Drying time of the prefabricated cellar until the installation of the prefabricated house

Hello everyone,
we have received very different statements on the topic of drying time for the prefabricated basement during the planning for a prefabricated house:

- Extreme 1: A prefabricated basement can be built on two days after installation. Although the concrete only reaches its nominal strength after 28 days, the significantly load-bearing parts have already dried beforehand and have their nominal strength. The residual moisture of the poured transitions can continue to dry out.
Claim: Those who want to let it dry for a long time do this only to bridge the long delivery times of the prefabricated house.

- Extreme 2: A prefabricated basement should dry out easily for 8-12 weeks to reliably achieve drying.
Claim: A shorter drying time is only intended to lure customers with short construction times.

Does anyone have an assessment regarding this?

Thanks!

I would quickly remove the 2-day period from my project. Even though concrete is usually sufficiently hard after 7 days (as a rule – outside temperature can have a big impact here!), and the remaining 3 weeks mainly account for the last 10%, you definitely don't want to put live loads on it after just one week.

Normally, the ceiling props for the ceiling have to stay there for the "28 days" – maybe most of them are removed after 7 days, but as mentioned, only self-weight, until it is fully cured.

Extreme 1 is at least feasible, albeit unusual. First of all, concrete does not dry, but cures. Excess water passes through the walls of the basement – and the basement ceiling could not care less. So yes. You can continue building on the precast basement just as quickly as on a concrete ceiling or floor slab without a basement. Construction continues there almost seamlessly. Just make sure the basement is properly ventilated.

Thank you all in advance for your answers! The provider of "Extrem 1" is, in our opinion, a reputable one. Hence our surprise. Addition: The basement is to be set and poured in winter. According to provider 1, this is advantageous for curing when it is cold, but there are no temperatures significantly below 0 °C. I will now assume that around 28 days of drying time are rather sensible, even for prefabricated basements.

I see it the same way as . If you are in a hurry.

I assume now that around 28 days of drying time is more sensible, even with prefabricated basements.

May be sensible, but it is unrealistic in practice. As with all concrete work in new construction. You don’t wait four weeks for every floor slab. It always continues a few days after concreting.