How long should concrete formwork stay on before removal?
Strip on strength, not on a fixed calendar day. As planning guidance near 20 °C (68 °F), vertical faces on walls, columns, and beam sides often come off in 24–48 hours, slab soffits in about 3–7 days with props left in, beam soffits up to 7–14 days, and cantilevers with props up to 14–28 days per the structural design. Verify compressive strength with maturity readings or field-cured cylinders before anyone touches a form.
Can you remove concrete forms too early?
Yes, and it damages the concrete and the panel at once. Early stripping spalls arrises and can crack load-bearing members under deflection. Green concrete bonded to the face also tears film or overlay on removal, which cuts the panel’s reuse life. Both failures usually trace to site timing and release practice, not to the sheet brand alone.
Do you strip formwork by time or by strength?
By strength. Clock time is only a proxy when temperature and cement type stay near the design assumptions. The concrete must reach the fraction of design strength the job requires, checked with maturity methods or field-cured cylinders. Guidance such as ACI 347 and EN 13670 frames removal around that strength target because the same mix gains strength at very different rates in cold weather.
When can you remove shuttering from a concrete slab?
The slab soffit face can often be struck in about 3–7 days at normal temperature, but the props stay longer until the slab can carry itself, often up to 14–28 days per the design. Removing the face is not the same as removing the shoring. Crews often back-prop immediately after striking the panels so the next lift can move without leaving the slab unsupported.
What slows down formwork stripping time?
Cold weather is the biggest slowdown, and near freezing the wait can roughly double. Slow cements with slag or fly ash, a high water-cement ratio, thin sections that lose heat, and a demanding fair-faced finish all push the strike day later. Rapid-hardening cement and warm weather bring it earlier when the engineer allows it.
Which formwork plywood suits high-rotation stripping?
Glue class and overlay decide how many pours a sheet can survive under good site practice. Vinawood’s phenolic Class 3 (EN 636-3) grades are Pro Form Lite, Pro Form, HDO Standard, and HDO Premium, with Pro Form rated up to 20 reuses. Form Basic and Form Extra use MUF core adhesive to EN 636-2, so they are not Class 3 panels even when they share a phenolic face film.
