Types Of Plastering Pdf
® SPECIFICATIONS • • • All Plaster Beads. If our total. Use with all types of thin-coat plaster work. 691 2204.K.A. To Plastering.pdf. Various types of models and moulds are made with plaster. “Interior plastering in the form of clay antedated even the building of houses of frame.
Types of Plaster Used in Construction Plaster is one of many building products that has been around for centuries and has been refined over the years to arrive at the variety of plasters we have today. In its primitive form it was used as a mud plaster and its basic purpose was to hold a simple structure together. Most plasters today are only suitable for use internally and their main purpose is to provide a smooth finish ready for decorating. They also help to add strength to a wall or ceiling and help to seal together building materials. There are several types of plaster available today which cover every aspect of coating a wall to provide a finish.
The most commonly available is called Multi Finish. It’s a plaster that is used as a final finish on all internal walls that have been undercoated in either sand & cement or one of the under mentioned 1st coat plasters. It’s also used as the final finish on plaster boarded walls and ceilings. This wall is ready to be plastered PVA bonding This white liquid is used as glue and has been popular in school classrooms for years. It is also marketed in different forms for use in the construction and DIY industries. It can also be used as a sealing & bonding agent and it is often diluted and brushed on to walls to allow the plaster to stick more easily and to prevent it from drying out too quickly. Be warned always use wet on wet.
Types Of Plastering Techniques
Do not allow the PVA to dry or it will form a sheet of plastic on the wall and the plaster will not stick. Browning plaster (not so commonly used now has been replaced by Bonding & Hardwall) This product is used as a 1 st or backing coat to the finishing plaster and is grey or pink in colour. It is suitable for use on more uneven surfaces, such as brick or blocks, and can also be used to cover surfaces that are more absorbent. The plaster can be applied in several layers of about 10mm thickness if required. Getting in a professional plasterer could save you a lot of hassle Bonding plaster Bonding plaster is very similar to browning plaster. Its very sticky will adhere to most surfaces it can also be applied to non-absorbent materials such as engineering bricks and can also be applied in several thick coats. It has the ability to be built up in depth to enable really poor walls that are out of true to be aligned However its very Hydroscopic and should not be used water borne areas.
Hardwall plaster This plaster used as a 1 st coat or backing plaster it dries to a hard finish and is ideal for areas where impact resistance is required. It’s quick drying and can be applied either by hand or by mechanical means. X-Ray Used for areas containing x-ray equipment in medical and dental installations. Tough Coat plaster This undercoat plaster offers better impact resistance. Suitable by machine or hand application One coat plaster This product is marketed as having the ability to do the job of providing a base coat as well as the finishing top coat.
It has not been so well received amongst the building fraternity and is usually passed by in favour of the other products. Plasters can come in many different types Finishing plaster Multi-finish or finishing plaster is applied over any of the surfaces mentioned above as well as directly to plasterboard. A board finish plaster would only be suitable for coating plasterboard.
In either case the plaster is applied in a coat about 2mm thick. There is an art to achieving a fine finish which involves experience and patience. The plaster is applied over a wall and is allowed to set to a certain level before smoothing and then finally polishing.
Hardwall plaster with finish coat being applied Metal Lathing plaster A plaster designed specifically to be used on expanded metal Lathing. Metal lathing is a galvanised or stainless steel mesh used in the construction industry it can be fixed over poor backings including timber in preparation for a plaster finish. The plaster is used as a 1 st coat or backing plaster and can also be used on timber laths on heritage type projects. Lime plaster Has been used since 7200bc This product is becoming increasingly popular with eco-friendly building work as it is an extremely environmentally friendly plastering substrate.
It is mixed using hydrated lime, sand & water. Horse hair was traditionally added as reinforcement. The down side to the professional builder is that it can be more expensive and time consuming to use. Because plastering is classed as a ‘wet trade’, it can take several months for the walls and ceiling to dry out properly and so new properties are often ‘dry lined’ to avoid using any plaster or other coating. Applying Lime Plaster to timber laths This technique involves fixing or bonding sheets of plasterboard that have a tapered edge to the walls and ceilings.
The sheets are then taped along the edges and then the joints are filled with joint filler which, when it has dried, is rubbed down to a fine finish. Because of the amount of rubbing down required it is not necessarily quicker to apply but the advantages are that the new walls are dry in 24hours & the property is ready to decorate and to move into straight away. Plaster coving Plaster coving is not so popular in contemporary properties today but still has a large following.
Using a coving avoids unsightly cracks that commonly occur where the walls meet the ceiling. A standard plaster coving is basically made in the same way as a sheet of plasterboard. The gypsum plaster is moulded and a paper sheet is wrapped around it to ensure it keeps its shape. Traditional Victorian Cornice, Coving & ceiling roses Many companies specialise in manufacturing period plaster cornices, mouldings, & ceiling roses. These are sometimes very elaborate and are made of casting plaster mixed with fibres which act to reinforce the cornice.
This can be important as they can be very heavy and will be suspended above people. The lengths of cornice are formed in moulds which can take several days to ‘cure’. Once the plaster is cured the finished product is released from the mould. In the first instance they are usually fixed into place using screws then the joints and gaps are all filled with plaster. This is then scraped into shape using various tools.
In heritage building moulds can be taken from the existing plasterwork so an identical match can be made. Image credit.
Internal plaster walls explained Over the years, different types of plaster internal walls have been used, the four basic types used since the early eighteenth century in the UK are:. on timber framework.
on timber framework (stud partitioning). on masonry walls.
plasterboard on masonry walls A repair to an internal plaster wall should be carried out using the same techniques and materials as the original wall. Traditional lime putty plaster used in older constructions are a lot softer than modern gypsum plasters and the two should not be mixed. Lath and plaster on timber framework Lath and plaster walling techniques (see right) were commonly used from the early eighteenth until the mid twentieth century for internal, non-load-bearing walls. The laths are horizontal strips of wood (normally about 25mm by 6mm (1 by 1/4 inch)) fixed by nails to vertical upright timbers forming the framework of the wall. The laths are spaced to give a gap of about 6mm (1/4 inch) between them - this gap provided the 'key' for the plaster coating. Lath and plaster walls were traditionally covered with three coatings of different lime putty mixtures:.
The first coating applied (referred to as the render layer) was applied so that it partly went through the gaps between the laths so achieving a strong bond - this coating was about 8mm (3/8 inch) thick and was left with a unsmoothed surface. The second coating (referred to as the floating layer) was applied to provide a much smoother surface for the final coating - this second coating was about 6mm (1/4 inch) thick. The third and final coating (referred to as the setting layer) was about 3mm (1/8 inch) thick and was smoothed off to give a suitable finish for decorating. The first and second coatings were typically a 1:3 mixture of lime putty to clean sharp sand; often animal hair was mixed in to the mixture to help it bind together.
The third layer was typically either just lime putty or a 3:1 lime putty to fine sand mixture. One advantage of using lime putty for the coating, was that it was fairly flexible so was able to cope with movement of the timber framework and laths. However, each layer could take up to 3 weeks to dry before the next coating could be applied; so the practice developed towards the end of the nineteenth century to add cement or gypsum to the mixtures to decrease the delay between the application of each layer.
These new mixtures were typically 1:1:6 (gypsum or cement:lime putty:sharp sand) for the first two coats and equal parts lime putty and gypsum for the final layer. The technique of using lath and plaster to cover internal walls was generally replaced by the introduction of pre-manufactured plasterboard in the middle of the twentieth century,. See also:. Plasterboard on timber framework (stud partitioning) Sheet plasterboard largely took over from the lath and plaster techniques in the middle of the twentieth century, with the plasterboard being fixed directly to the framework which previously would have held the laths - this gave stud partitioning (see right). A basic timber framework is erected for the wall and, instead of attaching the laths, the sheets of plasterboard were simply cut to size and nailed in place. To begin with, the joints between sheets were often just butted together and the whole surface skimmed with a setting plaster mixture - however, this often lead to cracks appearing in the walls along the edges of the plasterboard. Later the practice was introduced to apply 'scrim' (a fairly narrow (50mm (2 inches)) fine, flexible over-weave jute fabric or, more recently, plastic tape) over the joints before the plaster skim was applied, this technique prevented the plaster skim from cracking along the plasterboard joints.
Different Types Of Plastering
More recent still, the skim of plaster was replaced by just a thin application of a gypsum based sealant. See also:. Plaster on masonry Walls constructed of brick, block or stone have always been finished with plaster (see right). As with the lath and plaster walls above, three coatings were applied - the render, the floating and the setting layers. The plaster mixes were in days gone by the same as for lath and plaster - i.e. The render and floating layers 1:3 (lime putty:sharp sand) with animal hair often added and the setting layer either lime putty on its own or 3:1 (lime putty:fine sand). With the same mixtures as lath and plaster, the problem of the length of time required for each layer to dry sufficient for the next layer was also encounter.
Plastering Walls Techniques
Acdsee for pentax download free. Towards the end of the nineteenth century cement or gypsum was added to to the mixtures to decrease the time between layers. These mixes were typically the same as for lath and plaster of the same period - i.e.
1:1:6 (gypsum/cement:lime putty:sharp sand) for the first two layers and equal parts lime putty and gypsum for the setting layer. By the mid 20th century, lime had been largely replaced with the first two layers being straight sand and cement renders (1:6) (without added animal hair) and the setting layer a gypsum plaster alone. Modern (21st century) practice tend to the use of premixed manufactured gypsum based render (also referred to as 'browning') and finishing plasters.
See also:. Dry lining - plasterboard on masonry walls Dry-lining is a modern, popular, quick alternative to applying plaster on brick, block or stone walls. Plasterboard is simply held in place by numerous 'dabs' of plaster adhesive.
The masonry wall is covered with a series the adhesive 'dabs' spaced horizontally and vertically about 400mm (16 inches) apart and then the plasterboard sheeting is pushed onto these 'dabs', pushed up to adjacent sheets and leveled. The joints between the plasterboard sheets are then covering with scrim (as for stud partitions above) and a thin application of a gypsum based sealant applied. The surface of the plasterboard is not covered with a plaster coating.