Forming Foundation Walls

Formed concrete walls are built as foundation or retaining members in construction. Concrete wall forms are typically made of plywood, aluminum, or steel. Many consider aluminum and steel wall forming systems to be more productive, efficient, and even economical than wood forming.

Plywood forms are typically used where unique wall shapes, sizes, and embedment characteristics are present. Wood wall forms may also be used when renting prefabricated steel or aluminum forms is not feasible or desired. Wood forms are typically only used once but if cared for and used correctly may be used several times before requiring disposal. Below is a general list of the most common formed concrete wall assembly elements which are typical of wood wall form systems:

Panel – Plywood attached to the face of forming structure and provides the surface to which the concrete lays against

Stud – Vertical member that is attached to the panels and provides support and resistance to panel bending and the fluid pressure of the concrete

Waler – Horizontal member attached to the back of and reinforcing the studs from bending and axial movement

Strongback – Vertical member attached to the back of and reinforcing the walers

Wall Tie – Metal members spanning through the inside of the wall which attach to and hold the forms in place resisting the fluid pressure of the concrete

Flat Ties

Snap Ties

Bracing – Lumber forms (also refers to as kickers) which brace and support the fully assembled wall from the fluid pressure of the concrete

Spreader – Wood members cut to appropriate size placed periodically inside the wall to space the two walls apart consistently

Aluminum wall forms are commonly used in the residential foundation market to form basement, crawl space, and garage concrete foundation walls. Though less common, aluminum forms may also be used in commercial construction. Aluminum forms are typically lighter than steel and in many cases can be transported, unloaded, and placed more efficiently than steel. As seen below they are often transported in bundles.

Despite their decreased weight and increased efficiency over most steel forms, aluminum forms are not always as durable as steel, especially when used in heavier construction. Below is a general list of the most common formed concrete aluminum wall panel features and associated hardware:

–Hat – Horizontal bracing member built in to the panel, (somewhat similar to walers on a gang formed steel or wood formed wall system) often spaced anywhere between 5.5″ to 10″ apart vertically

–Backbone – Vertical Bracing member built into the panel (somewhat similar to a stud) often placed in the center of the upright panel.

–Face sheet – Aluminum sheet attached to the face of the structure providing a forming surface for the concrete within the wall

–Siderails – Perimeter reinforcement with similar bracing/strengthening features to the backbone (or stud)

Top and Bottom Rails – Perimeter reinforcement with similar bracing/strengthening characteristics to the Hats (or walers)

Handles – Handles fastened to the backbone (or studs) which allow for efficient picking up and moving forms

Pins/Wedge Bolts – Tie panels together at the side rails by firmly fastening and locking the panels together

Corner Gussets – Reinforcing members built into the panel at corners

Flat Wall Ties – Tie the assembled inner and out wall panels to eachother at specified intervals both horizontally and vertically

Inside Corner – 90 degree angled metal placed vertically which ties two perpendicular walls together at corners

Outside Corner – 90 degree angled metal placed vertically which ties two perpendicular walls together at corners

Bulkhead – Flat piece of aluminum or wood form meant for ends or terminations of wall

Window Opening Bulkhead – Flat piece of aluminum form meant to formout window openings

Door Opening Bulkhead – Flat piece of aluminum form meant to formout door openings

Wood Cavity Molds – Site built project specific wood forms installed with proper hardware within wall to formout window and door openings

Adjustable Waler Bracket – Brackets which attach to the forms and provide support for waler boards to provide additional wall alignment

Adjustable Wall Braces – Prefabricated braces meant to attach to the upper part of the back form and at a 45 degree angle down to the ground providing additional wall support

Fixed Braces – Adjustable prefabricated members which provide bracing between 2 parallel walls

Plywood Infill Panel Adapters – An aluminum angle that attaches to the perimeter of an opening in a formed wall so plywood may be utilized (mainly used for when a utility needs to pierce the wall

Scaffold Brackets – If wall will be higher than approx 6′, scaffold brackets are often required which attach to the forms and receive scaffold plank lumber for standing on and working up higher on the wall. Scaffold brackets also provide additional wall alignment higher up on the wall.

Steel concrete wall forms are commonly used in commercial building applications as well as heavy construction, i.e. roads, bridges, deep foundations, and retaining walls. Steel forms typically receive a reusable wood, composite, or plastic sheet ply on the face of the forms frame which requires periodic replacement upon excessive use and delamination. An industry standard product used for the facing sheet is High Density Overlay Plywood.

Steel forms are typically pre-engineered, factory made, reusable, and can be handset or gang formed. Most steel forms come in predominantly 2’ wide pieces with lengths ranging from 3’ to 10’ in 1’ increments. There are typically filler pieces which range from 2” to 22” in 2” increments. 1”, 1-1/2”, and 2” fillers are also commonly available. Wedge bolts connect the panels, fillers, and ties together. Below is a general list of the most common formed concrete steel framed wall panel features and associated hardware:

Panel – Prefabricated steel-structured panels with a plywood or composite face plies. Used as the primary forming structure for steel wall forms.

Wedge Bolts – Flat, triangular or wedge shaped bolts which – 2 combined function as a lock bolt set, one as a connecting bolt, other as a clamping wedge. For most standard walls, wedge bolts are only required at tie/panel connections. They may also be required at waler brackets, scaffold brackets, and other accessory locations

Long Bolts – A wedge bolt made longer for connections at filler pieces. Long bolt is typically punched with 2 holes to shorten the bolt and accommodate the different size fillers.

Adjustable Long Bolt – An even longer wedge bolt meant for use in areas where two steel fillers are used side by side.

Wire Tie – A wire tie secures the inner and outer wall panels to eachother between the side rails and is secured with a wedge bolt. The tie resembles a wire and often has a loop on either end to receive the wedge bolt. They are made so the loop ends may be broken off after the wall is in place and can be purchased in almost any length, depending on the thickness of the wall.

Flat Ties – A flat tie secures the inner and outer wall panels to eachother between the side rails and is secured with a wedge bolt. Flat ties are common in residential applications where an in wall recessed ‘breakback’ is not required after the panels are stripped.

Inside Corner – 90 degree angled metal placed vertically which ties two perpendicular walls together at corners

Outside Corner – 90 degree angled metal placed vertically which ties two perpendicular walls together at corners

Hinged Corners – These corners have hinges allowing them to bend and create unique wall angles

Waler Bracket – A waler bracket is a steel piece meant to attach to panel side rails which receives double 2×4 or 2×6 waler lumber which will ultimately straighten and reinforce the assembled wall. A waler is an alignment tool only and is not meant to reinforce the wall or resist lateral pressure from the wet concrete.

Strongback – A strongback is a vertical alignment and reinforcement member placed at 90 degree angles to the walers (perpendicular to the studs) to help align the waler system. A strongback is an alignment tool only and is not meant to reinforce the wall or resist lateral pressure from the wet concrete. 2×4 or similar lumber is often utilized with a clamp or bracket.

Brace Kicker – Prefabricated adjustable steel brace kickers are attached the forms where the panel siderails meet and also attach to the grade or pavement below.

Scaffold Bracket – Used when one or more levels of work platform are required for convenience and safety.

Filler Angle – Metal angle used primarily when a wall penetration is required and it is undesirable to cut into the ply facing material. Filler angle allows for use and attachment of job built plywood sections.

Steel Fillers – Typically cold formed U shaped steel filler pieces which are punched with connecting slots and allow for custom, more specialized wall dimensions.

Brick Ledge Bracket – Steel piece meant for attaching brickledge forms to the forms/strongbacks.

Keyway Forms – A keyway form is meant to be used primarily at wall pour section ends which casts a recessed slot. When the wall pour continues, the keyway allows for the new section of wall to pour into the recessed slot, creating a construction joint efficient in strengthening the wall from differential lateral movement of poured wall sections. A keyway form is a prefabricated bulkhead piece, fastened to the panels siderails with wedge bolts and horizontally placed bulkhead bars.

Beam Pocket Form – Prefabricated steel boxout form which comes in several different sizes to accommodate future steel or wood beam bearing locations recessed into the top of the concrete wall.