When to worry about a cracked foundation?

[db4570]

Hi, everyone.

We have a family property in Northern New York with a cabin on it that has been neglected for many years. The foundation has had some cracks for some years, but seems to be getting worse. There are now cracks between the blocks on all four sides, and some of the blocks have shifted outward up to about an inch. I am attaching pictures that show the worst of them.

The senior family member who built the cabin and laid the block seems very unconcerned about the cracks, feeling a little mortar patch will fix them right up. I'm worried that the foundation is going to continue to crack, shift, and eventually, collapse.

What is the general consensus? Is this as serious as I assume, and will it need a major repair in order to make right? What are suggested repair methods and possible costs? Thanks for any input!

David

[PEG688]

  I'd say it needs professional help. You If you where very handy , maybe you could repair it, BUT IMO it's beyond a "lil mortar will fix-er right up".

  And it's beyond a home owner repair.

Yes, it will get worst in NY state you get freeze / thaw cycles water will get in , it will freeze and the cracks will continue to get worst.


How quickly it will go depends on a lot of things, it could last ten / twenty more years with limited danger of collapse, then again it may not.

        G/L what ever you decide to do. PEG

   

[MountainDon]

Ditto PEG's comments. Looks quite serious.

[Squirl]

Wow, are those pictures recent?  Did you get snow?

Anyway, it looks very serious.  My concern would be what caused it.  If the foundation was too shallow, this will just keep happening.  The corner of the building of the first picture looks like a concrete footing.  Is this the case?  How deep does the foundation go?

[rocking23nf]

The wood above it looks about ready to rot also.

[Mike 870]

Water is often the culprit in situations like that.  Is there a broken downspout in the area?  Does the ground grade towards your trouble area?

[db4570]

Thanks for everyone's help with this. I had a feeling it was a bad situation.

How is something like this repaired, anyway? Is the house jacked up, the shifted blocks chiseled out, and new blocks laid in? I don't think anyone in the family is going to go through that effort or expense, so I'm guessing it is going to crumble and fall down, eventually. In the meantime, there's a huge tax burden on this 200 acre property that is unused. So it will probably be sold soon. It's a shame because it was once a nice, simple cabin on a nice chunk of land.

It does get real cold up there, about 5 miles from the Canadian border, so that's probably a major contributing factor. (Although, no, the pictures were not taken this week, but last winter!) I don't know how deep the footings are, but they are substantial, so I'm guessing he originally put them below the frost line. But who knows?

Any other ideas or suggestions appreciated.

Thanks,

David

[diyfrank]

What it looks like to me is water may have gotten in your blocks from around your window and froze.
It doesn't look so bad at the ground level. If you shore it up, it could probably be fixed by replacing the broken blocks if thats the only bad spots you have.  If you are going to loose the land anyway why bother. The pictures show the damage well, but it doesn't show the size of the cabin or how much support it has left.

[jb52761]

That one wall doesn't look very wide to me, although can't see the side. Is there any way it could be repaired by removing the window first, then support the upper joists from the inside corner with a pole jack, knock out the broken blocks and remortar new ones ?? I'm counting about 18 or 20 new blocks, which wouldn't break the bank. Just a thought.....jb

[jb52761]

Oops...meant to say get the pole jacks inside the corner first, then take out the window....etc

[db4570]

Sorry to revive this old thread, but I've been thinking about this property, and am having a hard time giving it up just yet. JB's suggestions put it into a bit better perspective.

I discussed the cracks with the family member who built the place, and he said the foundation is just fine.

We may have had a difference in nomenclature. I was calling the "foundation" anything that was made out of masonry. He considers the foundation to be the concrete and block below grade plus the poured concrete footings, and the exposed wall with the cracks to be just an exterior wall that isn't such a big deal to fix. He has a point. It seems that exterior wall could just have easily been built out of wood framing, and if it had been the repair wouldn't have seemed as intimidating to me. When I saw cracked masonry, I started imagining the entire foundation was shifting and crumbling. The wall may be cracking, but that doesn't mean it's necessarily anything more serious than that.

The repair doesn't seem to be too extensive, if in fact I can, with some strategically placed jacks, chisel out the cracked blocks and morter in some new ones.

The second development is that I talked to the town tax asessor, and he is going to review the property, and seems to think it is probably over-asessed from my describing it to him. So the place is getting more attractive to me.

So I'm thinking about trying to fix it. I have done a bit of concrete work in the past, but no masonry block. How hard can it be? As long as it's structurally strong, who cares if it's not perfect looking?

Any other ideas and suggestions on how to proceed, if I decide to tackle this? C'mon, guys. If you talk me into keeping this place, I'll probably be the most active forum member here, with a new catastrophe I'll need advice with every week! 

Thanks!

David

[Don_P]

How deep are the footings? I would want to incover and inspect them to see if they are intact or cracked and displaced. You may be able to probe with a section of rebar alongside of the wall and get an idea. If the problem is simply with a section of wall, I'd agree that it wouldn't be too hard to support that section and remove/replace. I've held up a couple of buildings and either installed or replaced sections before. It's labor intensive but not particularly difficult. Just work safe and realize you're working under a deadfall trap, take the time to support it very well.  Never support a building on a stack of unmortared blocks, the load goes to the highest point and can crush a block dropping the building... that's experience speaking  my buddy just got his hand out as it dropped 8". I use cribbing made of 4x4's and 6x6's stacked like this # under the walls and floor, wood might crush a bit but doesn't suddenly turn to dust. Its late in the season to start but a good time to assess and make a battle plan.

[JRR]

I agree with Don_P's and others who are concerned about the foundation-footings.  Are they heaving during frost and thawing seasons?  If you dig down to inspect them, you don't want to dig so deep beside them that you cause more troubles by the looking ... upsetting the bearing-soil.

If footing "heave" is found to be the root cause, you may be able to remedy the situation by insulating the footings.  Do some reading on "Insulated Shallow Footings" and you will get the idea.  After the footings are corrected, then the foundation wall can be repaired.

[John Raabe]

Here is one of the PDF files we have on insulated foundations at the main CountryPlans.com site:

http://www.countryplans.com/Downloads/shallowfound.pdf

[db4570]

Thanks for the info, guys.

I don't know how I would discover if the footings are damaged. By digging out enough near the cracked wall area to visually inspect them for cracks? What would I feel for with the re-bar method- a big, shifted, ledge in the concrete?

That article on insulated footings is interesting. It didn't really talk much about retrofitting existing foundations much, though. I'm guessing it would done by scraping down a little around the outside of the perimeter of the foundation, laying the foam panels flat, and covering with dirt.

Don's discussion of supporting the floor above while fixing the wall is interesting. I guess I was thinking that for removing a only 4-6 ft length of damaged wall, some sturdy floor jacks under every, or every other floor joist might suffice. I'll have to get back there and take a really close look at how it's put together.

Thanks for the ideas, and keep 'em coming!

David

[Don_P]

I was thinking that probing might give you an idea of how deep the footing is. I would dig all the way down to it if doing the repair and bring up a new section of wall from wherever the cracking begins. If it is a small section jacks or posts would work, as it gets more extensive I like something wide and stable under there. Don't leave the footings exposed over the winter though or you will heave them.

[JRR]

More reading on Frost Protected Shallow Foundations:
http://www.toolbase.org/PDF/DesignGuides/revisedFPSFguide.pdf
.
... note (buried) comments on "proper drainage" in most of these treatises.  Most insulation systems become compromised when wet.

[Squirl]

It seems that the argument seams to come down to whether water got into the wall and cracked it or it cracked from frost heave.  I may be misinterpreting the first picture.  Are the blocks 8x8x16 or 4x8x16?  My guess was that they were 8x8x16.  The corner of the picture it looks like a 8 inch concrete shelf off of the corner?  Then it is covered by grass.  If it is, is this a footing or the foundation? 

Either way, I would make sure that it goes down at least 4ft.

[db4570]

I hope it's not too inappropriate to resurrect such an old post, but I'm back on this project. I figured I'd pick up where I left off rather than start over...

If we just sold the place, as my instincts suggest, it would make the family member who originally bought the property and built the cabin very sad, so it looks like we are stuck with it for a while.

I have learned that the footer along the back of the cabin, where these cracks are, is only about 18" below ground level. This is in far northern New York a few miles from the Canadian border. So I understand why the wall is feeling a bit vulnerable.

I got chatting with the neighbor, who is a nice guy and a semi-retired contractor, and he seems to think the footer and block wall could be fixed fairly easily. He is suggesting having the rear of the cabin jacked up, and the old shallow footer dug out along the back and part way along the sides, and having it re-poured correctly.

The reason for doing it only partially is because the cabin is built on a slope, with a walk-out in the back where the footer is shallow, but it gets deeper under the earth along the sides where the slope comes up, with earth eventually even with the upstairs level at the front. So theoretically it is only too shallow toward the back where the ground slopes away. I hope I am describing this in a way that is understandable.

He says that a mason could then re-stack or replace the blocks where they are damaged and either mortar them or surface bond them. He seems to favor the surface bonding method, presumably thinking it's easier for a non-mason contractor to do. He describes it as an accepted and approved method for building block walls without mortar.

There is another crack that I have discovered that runs horizontally along one side wall that's big enough to see daylight through. He likes the surface-bonding method for that, too.

Thoughts? Critique?

Thanks!

David

[Don_P]

I'd agree, it sounded like a shallow footing moving seasonally. The horizontal crack sounds like a lateral, sideways pressure problem, these can buckle a wall, diagnose it. Surface bonding will work, price is higher but it is easier. Personally I'd mortar, rebar and grout cells in the repair.

[Squirl]

I agree with Don_P.  You got some good advice.

For minor cracks in masonry, it is not uncommon to chisel out a joint and repoint it.  Lookup brick pointing to see a guide for it.  There is a chapter devoted to it in most masonry books you can get from the library.

If you have never worked with mortar before, SBC is simple.  I would recommend putting it over a larger area and both sides so that the fiberglass can make a good connection and create a good diaphragm to hold. Pointing is a simpler and a lot cheaper than SBC, but is more intimidating to people who haven't worked with mortar.

[UK4X4]

coming from a brick house back ground...............that needs more than pointing !

I did'nt fully get the description but looks like its the tall end of the foundation thats failed

like the neighbor said jacking up the cabin inside behind the wall

Using steel props and load spreading timbers beneath- in the UK we commonly use rail road ties as their cheap

you can use a hydraulic jack on one post while setting the post next door's screw thread- quicker and easier than trying to lift stuff with the screw threads.

Once your good with the supports remove the failed wall and start again

To me the footers broken-  the walls then failed and cracked above

A lateral crack could also be due to one section of wall is well supported while the ground beneath the cracked section has settled

Is there any rebar in those walls ? footer ?

[db4570]

Good advice, guys.

I probably won't tackle this myself, although it is good to know something about it so I know if I am hiring a competent guy or not.

The newly-discovered horizontal crack in the side wall doesn't worry me too much. The wall seems straight and not shifted along it. It's just an open crack along the horizontal mortar line.

If I replace the footer along the back wall, should it somehow be mechanically tied in to the existing footer around the rest of the house? The footer will then be two depths, like a stair step. I assume that is kosher?

Thanks, and keep the ideas coming!

David

[Squirl]

Stepped footings are not uncommon on sloped land.  Probably what should have been done in the first place.



A horizontal crack will absorb water and get worse with freeze/thaw cycles and cause premature failure.  A DIY job can have that chiseled and pointed in under an hour for $5 of mortar.  They may even sell some type of crack filler at the big box store.  It is a cheap and easy fix.  Worth it imho.

[rick91351]

I stepped down the center footings in the house we are building.  As it was drawn there was to be only a 13 5/8" crawl space through the footings.  Our building inspector let us drop them down to ground level.  This footing however has a stupid amount of rebar all the way around.