Help! Slab sloping towards house

santacore · « **on:** 23 Sep 2015, 07:48 pm »

Hey all. One of the slabs on the side of my house has been raised over the years from tree roots. As you can probably see from the picture it now slopes toward the side of my house. When it rains it pools up a few inches deep and sits against the side of the house. Within the next year we are going to rip out the problem slab and redo it, but with El Nino coming, I'm looking for interim suggestions to help with the pooling issue. Any input would be appreciated.

jqp · « **Reply #1 on:** 23 Sep 2015, 08:05 pm »

Hmm that's tough.

I have a smaller version of that, a sidewalk size slab of cement is tilting toward the end of my house foundation, luckily it is at the level of the crawlspace below the house level. When it rains some water pools up there. I too see no solution other than tearing it out and repouring cement at the proper angle away from the foundation.

Anything other than cement will be a temporary mess (plastic, wood). You could direct water to the edge of the cement with plastic or wood set so that it creates the proper angle away from the house, and use a french drain to take it somewhere else.

One option is to pour some new cement at the proper angle, sitting on top of that cement - that will only work until the new cement cracks - which it certainly will. It may buy you a few months or only a few days - hard to say.

You probably will want to lower your yard near the new slab so water will always stay away from the house. You can't raise the house you can only lower the yard.

Charles Calkins · « **Reply #2 on:** 23 Sep 2015, 08:46 pm »

As a temporary repair you might try roof coating. Local hardware store should sell it. I've used Henry products.
Comes in different colors.
Easy to apply. let the first coat dry for a day. Next day do another coat. Do as many coats as you like.
That stuff will stick to anything!!! I know from past experience.

Cheers
Charlie

Bob in St. Louis · « **Reply #3 on:** 23 Sep 2015, 09:27 pm »

Check for contractors in your area that perform "mudjacking".
Here's a quick video:
https://youtu.be/KeC6dMZuAsU

JLM · « **Reply #4 on:** 23 Sep 2015, 09:41 pm »

Look for an injection contractor who can inject foam (yes styrofoam planks are used as fill under highways as cheaper to transport then gravel with good long term stability) or concrete to force the slab up. Can easily be cheaper than ripping out, landfilling the waste, and replacing the concrete. (Oops was composing when Bob posted, yes the concrete version is often called "mudjacking".

But those tree roots should be taken care of first by removing the tree(s). Recommend checking check with a couple of landscape firms. Many offer free design advice. And prices (with 12 month warrantee) can be as cheap as trying to DIY. That's what I've found, and you won't be stuck with stuff that doesn't grow (or grows too well). They might also suggest replacing the concrete with pavers on a gravel bed if you really don't want to lose the tree.

Tree planting advice: softer/faster growing trees should be planted beyond their mature height from the house; no tree (regardless of how hard/slow growing) should be planted within it's mature drip radius (maximum branch spread) of the house.

santacore · « **Reply #5 on:** 23 Sep 2015, 10:05 pm »

Thanks for the input guys. The mudjacking looks pretty cool. Unfortunately I couldn't find anyone listed locally that does it. An experienced contractor friend said he had never heard of it. I'll keep searching...

I believe the offending tree has been cut down, although another neighbor has some huge pine trees about 100 feet away or so, that could also contribute.

Bob in St. Louis · « **Reply #6 on:** 23 Sep 2015, 11:47 pm »

Your profile says you're in LA. I did a quick search, and the word "mudjacking" gave a couple results.
You can also search for [concrete floor leveling los angeles] and came up with several more companies.

Just a couple I grabbed:

http://www.saberfoundations.com/concrete-lifting/mud-jacking.html

https://foundationtechnology.com/services/mudjacking/

http://www.polylevel.com/polylevel-dealers/california/losangeles-concrete-lifting.html

Obviously, I found these on Google, so I have no idea of their level of service or quality of work.

Hope that helps,
Bob

smk · « **Reply #7 on:** 24 Sep 2015, 12:17 am »

It might not be called "mudjacking" where you are and they may not do very much in your area. But I'm sure a contractor knows about it. Just keep looking. I think you're experiencing the same problem I experienced recently. a lack of engineering terms to English dictionaries.

Bob Stark · « **Reply #8 on:** 24 Sep 2015, 12:25 am »

In our area it's called slabjacking. Try that. A concrete guy should have the capability.

JerryM · « **Reply #9 on:** 24 Sep 2015, 12:40 am »

What's the deductible on your Homeowner's policy? A claim should be considered if you can get the pad removed and replaced right now.

santacore · « **Reply #10 on:** 24 Sep 2015, 02:29 pm »

JerryM, I'm not sure, hadn't even thought about that option. The slabs were like that when we bought the house 2 years ago, so I doubt I would have a case.

Thanks to Bob for the links. It looks like there are a few foundation guys in Los Angeles that might help with this problem. Now to see how much they might charge!

Bob in St. Louis · « **Reply #11 on:** 24 Sep 2015, 02:48 pm »

You're welcome. I'm curious on the cost as well. Keep us posted.

Bob

jqp · « **Reply #12 on:** 24 Sep 2015, 04:39 pm »

there are many more-permanent solutions I see on Youtube

this process can be a temporary only fix depending on how it is done and the density/stability of the foam (remember foam has air bubbles by definition)

This one looks better https://www.youtube.com/watch?v=GBGvWFu7sw4

Than this one https://www.youtube.com/watch?v=_lKej0UAJ_U

and here is how this stuff flows https://www.youtube.com/watch?v=A7_tWvsiTsY

mick wolfe · « **Reply #13 on:** 24 Sep 2015, 04:42 pm »

Quote from: santacore on 23 Sep 2015, 07:48 pm

Hey all. One of the slabs on the side of my house has been raised over the years from tree roots. As you can probably see from the picture it now slopes toward the side of my house. When it rains it pools up a few inches deep and sits against the side of the house. Within the next year we are going to rip out the problem slab and redo it, but with El Nino coming, I'm looking for interim suggestions to help with the pooling issue. Any input would be appreciated.

[/quote

Probably the last thing you want to hear, but the best solution is to bite the bullet and remove / replace ASAP. I doubt you'll find a contractor that would attempt to jack up a compromised/cracked piece of concrete. Cheaper in the long run to do the permanent fix. The only temp solution I see might be to build up the area with gravel/AB and cover and seal with a thick sheet of plastic. Good luck.

Bob in St. Louis · « **Reply #14 on:** 24 Sep 2015, 04:54 pm »

Quote from: mick wolfe on 24 Sep 2015, 04:42 pm

Probably the last thing you want to hear, but the best solution is to bite the bullet and remove / replace ASAP. I doubt you'll find a contractor that would attempt to jack up a compromised/cracked piece of concrete.

Yea, I think this is correct. I didn't notice the big crack the first time I looked at it.
I'm not a concrete professional, and I didn't even sleep in a Holiday Inn Express last night.

santacore · « **Reply #15 on:** 24 Sep 2015, 05:10 pm »

Good point mick, thanks for pointing that out. There is definitely a crack in the slab, which you can see in the picture.

My original idiot idea was to mix up a bunch of concrete and just pour it on top in the hopes of leveling. Again, this is just a temp fix as we will rip out the whole section once our remodel is done(we are a year or so out).

It seems like the easiest solution now might just be to get sealer and go heavy handed around the base of the house. That way when it does pool up, it hopefully won't seep in too much.

Bob in St. Louis · « **Reply #16 on:** 24 Sep 2015, 05:20 pm »

In the interest of immediate time and money, that would be your best short term fix that I can think of.
Also, run some form of caulk between the rest of the walkway and the house, just to help "move" the water as it sheds off the siding.

But hey...contact some of those companies and email them your photo. See if they can work with what you've got after all.
If the concrete is steel reinforced, they may not be as concerned with the crack as we think.

Bob

mick wolfe · « **Reply #17 on:** 24 Sep 2015, 09:41 pm »

When I see a situation like santacore's, the first thing I assume is that the base course/sub base has been infiltrated/compromised by moisture and no longer offers any support for the concrete. Any attempt to repair the situation without dealing with a compromised sub base will fail. Removal of existing concrete and reestablishing a solid sub base is the only logical approach. This most likely will require removal of saturated sub base material to be replaced by dry material and properly compacted to new sub base grade. Now you're ready for new concrete. As I've said before, the temporary( but ugly) solution would be bring in AB/fine gravel to fill the void next to foundation. Grade it as you would if it were the new finished concrete. Now cover with plastic. Not perfect, but keeps water away from the foundation. Much of that same material could be salvaged and used as sub grade material for the new sub base.

santacore · « **Reply #18 on:** 24 Sep 2015, 10:28 pm »

Great info, thank you again mick!!

mick wolfe · « **Reply #19 on:** 24 Sep 2015, 11:42 pm »

You're welcome. I know what you're going through. I've tried a lot of temporary solutions in my day only to end up doing it properly in the end.