What Does Lathing Mean In Construction?
What Does Lathing Mean In Construction?
Lathing is a building process used to finish mainly interior dividing walls and ceilings. It involves the use of narrow strips of wood (laths) which are nailed horizontally across the wall studs or ceiling joists. These laths provide a base for plaster, which is then applied using a wooden board as an application tool.
Lathing has been used in construction since at least 6000 years ago, when it was part of the wattle and daub technique. It was widely used from the 1700s to the early-to-mid 1900s before being superseded by modern gypsum plaster and plasterboard.
Today, lathing is mainly done with metal lath, such as expanded metal lath (EML), which is usually fixed with clout nails to the studs of timber partitions. There are also some advantages to traditional lath and plaster construction, such as its sound-proofing properties and ability to delay and deter fire spread.
Types Of Lathing In Construction
Lath is a type of material used in construction to provide a base layer for plaster, drywall, stucco, masonry and other materials. Lath can be made from wood, metal, gypsum or insulated board. In many older residential buildings, narrow strips of wood were generally used as laths to support the plasterwork.
Gypsum lath is one of the most common forms of laths used in modern day construction and consists of thin sheets of gypsum sandwiched between two layers of heavy paper. It is lightweight and strong which makes it an ideal choice for wall insulation and joint reinforcement.
Metal lath may be needed for fire-rated assemblies or specific applications such as curved surfaces. Insulated boards are also available which are often used along with stone veneer or when additional insulation value is required.
Benefits Of Lath
Lath and plaster walls offer numerous advantages, such as protection against fire and mold, soundproofing, and heat insulation. While wood lath may be prone to decay and mold growth, metal lath coated in plaster creates an unfavorable environment for harmful molds.
Metal lath and plaster walls have exceptional fire resistance, with the ability to achieve a two-hour fire rating with a 2-inch-thick (5.1 cm) assembly, which is twice as resistant as drywall.
Additionally, 2 inches of plaster and lath can deliver the same sound reduction as 4+7⁄8 inches (12 cm) of drywall.
Lath Repair Methods
Repairing lath and plaster walls is generally more cost-effective than replacing them. Minor cracks can be easily patched, but for larger ones or if the brown coat is damaged, several base coats need to be applied beforehand.
It’s also possible to add metal lath onto wooden lath for increased strength. Furthermore, on the backside of existing laths, a bonding agent and plaster can be forced through the gaps in order to reinforce weak areas.
This type of repair method is often used by conservators when wanting to maintain the original look of a wall or ceiling.
Lath Failure
Lath walls can fail for several reasons, such as the use of non-galvanized nails leading to lath pulling away from frame, decay from moisture or insect damage, wooden lath expanding and contracting causing plaster to crack, and deterioration of plaster keys.
Hair addition in plaster helps to prevent this and provides strength. Problems can also occur with improper formation if laths are set too close together for the plaster to pass through.
Signs of key failure include looseness, sagging walls or ceilings, which sometimes result in breakage and collapse. Taking these precautionary steps can help prevent a wall or ceiling from failing prematurely.
How Is Lath Frame?
Lath can be secured directly to a structure’s frame – like timber studs. Alternatively, it can be fastened onto a furring, which is a wooden or metallic support structure connected to the building. Furrings are usually seen in masonry construction. Finally, frames are used when lath and plaster are combined to create ornamental or curved designs.
