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Why Repair Plaster Crown Molding in an Old House?

Plaster Trim Restoration Company Brooklyn NYC

Why Repair Plaster Crown Molding in an Old House?

Many older homes in the Brooklyn and surrounding areas boast beautiful plaster ceilings, decorative details, and crown molding. While plaster is a solid and durable material that can remain intact for decades, if not even centuries, it will occasionally need repair plaster crown molding.

A homeowner should repair plaster crown molding in an old house to avoid water damage in the home, reduce the risk of plaster falling away from the home’s framework, preserve that home’s value, and to prevent any potential spread of asbestos that might be in the plaster itself.

To better understand why it’s so vital to protect and repair the beautiful plaster crown moldings, ceilings, decorative trim, and other pieces in your home, note a few details about plaster and how it’s installed, and why it’s often used for interior walls, ceilings, and decorative finishing touches.

How are plaster walls made?

Plaster is a type of thick yet soft and pliable material, similar to clay. Construction plaster is very different than drywall, as drywall or sheetrock is made of several layers of a specialty type of paper. Drywall is solid and sold in uniform-sized sheets, scored and cut to size, and then nailed into place. The softer texture of plaster, however, requires this material to be applied in layers, similar to spreading cement or pouring concrete.

Plaster walls are constructed starting with what is called wood lath, or thin slats of horizontally set wood. This lath gives plaster a foundation on which to be applied and set. Plaster walls and ceilings are then formed by the application of several layers of plaster against this lath. Each layer needs to dry thoroughly before a new layer is applied. Eventually, the plaster is built up enough to create a solid wall or ceiling, often several inches thick.

Why repair plaster crown molding, ceiling, and trim in a home?


There are many reasons to consider calling for plaster repair in a Brooklyn area home when you notice any cracking, chipping, sagging or other such damage. To ensure you keep your home in tiptop shape, note a few of those reasons here:

  • Plaster does not have organic ingredients that feed mold; however, water leaks that damage a home’s framework and cause it to soften and shift are a common reason for the plaster to chip or crack. These water leaks may lead to mold growth behind walls or ceilings. When a plaster repair expert fixes cracks or other damage in plaster, he or she can often spot water damage and resultant mold growth along wall studs, ceiling joists, and the like so that you can address all these needed repairs at once!
  • Because plaster walls and ceilings are technically one large piece of material that is built up and layered upon itself, a damaged or weak area of plaster may cause an entire section of the material to collapse. If you notice a buckling or sagging area of plaster, most commonly seen in the ceiling, it’s vital that you have this section repaired as soon as possible, to avoid having large chunks of the material fall away from that wood lath foundation.
  • Your home’s overall value is often affected by its condition as well as its appearance! Fixing damaged plaster crown molding will ensure that the house is structurally sound and will also restore its valuable details and decorative designs in that plaster.
  • Repairing the plaster in your home is a chance to have new trim or decorative finishes added. For example, you might opt to have a plaster chair rail that matches your home’s crown molding installed in a dining room, to add visual interest and grandeur. Repaired plaster might also get a new paint color, for an updated look. Having this work done as plaster is repaired ensures that all details in your home coordinate and look cohesive and finished.

Another critical reason to always repair plaster crown molding, ceilings, and walls in a home is that old plaster may contain asbestos. Some decades ago, asbestos was sometimes added to plaster mixtures to give the material thickness and keep layers of plaster adhered together.

Asbestos becomes hazardous when inhaled, so it’s vital that asbestos fibers stay intact. When plaster that contains asbestos begins to crack or crumble, this can increase the risk of those fibers becoming airborne. Plaster repair will restore the durability of plaster and ensure asbestos fibers don’t become a hazard to you or your family.

What is involved in Plaster Repair?

You might repair a small, hairline crack in plaster with joint compound, but larger repair jobs are much more complicated! Understanding how plaster is repaired can ensure that you know to call an expert when plaster in your home is chipped, cracked, or sagging.

First note that plaster often chips, cracks, or sags because it has come away from its base, or that wood lath behind it. Plaster repair then typically begins at that base, behind the wall or ceiling. A plaster repair expert may need to nail, bolt, screw, or otherwise reconnect surrounding areas of plaster back to the lath, to provide added support for the entire span of material.

The damaged area of plaster needs to be thoroughly cleaned, to remove all traces of dust and broken sections of this material. A crack or chip might even be cut and widened, to create a better foundation for holding fresh plaster material.

As said, plaster itself is installed in several layers, and this process often needs to be repeated for new plaster applications or repairs. A repair person may even need to visit your home over the course of several days, applying layer after layer of new plaster so that the damaged area is filled in and looks cohesive with the rest of the wall or ceiling. Specialty tape might be applied between these layers, to give that plaster added strength and ensure the sides of a broken area stay intact and connected.

How is decorative plaster crown molding repaired?

Plaster can split or crack across a decorative finish or design, and filling in that crack may not be enough to restore plaster’s appearance. To repair decorative crown molding or decorated areas of a plaster ceiling, a repair person may then take a mold or cast of an undamaged area.

This mold or cast is used to recreate that decorative pattern in fresh, soft plaster. Recreating these decorative finishes is part skill and part artistry, as a repair person may need to gently press and shape that new plaster and manually add small details to these designs. Also, the paint color of the plaster needs to be matched precisely, so that the result is cohesive and without gaps or mismatched areas of repair.

The advantages of plaster in a home

Why Repair Plaster Crown Molding in an Old House?

Plaster has many advantages over drywall and other materials used to create walls and ceilings as well as trim in a home:

  • Plaster has no biological materials that promote mold growth, as said. In turn, mold cannot spread across or grow on plaster. Plaster is then an excellent choice for homes in the tropics, near lakes and other water bodies, or that tend to trap humidity for any reason.
  • Plaster can be easily stamped and shaped into any form before it dries. Many plaster installers will use forms and molds to create intricate patterns in new plaster so that your ceiling or crown molding can offer an amazing, artistic touch without the time and effort needed to carve those details into a home’s surface manually!
  • The density and thickness of plaster give it added strength. As a home settles and shifts over the years, the plaster may be less likely to crack than drywall and other such materials. It’s also far more difficult to punch or kick a hole through a plaster wall than through drywall!
  • The density, thickness, and substance of plaster make it far less combustible than drywall. If a fire should start in your home, plaster walls and ceilings won’t feed those flames as easily as drywall and other such flammable materials.

Some plaster repair terms to learn

If you’re thinking of having plaster walls or a ceiling installed in your home, or already have plaster surfaces and finishes, you might note some plaster terms to learn. These terms can help you better understand the work that needs to be done to apply and then eventually repair that plaster.

  • Skimming versus plastering. Skimming refers to plaster being added as a patch or repair, whereas plastering refers to the installation of new plaster. These terms are essential to understand, as you don’t want to tell a repair person that you need plastering done when you need repairs or skimming. You also don’t want to assume that skimming means that a repair person will merely add a thin layer, or “skim” new plaster onto a wall or ceiling, as their repair work often involves the addition of many layers of thick, fresh plaster.
  • Delamination refers to a type of damage suffered by plaster, where one layer separates from another. Delamination cracks are quite common in plaster and may start from underneath the outer layers of plaster. As these layers separate, the outer layer will shift and move out of place, and a crack will appear. It’s vital that delamination cracks be addressed by a professional, as these layers need to be reattached to each other rather than having the cracks just filled in and covered over.
  • Efflorescence may look like mold on the surface of plaster, but this damage is caused by a collection of salts that come to the surface because of moisture buildup.

Plaster decoration and trim terms to learn

It can also be good to note some terms used to describe plaster trim and decorative designs added to that material:

  • A bump-out is a process of layering surfaces of plaster, to create “steps.” This process is often done to give plaster some depth and visual interest. Crown molding will often have bump-outs added, for a decorative design that isn’t overly busy or detailed.
  • Dental molding is a square design pressed into the plaster. This design is referred to as dental molding because the rectangular shapes resemble teeth! Dental molding is an excellent choice for a room where you don’t want too much decoration but need more visual interest than a simple bump-out.
  • A frieze is a long span of decoration or design etched into the plaster. A frieze is like crown molding, except that crown molding is always attached to the top of a wall, like a crown. A frieze can run along the middle of a wall or be placed closer to the floor, for a simple decorative touch.
  • A cornice is a long and decorative piece that is similar to a crown molding, except that a cornice may go around a window or door frame, rather than just along the upper part of a wall.
  • A medallion is a rounded decoration, typically placed along a ceiling. A medallion often serves as an anchor for a light fixture and may have a simple border, or it may have lots of intricate designs and details within its span.
  • A chair rail spans the length of a wall but typically just two or three feet above the floor. Chair rails are often stamped with lots of decoration and detail on their front and may serve as a separation point, with the lower half of a wall painted a different color than the upper half.
  • Long spans of plaster can be finished in various styles; a smooth finish, as the name implies, is flat and even. A sand finish has tiny bumps, to resemble sand. A rough coat plaster finish involves the outer layer of plaster being pulled out slightly before it sets so that there are lines and grooves in the plaster face. Rough coating is a popular choice of styles for ceilings, as a rough coat adds an uneven texture and depth to a plaster surface.

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