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In many historic buildings lath and plaster ceilings play a major role for the prevention of fire spread. They are critical to the protection of horizontal elements such as timber joisted floors, including the flooring on top, which in terms of fire performance is often in a poor condition due to the
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wall board (essentially an early form of drywall) with holes spaced regularly to provide a 'key' for wet plaster. Rock lath was typically produced in sheets sized 2 by 4 feet (610 by 1,220 mm). The purpose of the four-foot length is so that the sheet of lath exactly spans three interstud voids
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hardwood laths of random lengths and sizes were often used. Early
American examples featured split beam construction, as did examples put up in rural areas of the U.S. and Canada well into the second half of the 19th century. Splitting the timber along its grain greatly improved the laths' strength
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One continued advantage of using traditional lath is for ornamental or unusual shapes. For instance, building a rounded wall would be difficult if drywall were used exclusively, as drywall is not flexible enough to allow tight radii. Wire mesh, often used for exterior
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and durability. As
Americans and Canadians expanded west, saw mills were not always available to create neatly planed boards and the first crop of buildings in any new western or northern settlement would be put up with split beam lath. In some areas of the U.K.
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is then applied, typically using a wooden board as the application tool. The applier drags the board upward over the wall, forcing the plaster into the gaps between the lath and leaving a layer on the front the depth of the temporary guides, typically about
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inch (6.4 mm). A helper feeds new plaster onto the board, as the plaster is applied in quantity. When the wall is fully covered, the vertical lath "guides" are removed, and their "slots" are filled in, leaving a fairly uniform undercoat.
340:, which is faster and less expensive to install. Drywall possesses poor sound dampening qualities and can be easily damaged by moisture. Traditional lime based plasters are resistant to moisture and provide excellent sound isolation.
281:(UK)). A smooth, white finish coat goes on last. After the plaster is completely dry, the walls are ready to be painted. In this article's photo ("lath seen from the back...") the curls of plaster are called
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by the
National Park Service. Contains detailed descriptions of Lath & Plaster construction and advisories on repairing and restoring these walls (especially in historic buildings).
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Traditional lath and plaster (including rock and metal lath varieties) has superior sound-proofing qualities when used with lime or gypsum plaster, which is denser than modern drywall.
325:(overlapping half a stud at each end of a four-stud sequence in standard construction), the studs themselves being spaced 16 inches (410 mm) apart on center (United States
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or not. Metal lathing was spaced across a 13.5-inch (340 mm) center, attached by tie wires using lathers' nippers. Sometimes, the mesh was dimpled to be self-
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Oliver, Paul (2006). Built to meet needs : cultural issues in vernacular architecture (First ed). Architectural, Amsterdam ; London
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began to be used toward the end of the 19th century. Metal lath is categorized according to weight, type of ribbing, and whether the lath is
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inch (9.5 mm) away from its neighboring courses. Metal lath is available in 27-inch (69 cm) by 8-foot (240 cm) sheets.
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standard measurements). By the late 1930s, rock lath was the primary method used in residential plastering.
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In three coat plastering it is standard to apply a second layer in the same fashion, leaving about
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Partially-exposed wallpapered lath and plaster illustrating the technique. Example from the
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which reinforces the plasterwork, thereby helping to prevent the keys from breaking away.
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Temporary lath guides are then placed vertically to the wall, usually at the studs.
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http://www.buildingconservation.com/articles/fireresist/fire_resistance.htm
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inch (6 mm) thick. Each horizontal course of lath is spaced about
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The wall or ceiling finishing process begins with wood or metal
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Lath and plaster methods have mostly been replaced with modern
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and are necessary to keep the plaster on the lath. Traditional
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is a building process used to finish mainly interior dividing
411:, The Telegraph (London), May 10, 2006. Retrieved 2012-03-30.
451:"Fire Resistance of Historic Fabric" by Peter Jackman -
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Finish mainly for interior dividing walls and ceilings
428:"Repairing Historic Flat Plaster Walls and Ceilings"
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inch (13 mm) of rough, sandy plaster (called a
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221:the laths were generally sawn, but in the
162:Learn how and when to remove this message
470:, Building Construction & Finishing
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426:MacDonald, Marylee (11 October 2016).
408:On the level: is the old plaster best?
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140:adding citations to reliable sources
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26:seen from the back with white
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234:was also used as a lath.
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468:Plaster Base Installation
316:In use as early as 1900,
287:lime based mortar/plaster
102:Winchester Mystery House
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297:Historical transition
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186:or ceiling
92:Description
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500:Plastering
484:Categories
381:References
344:Advantages
307:galvanized
303:metal lath
275:brown coat
184:wall studs
152:March 2012
51:wall studs
318:rock lath
291:horsehair
123:does not
495:Building
364:See also
279:browning
232:reed mat
217:and the
80:and the
334:drywall
311:furring
268:⁄
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144:removed
129:sources
86:drywall
59:plaster
28:plaster
375:Stucco
351:stucco
322:gypsum
243:gypsum
215:Canada
188:joists
78:Canada
55:joists
437:8 May
370:Laths
176:laths
47:laths
39:walls
439:2021
283:keys
239:Lime
180:wood
127:any
125:cite
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43:wood
24:Lath
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