Any concrete guys here? Couple questions on flatwork

[signcrafter]

I haven't done much concrete work, a few smaller things like fence posts and smaller slabs and stuff. Was watching some youtube videos and got to some concrete videos. Got me curious and have some questions.

So when pouring a slab or driveway you form it all up and the truck comes and starts dumping the slop. You spread it out and then screed it all to level it.

Then right away you use a bull float to smooth it all out right? When do you use a square bull float vs a rounded fresno float? Also you use a mag trowel to do the edges right? Do you do edges after the bull float or before or doesn't really matter?

After you float it all you let it set up a little bit right? I know it depends on many things but roughly how long do you wait for it to set up? Or how do you know when it's set up enough? Then you have to trowel the whole thing? Either using a power trowel or by hand? Can your really do a whole 24x24 slab by hand or is a power trowel a must? If you do it by hand what type of trowel do you use?

Then are you all done unless you want a broom finish or something else? I saw some spray a chemical or something on it from a pump up sprayer. What is this and when/why would you use it?

Any other steps I'm missing? I don't have any cement projects planned and I don't think I would ever try a decent sized pour without some experienced help but watching the videos got me curious about these things.

 

[ryan20021982]

Bull Float works up the cream for a nicer finish, you will want to do 1 pass with it and then let it sit and stiffen up some and then work a little more cream up. The Fresno is to get a smooth finish if your not brooming it, but we actually use the Fresno even if we are brooming just because it gives it a even finish for the broom. You will have to use a flat hand trowel around the perimeter just to clean up. For the rounded edges those are usually either steel or bronze and you will have to do this a few times but the first time you need to let it set some first or it will just fill back in, and then after you float do it again, you will know if you want the edge cleaner when you see it after each step.

 

[signcrafter]

Bull Float works up the cream for a nicer finish, you will want to do 1 pass with it and then let it sit and stiffen up some and then work a little more cream up. The Fresno is to get a smooth finish if your not brooming it, but we actually use the Fresno even if we are brooming just because it gives it a even finish for the broom. You will have to use a flat hand trowel around the perimeter just to clean up. For the rounded edges those are usually either steel or bronze and you will have to do this a few times but the first time you need to let it set some first or it will just fill back in, and then after you float do it again, you will know if you want the edge cleaner when you see it after each step.

So for a smooth finish you use the bull float and then let it sit. Any approximate on how long? I know there are a ton of factors but under ideal conditions are we talking 15 minutes or two hours or? Then you use a fresno to get it smooth and then you are done? Is the fresno kind of the same thing as a power trowel? You use one or the other? Or are there times when you use them both?

 

[oilslick]

I have watched a few pours, it looks easy. I did a few pours,not easy. Concrete set up completely different each time. Slump is key,keep out the add water or you end up with too much waiting,weak pour. I am eager to try again, but plan only to do broom finish stuff, leaving inside stuff to experience! Power trowel operating is key,knowing when and how long is so important. Pros make it look easy,I nearly flew off the pour on my first attempt at power trowel!

 

[KnurledNut]

Each job varies depending on the mixture, slope, temperature and direct sunlight, finish, thickness, etc.

Pour/place, screed, float immediately, and after the bleed water disappears, power or hand trowel. If power troweling, it should be hard enough to walk on with flat bottom shoes and only leave slight footprints.
I have rough finished slabs with two mag hand floats, one used to hold you up, one to finish with, alternating.

 

[Kaizen]

I have watched a few pours, it looks easy. I did a few pours,not easy. Concrete set up completely different each time. Slump is key,keep out the add water or you end up with too much waiting,weak pour. I am eager to try again, but plan only to do broom finish stuff, leaving inside stuff to experience! Power trowel operating is key,knowing when and how long is so important. Pros make it look easy,I nearly flew off the pour on my first attempt at power trowel!

What he said. Concrete is very unforgiving and mistakes are just as much work to fix. I might do a driveway to my garage entrance where the truck can pour right wheeze I want but I left my garage to the pros. I learned my lesson doing another pour.


Sent from my iPhone using Tapatalk

 

[Milton Shaw]

Unless you are in real good shape, you will be worn out before you are finished with what needs to be done. Get it ready to pour (formed and rebar placed) and then hire someone else with a crew to pour and finish the work. Trust me you will be glad you did hire pro's.. Friends will wear our before the job is finshed, ask me how I know.. Call the concrete supplier and get some names from them that they know do good work and show up before the truck comes and are reliable.

 

[LXCam]

Miltons advice is the best in your case. Find yourself a finisher that owns all the tools and toss $300 cash for his efforts. That's far to large of a slab for someone with no experience to tackle by yourself.

 

[signcrafter]

I don't have a slab to pour. And like I said in my original post I most likely wouldn't even try if I did have one to pour. I know how things can turn ugly real quick and concrete is very unforgiving.

I was just asking because I'm a curious person. I was watching some YouTube videos on something else and one click led to another and pretty soon I've watched an hour or two of concrete videos. This left me with some questions and since I hate when I don't understand something I just posted this to try and clear some things up for me. I would like to do a small concrete project someday, maybe a shed or patio or something just because I like to learn and do new things. But at the present time I don't have any projects and not going to just start pouring random chunks of concrete in the backyard so this was just a question for my own knowledge.

 

[brownbagg]

fresno float doesnt have enough weight to clip the high spots, but it will slick off like glass after the bull float, which is use to clip the high spots

 

[CB427]

New to using cement, the garage contractor mentioned the use of " chairs " to suspend the metal rods in the middle of the concrete, otherwise might fall to the bottom of the poured floor.

For a smooth finish, looking at a polished floor, same as some of the bigger stores. Use polished cement floor as the search finder.

 

[signcrafter]

OK I think I have most of it but one thing I'm still not sure I understand. After you screed and use a bull float you wait for the bleed water to dry up. Then you can use a power trowel OR hand trowel OR fresno float? Anyone of these will leave a finished surface? Seems like unless you have a power trowel a fresno would be the easiest instead of hand troweling? Or do you still have to hand trowel after you use a fresno? If you use a power trowel do you have to use a fresno or hand trowel besides at the edges?

 

[KnurledNut]

OK I think I have most of it but one thing I'm still not sure I understand. After you screed and use a bull float you wait for the bleed water to dry up. Then you can use a power trowel OR hand trowel OR fresno float? Anyone of these will leave a finished surface? Seems like unless you have a power trowel a fresno would be the easiest instead of hand troweling? Or do you still have to hand trowel after you use a fresno? If you use a power trowel do you have to use a fresno or hand trowel besides at the edges?

Depending on the application, you can finish with the bull float (exterior slabs), especially if brooming.
For a smooth finish (think interior), troweling leaves a hard, dense surface.
A fresno is not going to give you the same compaction as the repeated passes and pressure of hand troweling or power troweling. And yes, the edges still are done by hand if power troweled.

Regardless of method, you always want to be careful to not trap bleed water.

 

[brownbagg]

After you screed and use a bull float you wait for the bleed water to dry up.

if your slab has bleed water then you poured it too wet,the perfect slump will be just shy of bleed water

 

[n20junkie]

OK I think I have most of it but one thing I'm still not sure I understand. After you screed and use a bull float you wait for the bleed water to dry up. Then you can use a power trowel OR hand trowel OR fresno float? Anyone of these will leave a finished surface? Seems like unless you have a power trowel a fresno would be the easiest instead of hand troweling? Or do you still have to hand trowel after you use a fresno? If you use a power trowel do you have to use a fresno or hand trowel besides at the edges?

The problem is, time.

You don't have time to finish a pad beyond a broom finish unless you have a few guys that know exactly what to do and have some experiance.

The pad will go from bleed water rescession to stiff way faster than you think. 24x24 is a long reach for a float in inexperienced hands as well. You have to go fron the edges to the center, and that process alone can take too long if your a newb.

 

[matt_i]

I asked a lot of questions of the guys who finished my shop floor (interior). What I got from the oldest guy there is that you don't want a steel trowel to touch an exterior slab that's going to be broom-finished.

Pumping the slab made the first part pretty easy. We had the laser level running to rough-place with a come-along and mag trowel. The guys had a gasoline powered screed which was pretty amazing, the guy running that had a level built into his body. They pulled off some bleed water and then bull floated everything and were resting for an hour-90mins, I went on another errand and when back they had power troweled, leaving some "whipped froth" on the surface. After another short while, the guy steel-troweled the entire thing working from knee-boards.

I have some small flatwork to place next year (sidewalks and a drive going into the backyard) that I'm going to try to finish myself. Nothing too risky that couldn't be torn out if it was a complete disaster.

 

[signcrafter]

I asked a lot of questions of the guys who finished my shop floor (interior). What I got from the oldest guy there is that you don't want a steel trowel to touch an exterior slab that's going to be broom-finished.

Pumping the slab made the first part pretty easy. We had the laser level running to rough-place with a come-along and mag trowel. The guys had a gasoline powered screed which was pretty amazing, the guy running that had a level built into his body. They pulled off some bleed water and then bull floated everything and were resting for an hour-90mins, I went on another errand and when back they had power troweled, leaving some "whipped froth" on the surface. After another short while, the guy steel-troweled the entire thing working from knee-boards.

I have some small flatwork to place next year (sidewalks and a drive going into the backyard) that I'm going to try to finish myself. Nothing too risky that couldn't be torn out if it was a complete disaster.

So after power troweling it they still had to hand trowel it? I thought if you used a power trowel that would leave a nice finished slab?

 

[padroo]

One mistake inexperienced people tend to over work the concrete bringing a lot of soup to the surface.
Once this is done you have set yourself up for Spalding on the surface of your new concrete.

You can always hand trowel way before you can power trowel.

The surface will be very watery while bull floating then it will start to go flat meaning the water is disappearing from the surface and this is the time to start hand trowling.