Lath

A lath is a thin strip of wood.

It can be used on walls or roofs. It helps hold plaster in place. This happens because plaster oozes through the gaps. It then forms a little hook behind the wood. This hook keeps the wall strong.

Lath can also be made of metal. Some lath is used to grow plants. People also use it to make lobster traps. It is a very handy tool for building things.

A lath is a thin, narrow strip of wood.

It can also be made of metal or gypsum. Lath helps hold plaster on walls and ceilings. This works through a set of steps called keying. Plaster oozes through the gaps in the lath. It then hardens on the back side. This forms a little hook called a key. These keys hold the plaster to the lath.

There are many ways to make wood lath. Riven lath is split from a log. It is very strong. Accordion lath is sawn and then partially split. This makes gaps for the plaster. Sawn lath is made in sawmills.

Metal lath is used a lot today. It is strong and can bend. This makes it good for curves. Expanded metal lath has diamond holes. Plaster forms keys through these holes. Lath is also used for other jobs. It can support roof shingles. It can even be used to grow plants in a lathhouse. Some farmers use it to hang tobacco.

A lath is a thin and narrow strip of material used in building.

Most people know it as a wooden slat used under plaster. However, lath can also be made of metal or gypsum. It serves as a base for many different surfaces. You might find it holding up roof shingles or tiles. It is also used to make garden trellises or window shutters.

Builders use it to create strong and smooth walls.

Lath works by using a special way it stays attached called keying. When builders apply plaster, it oozes through the gaps in the lath. This happens with wooden slats or metal mesh. The plaster travels to the back side of the material. Once the plaster hardens, it forms a little hook called a key. These keys create a mechanical bond that holds everything together.

Without these tiny hooks, the plaster would simply fall off.

People have made different types of wood lath for a long time. One old way is called riven lath. This is made by splitting wood like oak or pine along the grain. Because it is split, riven lath is very strong. Another way is accordion lath, which is sawn and then partially split. This makes it look like an open accordion to create gaps. In the early 19th century, the circular saw changed things. Now, lath can be sawn in sawmills and delivered to sites.

Modern building uses many different kinds of lath today. Metal lath became popular in the late 19th century. It is very strong and can bend into smooth curves. One type is expanded metal lath, which has diamond-shaped holes. Another type is gypsum lath, also called rock lath. This is made of gypsum plaster sandwiched between two sheets of paper. It is very useful because it does not burn easily.

It is often used on straight walls because it is quite rigid.

Lath is part of many things you see every day. It helps make walls that block sound and keep heat inside. Metal lath walls can even be twice as resistant to fire as drywall. On farms, workers use lath to hang tobacco plants in barns. They might use a "spear" lath or a "hook" lath for this task. In the 1880s, people in Cape Cod even used laths to build lobster traps. It is a simple tool that helps build our world.

A lath is a thin, narrow strip of material used as a base for various surfaces.

While many people think of lath as only wooden slats, the term now includes any backing material for plaster. This includes metal wire mesh, expanded metal, or even gypsum products known as rock lath. Lath serves many different purposes in construction and agriculture. It can support roof shingles or tiles on a roof. It can also be used to create garden trellises, window shutters, or Venetian blind bars.

In some places, like the Connecticut Valley, tobacco farmers use lath to hang plants in barns.

To understand how lath works, you must understand a process called keying. This is how plaster or stucco stays attached to a surface. For wooden or metal lath, the material must create a mechanical bond. When a builder applies wet plaster, it oozes through the gaps or holes in the lath. The plaster travels to the back side of the material. Once the plaster hardens, it forms a shape known as a key. These keys act like tiny hooks that lock the plaster to the lath.

Without these keys, the plaster would not have the strength to stay on the wall.

Historically, there were three main ways to produce wooden lath. The oldest method produced riven lath. This was made by splitting hardwoods like oak or chestnut, or softwoods like pine, along the grain. Because it was split with the grain, riven lath was very strong. Another method was accordion lath. These were thin, sawn boards that were partially split with an axe. The splits were spread apart to create gaps, much like pulling an accordion open. In the early 19th century, the circular saw changed production. Lath could then be sawn in sawmills and delivered directly to building sites.

Modern construction uses several specialized types of lath. Metal lath became common in the late 19th century and is used extensively today. Expanded metal lath is made by slitting and pulling apart a thin metal sheet to create diamond-shaped holes. Ribbed lath features V-shaped ribs to add stiffness for spanning larger distances. There is also self-furring lath, which is dimpled to hold it away from a surface. For corners, builders use pre-bent corner lath or a wire mesh called Cornerite.

These metal options provide both a matrix for the stucco and added rigidity to the structure.

Another important modern material is gypsum lath, also called rock lath. This consists of gypsum plaster sandwiched between two sheets of absorbent paper. Unlike wood or metal, gypsum lath does not rely on mechanical keys to stay attached. Instead, the finish side is treated with gypsum crystals so the plaster can form a chemical bond. It is often used on straight walls because the material is very rigid. Gypsum lath is also noncombustible, which makes it a safer choice for many buildings. Some versions even include a foil facing to act as a heat reflector or vapor barrier.

Even though lath is very useful, these walls can sometimes fail. One reason is the use of non-galvanized nails, which can cause the lath to pull away from the frame. Moisture can also cause wooden lath to decay or expand and contract. This movement often leads to cracks in the surrounding plaster. Sometimes, the keys themselves fail if they were not formed properly. If the laths are set too close together, the plaster cannot travel through to form a strong hook. This failure can cause walls to sag or even collapse.

Despite these risks, lath and plaster systems offer many benefits. They provide excellent soundproofing and help with heat insulation. Metal lath and plaster walls are especially impressive regarding safety. They can be twice as resistant to fire as standard drywall. A specific assembly can even achieve a two-hour fire rating. Additionally, two inches of plaster and lath can match the decibel rating of drywall for sound control. This makes lath a vital component in creating durable, safe, and comfortable living spaces.