Distemper Painting Preparation
Neither distemper paint nor emulsion paint will take properly over old gloss paint or enamel, on walls and ceilings, and with these types of under surfaces it will be necessary, in addition to cleaning down, to remove as much of the gloss as possible with a wire brush or with coarse wire wool.
If a ceiling is being treated, as much of the old distemper as possible should be washed off before applying the new coats. The surface under treatment should roughly be divided into sections of a size that can easily be handled at one time. The surface area should then be coated with water, preferably applied with an old distemper brush, and the flat of the brush should be used to scrub the old surface and loosen the previous decoration. The area is then cleaned with a sponge, washing the sponge out frequently to remove as much of the old distemper as possible. The surface should then be rinsed and sponge dried. During the work of cleaning down, the water used for the job should be changed frequently. The methods of cleaning down described here apply to ceilings or wall surfaces.
If the old distemper is of the washable variety, much of it may be removed by washing down with sugar-soap. Sugar-soap is obtainable in cartons and it is mixed and used according to container instructions. Sugar-soap is applied with an old distemper brush or a sponge, scrubbing the surface vigorously, and followed by a good rinsing before drying with a sponge.
The inexperienced handyman will find the work of washing and cleaning surfaces, particularly ceilings, a very messy business, but there is quite a lot that can be done to avoid making too much mess. The floor of the room should be covered with old sacks or newspapers and the worker should wear a boiler-suit or old clothes. A lot of splashing, particularly from dirty water running down the arms, can be avoided by making a sponge bracelet. Cut a decorator’s cellulose sponge in two parts lengthways, bind the pieces round the wrists with a piece of string and when the bracelet becomes too wet squeeze it out into the bucket.
Particular attention should be paid to corners when cleaning down to remove every trace of the old material; this is particularly necessary when washing down ceilings that have been previously treated with a colour wash, most generally referred to as whitewash. Any thickly encrusted mouldings or corners should be scraped gently with the point of a putty knife. The methods of cleaning described above are applicable to walls that have been distempered. If the surfaces being redecorated have been hung with wallpaper it will be necessary to remove the old wallpaper before distempering or coating the surfaces with emulsion paint. If you distemper over the paper it may well soak through the wallpaper and loosen the old paste; after a short while, usually a few weeks after completing the job, the paper may loosen and peel away from walls and ceilings. The only way of ensuring a first-class finish is to remove old wallpaper.
Wallpaper is removed from walls and ceilings by wetting it to soften the paste and scraping it with a broad stripping knife. To do the job properly it is necessary to thoroughly soak the paper with water. The water may be applied with an old distemper brush, a paint-roller, or a sponge. The best plan of campaign is to coat all the surfaces, then work over them again with water to ensure that the paper is thoroughly wetted. The stripping knife should not be brought into use until the paper is soft enough to slide easily from the wall and a great deal of hard work can be avoided by the thoroughness of the soaking treatment. The stripping knife should be held with the end of the blade flat on the wall surface, keeping the handle as low as possible, and it is used to slide the paper from the wall rather than scraping.
Care should be taken when doing this part of the job to avoid damaging the plaster with the corners of the stripping knife. Every scrap of the old paper should be stripped from walls and ceilings, the surface should then be washed over and, finally, lightly rubbed down with grade middle-two glass-paper to remove any crumbs of old wallpaper still adhering to the surfaces. If there are any cracks or holes to be repaired, the light rubbing with glass-paper is best done after carrying out the repairs.
This method of preparation for distempering is also applicable to preparing for paperhanging, in that old surfaces are washed down, the paper scraped off and any damaged plaster is repaired before the next part of the job is done. Plaster surfaces that are to be distempered or covered with wallpaper should be sized. Plaster surfaces that are to be coated with emulsion paints should not be sized. The best type of size to use is a cellulose-based size which is obtainable in granule form in packages or cartons. Only a small amount of this granule size is required to cover quite a large area and a 2-oz. packet is sufficient for a room of average size. Directions for mixing size are given on containers. The stated amount of granules are mixed with cold water.
The size is applied with a distemper brush or with a paint-roller, and a small clean paint-brush is used for cutting in at edges and corners. Any spots of size splashed on woodwork or floors should be wiped up as the job progresses. As an alternative to cellulose size, decorators’size may be used. This is also obtainable in carton form and directions for mixing are given on the containers. Glue size may be used if the surfaces are to be distempered, but if a new covering is to be wallpaper it will be found advisable to use cellulose size, the granules of which may also be mixed to make paste for hanging wallpaper.