21 Sep Understanding Plaster Walls
Whether you’re remodeling a kitchen, adding on to your home, or just hanging a mirror, understanding wall coverings is essential. The most common interior wall surface is gypsum wallboard, also called drywall and plaster.
Not Just For Luxury: The History of Plaster
If yours is an older home, built before the 1950s, chances are it contains plaster walls and ceilings. Appreciated for its versatility, ability to reduce noise, and fire resistance, plaster was commonly used as the wall covering of choice over brick, stone, and frame construction. Because of its pliable nature, and the fact that it can be manipulated to fit just about any nook, cranny, or curve, it continues to be an excellent solution for many challenging surfaces and wall designs.
Even in smaller houses, it was standard to apply plaster to finish interior walls and then paint or cover with wallpaper. Traditionally, plaster is a mixture of Portland cement, sand, and water that is applied in layers to a base of wood or metal lath, or to perforated plasterboard. The traditional steps of plastering are as follows: 1) a scratch coat is trowelled onto the lath, 2) the plaster is allowed to ooze through the lath and grip the backing as it hardens, 3) a second coat known as a “brown coat” is trowelled over the scratch coat, and 4) a finish coat, known as “white coat” (a mixture of lime putty, gauging plaster, and water), is trowelled onto the brown coat and smoothed out to achieve the final surface.
Don’t Give Up Hope: The Problem With Plaster Walls
Over time, plaster walls have a tendency to develop stress cracks. A plasterer has the materials and techniques needed to repair these cracks, based on the extent and condition of the damage. A professional plasterer can also advise on stripping paint from plaster walls and can ensure that the new paint adheres to the surface. This can be a major issue if you’re looking to remodel or re-design your home.
Decorative plaster in historic homes may seem beyond repair, though often a skilled plasterer has the information he needs to save it without undertaking major renovations. Sometimes simply applying a new layer over the old can do the trick. Of course, if you’re not as interested in preserving the historical integrity of your older home as you are in functionality, stripping the decorative plaster and replacing it with “white coat” plaster is going to lead to fewer maintenance problems down the road.
The Economical Method: Plastering Without Plaster
In new home construction, additions to older homes, or remodeling, there are materials available which will simulate the look of original plaster without using the actual product. Some of the materials for new interior construction are similar to drywall, but are stronger, more durable, and can be finished with a finish coat to provide the beauty and feel of plaster. This system involves installing “blue board” (like sheetrock but stronger and more durable) first and then a fiberglass mesh along with a base coat, which is trowelled down and prepared for the finish coat. The finish coat is applied and smoothed out to resemble the traditional “white coat” finish. This system is known as veneer plastering and has become an extremely popular and cost-effective alternative to both traditional plaster and drywall.