Parts of a Foundation – Footing, Wall, Slab and Drain

All 13 parts on the diagram

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Start here: 7 main parts 7

Footing The base of the foundation; it spreads the load onto the soil.
Foundation wall A bearing wall below the first floor, resting on the footing.
Basement floor A concrete floor slab, placed after the walls, over gravel fill.
Sill plate It is leveled on the wall; the floor frame rests on it.
Anchor bolt Set in the wet concrete; it holds the sill plate down.
Crawl space The low space between the ground and the floor joists.
Concrete slab A slab on the ground; its thick edge serves as the footing.

With a basement 4

Backfill Excavated earth put back against the wall once it has set.
Dampproofing A coating on the outside of the wall, from footing to grade.
Drain tile Pipe laid round the footings to carry ground water away.
Gravel The drain tile is covered with gravel or crushed stone.

With no basement 2

Pier A short column of masonry or concrete that carries the floor frame.
Vapor barrier A sheet under the slab that keeps soil moisture out of it.

How this list was compiled: Read 2026-09-30; a name is kept only where two of these use it. (1) US National Bureau of Standards, Building Materials and Structures Report BMS91, A Glossary of Housing Terms, https://archive.org/details/glossaryofhousin91subc : footing (the spreading course or courses at the base of a foundation wall, pier or column), foundation (the supporting portion of a structure below the first-floor construction, including the footings), foundation wall, pier (a column of masonry used to support other structural members), backfill (the replacement of excavated earth against a structure), dampproofing, drain tile. (2) L. O. Anderson and O. C. Heyer, Wood-Frame House Construction, US Department of Agriculture, Agriculture Handbook No. 73 (1955), https://archive.org/details/WoodFrameHouseConstruction : footings act as the base of the foundation and transmit the load to the soil; draintile laid round the perimeter of the wall footings and covered with gravel; poured walls damp-proofed with a coat of hot asphalt or tar from the footings to the finish gradeline; anchor bolts for sills placed while the concrete is plastic; the sill plate leveled on the wall; masonry or poured concrete piers under houses without basements; crawl spaces; concrete floor slabs on ground, combined slab and foundation, vapor barrier under the slab, gravel fill; basement floors. (3) Canada Mortgage and Housing Corporation, Canadian Wood-Frame House Construction, https://archive.org/details/CANADIANWOODFRAMEHOUSECONSTRUCTION : footings, foundation walls, basement floor slabs, slabs-on-ground, foundation dampproofing, perimeter drain tile under crushed stone, backfilling, anchor bolts for the wood sill, sill plates, crawl spaces, piers, vapour barrier. (4) US Naval Education and Training Command, Builder 3 & 2 (1981), https://archive.org/details/ERIC_ED210471 : footing, foundation wall, basement floor, backfilling, anchor bolts, sill, crawl spaces. 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 foundation is everything below the first floor that holds a house up and keeps the ground's water out. These are the names on a builder's drawing, for a basement, a crawl space and a slab.

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With a basement

The footing is the base; it spreads the load onto the soil. The foundation wall stands on it, and the basement floor is placed inside. Drain tile round the footing carries ground water away, under a cover of gravel. Dampproofing coats the outside of the wall before the backfill goes in. Anchor bolts hold the sill plate to the top of the wall.

With no basement

A crawl space is a low space under a wood floor, with piers carrying the floor frame between the walls. A concrete slab lies on the ground over a vapor barrier; its thickened edge does the work of a footing.

Footing and foundation are not the same thing: the footing is only the wide base at the bottom.

Questions and answers

What are the parts of a foundation called?

From the bottom: the footing, the foundation wall and, on top, the sill plate held by anchor bolts. A basement adds a floor slab, drain tile, dampproofing and backfill. A house without one has a crawl space with piers, or a slab on the ground.

What is the difference between a footing and a foundation?

The footing is the wide base at the bottom that spreads the load onto the soil. The foundation is everything below the first floor, footing included, so the footing is one part of it.

What are the three types of house foundation?

A full basement, a crawl space and a slab on the ground. A basement has tall walls and a floor below ground. A crawl space is a low space under a wood floor. A slab is concrete placed on the ground.

What is the pipe at the bottom of a foundation?

Drain tile, also called a footing drain. It is laid round the outside of the footings under a cover of gravel and leads ground water away from the wall.