Thread: Garage floor

Just inspected a 4-yr detached. It was raining the whole week. How will you address this garage floor? Thanks

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That is more then usual amount of cracking for a new floor slab. That is, I'm used to seeing better quality in new construction here.

That moisture looks like it is surface water, like water has dried on the flat surfaces but is still evaporating at the cracks and puddles. But judging from the poor concrete work, there could be trouble below as well. I would tell them to have the perimeter drains checked maybe.

Originally Posted by John Kogel

That is more then usual amount of cracking for a new floor slab. That is, I'm used to seeing better quality in new construction here.

That moisture looks like it is surface water, like water has dried on the flat surfaces but is still evaporating at the cracks and puddles. But judging from the poor concrete work, there could be trouble below as well. I would tell them to have the perimeter drains checked maybe.

Thank you John

I know cracks esp hairline shrinkage on the large concrete slab is usual. This one is a little different. I noticed tiny heave at the cracks joints which is way out the same surface level. You may noticed the big patch under the door. Although this property has 7' basement which drain tile should be properly installed, this is not related to garage floor foundation. I doubt enough gravel & thickness of slab have been applied. By the way, should a moisture barrier in between? I think normally it does. But this property grade is very good. The moistuer barrier seems not that important.

Also the builder said reinforce bar applied. This made me worried even more on the metal bar rust causing the cracks worse.

You are correct, it looks suspicious and you can only report what you can see. No matter what the builder says, I would not report it as fact. Yes they should still install a poly VB.

May be coincidence but the water in the last photo appears to becoming from the water spigot/hose.

Also if the concrete was poured directly on the subsoil and not gravel was added then hydrostatic pressure could be at play given all the rain.

I'm not discounting any of the previous theories but have they been parking the car there? Pulling a wet car in out of a heavy rain can bring a serious amount of water with it. Do that daily over a few weeks might be the source of the water.

Something about that does look odd..... in that first picture it looks like the water is coming up out of the crack. Of course, it's hard to say from a few pictures on one day under unknown circumstances. It's enough that I'd be asking some questions (as you obviously are )

I often struggle trying to explain things I can't, but the longer I do this am more comfortable telling people that - basically, it looks odd and some more investigation/information is needed. I'll often encourage people to keep in touch with me after talking to the seller or anyone else involved. Not only is it great customer service, I sometimes learn a lot once something gets an explanation..... or a jackhammer or two.

Peter,
Addressing the 4yr old floor floor for the client could be varied depending on your experience with concrete.
A short and simple comment on the floor might be as simple as "The floor has many cracks and it will only get worse over time and ultimately the floor will need to be replaced. There was water present the day of inspection which may be coming from under the floor which requires further evaluation by a licensed contractor."

In general wet cars will not effect a concrete floor. Water going into cracks will have a range of various effects.

Getting into the causes of the excessive cracks is another issue. There are many that could create the cracking, to name a few that will cause the cracks pictured.
1) The concrete mix was bad (low psi) and/or to much water.
2) Pour not thick enough.
3) Improperly graded and compacted.
4) Concrete poured directly on dirt.
5) Stone not compacted prior to pour.
6) Rebar not set correctly.
7) Not enough rebar.
8) Wrong type of reinforcement wire.
9) Concrete poured in winter and to much additive used.
10) Incorrect curing of concrete.
11) Concrete excessively agitated causing stone to settle to much.
The list could go on.....But these are the basic causes that could have caused the cracks from what I am seeing in the picts. Looking at pictures and being there makes a big difference. With some experience you can make some conclusions by sounding the floor with a hammer. Making a definitive determination as to the actual cause would be time consuming and would require cutting some core samples. In general the floor should not look like that and I would say was a bad job, no mater what the builder had to say. To often the builder was not on site when work is done. He should know what should have been done and what was speced, but was he there the entire time supervising the workers?

great info, thx all

Originally Posted by Peter Louis

Just inspected a 4-yr detached. It was raining the whole week. How will you address this garage floor? Thanks

It is pretty obvious that a wet car had been in the garage because you can still see the tred marks thru the water.

Peter,
Just fore your own edification on why the floor looks like it does, I am pretty sure that the base was not compacted in conjunction with the mix being to wet when poured.