Garage floor repair project

[cjac]

Hi all,

I'm in an 8 year old town house with a 20X20 framed garage. The concrete slab is cracked into 4 pieces, one lengthwise and one widthwise, making a giant 4-square of 4 roughly 10x10 quadrants, if that makes sense. Its starting to a heave a bit on the cracks.

Whats the best way for me to fill the cracks? Seems like a seam putty or caulk would take a long time to fill 40 linear feet of crack, is there an alternative? I'd like something that after they're filled I can put a floor seal down on top of the entire concrete pad. If it's a caulk type job, what products are best and what's the best pre-work to ensure it holds?

Not looking for perfection, rather functionality and preventing further cracking and heaving. I did contact the assn, but that's considered the homeowners responsibility.

Thanks, Chris

[MNcanepole]

I'm not a cement man, but I know from working on construction they put I think the name is zip strips into the concrete, so the cocrete will crack in those spots. The concrete moves alot with frost and if it didn't do what it did do it would have cracked all over the slab. I don't think it would hurt to caulk the cracks but I'm sure someone with more knowlege on this subject will let you know. Good Luck

[Roofer]

RRRRRRR this should not be happening.....heaving inside a garage. I sure wish they would make those sloppy multi-family house builders do something right!!!!

Did you get the name and number of the builder? I would find out if there is any type of warranty. This is poor preparation on the builders part OR he was just being a cheap ARSE!

Sorry.

[Roofer]

This makes you wonder what your footings are sitting on??????????

[cjac]

Thanks Roofer, not the best news but right along the lines of what we were thinking. Anything to save a buck.....

I'm not the handiest and keenest of eye on workmanship, but I've seen so many points of evidence of throwing these units up as quickly as possible. RRRRRR is right....

I'll follow up again with the assn, but I'm afraid at that after 8 years I'm SOL. Just had to replace the water heater from the mounting bracket screws that direct the line across the top of the heater being too deep and puncturing the top of the tank bladder. Simply shoddy work done 8 years ago......took a while but it let go and leaked and leaked and leaked......

Thanks guys, Chris

[Tom7227]

I had a similar problem. The blocks put in as footings weren't filled. Over time the sand under the garage floor worked it's way down into those blocks. I re-did the driveway and when the apron was taken out there was a void big enough to crawl into. I packed material in there as best I could and filled the blocks again. Now about 8 years later I can hit the floor and hear that it's hollow under there again. You may want to rap the cement in a few places and maybe you can tell if you have a void under it. My guess is that there's some reason why it cracked and some goo you put on top isn't going to solve it.

[Roofer]

Sorry to be negative, but it just bothers me.

In the end, is the builder or the consumer wanting a good deal? It's hard to tell.

Maybe one of the masons here could give you an idea on what to do for a short term solution.

[cjac]

 Quote:

Sorry to be negative, but it just bothers me.

Quite the opposite Roofer, I appreciate the real reply. Thanks! Bugs me too!

We bought three years ago, and intersetingly enough, coupled with the post from Tom7227, there is a patch in the driveway. Either from a water main issue or possiblty a cable co. tapping down? No idea.... I've seen that since I've been in this development. Could create weak spots or voids, makes me wonder.

Anyhow, thanks guys, good stuff.

[hanson]

I'm in full agreement with Roofer on this one.

A garage slab should NOT crack, nor settle.

On my last commercial project, the entire Gymnasium slab was poured in one monolithic pour (no control or expansion joints). That sucker better not crack or someone's warranty is paying for it. Alot of time on slabs such as this, the finish flooring material would be a full glue down rubber material (sort of VCT only thicker). Any cracking at all would telegraph through the flooring material if it happened and makes owner's unhappy.

Your problem is with the soil. Its settling. Whether its poor soil, bad compaction, or both!, its settling. Like Roofer said, makes you wonder what your footings are sitting on??

At this point... whatever you do to your floor would more than likely be temporary. It'll continue to settle. One point I've seen Roofer bring up a number of times is gutters and downspouts. How is the drainage around you townhouse and what kind of roof drainage do you have? Water around your foundation is not good at all.

The primary reason your garage floor is cracking is the soil is settling around the perimeter of the garage. Over time... you could probably measure how much the slab settles compared to the foundation wall.

IMO... the proper "fix" would be to mudjack the portion of the slab that has settled back up to the height it is supposed to be. They basically drill some holes in the slab where it is sinking and pump a very liquid mortar under the slab which lifts it back to the height it is supposed to be at. Then patch the cracks and put your finish down.

Hate to tell you but your cracking will keep recurring or getting worse until you fix the "problem", or the soils stop settling.

[Shack]

 Originally Posted By: MNcanepole

I'm not a cement man, but I know from working on construction they put I think the name is zip strips into the concrete, so the cocrete will crack in those spots. The concrete moves alot with frost and if it didn't do what it did do it would have cracked all over the slab. I don't think it would hurt to caulk the cracks but I'm sure someone with more knowlege on this subject will let you know. Good Luck

This was my thoughts as well (cracks never run in a uniform pattern), coupled with no rebar or mesh to hold concrete tight. Cracks are cracks and in MN, they will occur not matter what. The heaving should not occur if the site was prepped correct before the pour.

The zip strips give you a smooth floor, while allowing for cracks to run even. When you put a cut in concrete, the crack runs the length of the cut down in the little valley. You never really see the crack, until you look down inside the cut. 99.9% of the time your cut (after a year) will have a crack in the valley.

[hanson]

 Originally Posted By: shackbash

This was my thoughts as well (cracks never run in a uniform pattern), coupled with no rebar or mesh to hold concrete tight. Cracks are cracks and in MN, they will occur not matter what. The heaving should not occur if the site was prepped correct before the pour.\

My first thought Shack was adequate reinforcement as well. But even with adequate reinforcement, proper soils preparation is critical.

Regardless... the "correct" repair would not be cheap.

[cjac]

Well, aren't you guys a breath of fresh air!!!

So, basically, I'm stuck in concrete boots in rising neck-high water with a garage slab that sucks!

Really, thanks for the input, gives me some grounds for my case. On the upside, the rise in the concrete stops the boat trailer from rolling! Regarding the drainage questions......it's cheap and inadequate, typical of a "throw it up fast and run" development. I've modified and added to a few spouts but not enough I'm sure. Get a hard rain and there's puddling water in the driveway near the concrete apron. Pretty much say it right there.

Ugh.....time to move, eh?

[Shack]

 Originally Posted By: Tom7227

I had a similar problem. The blocks put in as footings weren't filled. Over time the sand under the garage floor worked it's way down into those blocks. I re-did the driveway and when the apron was taken out there was a void big enough to crawl into. I packed material in there as best I could and filled the blocks again. Now about 8 years later I can hit the floor and hear that it's hollow under there again. You may want to rap the cement in a few places and maybe you can tell if you have a void under it. My guess is that there's some reason why it cracked and some goo you put on top isn't going to solve it.

I had seen this on a nightmare job I did down in the cites a couple years back. It started out as a simple tear out and redo of some poorly mixed and applied concrete. Well, when things started to roll, the home owner added some things. I figure O.K. They had an asphalt drive way right up to garage slab (no apron). They wanted an apron put in. Then they wanted a 16’x12’ patio slab tied in to the walk way around back. We cut the tar in front to expose small caves under two entry points on either side of the front garage door. Then we prepped the area in back for the patio. I will add, this house was a multi level split built into a bluff. The ground was almost all clay (yuck). The house was built in 86 or 87 and the year I did this it was a very wet summer (2005). I moved my skid steer around back to level area for slab. It was like I was on Jello/pudding. After these two issues exposed, the home owner confessed my worse fears. In the basement, they had in floor duct work for heating and a/c. When it would rain hard, they would have to run a pump to keep water rising into basement threw the vents. They did not want to say anything at first because they pump water into the lower basement tube and I guess in this city that is illegal.

To make a long horrible nightmare situation short, I learned a lot about mud jacking, drain tile and a hole mess of other stuff.

The water entered in the front drive way area and traveled under house down the hill and pooled up against the back foundation wall. I had to expose the footing and drain hundreds of gallons of nasty water out from under this house for like 3 weeks. The clay would never let water soak into ground and it just pooled up against back foundation wall, 6’ down to footings. I had drain holes all the way down to footings and water poured and drain out for 3 WEEK.

The front garage floor caves where back filled with pumped concrete. We did 1’x1’ on center rebar threw out the project and anchored all the concrete (sidewalks, patio and apron) to existing slabs and foundation. I wanted to make sure the front apron never separated or dropped and the rest of the project was all on a down grade because of the bluff.

It has been three years now and the last I spoke the home owner, all is good and no more pumping of water in basement. Plus the house has not slid down the bluff yet.

I still know there is a major cavern under their lower basement that held a ton of water, but the insurance agent did not feel a borascope exploratory threw the foundation block was needed and the home owner did not push the issue, even though I expressed my views. Also I brought up mold issues, that my knowledge where never acted upon or tested. One question I had was where did all the fill/clay go under the basement foundation. I guess with the slight pressure of the water running down hill, the absorption qualities of wet clay and the unknown.

I made money, but it was a 3-4 day project, that turned into a couple month ordeal. Many times I just wanted to leave and let the home owner deal with it. It was far away from home and consumed all my free time (this was a side job), but I stayed until the sod was laid.

[cjac]

Update, Lovely town house for sale in Maple Grove at ##### Mockingbird Lane.....

Yikes, thanks for all the info, but now I'm not feeling so good....

[Shack]

 Originally Posted By: hanson

 Originally Posted By: shackbash

This was my thoughts as well (cracks never run in a uniform pattern), coupled with no rebar or mesh to hold concrete tight. Cracks are cracks and in MN, they will occur not matter what. The heaving should not occur if the site was prepped correct before the pour.\

My first thought Shack was adequate reinforcement as well. But even with adequate reinforcement, proper soils preparation is critical.

Regardless... the "correct" repair would not be cheap.

Hanson, I just read both of your posts. You are right on the money dude. I was writing my last post and did not know you even posted. You know your stuff! Nice post.

Like Hanson said, site prep is the key to minimizing garage and exterior concrete cracking. I have had some jobs, that I have put extra effort in to have no cracks at all, that eventually end up with a crack. I have had some jobs I did very little ground prep because of cost issues with the home owner, that never cracked, even when I would bet money it would have.

The one time I can guarantee a crack is when you tie into an existing concrete with a crack and do not put a cut up to crack in existing crack in fresh concrete.

Last fall (the day of the porty mod get together), I did a slab out front of a garage with an existing apron on it. The home owner did not want to tear out the over sized apron. When I laid out my cut points, they had a fit that they where not all that eye appealing. Basically I had jogged a cut line over a little to meet up with this crack from the existing apron, but it did not make all cut squares equal. I mean who looks at a drive way that hard. I expressed this to the home owner and they did not want anything to do with it. They also paid extra for ground prep, because they did not want “any” cracks.

Sure enough I get a call a month later. The crack traveled from the apron right almost down the middle of that cut square to the opposite side cut. They wanted to know what could be done.

I will also add Hanson, residential and commercial are too whole different worlds and price ranges . I know you know that, but I thought I would stress that for others.

You get what you pay for when it comes to concrete.

As far as repairing this, Hanson is right. To repair correctly, it will entail removal of existing concrete and replacing the correct way.

Now, patching and coating will work for awhile. Once heaving starts, I have found it is about 70% chance after 4 years it will still move again. Like Hanson said it will depend on what under the slab, to determine if it will move more in future. Best thing for the time being (cost effective and IMO) it to patch area as smooth as you can and try a epoxy floor coating. Or, better yet those tile squares for garages and hope slab does not move further.

[hanson]

Well Chris... I don't think its as doom and gloom as Shack's example but there are some concerns in my mind. Not your house falling over type of concerns but these cracks resulting from settling might always be a problem. You patch 'em, they come back type of deal. How do your interior doors shut? Any doors starting to get "out of square" in their frames?

There obviously is the "right" way to fix your problems which equals $$$$. And if $$$$ is an issue, you're looking to find the best way to temporarily improve your cracking situation. Tough call...

When's fishing opener again?

BTW... I'm NOT buying the RiverPro!

[Shack]

Yes,

I am sure your situation is nothing like what I just posted. Did not mean to scare ya.

Fan out some patch, wait six months to a year and see if slab moves. If it does not, do a floor covering.

As old as the slab is, I am sure it will not move much more.

You are not on clay are you?

[hanson]

 Originally Posted By: shackbash

Hanson, I just read both of your posts. You are right on the money dude. I was writing my last post and did not know you even posted. You know your stuff! Nice post.

I would pat myself on the back but I do commercial architecture for a living. It ends up being day to day work and when I pop into FishingMinnesota here, I don't usually like to talk about work, its my "fun" time. I deal with soil conditions all the time however, it is one aspect of a project that you can never plan for. Even when soil borings and testing indicates adequate soils, they can easily miss debris, contamination, or underground fuel storage tanks even. You never know whats underground until excavation starts. Then it becomes my fun job to explain to an owner how we didn't know an oil tank has been buried directly under where they wanted to build for 25 years and it is going to cost them $$$$ to remediate the soils in that area. Fun! Fun!

Hmmmm... the fun word "Change Order" comes to mind.

 Originally Posted By: shackbash

I will also add Hanson, residential and commercial are too whole different worlds and price ranges . I know you know that, but I thought I would stress that for others.

Most definitely correct there Shack!

[cjac]

Interior doors are square, however they are a couple feet up from the foundation level. Concerns, yes! Structurally, to my novice eye, most is good. I have noticed some electrical shortcuts, as bro-in-law is an electrician. He simply shakes his head......especially after the water heater project. Sump pump is dry, which is a good sign I assume.

$$$ is an issue, but a little $$$ now is better than long term big $$$. This information gives me a starting point to initiate my "discussions", for lack of a better term. Thanks again to all! Short term plan is to caulk the cracks, make it look pretty and see what happens from there. Any rec's on the best caulk product?

Hanson, still sure you want a house? That RiverPro is built better than any 4 walls you can buy! Opener can't come soon enough! You want to see questionable footings, see the Haider family cabin! Another discussion on it's own.......

Thanks again to all for the info.

Chris

[cjac]

 Quote:

You are not on clay are you?

More clay than Clay Montgomery, Clay Atkins, and Cassious Clay put together.......... Saw a driveway down the road dug up, all red clay. Not good, eh?

Regardless, I'm leaning towards caulking it up, make it look pretty, seal after a while, and hope for the best.

[Shack]

Cjac,

If you want to take care of that heave in the future, I have had some pretty good luck on jacking/chipping away a circle area in and around the heave, below the level mark a ¼” to 3/8”. Make sure the outer area edges are level with each other. Then take some fine wire mesh, just under size of the circle and Tapcon screw mesh down. Get a good commercial vinyl patch and fill in. Depending on how good the finish was burned on your garage floor, a sponge trowel (cheap) will blend in most concrete patch to existing concrete.

Now the cracks are a different story though. I just have used a good concrete look-a-like brand tube from Menards. Fill crack and swipe with drywall knife/trowel clean.

Good luck.

[cjac]

Thanks Shack, much appreciated. I'll let y'all know how it plays out. Got a few calls to make first......

More importantly, Mille in a few weeks? Muskies in just over 6 weeks! The chase will soon be on! Wahkon has my number for 'skis!

[King Canada]

I doubt that there is anything wrong with the floor or the soils. The floor was designed to shrink and crack along the zip strips. The slab simply lays along the foundation ledge and floats across the soil. If after 8 years there may be a "bit" of heaving I think you've got a normal situation that's not worth worrying about.