Plaster walls once framed home interiors, molded onto a lath with trowel and manipulated with a float until a smooth finish is achieved. They were heavy to handle and requires skill, making it all but obsolete in new construction. Solid plaster often provides a superior sound barrier and is harder and stronger than what has all-but-replaced it, which is drywall. Drywall became a common usage in modern house interiors because it is manufactured in sheets that can be cut to size, is easy to install and requires less talent. The drywall is then covered with plaster to create the interior cosmetic finish. Oftentimes the interior plaster is sprayed on and textured. Spray-on plaster can even be pre-mixed with paint to save considerable time and labor.
All is not lost however for plaster walls. The advantages of plaster are many, especially if you’re thinking long-term benefits. Plaster walls look better with a flatter even surface. They also take paint uniformly especially when a semi-gloss paint that accentuates imperfections is used. With drywall, paint often appears different over the joint compound than over the drywall. Plaster wall also nicks less easily than drywall to maintain its beauty even with children around. It can be washed without the possibility of water damage with drywall. Once cured, plaster is resistant to short-term water exposure. It is also easier to strip old wallpaper off plaster without damaging the wall surface. You can use stronger enzyme solutions and scrape more vigorously to remove the old adhesive.
Decide on whether a plaster or drywall is desired before any wall finishing has begun. The gypsum lath panels are nailed to the studs on the walls for the plaster base before a thin 1/16 inch layer of plaster is applied over this to create a smooth hard finished surface. If you have already put up the drywall, it is too late to select plaster if you decide to do so late. These special panels/plasterboards are often called “blue boards” because they have a special water resistant paper coating with a bluish color. This special water resistant coating prevents the moisture in the plaster from damaging the inner gypsum core. This application moisture is why standard drywall cannot be used with plaster.
Tools and materials needed:
- Drywall saw
- Plaster/Roll-on plaster
- Plaster/blue board
- nails or screws
Things to remember when installing plasterboards
- Plasterboard sheets should always be placed at right angles to framing members.
- Plasterboard should always have a 10mm gap between the floor and the 1st wall sheet.
- Never place a nail next to or through a daub of plasterboard adhesive.
- Only apply plasterboard adhesive when you are ready to fix the plasterboard sheet. If the plasterboard adhesive is applied too soon, it will form a skin and not bond to the plasterboard sheet.
- Evenly space plasterboard adhesive daubs across the width of the sheet.
- Do not nail centre of plasterboard wall sheets. If the plasterboard sheets need pinning back, nail through a temporary plasterboard block and remove the block and nail after the plasterboard adhesive has set. This will prevent popped nail heads.
- Keep plasterboard nails around doors and window close enough to the edge so the architrave will cover them.
- Make sure all plasterboard nail heads are below the surface. (If you break the paper around a nail head put another nail beside it to avoid popping).
- Double nail or screw the center of plasterboard ceiling sheets about 40 mm apart, this helps prevent plasterboard nails or screws popping.
- Wherever possible keep plasterboard recessed edges together and butt edges together. Avoid plasterboard recessed edges and butt edges adjoining each other.
- Never place plasterboard butt joints directly over the door stud or window stud.
- Always back block plasterboard ceiling joins.
- Use plasterboard back blocking cement or cornice cement for back blocking.
- Citric acid will slow down the setting time of plasterboard back blocking/cornice cement, use about a teaspoon full in a back blocking mix.