Bad troweling?

Pooling, butter, overtroweled, burnt finish, scaling, shaking, spalling are among many of the terms i’ve heard for this, but yes basically it is from over troweling to get a nice finish on a problem area, too much water comes to the top with not enough other ingrediants to create a hard surface. past experience shows that it is hard to get a nice looking blending patch on this,but patching is about all you can do

This is my experience too. :wink:

I had this problem on my current build job and it just made me sick.
My crew and I did the best pre-pour prep we knew…Compacted gravel base, rebar,vapor barrier,4 1/2 " chaulked depth line, and perfect weather.
But then the wind picked up. The concrete began to cure too quickly so that the slurry that forms on top was basically turning into a parge coat and power troweled over a realitively dry surface below.
You just can’t control things like weather.
It isn’t too pretty and very disappointing… but cosmetic.

In my case I just chipped out the spots,(they’re easy to find.If you can’t see them you can tap the surface and hear them.), with very little effort and applied a floor filler/leveler.It’s staying so far but highly likely not forever.


That’s good information, thanks. Sorry about your recent build but as you say, it’s cosmetic. I never thought such a minor defect could be so interesting.

Good post.

Go to this website for a very cool and superior product that will quickly provide a solution for this situation and similar problems with finish concrete.



Their desinger floor product looks interesting. I’ve been thinking of pulling up about 1200SF of cermaic tile that I have on the first floor of my home and going with a stained concrete surface.

I’ve been trying to learn more about the options before I decide.

This is a very impressive product. There are many different products in their arsenal for the many different types of applications or needs. One such is a self-leveling topcoat that has a finished compression strength of over 6000 psi. When I first heard about this stuff was to cover some bad spalling concrete for a customer. The finished job looks like a brand new pour and took one afternoon and was ready for use the next day and costs a fraction of what a replacement job would have. Ive seen several places, both commercial and residential that has the concrete custom finished floors and it looks fantastic. Hope this helps you out.

I call it ‘plastic shrinkage cracking’. Itg is caused by the surface of the slab drying too quickly (as opposed to curing) and cracks and flakes off.

All concrete (slabs, foundation walls, basement slabsm etc) shluld be covered with plastic to keep them moist for at least the first week of the curing process (for non-special cocnrete mixes).

See this site:

Hope this helps.

Sealers now replace covering with plastic in the Northeast.


I would have to comment at this time that Steve is the closest to the problem at hand.

Casting and finishing slabs on grade, especially in the Texas arena, is most difficult.

Improper timing of floating and finishing is always a pay me back later for your inattention. Most flat slab finishers wait to long and then find out it is curing and hardening faster than they can keep up with. They add water to the surface to soften it up to get more paste and accelerate the trowel machines to peak RPM’s and all they are doing is cooking the top 1/4" of the slab. The over heat combined with the accelerated hydration ,compound the delamination, blistering, checking, and further cracking, before it is even cut at the control joints. Common mistake.

Marcel:) :slight_smile:


That is my point. In our area, we have both extremes. Very hot summers (sometimes humid, sometimes not) and very cold (and recently, very variable) winters. Temperatures between the pour and the cure (3-7 days) can changes as much as 30 - 40 degrees. Finding responsible and reputable concrete suppliers is hard.

I have always insisted on testing the moisture content and slump before the pour is started and insist (usually to the jeers of the contractor) that the slab be sprayed with a fine mist of water after the float and covered with plastic for at least 3 days.

But, I have never had this complaint.

if it is stupid, but it works, it ain’t stupid.

Hi. Will;

In my part of the States and close to the same environment as yours, concrete slabs poured in the elements, should be protected from the elements at hand and also covered with 6-mil Polly at the end of troweling or wet cured for 7 days. This procedure will eliminate all these problems, well maybe not all, but the majority.
I am a Commercial Builder and think a little bigger, sort to speak, than a Residential Builder. Concrete that I pour, is always tested by an Independent Testing Source and the Concrete is usually 4000 psi. and no air entrainment if it is a slab. Air plays a big role in the topic of this discussion. 5%-7% air in concrete subjected to freeze and thaw, is good. Slabs at the interior, no. 3000 psi concrete with no air. There was a day where some Engineers thought that 4000 psi was better, but I have found the shrinkage was the demise to this logic.

These types of problems, as an HI. should recommend Consultation of a Concrete Expert and/or a Structural Engineer to assess the problem. There are a lot of variables to this type of cause.

Hope this helps.


Agree Marcel;

You just said it better. :mrgreen:

I do some commercial inspections, but mostly the slabs I see are 3-4 car garages and huge basements.

The basements are the big problem. Most new construction builing around here (4,500 - 6,400 SF) leave the basements unfinished (and the basement slab is between 18 - 25 feet below grade, fer gosh sakes!).

You can just see the buyer’s eyes glow at the ‘possibilities’.

I tell them to wait, at least a year, as see how the slab cracks. They say, ‘The basement floor will crack?!?!???’ I tell them, “Hey, if it doesn’t crack, it ain’t concrete”.

Tell them to make sure that the slab is covered with vapor (and water!!) barrier and the floor raised before they but down that pretty carpet or hardwood floor. If not, they will just have to tear it all up in 2-3 years.


Where in Gods name would anyone have a basement level at 18-25 feet below sea level, ha. ha.
Is’nt that opening another can of worms?

Marcel:) :slight_smile:

In the tonws of Glenview, North Barrington, Glencoe and Wilmette.

I have seen many. New construction. They have these wide and tall window wells that they cover with a translucent, stained glass window. Makes you feel like you are on the ground floor.

One guy actually put in a basketball half court.

Go Figure.

If this is only in spots on this slab then it looks like dirt fines got into the concrete mix, the fines could have been deposited by the finisher boots when he was walking across the slab.

Hi. Will;

Pretty hard to fanthom sometimes that houses can be big enough to have a baseball court, whether half size or full size.

Thanks for the update that makes Maine’rs look like, where have you guys been. ha. ha.