“Sometimes in our frenzy to get all the projects and demands looked after we forget to protect our work from impending winter.”
2024 is poised for its last act. And with that comes the uncertainty of what it will be. It could be more or less balmy until Christmas. Or it could be rainy and cold and miserable. Or, we could get an early freeze up and winter. More often than not in South Central Ontario we get a mixture of all three. With adverse fall weather and shorter daylight hours it can be a challenge to meet schedule. Additionally there’s the extra pressure to complete projects before any winter costs start applying.
Sometimes in our frenzy to get all the projects and demands looked after we forget to protect our work from impending winter. One of the primary enemies of concrete is freeze thaw cycles. Here in Ontario our winters seem to produce more and more freeze thaw cycles. We get a cold snap and mild spell, over and over.
Two things to remember.
If you are pouring flatwork late into the fall, be conscious of newly placed concrete being exposed to moisture and freezing before its cured. And secondly, put a permanent freeze-thaw protection on concrete driveways and pavements.
Often when pouring exterior flatwork into the fall, if the temperature drops a few degrees below freezing at night and rises again for the day you will be fine. The heat coming from the hydration process within the slab will be enough to offset the cold. Especially in finished floors. If you are doing a brush finish on an exterior slab and there is excess moisture on or at the surface you may want to be more aware of night time temperatures.
Let me tell you one of my stories of a freshly placed floor and freeze-thaw.
We were doing a finished poultry barn floor on a nice sunny fall Friday. The barn had not yet been built, so the floor was outside. The access driveway beside the slab was terrible. Our pump immediately got stuck. We had a dilemma of a stuck pump and probably 10 concrete trucks on site or en route.
We put a hold on loading more concrete and quickly scrounged up another pump. We poured as far as it could reach from the end of the building . In the meantime we got a tow truck to rescue the stuck pump and fixed up the access lane to be able to pump the back half of the floor. When things looked safe to remobilize we released the rest of the concrete and finished the pour.
Most of the floor finished up beautifully in the warmth and sunshine of the day. But because of the interruption in concrete delivery, the last 3rd of the floor didn’t finish before sunset, and with the cold and damp of a fall night it lingered until midnight before polishing up.
On Saturday it rained. On Sunday the weather turned cold with temperatures of 4 or 5 degrees below freezing. The following spring as the building was being finished and prepared for use, the story became clear. The first part of the floor that had initially cured and finished quickly had withstood the weekend freeze thaw. The latter part of the floor that was delayed was spalling everywhere. To make a long story short, it became a difficult and frustrating repair project. Technically it was a result of freeze thaw, but arguably ultimately from site accessibility issues. (refer to last month’s spin)
Most driveway contractors I know have torn out and replaced projects from freeze thaw damage. Driveways are particularly susceptible to freeze-thaw from vehicles dripping salt all over them. The salt thaws the surface of the concrete, the moisture enters and then freezes and the concrete spalls.
The answer is to keep the moisture from entering. Most customers are interested in doing something to protect their investment. And we as contractors should be too.
It can be particularly difficult to know what to do with a thousand products on the market competing for the claim to protect our concrete.
My philosophy has been to pick a product that works to the best of my knowledge until I learn of a better one.
Pavix 100 is one of those products. Pavix is not like regular sealers that produce a membrane on top of the slab and needs to be maintained year after year, or a like a densifier that permanently closes the pores and hardens the surface.
Pavix is like an active product that lives in the surface substrate and with crystallizing effect blocks the pores and resists moisture when it tries to intrude. Pavix is considered one time application. Preferably applied after a couple weeks of cure.
It will not alter the general appearance of the concrete. I wouldn’t recommend for stamped concrete because it will not bring out the shine and the color and will resist any future applications of sealer.
I hope you have a great fall. Amongst the pressure of projects still to complete, it is equally important to protect the ones you have already done.
Like the old saying goes, an ounce of prevention is worth a pound of cure.
