Column (post)An upright of wood, metal, brick or stone; it carries the top.
Beam (girder)It runs along the tops of the columns and is often doubled.
Lattice stripsThin strips laid across the rafters; vines spread over them.
RafterOne of the crosswise timbers that rest on the two beams.
Footing (pier)A concrete pier in the ground that the column stands on.
From the side 2
Cap (capital)The spreading top of a column, under the beam.
BaseThe wider foot of a column, where it meets the ground.
From the end 2
Rafter endThe overhanging end of a rafter, usually cut to a shape.
Anchor rod (anchor bolt)A rod set in the footing; it holds the column against wind.
How this list was compiled: Read 2026-09-30; a name is kept only where two independent sources use it. (1) A cypress lumber association's booklet, More Pergolas, 1920, https://archive.org/details/CypressPocketLibraryMorePergolasEtc.ofCourseVolume40 : posts and turned wooden columns; girders and rafters; rafter and girder ends can be cut to suit the fancy; columns with bases and caps; a bolt anchored in the concrete base so that the column base may be bolted down; anchor the end columns to their foundations to prevent high winds from overturning the structure; lattice strips from column to column are the chief distinguishing feature between the arbor and the pergola. (2) A pine lumber association's plan book, Beautifying the Home Grounds, 1926, https://archive.org/details/BeautifyingTheHomeGrounds : the main beams resting on the columns are doubled; rafters; the ends of the rafters should be nicely finished; lattice strips; a post partly in the ground should be set in concrete. (3) A column maker's catalog, The Pergola, 1924, https://archive.org/details/pergola00hart : columns with caps and bases; its cross views are labeled girders, cross rafters, lattice strips and concrete footing; iron rods anchor the columns to the foundation; the most satisfactory foundations are concrete piers. (4) A metal column maker's catalog, 1920, https://archive.org/details/UnionMetalPergolasAndGardenFixtures : columns with base and capital; beams and rafters; a tie rod from the superstructure down through the column into the concrete. (5) US National Bureau of Standards, A Glossary of Housing Terms, https://archive.org/details/glossaryofhousin91subc : pergola, a structure whose roof, composed of girders and cross-rafters, is open to the sky, usually supported on piers or posts in parallel rows. (6) Wikipedia, Pergola: upright posts or pillars that usually hold up crossbeams and a sturdy open lattice, upon which woody vines are trained; how an arbor differs. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
A pergola is an open frame of columns, beams and rafters over a walk or a sitting area, made for vines to climb. These are the names builders use for each part.
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From the side
Columns, or posts, carry everything. Each has a base at its foot and a cap at its top. A beam, also called a girder, runs along the top of each row of columns, and it is often doubled. Lattice strips lie along the very top.
From the end
Rafters cross from one beam to the other and overhang each side. Their ends are usually cut to a shape. Under the ground each column stands on a concrete footing, and an anchor rod set in the concrete ties the column down against the wind.
A pergola is open between its columns. Lattice panels from column to column make it an arbor.
Questions and answers
What are the parts of a pergola called?
Columns, or posts, stand on footings. Beams, also called girders, run along the tops of the columns. Rafters cross over the beams, and lattice strips run over the rafters. The shaped rafter ends overhang each side.
What are the boards on top of a pergola called?
The first layer across the beams is the rafters. The thinner pieces laid over the rafters, the other way, are lattice strips. Vines are trained over them for shade.
What is the difference between a pergola and an arbor?
The two words are often used for the same thing. Where they differ, an arbor is smaller and closed in with lattice panels at the sides, often with a seat, and a pergola is larger and open between its columns.
What holds a pergola down?
Its footings. Each column stands on a concrete pier, and an anchor rod or bolt set in the concrete ties the column down so that a high wind cannot overturn the pergola.