New Patio Slab - Uneven, Help!

[Unregistered]

Just had a concrete slab poured. It's been covered for @5 days now curing. Looked good under the plastic. However, just walked on it today and noticed that there are a couple of spots where the concrete has a "bump" in it. Looks like when the concrete was being leveled with the 2 x 4 it got a bit uneven. So I have a couple of spots where the concrete is essentially raised above both sides, like a mini-speedbump. Not sure what to do about this.

Should I try and sand/grind it out? If so, could I letting myself in for bigger problems like tearing up the slab or exposing the wire mesh underneath? Alomst wish I hadn't covered it up as I would have seen the problem earlier and maybe been able to fix it the first night before it starting curing.....

Ideas?

thanks

[joed]

How big are the lumps? Try and live with. You could grind it off but it will be very noticable. The finish will very different from the rest of the slab.

[mdshunk]

Are you saying all you did was screed off the slab, and you didn't float it and trowel it? Holy cow. It sounds like this slab project might have been headed for disaster from the minute it was poured.

[Unregistered]

Lumps aren't too big, but definitely noticeable. I did not do the job. SOmeone else did it. I'm having a screened porch put in. And no they didn't float or trowel it. I asked but they said it wasn't necessary. Tough to argue as I wasn't sure and they were in the middle of the job. Other than looks (and someone possible faling over and suing me), should it be ok structurally?

dp

[Mr T]

Was this a contractor? Did you pay them yet? Have them redo it.. They screwed up. period. It may be ok for you, but if that porch is a big eyesore when it comes time to sell, you may have problems selling at asking price. Someone may want it redone, or an allowance for it.

How smooth is the surface now? Without the proper surface put on it, is it going to get very slippery when wet? If someone gets hurt and a claim is filed, your insurance could go up in price, or you could get non-renewed.

I am not a concrete pro... so I dont know if it will get worse over time.

If it was a friend/ect....dont know what to say.

[mdshunk]

And no they didn't float or trowel it. I asked but they said it wasn't necessary.
My reaction to that is somewhere between "Oh my" and "Holy smokes!". This couldn't have been a professional job. These guys should let their heads cure for 28 days before they attempt any more concrete work. :o

[Unregistered]

Well, unfortunately it is in now and I have to deal with it. Little over a barrel here. I appreciate the comments.

Looking for good ideas on how to make things better without tearing it out. Would renting a grinder/sander of some type to smooth it out be worthwhile? Then maybe trowel on a very thin top coat of concrete repair? I have seen this done (on TV) for sidewalk repairs.

Other ideas? The slab is just below the rear door sil so I have little room to work with.

thx, dp

[mdshunk]

There are special grinders for this purpose that look like a floor buffer that take four stones in the head of different grits. If you grind the high spots down, it will look like terrazzo in the areas in which you ground. I highly doubt that this is a tool that is available at a DIY tool rental store. You might have to go to one of the national pro tool rental place like United Rentals or Nations Rent.

Skim coat? Eh, maybe that'll work. I just hate to see people mickey mouseing new work.

[bmwpower]

I've seen little handheld type grinders which may work. Not sure how big of an area this is, but then again you would see a difference in texture.

If they didn't float or trowel it, I wonder what they did to prep the ground...

[Unregistered]

Ground was prepped (sp) very well. No issue there thank goodness. Hoping this is simply a cosmetic issue that I can resolve without suing anyone...... May just grind down the high spots and have them put a thin resurfacing coat on, then seal it later. Not sure how long to let it cure before starting to grind and resurface though. Ideas on that?

dp

[Mr T]

Who put this in? If they are a concrete contractor, they may have something for this purpose. (hopefully they dont need to use it alot)

I'd get them to do the grinding... Their screwup.

[Wgoodrich]

There are products out there such as colored gravel and a specific patch mix that can be applied over that rough grade concrete making a pebble finish even with your initials designed into the pebble finish by using colored pebbles. I would contact an experienced concrete finisher for product availability on specialized finishes. This has been commonly done on in ground pool patios in my area.

Might be worth checking into

Wg

[xkvator]

There are special grinders for this purpose that look like a floor buffer that take four stones in the head of different grits.
i used one years ago to take a broom finish off and ended up with a smooth, terazzo looking patio. the cost is hourly + $ for each 1/8" of stone you use.
you have to make sure you keep the stones wet.
how high would you guess the "humps" are?
as others said...the so-called contractor should take care of this, but my guess is he won't.
if this is a screened in covered porch and you don't like the look after grinding, you could cover it with outdoor carpeting - they make colors other than the common green.

[bcreely]

the biggest problem i see with screeded and not trowelled concrete is that the fines were not worked to the surface to protect the body of the concrete. with the coarse aggregate close to the surface, spalling will become an issue down the road, especially if exposed to the elements.
bobc