Concrete formwork types and systems field guide

What formwork has to do, and the three demands on it

Concrete formwork is the temporary mold that holds fresh concrete to the shape you want, plus the framing and hardware that keep that mold in place while the concrete is still a liquid. Every form, from a job-built footing box to a hydraulic self-climbing core, is answering the same three demands. Hold the wet concrete to the exact shape and dimension. Resist the lateral pressure that the fluid concrete pushes back with. Leave the finish the job calls for, then strip off clean without tearing the concrete or wrecking the form.

The shape and the pressure are structural problems. The finish is a surface problem, and the strip is a practical one, because a form that will not release is a form you damage getting off and a wall you damage in the process. A good system does all three without a fight. A bad pick does one well and the other two badly, and you pay for it on every cycle.

Formwork is temporary, but its failure is not. A blown wall form or a buckled shoring tower drops tons of liquid concrete and collapsing material on a crew, and formwork collapse is one of the top killers in concrete work. So the form gets designed like the structure it is. This guide is about the form types and how to choose, the shape and the pressure and the finish. The support side, the shoring that carries a young slab to ground and the reshoring that protects the floors below, lives in the companion formwork, shoring, and reshoring guide, and the two go together on any elevated pour.

How much pressure does fresh concrete put on a form?

Fresh concrete behaves like a heavy liquid, so a vertical form has to resist the same kind of pressure a tank does, highest at the bottom and rising with the depth of wet concrete above it. Normal-weight concrete runs about 150 lb per cubic foot, and if the whole column stayed liquid, the pressure at the base would be full hydrostatic head, the unit weight times the height. Real walls survive because the lower concrete begins to stiffen and set before the top is placed, so the peak pressure tops out below full liquid head on most ordinary pours.

Two field variables decide where it tops out: the rate of placement and the concrete temperature. Pour fast and the whole column stays liquid at once, so the pressure climbs toward full head. Pour cold and the set is slow, the relief never arrives in time, and the pressure stays high. Fast and cold is the combination that blows forms. ACI 347 turns that relationship into design pressure equations for walls and columns driven by the placement rate and the temperature, with a hard floor and a full-liquid-head cap on the result. The equations and the coefficients live in the companion shoring guide. The point here is that pressure is the load every wall, column, and climbing form is sized for, and the form and its ties have to win against it.

This is why the form type and the pour plan are one decision, not two. A system rated for a 4 ft per hour rise is not safe at 8 ft per hour just because the panels look heavy. If anything about the mix or the pour is uncertain, a self-consolidating mix, a deep vibrated lift, a heavy retarder dose, you design closer to full liquid head and let the engineer set the number.

The form face: plywood, overlays, steel, and liners

The form face, the sheathing, is the surface the concrete sets against, and it decides the finish you get when the form comes off. Job-built and panel forms mostly use plywood, but plain plywood is the bottom of the range: it raises grain, soaks up water, marks the concrete, and gives you a handful of pours before the face is junk. The trade reaches for overlaid plywood instead. Medium-density overlay, MDO, has a resin-paper face that leaves a matte finish and runs maybe 5 to 15 reuses. High-density overlay, HDO, has a thick phenolic resin face, hard and near non-porous, that leaves a smooth steel-form finish with less grinding after, and gets 25 to 50 pours when it is handled well.

Where the face has to last, or the finish has to be glass-smooth, the face is not wood at all. Steel and aluminum panel faces give a hard, consistent surface and hundreds of cycles, which is why modular and gang systems run them. Plastic and fiberglass faces show up on column tubes and specialty forms. And where the architect wants texture, board-form lines, brick, stone, a fluted pattern, you line the face with a form liner, an elastomeric or plastic insert that casts the pattern into the concrete.

Match the face to the finish class before you order it. A structural wall buried in backfill does not need an HDO face. An exposed architectural wall does, and it needs the liner and the joint layout planned, because every seam in the face and every tie hole reads on the finished concrete.

Job-built lumber forms

A job-built form is exactly what it sounds like: built on site from plywood sheathing and dimensional lumber, the studs and walers cut and nailed to suit the pour in front of you. It is the oldest method and still the right one for work that does not repeat, footings, grade beams, pile caps, odd transitions, small walls, and the one-off shapes that no panel system fits.

The strength of job-built work is that it goes anywhere and forms anything. The weakness is labor. You measure efficiency in square feet of contact area per man-hour, and a stick-built form is slow to build and slow to strip compared with a system you set and clamp. So it pays where the geometry is custom and the quantity is low, and it loses badly where the same wall repeats fifty times.

The thing crews get wrong on job-built work is treating the lumber layout as carpentry instead of structure. The stud and waler spacing carries the concrete pressure the same as any engineered form. Eyeball the spacing, or open it up to save a stud, and the bottom of the form sees a pressure the framing was never sized for. Build to a layout, tighter near the bottom where the pressure is highest, and brace it for the lateral loads, not just the straight-down weight.

Modular and panel form systems

Modular formwork is a kit of standardized panels and hardware that connect fast and come apart fast, the everyday answer for repetitive walls. The panels have a steel or aluminum frame and a faced deck, they come in a grid of standard sizes plus fillers, and they lock together with wedge clamps or pins that one worker drives with a hammer. Set the panels, clamp the joints, run the ties, brace it, pour, strip, and move it to the next wall.

Two families cover most of it. Handset panels are sized so a worker can carry and set them without a crane, which suits foundations, walls in tight spots, and any job where the crane is busy or absent. Crane-set panels are larger and faster per square foot but need a pick for every move. The clamp and tie hardware is what makes the system, because a consistent connection at every joint is what lets the form go up fast and come down clean.

Panel systems are the volume worker for cast-in-place walls because the speed is in the repetition. The first wall is no quicker than stick-built. The tenth is, and the fiftieth pays for the rental. The trap is mixing parts or skipping a clamp to save a minute. A panel joint that is not fully clamped is a leak at best and a bulge or a blowout at worst, right where two panels meet.

What is a gang form?

A gang form is a large form built up from many panels joined into one rigid unit, sized so the whole assembly is set, stripped, and flown to the next pour by crane as a single piece. Instead of handling dozens of small panels every cycle, you assemble the gang once, add a strongback frame and a work platform, and then move the entire face in one pick. It is the modular idea scaled up for big, repeating walls.

Gang forms pay off where the wall is large and the cycle repeats: tall foundation walls, shear walls, tank and reservoir walls, retaining walls, the cores of parking structures. Fewer cycles means fewer crane picks, fewer joints to clamp each time, and a faster floor-to-floor or bay-to-bay pace. The cost is up front. You spend the assembly time and the engineering once, and you need the crane and the room to fly and land a panel that can be tens of feet on a side.

Gang forms almost always run taper ties rather than lost ties, because a reusable through-tie that pulls completely out of the wall after the pour lets you strip and fly the gang without leaving hardware behind. The whole economy depends on the gang coming off clean every time, so the face, the release agent, and the tie system are chosen to make stripping fast and damage-free.

What are form ties?

Form ties are the tension members that hold the two faces of a wall form together against the outward pressure of the fresh concrete, and they also set and hold the wall thickness. Without ties, the pressure would spread the form and the wall would bulge or burst. The load path on a wall form is face to stud to waler to tie, and the tie is the part carrying the lateral load in tension. Pick the tie for the load, then space the ties so no single tie ever sees more than its rated safe working load at its height on the form.

Four types cover most wall work. Snap ties are the light-duty lost tie, a flat or rod tie with a built-in break-back; you snap the ends off about an inch into the wall after stripping and patch the hole, and they commonly run around 24 in on center. She-bolts are heavy-duty reusable end units joined by an expendable inner rod that stays in the wall, used on heavier forms and often around 32 in on center. Coil ties use welded helical coils at each end and suit medium to heavy forms, with the coils left in the concrete. Taper ties are fully reusable through-ties that pull completely out after the pour, the standard for gang forms.

Spacing follows the pressure, and the pressure is not uniform. It is highest at the bottom of the pour and falls off toward the top, so the ties go tightest near the base and can open up higher. The mistake that starts blowouts is spacing the whole form to the average pressure. The bottom row then carries more than its rating, the most-loaded tie lets go, and the failure unzips along the wall. Space to the pressure at each height, tight at the bottom.

Flying and table forms for repetitive floors

A flying form, or table form, is a large slab form built as a single deck-and-truss table that gets flown by crane from one floor to the next instead of being torn down and rebuilt each time. The crew strips the table from the slab it just formed, the crane lifts it out through the building edge, and it lands and resets on the floor above. On a high-rise with the same floor plate repeating up the tower, that is the fastest way to form an elevated slab.

The economy is in the cycle. A table that takes hours to assemble the first time gets reused on every typical floor, so the per-floor labor drops to stripping, flying, and resetting. The structure has to suit it: a regular column grid, a floor plate that repeats, and a building edge the table can fly out through. Irregular floors, transfer levels, and one-off plates break the repetition and the table loses to other methods.

Flying forms carry both the gravity load of the wet slab and the safety problem of a large object moving on a crane near an open edge. The pick, the rigging, the edge protection, and the landing are engineered, and the table is shored at its destination before anyone loads it. This is a slab form sitting on shoring, so the shoring, the bearing, and the reshoring below it follow the support rules in the companion shoring guide.

Slip forming for tall continuous structures

Slip forming is a continuous-pour method where a relatively short form is filled and then raised slowly and steadily while the concrete is still being placed, so the structure rises in one monolithic pour with no horizontal construction joints. The form, the working deck, and the finishers ride up together on jacks climbing embedded rods or the wall itself. It is the method for tall, uniform vertical structures: silos, grain elevators, chimneys, communication towers, bridge pylons, and building cores.

The rate is the whole discipline. The form moves at a speed that leaves concrete behind it just set enough to stand on its own as it clears the bottom of the form, often around a foot or so of rise per hour depending on the mix and the temperature. Too fast and the concrete slumps as it exits the form because it has not set. Too slow and it grips the form and tears, or sets against it. The pour runs continuously, day and night, because stopping a slip form mid-height creates a cold joint and a recovery problem you do not want.

Slip forming buys speed and a joint-free structure, and it pays for that with planning. The mix is tuned for an early set that matches the climb rate, the placement and reinforcing crews work around the clock, and any embed, opening, or change in wall thickness has to be built into the rig and the sequence ahead of time, because you cannot stop to figure it out.

Jump and self-climbing forms for cores and piers

Jump form, or climbing form, is the other way to build a tall vertical structure: instead of moving continuously like a slip form, the form is locked in place, the lift is poured and allowed to gain strength, and then the whole form is raised, jumped, to the next level for the next lift. It builds in discrete pours with a construction joint at each lift, where slip forming builds in one continuous pour. Jump forms are the common choice for lift and stair cores, shear-wall cores, bridge pylons, and heavy piers.

There are two grades of it. A crane-climbed jump form is repositioned by the tower crane each lift, which is simple but ties up the crane. A self-climbing, or auto-climbing, system carries its own hydraulic jacks and rails and anchors to the wall it just poured, so it lifts itself to the next level without a crane pick. Self-climbing systems shine on tall cores where the crane is the bottleneck and where the working platforms, the form, and the access all need to move up as one engineered unit.

Climbing systems hang their load off anchors set in the concrete below, so the strength of that concrete before you climb is a hold point, not a guess. You climb when the anchorage concrete has made the strength the system requires, confirmed by test, the same strength-not-calendar discipline that governs stripping. Pull the climb early and you are loading green concrete with the entire rig.

Insulating concrete forms and stay-in-place systems

Insulating concrete forms, ICF, are a stay-in-place system: hollow blocks or panels of rigid foam are dry-stacked like interlocking blocks, reinforced, and filled with concrete, and the foam stays as permanent insulation on both faces of the finished wall. The form never comes off because it was never meant to. Two faces of foam, held a fixed distance apart by plastic or metal webs, become the wall's continuous insulation, its air and sound barrier, and the substrate for finishes inside and out.

ICF is one member of a larger stay-in-place, or permanent, form family. Composite metal deck on an elevated slab is left in place and acts as part of the structure. Precast plank and precast form panels stay as the soffit. These permanent forms trade reusability for what they leave behind: insulation, a finished soffit, or a structural contribution that earns the form its keep instead of stripping it off as scrap.

ICF has its own design report, and the pour discipline is specific. The foam is light, so the form wants to float, bulge, or blow out if you pour too fast or in too deep a lift. You place in lifts, consolidate carefully, and brace and align the wall before and during the pour, because once it sets crooked inside the foam, there is no stripping it to fix the face. Treat the lift height and the rate as the limit the system is, not an afterthought.

Column forms: round tubes and square boxes

Column forms come in two shapes and a few materials, and the choice is mostly the finish and the reuse. Round columns are usually formed with a fiber tube, a single-piece spiral-wound cardboard form with a select diameter that you cut to length on site, set plumb, brace, pour, and then peel off and throw away. They are quick and cheap for a handful of columns and leave a smooth round face, sometimes with a faint spiral seam to grind. Where the columns repeat or the finish has to be perfect, a steel or fiberglass round form gets reused many times and leaves a cleaner face.

Square and rectangular columns are formed with panel sets or job-built boxes, often the same modular panels used for walls, assembled into a four-sided box with the corners detailed and clamped. The corners are where columns leak and where the line on the finished concrete shows, so the corner hardware and the tightness there matter more than the flat faces.

Columns are poured fast in a small footprint, so they develop high lateral pressure low on the form, and the column equation in ACI 347 runs straight off the placement rate. That is also why columns are usually the first forms you can strip. The form is mostly resisting that lateral pressure, and once the concrete sets the pressure is gone, so column and pier forms commonly come off ahead of the beam and slab forms, as long as the concrete can take handling and edge damage.

Slab and deck forms, and the shoring under them

An elevated slab form is a horizontal deck held up in the air, and the form is only half of it. The concrete sits on the deck sheathing, the sheathing spans to joists, the joists land on stringers, and the stringers are carried by shores down to a level that can take the weight. The form gives the slab its shape and bottom finish. The shoring carries the gravity load. On a slab on metal deck, the steel deck is both the form and a permanent part of the structure, and it is shored or not depending on the span and the design.

This is the line between the two systems, and it is worth saying plainly. The formwork holds the shape. The shoring holds the weight, until the concrete cures enough to hold its own. That distinction, falsework and shoring, is where a deck pour is won or lost, because a deck form can be perfect and still come down if the shores are undersized, out of plumb, or standing on bad bearing.

Because the shoring side carries the load and the life-safety risk on elevated work, the depth on it, the shore types, the bearing and mudsills, the bracing, and the reshoring that protects the floors below, lives in the companion formwork, shoring, and reshoring guide. Pour a deck without reading it and you are forming the easy half and guessing at the half that holds people up.

Release agents and form oil

A release agent, form oil, is what lets the form strip clean instead of bonding to the concrete and tearing the face. Fresh concrete will grip bare wood, steel, and many faces hard enough that pulling the form lifts the surface off the wall or splits the form. A thin, even film of the right release agent breaks that bond so the form comes off in one piece and leaves the concrete face intact, and it protects the form so it survives more cycles.

The right product depends on the face and the finish. Plain barrier oils suit structural concrete that nobody will see. Chemically reactive release agents are made for architectural faces and for steel forms, because they leave less residue and give a cleaner, more uniform color. The face material matters too: what works on plywood is not always right on steel or on a foam ICF block, and a liner has its own requirement.

Application is where it goes wrong. Over-apply and the excess pools, runs, and stains the concrete a blotchy color, and it can dust or weaken the surface and kill the bond of any coating or topping you put on later. Under-apply and the form sticks and tears the face on strip. A thin, complete film is the target, wiped or sprayed and back-rolled so there are no puddles and no dry spots. On an architectural wall, a release problem is a finish problem you cannot grind out, so test the agent on the actual face before the pour that counts.

Form finish classes: structural vs architectural

The finish you get off the form runs on a scale, and the spec usually names a class. At the structural end, the concrete is buried, backfilled, or hidden, so the only requirements are dimension and soundness; tie holes, form marks, and minor offsets do not matter and a basic face and plain oil are fine. At the architectural end, the concrete is the finished surface, so the face material, the form liner, the joint and tie-hole pattern, the release agent, and the consolidation all have to deliver a wall someone will stand and look at.

The jump in cost and care between the two is large, and it is decided by the form, not the concrete. The same mix poured against plain plywood and against an HDO or steel face gives two different walls. The architectural finish needs the smooth face, the deliberate layout of every seam and tie, a release agent chosen for color uniformity, and vibration discipline so the surface comes out without bug holes, honeycomb, or sand streaks.

Those surface defects, bug holes, honeycomb, sand streaking, form-line offsets, color variation, are a finish topic of their own, driven by the mix, the placement, the vibration, and the form together. The form sets the ceiling on the finish. You cannot vibrate a great wall out of a bad face, and you cannot save a great face with a careless pour.

When can you strip the forms?

You strip a form only after the concrete can take whatever comes next, and that depends on which job the form was doing. Vertical forms, walls, columns, and piers, mostly resist the lateral pressure of the fresh concrete, and that pressure is gone once the concrete sets. So those forms can come off relatively early, often the next day, as long as the concrete is hard enough to handle without damaging edges and corners. Horizontal forms and the shoring under beams and elevated slabs are different, because they are holding up gravity load that does not go away when the concrete sets.

For those supporting forms and shores, strength runs the clock, not the calendar. ACI 347 recommends removing support from beams and slabs only after the concrete reaches about 70 percent of its specified strength, unless the engineer directs otherwise, and the licensed design professional sets the required strength for the project. Time is a poor proxy because strength gain depends on the mix and the temperature, and a cold week leaves concrete far weaker at three days than the schedule assumed.

Prove the strength, do not guess it. Field-cured cylinders broken to confirm in-place strength, or the maturity method calibrated to the mix, are how you clear the strip. This is also where the mix design ties back in: the same water-cement ratio and specified strength the supplier proportioned are what you are now testing against. Strip a slab early and you can crack it, deflect it permanently, or drop it. The reshoring that protects the floors below as you strip is a separate engineered step covered in the companion shoring guide.

Why does formwork fail?

Formwork fails for a short list of reasons, and the failures are catastrophic because the form is carrying a liquid load until the moment it lets go. A wall form blows out when the ties are under-spaced or the pour rate ran past what they were sized for, and the bottom row, where pressure is highest, lets go first and unzips the wall. A shoring tower buckles when it is out of plumb, under-braced, or standing on bearing that punches in. And a slab comes down when it is stripped before the concrete made strength. Almost every one traces to the form being loaded harder than it was designed for, or stripped before the concrete could carry itself.

The pour rate is the field cause that hides in plain sight. The ties and the form were sized for a planned rate of placement. The pump gets ahead of the crew, the concrete comes in faster and colder than planned, the pressure climbs past the tie spacing, and the form does exactly what an overloaded form does. The hardware met its rating. The pour broke the assumption the spacing was based on. Watch the rate, not just the ties.

Tall, heavy, and unusual forms get engineered, period. ACI 347 is the design guide and OSHA Subpart Q is the enforceable floor: the formwork is designed and braced to carry the loads without failure, the drawings are on site, a competent person inspects the form before the pour, and the shoring is watched before, during, and after placement. A blowout gives a few seconds of warning, a bulge, a creak, a tie singing, and a crew that is watching with a stop plan can clear the line. A crew with their backs to it cannot.

Reuse and economy: the cycle drives the cost

The cost of a form is not the form. It is the cost per use, and that is set by how many times you turn it over and how fast each cycle goes. A job-built form is cheap to build and expensive to run, because every cycle is labor. A panel, gang, or table system is expensive up front and cheap to run, because the cost spreads across many cycles of set, pour, strip, and move. The break-even is repetition.

So the choice is mostly an estimating question before it is a means-and-methods question. Few pours of an odd shape: job-built wins. Many pours of the same wall: panels and gangs win, and they win bigger the more times the same form goes up. A tall repeating tower core: a climbing or slip system wins because it forms the same section over and over without rebuilding. Count the cycles honestly, because the wrong call shows up as either rented systems sitting idle or a crew stick-building the same wall fifty times.

The face is part of this math too. Pay for an HDO or steel face on a high-cycle form and the face survives the run. Put a cheap face on a gang form and you are replacing the face mid-job, which kills the cycle economy that justified the gang in the first place.

Heavy mats and walls: data center and industrial forming

Big-pour work, data centers, industrial plants, heavy civil, pushes formwork harder than ordinary commercial work, and it does it in two ways. The thick mat foundation is the first. A mat several feet deep is an enormous pour, and at the edges and around any blockout the deep column of fresh concrete develops high lateral pressure against the edge forms. These are also mass pours where the heat of hydration matters, so placement is slow and staged, which interacts with both the form pressure and the cold-joint window at once. The edge form, the mix, and the thermal plan are designed together.

The walls and elevated decks are the second. Data center structures run thick slabs and tall, heavy walls, so the forms carry more, the shoring is denser and taller, and gang and climbing systems earn their place because the same large element repeats. The reshoring carries more load through more levels than a typical office frame, and the construction loads from stacked trades and heavy staged equipment on young floors are real and have to be in the plan.

Scale removes the margin you get away with on small work. A tie spacing or a face choice that is forgiving on a thin commercial wall is unforgiving under a deep mat or a heavy industrial wall. On these pours the form design, the pour rate, and the reshoring plan are engineered tightly and followed exactly, because the loads are too large to absorb a mistake.

What to document

The formwork record proves the system you poured against was the system that was chosen and sized for the job, and it is what a reviewer reads if anything moves or the finish comes out wrong. Capture it before the pour, tied to the drawing and the rated hardware, not from memory afterward.

For each element, record the form system and where it is used, the face material and the finish class it has to deliver, the tie type and rated safe working load with the spacing actually built, the planned rate of placement the form was sized for, the release agent and that it was applied right for the face, and the in-place strength required to strip with how it will be proven. The table below is the short version of the same idea, organized by system.

Common mistakes

• Pouring faster than the rate the form was designed for and driving the pressure past the tie spacing into a blowout.
• Under-spacing or over-spacing the ties, especially the bottom row where pressure is highest.
• Building tall or heavy forms by feel instead of to an engineered design with the drawings on site.
• Picking the wrong face for the finish, then trying to grind a structural face into an architectural wall.
• Over-applying release agent so it pools and stains the concrete, or under-applying so the form tears the face on strip.
• Stripping forms or shores before the concrete has proven the strength to carry itself.
• Skipping the bracing, or pulling a brace to move equipment through, and leaving the form short of lateral capacity.
• Choosing a form system on habit instead of the cycle count, so a low-repetition job carries a high-cost system or the reverse.

Field checklist

Standards and references

ACI 347, the guide to formwork for concrete, is the design document the trade works to. It defines formwork as the whole system, sets the design loads, gives the lateral pressure equations for walls and columns driven by the rate of placement and concrete temperature, and recommends the in-place strength for stripping, commonly about 70 percent of specified strength for horizontal members unless the engineer directs otherwise. ACI 347.2R is the companion guide for shoring and reshoring of multistory buildings. ACI also publishes a design and construction report for insulating concrete forms.

ACI 318, the building code requirements for structural concrete, sets the specified strength the structure is designed to, and the strip strength is tied to a percentage of that strength as the licensed design professional specifies. ACI 301 is the reference specification that project specs commonly invoke for formwork tolerances and finish classes. The exact recommended percentages and tolerances shift between editions, so confirm them against the current standard editions and the project specification before you rely on a number.

OSHA 29 CFR 1926 Subpart Q, concrete and masonry construction, is the enforceable safety standard, with the cast-in-place requirements governing formwork design, the drawings on site, the shoring inspections, and the strength needed before stripping. The form supplier and the formwork engineer publish the safe working loads and the system design that govern the hardware. For tall, heavy, or unusual forms, the engineered formwork design is the one that controls, and the project specification overrides any rule of thumb when it is stricter.

Units, terms, and conversions

Formwork mixes a few unit systems across the design drawings, the supplier data, and the field, so the same quantity reads differently from one sheet to the next.

Form pressure is in pounds per square foot, psf, in US practice and kilopascals, kPa, in metric, where about 1 kPa is roughly 21 psf. The unit weight of normal concrete is about 150 lb per cubic foot, near 24 kN per cubic meter. Rate of placement is the vertical rise of concrete, in ft per hour or m per hour. Tie and shore capacity is given as a safe working load, the rated load with the safety factor already taken out of the breaking strength. Strip strength is a percentage of the specified compressive strength, f'c, proven by cylinder breaks or the maturity method.

Formwork (shuttering)

The temporary mold and framing that shapes fresh concrete and holds it until it sets; shuttering is the same thing in British usage

Form face / sheathing

The surface the concrete sets against, which decides the finish: plywood, overlaid plywood (MDO/HDO), steel, plastic, or a lined face

Form tie

The tension member holding the two faces of a wall form against the lateral concrete pressure and setting the wall thickness

Gang form

Many panels joined into one rigid unit that is set, stripped, and flown by crane as a single piece for large repeating walls

Flying / table form

A large slab-form table flown by crane floor to floor on repetitive elevated decks

Slip form

A short form raised continuously during a non-stop pour to build tall monolithic structures with no horizontal joints

Jump / climbing form

A wall form locked, poured, and then raised to the next lift; self-climbing versions carry their own hydraulic jacks

ICF

Insulating concrete form, a stay-in-place foam form that becomes the wall's permanent insulation and finish substrate

Release agent (form oil)

The film applied to the form face so it strips clean without bonding to or staining the concrete

Safe working load (SWL)

The rated load for a tie or shore, the breaking strength reduced by a built-in safety factor

Related tools

Calculators and readiness checks for this work

Compare your options

FAQ

People also ask

• What is concrete formwork?
• What is a concrete mix design?
• What is a concrete admixture?
• Why does concrete crack?
• What is a footing?