I have took on the task of forming and pouring my own driveway ! I know form and pour the concrete , but I am not real sure finish it with a power float , to where the finish will be right ! Question .... how long should I smooth it with the power float ? how smooth should it be for a drivway ? I have been told that you can power float it to much and cause problems ? or not enough and rocks will show through the serface ? I need a baisc understanding of float it down to get good finish product ! and not a mess !!!!! Can anyone HELP ? Thanks in advance !
At ones residence and other high profile areas one want the absolute best exterior finish possible and that means a light broom finish with CLEAN crisp joints and edges.
Do not use the power trowel and I’ll tell you why later as I’m pressed for time right now.
In the mean time post the size of the driveway, dimensions and depth you plan to pour.
Exterior broomed work like adriveway is not power trowelled. It is simply screeded, bullfloated, edged, jointed, and broomed (if your screeding and bullfloating were good enough not to leave big holes). Some folks retool the edges and joints after brooming to picture frame the sections; others don't. Some people use a joint tool to cut the joints before the concrete sets; others sawcut the joints the next day, or as soon as the saw will work without ravelling and chipping the edges of the cut. At any rate, joints should be at least 1/4 as deep as the thickness of the slab. That means at least 1 deep on a 4 slab, 1.5 deep on a 6 inch slab, etc. Good luck.
Pecos
Also, if you are in a freeze/thaw climate, make certain to use air-entrained concrete, and pour no more than a 5 inch slump.
Pecos
I hate to discourage anyone from a DIY, but having had a portion of a garage floor poured and finished a couple of months ago, I can tell you for sure that putting a decent-looking finish on a concrete project as large as an averaged size driveway requires SEVERAL EXPERIENCED workers. I had no prior experience, and so I engaged a couple of experienced guys to do the finishing-all I did was haul the stuff from the delivery truck in a wheelbarrow. I did try my hand at a small area. It is nowhere near as easy or simple as it looks to do right. The concrete won't wait on your personal learning curve to set up. I'm quite sure Jorge and Javier had a good private chuckle about having to fix that spot up right for me.
Power trowels are designed for working large sq footage areas and to burn in a tight-finished surface. This finished surface is more resilient to liquids and much harder should something heavy be dropped on it. (industrial use) but the slab does experience discoloration and is extremely slippery when wet. The power trowels float blades are removable and replaced with trowel blades as the concrete sets up, they are only part of a finishing process and have less to do with flattening the surface as does a properly poured slab. All the power troweling in the world will not flatten out a poorly struck-off or poorly bull floated surface.
Exterior concrete finishing is exactly the opposite, the less you work it (especially with a steal trowel) the better it is for the concrete surface, but not necessarily the best looking finish. A bull float is made out of magnesium and not steal, so it does not seal in bleed water that can cause surface popping later. BUT, the “bull float and broom” finish is un-attractive and leaves heavy broom marks in the surface, and because it is done before the concrete hydration process is complete and shrinkage is still occurring… it can leave small water puddles on the surface when it rains. Which is why many think a hard troweled surface is the answer… it is not, a hard troweled exterior surface is dangerous when wet and will be for three to four years.
What I do is a combination of both for residences and high profile business entrances, and I learned this from the old Italian finishers in Chicago who were experienced in the ART of finishing, passed down for generations. (After all the Romans did invent the product) While the bull float and broom guys are packing up their tools and heading for the bar… I wait! When the time is right, I hit it again ONCE with a steal trowel and work my edges and joints as I trowel; timing and speed is essential. Then I hit it ONCE with a concrete broom by reaching across the slab and pulling toward me; not push and pull. The results are nice CLEAN edges and well-shaped joints with a flat surface that has good water run-off and is less likely to puddle. The fine broom is just enough to take away the slickness when wet. It will bleach out to a nice white and look FABULOUS!!
Concrete is a part of the landscaping and a product one will live with for a long, long time.
NOTE: with this type of finish I use an edger with a large radius and cut my joints with a jointing tool as apposed to a saw cut joint later. Garage floors are considered interior slabs and should be hard troweled.
Tags: finishing, concrete, driveway, hard troweled, power float, before concrete, bull float, concrete sets, edges joints, finish with
