An old concrete guy here. That vapor barrier is also very useful to prevent overly rapid drying of concrete on substrates that are too dry.. I've seen concrete poured on dry ground actually cracking as it was being finished. Good video by the way. You know your stuff!
I also use plastic under concrete to prevent the wet concrete from losing moisture too quickly. Some water drains curing concrete. Drainage too fast can cause the surface to dry faster than the underside and cause cracking.
I like your videos, I always learn something useful, keep them coming 🙂 I did concrete work for a decade and no one ever explained why we put down vapor barrier other than, if you don't the slab will fail over time. I mostly set and poured wall, so it only came up in the winter when we helped the flatwork crew indoors.
They are (were) used as part of my first generation siphon feed foam generator for making aircrete. As for where I collected the unicorn farts I can only tell you that it took FOREVER to collect them!
There are pros and cons to using plastic. It all depends on the subsoil, drainage and how much surface water the slab will see. Counterpoint: If you have a slab with poor drainage, a vapor barrier under it will pool water in the slab and destroy the steel rebar. Best to have a well draining subsurface, wet right before the poor to mitigate suction from the concrete.
Think of it this way, each one changes the surface area of paste. Having more surface area allows more water to evaporate while curing. A mag float will yield a slicker surface, whereas a wooden float will make a rougher surface.
This maybe way off topic to ask Here? Just not found an answer searching the interweb... will quickrete stick to a plastic drink bottle? I wanted to make a shoe/boot flower pot from a soda bottle an covet it with quickrete? Sorry if this is to off topic and understand if you don't wanta reply..
An old concrete guy here. That vapor barrier is also very useful to prevent overly rapid drying of concrete on substrates that are too dry.. I've seen concrete poured on dry ground actually cracking as it was being finished. Good video by the way. You know your stuff!
I also use plastic under concrete to prevent the wet concrete from losing moisture too quickly. Some water drains curing concrete. Drainage too fast can cause the surface to dry faster than the underside and cause cracking.
I like your videos, I always learn something useful, keep them coming 🙂
I did concrete work for a decade and no one ever explained why we put down vapor barrier other than, if you don't the slab will fail over time. I mostly set and poured wall, so it only came up in the winter when we helped the flatwork crew indoors.
Thanks for sharing, but I gotta ask... where did you get the unicorn farts, and what are they used for?
They are (were) used as part of my first generation siphon feed foam generator for making aircrete. As for where I collected the unicorn farts I can only tell you that it took FOREVER to collect them!
There are pros and cons to using plastic. It all depends on the subsoil, drainage and how much surface water the slab will see. Counterpoint: If you have a slab with poor drainage, a vapor barrier under it will pool water in the slab and destroy the steel rebar. Best to have a well draining subsurface, wet right before the poor to mitigate suction from the concrete.
It also reduces cracking. As the concrete dries it shrinks and the movement is easier with less resistance on the ground.
Wonderful information super helpful.
Thanks - interesting. Do you know anything about floating the concrete with a magnesium float, or composite or wooden float? Any difference?
Think of it this way, each one changes the surface area of paste. Having more surface area allows more water to evaporate while curing. A mag float will yield a slicker surface, whereas a wooden float will make a rougher surface.
This maybe way off topic to ask Here? Just not found an answer searching the interweb... will quickrete stick to a plastic drink bottle? I wanted to make a shoe/boot flower pot from a soda bottle an covet it with quickrete? Sorry if this is to off topic and understand if you don't wanta reply..
How do a person bond concrete to polyurethane plastic?
You can't. Why your question?
Why is anyone mentioning that the vapor barrier is also a radon-preventer
That's right
OMG its swimming pool steve!