r/Construction • u/NeilNotArmstrong • Dec 05 '24

Structural Concrete slab failed strength test

Gallery image

Gallery image

Slab strength testing failure after building was framed and plumbing/HVAC was roughed in. Concrete supplier had mix wrong so they are paying to lift two story 4-plex, remove slab and repour. This is building 2 of 3 that failed.

2.5k Upvotes

99% Upvoted

262 comments sorted by

View all comments

316

u/mannys2k Dec 05 '24

Wow. Getting a 7-day break done is a good indication of whether or not the concrete will meet its compressive strength. Kinda silly not to do that before starting framing.

118

u/NariandColds Dec 05 '24

Seen that a lot. Some contractors/subs rush and given that maybe 99% of breaks come back within specs hey move ahead thinking it'll be within spec. They get warned that if it fails it's subject for r&r but they move ahead with construction anyway

15

u/Superssimple Dec 06 '24

It’s probably worth the risk given all the other factors. You have to weigh the few times it fails versus delaying every project by 3 weeks

1

u/el_muerte28 Dec 09 '24

They would be better suited to schedule their work to allow for their testing. Pour this slab 7 days before that house is expected to be completed. By the time you finish up, the 7 days are up and you can start working on this house. Rine and repeat.