Plaster is basically a substance used to cover walls and ceilings. Plaster can be described in two forms, Firstly there is the backing plaster and secondly there is finish plaster.
Starting with the backing plaster, most Plasterers will use Gypsum Hardwall or Gypsum bonding coats. Hardwall is used on medium to high suction backgrounds where as Bonding is used on low suction backgrounds such as plasterboard or pre treated PVA surfaces, both materials can be applied up to 11mm thickness.
Another backing coat is sand and cement mixture known as render but is becoming less and less popular with the products that have come onto the market in the last 20 years as described above.
The finish plaster as we call it in the trade is the layer of plaster we apply to the various backing coats. (The surface that will be decorated). This must be finished to a very high standard otherwise imperfections will show through the paint. Most finish plasters we use consist of gypsum rock mined from the earth with several addictives to help slow or speed up setting or drying times on various backgrounds.
The gypsum rock is crushed and then heated to remove moisture and that produces the fine pink coloured powder we buy from the builders yards. All we need to do is add water to the powder and mix with a mechanical drill/whisk until we get a creamy spreadable texture which we apply at about a 2mm thickness.
What is Dry lining??
Dry lining has grown immensely in popularity over the past 15 years in this country due to it being quick and relatively clean to apply compared to two coat plaster systems. Dry lining quite simply means the application of plasterboard to surfaces such as timber, masonry or metal using different fixings for each background.
When Dry lining Timber or metal we call this ‘Tacking’ and this is a fairly easy process. Measure the sheet of plasterboard, make any necessary cuts then fix the plasterboard to the timber ceiling joists or timber stud walls using clout nails or preferably drywall screws for better strength.
When dry lining Masonry this is commonly known as ‘Dot and Dab’ this form of dry lining is much more skilled than the above ‘Tacking’ as it involves using plasterboard adhesive. The adhesive is applied to the wall as fist sized dabs using a hawk and trowel. The plasterboard is then gently pushed onto the evenly spaced dabs and checked for levels and square vertically and horizontally.
I hope you find this article is informative. If you would like to know more about plastering or need a quote for any type of Rendering or Plaster work please call 07989 078995