Internal plastering

Internal plastering is used to cover up differences in level which are unavoidable in most internal walls and to provide a surface which is suitable for the final decorative finish. It is generally applied as one or more undercoats, followed by a finishing, or skim coat. 

Until the late 1800s, most internal plasters were predominantly lime-based. Thereafter, mixes using cement and gypsum (actually de-hydrated gypsum) 

Although most of the requirements for internal plastering and those for mortar and external rendering are similar, there are several important differences [26.28]. The requirements are described in full, to avoid undue cross-referencing [26.39]. 

Plasters should have a good workability and be cohesive so that they can be applied easily and achieve intimate contact with the background material. They should set and dry reasonably quickly to maximise productivity. 

The plaster should be durable and capable of withstanding normal wear and humidity. In kitchens and bathrooms, for example, plasters gauged with cement should be used in preference to those containing gypsum. 

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Solid walls can only be improved either by removing the internal plaster layer and providing suitable blanket insulation fixed to battens and then covering with the required... 

The sands used for internal plasters are specified in BS 1200 [26.31], Gypsum building plaster should comply with the requirements of BS 1191 [26.55]. Cement should comply with the requirements of ENV 197 [26.32] (N.B., high alumina cement should never be used with lime). Lime used for internal plastering should comply with the requirements of EN 459-1 [26.18] — see section 26.6.7. 

The choice of mix for internal plastering depends on the background material, the finish required, the method of application (manual or spray) and whether the mix is being used as an undercoat, or a finishing coat [26.16]. 

Treatments used for various types of fractures are cast immobilization, traction, and internal fixation. A plaster or fiber glass cast is the most commonly used device for fracture treatment. Most broken bones heal successfiiUy once properly repositioned, ie, fixed in place via a cast. This type of cast or brace is known as an orthosis. It allows limited or controlled movement of nearby joints. This treatment is desirable for certain fractures. 

Uses.—Ammoniacum is principally employed in medicine internally, its chief, almost sole use, is in chronic pulmonary affections, and even in these cases, it is unsuitable if there be irritation or inflammation of the bronchial membrane. Externally, it is applied in the form of plaster to glandular enlargements and indolent affections of the joints, as a discuticnt or resolvent. —Pereira,... 

Joint suitability Internal joints fixtures and fittings plaster cracks etc. 

Salicylic acid (1) is not employed internally as an analgesic due to its local irritating effect on the gastrointestinal tract. It is employed externally on the skin, where it exerts a slight antiseptic action and a marked keratolytic action. The latter property makes salicylic acid a beneficial agent in the local treatment of warts, corns, fungous infections, and certain forms of eczematoid dermatitis. Tissues cells swell, softer, and ultimately desquamate. Salicylic acid is applied as a 2 to 20% concentration in collodion, lotions, or ointments, and as a 10 to 40% concentration in plasters. Salicylic acid plaster is used for the destructive effect of salicylic acid on hardened, keratinized tissue. The so-called corn plaster are typical. 

A Brief History of Plaster and Gypsum. Association of Lifecas ters International. 

Lime plaster is a form of lime mortar, which is applied to ceilings and internal walls. 

Bardhan N., Roy S., Jena A. K. and Bhargava P., Influence of plaster of paris mold microstructure on sintered slip cast compacts, presented at International Seminar on Ceramics - CeraTec 2007, Vishakhapatnam, India. 

A test room of 3 m x 5 m with an internal height of 2.8 m was furnished with vertical PVC, polyethylene, and glass fibre-reinforced polyester pipes of 25 to 90 mm dia., empty or water-filled. Some of them were covered with black-plaster wall. In a second experiment, pipes were mounted horizontally on the walls or under the ceiling. Exhaust conduits of 150 mm dia. were also incorporated, either of glass-fibre-reinforced polyester or PVC/glass-fibre-reinforced polyester composite. Pipes on the wall and the exhaust conduits were loaded with water and air streams, respectively, while the pipes under the ceiling were empty. 

The main or sole constituent of plaster of Paris is calcium sulfate hemihydrate. If natural gypsum is used as the starting material the plaster may also contain some anhydrite, calcite, or clay minerals. The binder consists of individual particles whose size and shape corresponds to those of the starting dihydrate. They exhibit a distinct internal porosity and a relatively large specific surface area as a result of the dry dehydration process. 

Parge, Parget, Pargeting. The coating of the surface of brickwork, as with plaster. The term pargeting is used in the building trade, e.g. for the internal coating of chimney flues with lime... 

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