When Can You Remove Concrete Forms? (Cold-Weather Times)
Wall and column side forms often come off after 12 to 24 hours; forms that carry load wait for tested strength. Cold weather can add days. Rules by spec.
Short answer: Side forms on walls, columns and beam sides commonly come off after 12 to 24 hours, once the concrete holds its shape. Forms and shores that carry load stay until tested strength allows removal. OSHA 29 CFR 1926.703(e)(1) bars removal until the employer confirms the concrete can carry the load. Cold weather can add days.
Most DIY guides give a single number of days and ignore temperature. On a real job, the answer comes from three places, in this order: your project specifications, the strength of the concrete in place, and published guide times when the engineer hasn't set anything.
What does OSHA require before stripping forms?
OSHA doesn't set a time. It sets a test. 29 CFR 1926.703(e)(1) says forms and shores "shall not be removed until the employer determines that the concrete has gained sufficient strength to support its weight and superimposed loads." That determination must be based on either:
- conditions for removal stated in the plans and specifications, which have been followed, or
- an appropriate ASTM test showing the concrete's compressive strength is sufficient.
Reshores follow the same logic under 1926.703(e)(2). They stay until the concrete they support can carry its own weight and the loads on it.
What are the typical form removal times?
When the engineer hasn't specified stripping times, Los Angeles County's Building Code Manual gives these guide times, "extracted from ACI Manual of Concrete Practice":
| Form | Guide time | Notes |
|---|---|---|
| Vertical forms: sides of walls, columns, beams and girders | 12 hours | Carry no load once concrete is self-supporting |
| Beam soffits or shores, clear span over 20 ft | 21 days | Or when tested strength allows |
| Beam soffits or shores, clear span under 20 ft | 14 days | Or when tested strength allows |
| One-way slab soffits or shores, clear span over 20 ft | 10 days | Or when tested strength allows |
| One-way slab soffits or shores, clear span under 20 ft | 7 days | Or when tested strength allows |
| Post-tensioned slabs | When full post-tensioning has been applied |
The same manual warns that cold weather, slower cements and higher water-cement ratios lengthen these times. It says the design engineer or architect should specify the minimum strength for removal, usually backed by cylinder results. ACI 306R-16 section 8.9 points to ACI 347R and ACI 347.2R for the details of form and shore removal and reshoring.
What do state DOT specs require?
DOT specs set firm rules, and most of them tie stripping to strength.
| Spec | Non-load-bearing forms | Load-bearing forms and falsework | Section |
|---|---|---|---|
| WisDOT 2025 | 12 hours after casting, if the concrete is self-supporting | 2,000 psi for spans of 12 ft or less; 2,500 psi over 12 ft. Bridge slabs: at least 7 days, not counting days the surface was below 40°F | 502.3.4.1, 502.3.4.2 |
| MnDOT 2025 | Curb, sidewalk and barrier forms once the concrete holds its shape; other forms at least 24 hours | Bridge superstructures: 2,000 psi to pull forms. Retaining-wall form cure rises from 12 to 24 hours under cold weather protection | 2401.3G, Table 2401.3-2 |
| NYSDOT 2026 | 2,400 psi and two full curing days | Arches and pier caps: 3,600 psi and seven full curing days | 555-3.09 |
| ODOT 2023 CMS | When hardened sufficiently; damage before 85% of f'c is the contractor's responsibility | Falsework (QC/QA items): 85% of f'c by field-cured cylinders or maturity | 511.14 B, C |
MnDOT also requires the engineer to verify the minimum strength when air temperatures drop below 40°F during the curing period. NYSDOT only counts a "curing day" when the air at the concrete surface stays at 45°F or higher for the whole day.
How much longer do forms stay on in cold weather?
Longer, and the extra time depends on how cold the concrete actually is. NRMCA's CIP 27 says a 20°F drop in concrete temperature roughly doubles setting time. It puts typical stripping at "1 to 7 days depending on rate of strength gain, ambient conditions, and anticipated loading."
ACI 306R-16 Table 8.8 shows the gap in days for concrete held at 50°F versus 70°F:
| Share of 28-day strength | Type I cement at 50°F | Type I at 70°F | Type III at 50°F | Type III at 70°F |
|---|---|---|---|---|
| 50% | 6 days | 4 days | 3 days | 3 days |
| 65% | 11 days | 8 days | 5 days | 4 days |
| 85% | 21 days | 16 days | 16 days | 12 days |
| 95% | 29 days | 23 days | 26 days | 20 days |
ACI notes those figures come from 3,000 to 5,000 psi concretes without fly ash, and are approximate. Mixes with slag or fly ash gain strength more slowly in the cold.
WisDOT turns the same idea into a counting rule for structures. With no strength data, a calendar day only earns a full "equivalent curing day" if the daily average concrete surface temperature is 60°F or more. A day averaging 40°F to below 60°F earns 0.6 of a day, and a day below 40°F earns nothing (502.3.10.1.1). A form that would come off on Friday in September may need most of the next week in November.
How should you check strength before stripping in winter?
Test the concrete in place. ACI 306R-16 section 8.1 says to base removal of forms and shores on "in-place concrete strength rather than on specified time duration." Section 8.2 goes further and calls field-cured cylinders "inappropriate" in cold weather, because they rarely match the temperature of the structure. It recommends in-place testing, maturity testing, or both.
Sources disagree here. WisDOT, ODOT and NRMCA still accept field-cured cylinders for stripping decisions. WisDOT requires that they be cured in conditions no better than the most unfavorable concrete they represent. Follow the method your spec names. Where you have the choice, maturity is the stronger method.
The maturity method (ASTM C1074) uses sensors cast into the concrete to track its temperature history. You need a strength-maturity curve for that exact mix. ACI 306R-16 says to validate it before stripping and build a new curve if test results differ from the curve by more than 10 percent.
Form removal checklist for cold weather
- Find the stripping criteria in your contract documents. ACI 306.1 tells specifiers to state "the concrete strength required for each structural member before form removal."
- Track the concrete temperature, not just the calendar. Log surface temperatures at corners and edges.
- Confirm strength by maturity, in-place testing, or the cylinders your spec allows.
- Check the stripping won't shock the concrete. ACI 306R-16 section 7.6 covers allowable temperature differences when stripping, and NRMCA warns that removing forms shouldn't cause thermal shock.
- Strip side forms first if allowed. Leave soffits, shores and reshores until the strength criterion is met.
- Cover and keep curing immediately. MnDOT requires curing to resume on each formed face within 30 minutes of stripping during the curing period. NYSDOT requires curing compound immediately after form removal.
- Record what you did: date, time, temperature and strength result.
Asking on site
A carpenter foreman can ask Verika "can we strip the wall forms, poured Monday, it's been in the 30s?" Verika answers from the spec loaded for that state and ACI guidance, plus your company's own stripping procedure if you've uploaded it, and cites each source. Cold-weather rules for Wisconsin are on our Wisconsin cold-weather answer, and Minnesota's are on the MnDOT cold-weather answer. Curing after stripping is covered on the WisDOT curing answer. For keeping the concrete warm while you wait, see how long to keep blankets on new concrete.
Your project specification and engineer of record have the final say on stripping times.
Sources
- 29 CFR 1926.703(e), Removal of formwork — OSHA
- Building Code Manual 1906 Article 1, Design and Removal of Forms (2011) — Los Angeles County Department of Public Works
- ACI 306R-16, Guide to Cold Weather Concreting (excerpt: sections 8.1–8.9; Table 8.8) — American Concrete Institute, 2016
- ACI 306.1-90 (Reapproved 2002), Standard Specification for Cold Weather Concreting, preview and checklists — American Concrete Institute
- CIP 27, Cold Weather Concreting — NRMCA
- WisDOT Standard Specifications 2025, Section 502 (502.3.4, 502.3.10) — Wisconsin DOT
- MnDOT Standard Specifications for Construction, 2025 Edition (2401.3G, Table 2401.3-2) — Minnesota DOT
- NYSDOT Standard Specifications (USC), January 1, 2026, Vol. 2 (555-3.08, 555-3.09) — New York State DOT
- ODOT Construction and Material Specifications, 2023 (online version 07/17/2026), 511.14 — Ohio DOT
Frequently asked questions
›How long should forms stay on a concrete wall?
Side forms that carry no load commonly come off after 12 to 24 hours if the concrete is self-supporting and won't be damaged. WisDOT allows 12 hours; MnDOT requires at least 24 hours for most forms. In cold weather, expect longer.
›Does OSHA set a form removal time?
No fixed time. 29 CFR 1926.703(e)(1) says forms and shores can't come off until the employer determines the concrete can carry its own weight and superimposed loads, based on the plans and specs or on ASTM strength testing.
›Can I strip forms early and put blankets on instead?
Sometimes, but forms are insulation. NRMCA notes that non-metal forming materials hold and spread heat and give adequate protection in moderately cold weather. If you strip early, cover the concrete immediately and keep curing, and don't let the surface cool too fast.
›Are field-cured cylinders good enough to decide form removal in winter?
Sources conflict. ACI 306R-16 section 8.2 calls field-cured cylinders inappropriate in cold weather and recommends in-place or maturity testing. Several DOT specs still use field-cured cylinders. Follow your spec; where you have the choice, maturity testing is the stronger method.