Installing plaster

Lay out drop-cloths to keep your work area clean. Some cheap canvas sheeting or a couple plastic tarps will provide a barrier against dust, spills, and muddy mortar footprints. Plastering can get pretty messy, so this simple measure can spare you an exhaustive cleanup process later on.

Plaster is hardest to clean off dark walls because you will have to wash of any plaster that dropped with rags and water later. For airtight protection, use painter's tape to secure the dropcloth directly to the floor beneath the wall. When you're finished, just roll up the drop-cloths, take them outside, and spray them clean. The biggest cause of plaster falling off of the tools is mixing in too much water.

As you get better, you will drop less plaster, you will get less on your hands and cleanup will be less. Clean the wall to remove dust and debris. Scrub the wall from top to bottom with a dry stiff-bristled brush. Pay particular attention to the areas with heavy buildup, or where stripped layers of old plaster have left behind clumps.

Prime over stained areas to ensure the plaster will adhere properly. Repair any cracks in the wall before plastering it. Make sure the wall and ceilings are plumb and flush before you start plastering.

Otherwise, there may be bumps and indentations on the finished wall. To test whether the wall is ready to accept new plaster, run your finger over the surface. If it comes away caked with dust, it still needs some work. Spraying the wall with water will help the new plaster to adhere to the old wall. Dust, soap, oil, tar and mold all cause the plaster not to adhere to the surface.

Also a wall that is too dry causes the water to be absorbed out of the plaster and set before it has time to stick to the wall. Brush on PVA glue to prepare the wall to hold the plaster. Combine one part PVA glue with four parts water in a disposable paint tray and mix thoroughly. Roll or brush the PVA over the entire wall, aiming for total coverage. For best results, the plaster should be applied while the PVA coat is tacky but not completely dry.

A preliminary coat will also prevent the substrate from leaching moisture from the plaster, which can cause crumbling. Mix your plaster in a 5 or 7 gallon Fill the bucket to the halfway mark with cool, clean water. Open a new bag of plaster mix and shake it into the bucket until it forms a mound above the surface of the water.

Then, use a plunger or stirring rod to begin incorporating the dry plaster particles. Always add the plaster mix to the water, not the other way around. If you add water to the plaster, you will have to apply pressure to mix the plaster at the bottom of the pail and you will over-mix the plaster and it will set too fast to work with. Stir the mixture as you add in the plaster. An electric drill with a paddle attachment can save you a lot of time if you're mixing up large or multiple batches.

You must know that mixing the plaster with an attachment on your drill will cause the plaster to set much faster. Use the attachment for large jobs, where you will apply a lot of plaster in a short amount of time.

If you are doing small patch-work, use a smaller bucket and mix by hand so that the plaster will set slower and give you time to work. Stir the plaster continuously to thicken it. Keep mixing until it's perfectly smooth and free of lumps. Every now and then, scrape the sides of the bucket to loosen any clinging dry pockets. By the time you're finished, the plaster should be roughly the same consistency as peanut butter. If it stands up on its own, it means your plaster is just right.

Part 2. Heap some fresh plaster onto your hawk board. Scoop the plaster out of the bucket with the edge of your trowel. If you want, however, you can wet the hawk slightly to help it release. Use your trowel to ready a small amount of plaster. Slide the flat edge of the trowel under one end of the plaster and pick up enough to layer on a strip from floor to ceiling. To ensure accuracy and efficiency, make sure the plaster is sitting directly in the center of the trowel.

Start with a conservative amount of plaster and add more as needed. Smear the plaster onto the wall, starting with the bottom corner. Crouch down and push the plaster up the wall in a gentle arc, standing as you go to reach the higher parts. At the top of your stroke, slide the trowel over inches cm , then reverse the motion and bring it down again.

Keep your trowel at a slight angle. Holding it flush can pull plaster away from the wall. Plaster the wall in sections. Continue working your way along the wall, spreading the plaster from bottom to top.

Pause as needed to scoop more plaster onto your hawk board. Repeat this pattern until the plaster has been spread evenly over the entire surface. Smooth the first coat of plaster.

Once the plaster is in place, clear your trowel and run it over the wall in all directions. Apply a consistent amount of pressure, focusing on spots where the plaster is thicker or the higher edges have created seam. This will make them respond better to the trowel. Scrape the plaster to add texture before adding the second coat optional. Consider scoring the wet plaster to create a better base for the second coat.

Rake the plaster vertically from one end to the other with a deviling float or notched trowel. Scoring creates shallow grooves that increase the overall surface area of the wall and allows the second coat to adhere better. Part 3. Spread on a second and final coat of plaster. Apply this coat exactly as you did the first, making sure there are no obvious gaps or seams.

Use a float to get an even finish. Glide the float lightly over the surface of the wet plaster in all directions to work out any lumps, lines, holes, and inconsistencies in thickness.

Smoothing plaster is a painstaking task, but one that is important to do correctly. Be careful not to polish the plaster too much. Eventually, it will begin to take on a glossy quality, which can weaken the hold of paint and wallpaper. Allow the plaster to set.

Depending on various conditions, plaster can take anywhere from days to fully harden. Avoid handling the fresh plaster as it dries. Any imperfections it picks up during this time will be visible in the finished wall. The wall should be totally dry before you add paint, wallpaper, or any other decorations. Did you know you can get expert answers for this article?

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Include your email address to get a message when this question is answered. By using this service, some information may be shared with YouTube. Use plaster on interior walls. Plaster decomposes with a lot of moisture. Marking an external corner: Hold a length of coving up to the wall and, with a pencil mark off the end of the wall on its lower edge. Without moving the coving, then mark where the top edge intersects the guideline on the ceiling. Repeat for the coving on the other side of the corner.

Cutting the miter: Lay the coving on its back on the floor, using a straightedge and pencil, draw a diagonal line from the marked point on the top edge to the lower corner for an internal corner, or between the two marked points on the top and lower edges for an external one.

Put the cornice in a miter box and cut along the marked lines. Then lift two pieces up to the corner at the same time to check the join. Fixing the coving: spread adhesive along the flat surfaces on the back of the first length of coving. Press it firmly but gently against the wall and ceiling and push the pointed lower edge into the corner. Make sure the coving grips the wall along its top and bottom edges. With a damp cloth, wipe away any adhesive that squeezes out from behind the coving.

To hold it in place until the adhesive sets, knock a few nails into the wall at regular intervals under the lower edge. Fitting the remaining coving: Spread adhesive on the adjacent lengths of coving and press them into position in the same way to form neat butt joins. Continue fitting the rest of the coving round the room. Hiding joins: When the adhesive is set, remove the supporting nails and fill the holes in the wall and any gaps between the joins with fine surface plaster filler, smoothing it in with your fingertip.

Leave it to dry before painting the coving. The procedure for measuring up, cutting and mitering traditional fibrous plaster coving is identical to fitting the gypsum plaster type except that you need to knock some galvanized nails through the coving itself into the wall and the joists in the ceiling to hold it permanently.

Use a nail punch to bury the nail heads under the plaster and fill with fine surface filler when tidying up the corners and joins. You can buy an embossed cove border to add color and patter to the plain gypsum plaster coving. You simply use a wallpaper adhesive to stick it along the concave face of the coving. If you lake you can add another strip over or under a dado rail to achieve a comprehensively molded look. Polystyrene is the simplest of all coving types to put up, because it is so light and manageable.

You just have to be careful not to push your fingers or nails through the soft polystyrene when you are pressing it to the wall and ceiling. Polystyrene molding covered with paper is more robust but just as lightweight. To avoid creating a serious fire hazard, always use emulsion paint for decorating polystyrene coving; never paint over it with gloss paint. Preparing the surfaces: Prepare the walls and ceiling and mark in the guidelines as for gypsum plaster coving.

Fitting corner pieces: Fix all the corner pieces before fitting the straight pieces. Spread plenty of adhesive along the flat back and top edges of the first corner piece and press it firmly but gently into position in the corner. Pre-mitered external and internal corner sets to match paper-covered polystyrene coving save having to cut the miters yourself.

Plain polystyrene coving comes with embossed corner pieces that serve the same purpose. You can paint both sorts with emulsion paint to complement the rest of the room. Cutting the coving to fit: Measure the length of each wall between the corner pieces. If necessary, using a kitchen knife and a steel straightedge, cut straight across the coving to make it fit.

Glue straight pieces along the wall, butting up the ends to the corner pieces and each other. Scrape away excess adhesive that squeezes out from under the coving with a filling knife and use it to neaten the joins. Your email address will not be published.