Foundation, Wall and Basement Terms

Reviewed October 2026 · 66 terms

Footings, slabs, stem walls, retaining walls, basements and below-grade waterproofing: what each one is and how it changes the cost of demolition and removal.

Prices for this work: demolition · waterproofing · concrete and asphalt removal · excavation and grading · hauling and disposal · all 2026 prices

Related services: Concrete removal · Structure removal · Selective demolition · Exterior demolition

• Foundations and concrete
• Walls
• Basements and below-grade structures
• Waterproofing
• About this topic

Foundations and concrete

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Anchor bolts

Steel bolts cast into a footing or stem wall that tie the wood sill plate to the foundation. They are cut or pulled during demolition. Building codes generally require them no more than 6 feet apart and within 12 inches of each end of a sill plate.

Caisson / pier

A deep concrete column drilled into the ground to carry a building down to firm soil or rock. Caissons are usually cut off below grade rather than pulled, unless the new design calls for full removal. When they stay in place, the next building’s foundation has to be designed around them.

Concrete crushing

Breaking removed concrete into graded aggregate with a crusher, either on site or at a recycling yard. Crushing on site can cut hauling and supply base material for the next project. A portable crusher needs an air district permit or state registration, plus water sprays for dust.

Control joint

A groove cut or formed into a slab so it cracks along a straight line instead of randomly. Control joints give a natural break line during removal. A common rule spaces them 24 to 36 times the slab thickness, roughly 8 to 12 feet for a 4-inch slab.

Curb and gutter

The concrete edge along a street that carries runoff to the storm drain. Work on it is in the public right-of-way and needs a city encroachment permit. Many Southern California cities build it to the Standard Plans for Public Works Construction.

Driveway approach

The sloped concrete section between the street and the property line. Removing or replacing it is city right-of-way work, built to the city’s standard plan under an encroachment permit. New approaches usually have to keep the sidewalk crossing at no more than a 2 percent cross slope for accessibility.

Expansion joint

A gap filled with compressible material between two slabs, or between a slab and a wall, that lets concrete move with temperature changes without cracking. Unlike a control joint, it runs the full depth of the slab.

Flatwork

Ground-level concrete such as sidewalks, patios, driveways and equipment pads, as opposed to walls and footings. Flatwork removal is priced per square foot by thickness. Flatwork is often unreinforced or has only wire mesh, so it breaks faster than footings. Concrete and asphalt removal

Footing (continuous)

A strip of concrete poured in a trench under the full length of a wall to spread its weight into the soil. Also called a strip or wall footing. Footings add depth, rebar and haul weight to a demolition-to-dirt price. Code minimums for a one-story house are typically 12 inches wide and 12 inches below grade, and older houses often have less.

Footing (spread / pad)

A square or rectangular block of concrete under a single column or post. Commercial buildings often have dozens, each broken out and backfilled separately. Each one is sized from the column load and the soil bearing pressure in the soils report.

Grade beam

A reinforced concrete beam at or just below ground level that ties footings, piers or caissons together. Grade beams carry heavy rebar and take longer to break out than ordinary footings. On expansive or soft soil, they often span between caissons so the load doesn’t rest on the surface soil.

Hoe ram (hydraulic breaker)

A hydraulic hammer mounted on an excavator or skid steer that breaks concrete, asphalt and rock. It is the main tool for slab, footing and foundation removal. Breakers are sized by impact energy, and a bigger hammer on a bigger machine breaks thick footings much faster. Our concrete removal work

Hold-downs

Steel connectors that tie wall framing to the foundation so it resists uplift in earthquakes and wind. They come out with the framing or the foundation. Homes built or retrofitted after the 1994 Northridge earthquake typically have more and larger hold-downs.

PSI (concrete compressive strength)

Pounds per square inch, the measure of how strong cured concrete is. House slabs are often 2,500 to 3,000 psi; commercial and structural concrete is commonly 4,000 psi or more, and harder concrete takes longer to break. Concrete keeps gaining strength for years, so old concrete is often stronger than its original design.

Pulverizer

An excavator attachment with crushing jaws that breaks concrete walls and slabs and frees the rebar for recycling. It is quieter than a hammer and causes less vibration, which helps next to occupied buildings.

Raised foundation (crawlspace)

A wood floor built on stem walls and piers above a crawlspace, common in older homes. When the site goes to dirt, the stem walls, piers and footings are removed too. Crawlspaces in older homes can hold asbestos pipe insulation, old ducts and debris that must be cleared first.

Rebar

Steel reinforcing bar cast into concrete, sized in eighths of an inch (a #4 bar is 1/2 inch). More and heavier rebar slows break-up and raises removal cost. Bars have raised ribs so concrete grips them, and the size number is rolled into each bar.

Recycled concrete

Broken concrete taken to a recycler instead of a landfill, usually for a lower tipping fee. It counts toward CALGreen diversion and is reused as base rock. Recyclers can reject loads mixed with wood, trash or too much dirt, so clean loads get the best rate.

Sill plate

The bottom wood member of a framed wall, bolted to the top of the slab or stem wall with anchor bolts. In California it must be pressure-treated or naturally decay-resistant wood where it sits on concrete. Treated sill plates removed in demolition are treated wood waste in California and go only to approved landfills.

Slab thickness

The depth of a concrete slab, usually 4 inches for houses and 5 to 8 inches or more for commercial and industrial floors. Removal is priced by thickness because breaking time and haul weight rise with it. Thickness can vary across one slab, so cores or test cuts confirm it before large removals are priced.

Slab-on-grade

A concrete floor poured directly on prepared ground, the most common foundation for Southern California houses and commercial buildings. Removal is priced by square foot and thickness. Many older slabs have plumbing, radiant heating or electrical runs cast inside them. Concrete removal service

Stem wall

A short concrete or block wall that rises from the footing to the floor framing, common under raised-floor houses and along slab edges on sloped lots. Stem walls come out with the footings in a demolition to dirt. On sloped lots they can be several feet tall and hold back soil, which changes the removal sequence. Structure removal service

Vapor barrier (under-slab plastic)

A plastic sheet, often 10 or 15 mil, laid under a slab to keep ground moisture from coming up through the floor. It comes out with the slab and is hauled as mixed debris. CALGreen requires a vapor retarder and a capillary break under slabs in new homes.

Welded wire mesh

A grid of steel wire used as reinforcement in older slabs, driveways and sidewalks. It is lighter than rebar but still slows break-up. Mesh often ends up near the bottom of the slab after being stepped down during the pour, so it adds less strength than intended.

Walls

Cap / coping

The top course of a wall, often precast concrete, stone or brick, that sheds water off the wall. Pool coping comes off as part of pool demolition. Precast caps are usually set in mortar and can be lifted off in pieces before the wall comes down.

CMU / block wall

A wall built of concrete masonry units, typically 8 by 8 by 16 inches, often filled with grout and rebar. Common for property-line walls, retaining walls and commercial buildings. A standard block actually measures 7-5/8 by 7-5/8 by 15-5/8 inches, leaving room for 3/8-inch mortar joints. Our exterior demolition work

Load-bearing wall

A wall that carries the weight of the floors or roof above it. Removing one takes an engineer’s design and temporary shoring or a new beam before demolition starts. Clues include walls running across the floor joists, walls over beams, and walls stacked over walls below. Selective demolition service

Non-bearing partition

An interior wall that divides space but carries no structural load. It can usually come out without shoring, which makes it some of the lowest-cost interior demolition. Even a non-bearing wall can hide plumbing, wiring or ducts that have to be capped first. Our selective demolition work

Parapet wall

The short wall that extends above a roofline, common on commercial and older masonry buildings. Unbraced masonry parapets are a falling hazard and are taken down early or braced during demolition. Los Angeles and other cities have ordinances requiring old masonry parapets to be braced. Our selective demolition work

Retaining wall

A wall that holds back soil where the ground changes level. Removal includes the footing and often temporary slope support, and is priced by height, length and wall type. Walls over 4 feet tall, measured from the bottom of the footing, generally need a building permit. Exterior demolition service

Shear wall

A wall braced with plywood, steel or reinforced concrete to resist sideways forces from earthquakes and wind. Shear walls are part of the structure and are removed only at an engineer’s direction. Its nailing pattern is part of the design, so even a small opening cut into it needs the engineer’s approval. Selective demolition service

Tilt-up panel

A concrete wall panel cast flat on the slab and tilted into place with a crane, the standard construction for Southern California warehouses. During demolition, panels are braced, cut and lowered. Panels can weigh well over 50 tons, so they are cut into smaller pieces or lowered with a crane.

Unreinforced masonry (URM)

Brick or block walls built without steel reinforcing, common in California buildings from before the mid-1930s. Many cities, including Los Angeles, require URM buildings to be retrofitted or removed. California’s URM Law of 1986 required local governments in high seismic zones to inventory these buildings.

Wall tie-in / patch-back

Repairing the edges where demolished work meets what stays, such as closing a wall opening or rebuilding a cut slab edge. Patch-back is priced separately from demolition. The patch is matched to the existing finish, so it is priced by finish as well as by area. Patch-back and finishes service

Basements and below-grade structures

Basement fill-in

Breaking holes in a basement floor for drainage, knocking the walls down to a set depth and filling the space with compacted soil or flowable fill. It costs less than full removal, but the area may need engineering before building over it. The floor is broken so water can drain through instead of collecting in a buried bathtub. Our structure removal work

Basement removal

Taking out the basement walls, floor and footings completely, then backfilling and compacting to the soils engineer’s specification. The backfill can run several feet deep, so it goes in by lifts and is tested like any other fill. House and building demolition

Bentonite waterproofing

Panels or sheets of bentonite clay that swell when wet to seal below-grade walls and slabs. It has to stay confined and damp to seal, so it works below grade but not on exposed walls.

Blindside waterproofing

Membrane fastened to the shoring or lagging before the foundation wall is poured against it, used where there is no room to work outside the wall. Because the wall is poured against it, the membrane can’t be inspected or repaired from outside afterward.

Block (CMU) basement walls

Basement walls built of concrete block, often grouted and reinforced. They break more easily than poured walls but may hide rebar and grout. Cells that weren’t grouted can collect water, which often shows as staining at the base of the wall.

Cellar

A small below-grade room, often under part of an older house or commercial building, used for storage, utilities or coal and oil. It is often found only during demolition. Old cellars sometimes hold oil tanks, coal chutes or abandoned utility lines.

Footing drain (subdrain)

A perforated pipe in gravel along the bottom of a below-grade wall that collects groundwater and carries it away. Sometimes called a French drain. The pipe is usually laid with its holes facing down, so water rises into it from below.

Full basement

A basement under the whole footprint of a building, with walls of poured concrete or block below grade. Demolishing it means removing the walls and floor, or breaking them and filling the hole, then compacting. Basements are less common in Southern California than in colder regions, where footings already have to go below the frost line.

Hydrostatic pressure

The pressure groundwater puts on below-grade walls and floors. It drives leaks in basements and pushes up on empty pools and tanks. Water pushes with about 62.4 pounds per square foot for each foot of depth.

Lightwell (window well)

An excavated opening outside a basement window, lined with a wall, that lets in light and air and provides an exit. A window well for bedroom escape must be at least 9 square feet, with at least 36 inches in each direction.

Negative-side waterproofing

Waterproofing applied to the inside face of a below-grade wall, where the outside can’t be reached. Used for basements and vaults that already leak. It holds water back at the inside face, so the wall itself stays wet.

Partial basement

A basement under only part of a building, with the rest on a slab or crawlspace. Pricing depends on the basement’s depth and wall area as much as on the house. Footings step down where the basement meets the slab or crawlspace, which adds removal work at the transition.

Podium structure

A building with one or more concrete levels, often parking or retail, carrying wood-framed floors above. Demolition separates the wood frame from the concrete podium. The common version is called a five-over-one: five wood floors over one concrete level.

Poured concrete basement walls

Cast-in-place reinforced concrete walls that hold back soil around a basement. They take heavy breaking equipment to remove. Walls are often 8 to 12 inches thick, with two layers of rebar in thicker walls.

Shotcrete wall

A concrete wall sprayed in place against shoring or forms, common for basement and retaining walls. Wet-mix shotcrete is mixed before pumping; dry-mix, often called gunite, adds the water at the nozzle.

Soldier pile and lagging

Excavation shoring of steel beams set in drilled holes, with wood or concrete lagging placed between them as the dig goes down. Common around basement and garage excavations. Piles are often spaced about 6 to 8 feet apart, with the lagging spanning between them.

Sub-basement

A level below the main basement, common in older commercial buildings and parking structures. They often hold mechanical rooms, old boilers and tanks that need a hazardous materials review before demolition.

Subterranean parking garage

One or more parking levels below grade, usually concrete with shoring walls around the excavation. Removing one is major structural demolition with dewatering, shoring and large concrete volumes. Garage slabs are often post-tensioned, so scanning and an engineered sequence come first.

Sump pit and pump

A pit in a basement or below-grade floor where water collects, with a pump that lifts it out to the storm drain. Most pumps have a check valve so water already pumped out can’t flow back into the pit.

Tiebacks

Steel anchors drilled at an angle into the soil behind a shoring wall and grouted, so the wall can stand without internal bracing. Tiebacks that reach under a neighbor’s property need the neighbor’s written permission.

Underpinning

Extending a building’s foundation deeper, often in sections, so it won’t settle when nearby soil is dug out for a basement or excavation. California law requires reasonable notice to neighbors before excavating near their foundations.

Walk-out (daylight) basement

A basement on a sloped lot with one side at ground level, often with doors or full windows on that side. The open side lets equipment drive in at grade, which makes removal easier than a fully buried basement.

Waterstop

A strip of PVC, rubber or swelling material cast into a concrete joint to stop water from passing through it. Swelling waterstops expand when wet to seal the joint.

Waterproofing

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Concrete surface profile (CSP)

A 1-to-10 scale of how rough prepared concrete is. Waterproofing membranes and coatings specify the profile they need to bond. CSP 1 is nearly smooth, like a troweled floor, and CSP 10 is heavily roughened, like scarified concrete.

Detail coat

An extra layer of waterproofing applied over cracks, inside and outside corners and pipe penetrations before the full membrane coat. Most membrane leaks start at corners, cracks and penetrations, which is why they get the extra coat.

Drainage composite

A dimpled plastic sheet with filter fabric placed against a below-grade wall over the waterproofing. It protects the membrane and lets water run down to the footing drain instead of pressing against the wall. The fabric faces the soil so fine particles are filtered out and the drainage channels stay open.

Fluid-applied membrane

Liquid waterproofing rolled or sprayed on that cures into a seamless rubbery sheet at a specified thickness, measured in mils. Thickness is checked with a wet-mil gauge while it is being applied.

Mil

One-thousandth of an inch. Waterproofing membranes and plastic sheeting are specified in mils. A 60-mil membrane is about as thick as two credit cards.

Positive-side waterproofing

Membrane applied to the face of a wall that touches soil and water, the usual method on below-grade walls when the outside can be dug out. It keeps water out of the concrete itself, which also protects the rebar from corrosion.

Protection board

Board or dimpled drainage mat placed over a waterproofing membrane before backfill, to protect it and let water drain down to the footing drain. Backfill rocks and compaction equipment can puncture an unprotected membrane.

Termination bar

A flat aluminum or plastic strip fastened along the top edge of a waterproofing membrane and sealed, so the edge can’t peel back or let water behind it. Fasteners are typically spaced 6 to 12 inches apart along the bar.

Water repellent

A penetrating sealer that soaks into concrete or masonry so the surface sheds water while still letting vapor out. It isn’t a substitute for a membrane on walls that hold back soil. Silane and siloxane sealers are common types; they soak in rather than forming a surface film.

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