Tips & tricks for 1st concrete pour!
I’m getting ready to pour my first series of concrete pads for a beam and column replacement in my basement. The rebar mats have all been completed. Nice and tight. I’m borrowing a mixer which can hold (2) 80lb bags at a time.
I’ve got 3 pits to fill (but I don’t feel the pressure to do them all same day). I don’t have to worry about plywood forms bc the concrete will be contained by compacted earth on all sides. Each pad will be between 12-15” deep. Two pads are 2’x6’ and the other is 5’x5’.
What are you best tips and tricks that can only be learned by experience? I’ll have a mixer. I also purchased a concrete vibrator. I’m sure timing is a big issue. I’ve worked with concrete before (fence posts, etc)…but have never used a mixer before. I’m open to any and all wisdom. Thanks everyone!
Replies
You've got about 2 yards of concrete. If you mixer is in the basement you'll have about 90 bags of concrete mix to move by hand. If you mixer is not in the basement you'll have about 10000 lbs of wet concrete to move by hand. If you put any value at all on you time and back (this will take a lot of time), think about having transit mix pumped.
Like Mike said, that's a lot of concrete to mix. I had about 2.5 yards to put into a basement room (put in a floor that had been dirt). Considered mixing and the cost and labor was just outweighed by having a volumetric (mix on site) with a truck pump and 2" hose do this. Key was having a good pump operator who knew that you had nowhere to put a lot of fluid before the concrete started flowing. Given that this is three separate areas, doing 25-40 bags at a time, with a mixer, is not insurmountable. Moving the bags is going to be a big deal (know some cheap laborers?). When I've done bag mixes, sometimes have found mixing 1-1.5 bags at a time is faster than trying to get both bags in and it just seems to take longer for the mixer to mix two bags. If you have everything staged, you can mix 25-30 bags pretty quickly. WEAR a good mask since the dust will be significant.
VERY HELPFUL! I already carried every bag into the basement. (Considered it my workout for the day! ?).
Love the recommendation for 1-1.5 bags.
Now where to find a mask?!! All the big boxes are sold out due to corona virus ?.
I assume you have the mixer in the basement. Position it so that you can pour right out of the mixer. Measure your water. Most beginners make concrete too wet. With a vibrator you can make it very dry. Pour your smaller pads first for practice. You may find a non disposable mask that hasn't been sold out. A good helper would be a plus.
Set up your workflow so you don't have to bend over all the time. If you can stage your bags at mixer height (at least in a few groups) you will be able to work a lot longer. Keep upright and you can work forever.
Do mix it too wet - that's a huge temptation.
Clean the mixer with the hose after each mix. Shoot the hose in there for a count to get the right amount of water for a good mix. I keep a trowel on hand to scrape the mouth as it spins.
When you open the concrete bags, cut in the center with the trowel, lift the middle and then you have two half bags to dump into the mixer.
Grease the mixer bearings - start and midday.
Don't stick your arm in there while it's running, no matter what. Nothing like getting it torn off to make for a nice workday.
You have to have a square end shovel
It's best to wear a dust mask, but I don't like them. I set up a fan to blow the dust away from me.
I agree - mix 1.5 bags, not two. Depending on the mixer, it gets bogged down. Also, if you are doing "heaving lifting" you can't keep at it. Doing this all day is a marathon.
I've done about 110 bags in a day as my max, with my son helping me. I was beat at the end of it. You should be able to do 50 and not over do it.
Good luck - I hope it goes well.
Thank you @tfarwell. These are some great tips! Very helpful indeed. I’m not going to rush it, so just one pit at a time.
One question: how and with what do you grease the mixer bearings?
Good idea. One pit at a time makes sense.
You typically grease the bearings at the zerk fittings. Check the mixer for them. The start of this video shows what I'm referring to: https://www.youtube.com/watch?v=pjsxLroxXf8
You can get a cheap grease gun at harbor freight, home depot, etc. I'd assume whoever let you borrow it would have a one.
One more thing: resist the urge to use your hands to rub any wet concrete off of anything. You'll quickly sand your hands down. A good pair of gloves helps. I personally don't wear them, never have - but I learned to be careful years ago.
First pit filled tonight! I have to say...all the advice here was so helpful! Took me 2 hours start to finish...but I was happy with that.
And the concrete vibrator made all the difference! That thing was worth every penny!
Nice work.
Thank you for your advice
All 3 pads are complete! Thanks again for all the help and tips! Definitely made a difference.