plastering companies in the city.
On external building surfaces of low strength and high porosity such as low-quality waft, concrete prevents the external rendering should not be strong than a 1:1:6 mix as above and strong cement mix with little or lime should not be used.
For internal building rendering the best ratio is 1 lime, 1 cement, and 6 sand; or 2 lime,1 cement, and 9 sand; or a lime mix only of 1:3 or 4 may be used, paying attention to that the cement increases the strength and stability and decrease the period of hardening. For normal water containers such as fishponds, only cement plasters should be used.
During plaster, blueboard rendering may have important change the finish work. External architectural solid plaster rendering in new cities like Melbourne should be started on the in shade part of the building to keep it unexposed to the sun as long as possible. No plastering should be done in cold weather. In cool weather plaster hardens very slowly and many times between coats should be allowed. In hot weather, these coats must be kept wet and protected against dehydrating out for at least two times after applications. Draughts and regional sources of heat may cause too quickly dehydrating out. Normal heat and regular ventilation are the best circumstances for plastering.
The cement plaster rendering of concrete, stone and mud homes has been used for years and years to improve the appearance (and sometimes weather resistance) of external surfaces. It can be seen in different types all over southeast European. Different countries have their own styles and traditional shades. This insights and knowledge has been shared by Crown solid plasterers in Melbourne, Victoria.