What we're discussing are general and typical cracks. Certainly for those not familiar with cracks--whether home inspector, Realtor, seller, or buyer--then hire a professional to help you. This discussion, however, should help you be a little more knowledgeable about cracks so that you don't just automatically assume the worst. Cracks happen, kind of like Active Rain blogs - LOL.

Lesson Four

Read Lesson One here.

Read Lesson Two here.

Read Lesson Three here.

Music for your reading pleasure

 
"Another Lesson Bites the Dust," Queen

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So far, we've discussed

1. curing and shrinkage cracks in the foundation stem wall in the garage, and
2. cracks in the garage floor.

Let's move to the foundation of the house proper and the interior living area. Cracks in the foundation here can be much more problematic because of what we have going on inside. Certainly no one wants to sit it a sloping living room, or have to put a brick under one side of the entertainment center in order to level it, or to have dozens of ugly cracks in the walls and ceilings.

If you see a crack like we saw in Lesson One that initiated this discussion, it's probably one that can also simply be repaired with epoxy. However, before making that determination, go to the inside of the house where that crack is and look at the ceiling, wall, and floor there. If there are cracks in that area, it's probably best to have that area of the house looked at by a qualified foundation professional or structural engineer. There are exceptions, depending on the type of foundation (crawl space, basement, or slab-on-grade), the type of wall (drywall or lathe-and-plaster), and the type of crack (length, width, and whether it's a diagonal, straight, or stair-stepped crack). We'll discuss all of those in a future lesson, but as you can see, it takes a lot of knowledge and experience working with concrete to put 2, 7, 5, 1, 7, 3, and 4 together to get 29. Being off just one number can make a significant difference.

Following are some pictures of some cracks in slab-on-grade foundations that can indicate more serious problems.

Figure 1 shows a Y crack.

  Figure 1

Almost any V, W, X, or Y crack, either right side up or upside down, indicates some severe stresses in the area. That's because stresses tend to move in the line of least resistance (the weakest link, so to speak), so to have two lines of least resistance right next to, and intersecting, each other indicates something serious going on.

Sometimes it's simple to determine the cause, such as damage to the foundation there by the highway engineer testing his new jackhammer on the other side of that wall (this was a garage foundation). Other times it requires an engineering professional to try to track down the cause.

Figure 2 shows an exposed foundation footing, which is always bad. Every time that I have found an exposed footing, usually due to erosion, I have found cracks. They seem to go together.

  Figure 2.

When the foundation footing and the stem wall are cracked, I'm pretty sure that I'll find a cracked slab inside the house, and that's exactly what we found at this house. Fortunately, the interior floor covering was carpet, and the sellers were only too happy to cooperate with the buyers in their due diligence.

We caught this problem in time because there was no damage to the interior foundation, so some epoxy, added soil to cover and support the footing, and some gutters and downspouts on the roof (sadly lacking on San Diego homes due to our measly 11 inches of rain a year) to prevent erosion should abate any future problems here.

"Cracked slab" seems to be a dirty word in real estate, but many cracked slabs also involve simple curing and shrinkage cracks. What one has to be aware of is expansive soils, lack of a vapor barrier between the concrete and the earth (difficult to tell unless you saw the house being built), and where the through-slab plumbing is located.

Any hole through the slab creates a weak point, so if the weak point is contributing to the cracks in the concrete, a professional engineer might be required to determine abatement options. Sometimes the water and sewer pipes will have to be rerouted.

Figure 3 shows a fairly straight horizontal crack. This specific type of crack is what we call a "cold pour" crack, and they usually occur in corners, such as this little corner, and other areas of the foundation that are difficult to work in, such as bathrooms.

  Figure 3

A cold pour usually means that:

1. the union bell sounded Friday at 3:00 p.m. and everyone took off to celebrate the weekend without finishing the job
2. the first concrete truck ran out of concrete and the next one wasn't due until the next day
3. the South-of-the-Border workers just got paid and had to head South to celebrate

In other words, it happens when concrete is poured but more is needed and not available until several hours later, usually the next day. Newly poured concrete will not adhere to partially cured concrete very well, and this is the type of crack that results.

Cold pour cracks usually are not of a structural concern as long as you keep water away from the foundation -- note that irrigation sprinkler head right there, which is why I took that picture to help explain to my Clients not to water there -- so that the soil doesn't turn to Jello or erode. Jello is great to eat but it doesn't support much of anything.

Figure 4 shows what can happen to a could pour crack if the soil is waterlogged. You can see the wet soil there and how the crack has opened up.

  Figure 4.

This now becomes much more serious because there's virtually nothing supporting the interior floors. At this house, the floor on this side of the room had a serious slope in it, a slope that I could feel just by walking the floor. Didn't even need a manometer survey here.

That's it for this lesson. Still to be discussed:

1. foundations with basements
2. foundations with crawl spaces
3. retaining walls
4. solid fences
5. driveways and walkways
6. chimneys
7. interior floors
8. interior walls
9. interior ceilings
10. pools and spas

For a previous blog entry on foundations not related to our lessons here, click here.

As always, if you are not comfortable discussing common concrete cracks, hire a professional to help you.

Join us soon for Lesson Five.

Be sure to scroll down for titles and quick links to some of my other blog entries.

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Some of Russel's other blog entries

1. 12 reasons why I won't comment on your blogs
2. Concrete cracks: Lesson One
3. Concrete cracks: Lesson Two
4. Concrete cracks: Lesson Three
5. How a Seller can cancel the purchase contract during the home inspection
6. What do you do when the listing agent is, uh, blind maybe?
7. Help! I need somebody! Help! Not just anybody! Help! You know I need someone! Help!
8. What do you do when deceit is obvious? (chapter two)
9. The garage is not a playground.
10. Need to vent? Feel free to vent (your attic) here.
11. Down in the boondocks: A classic homeowner improvement.
12. How to help your Clients' house burn down. 
13. I admit it. I'm a sucker. Yep. A sucker. 
14. That just ain't the way we do it out here, Sonny Boy
15. Not responsible for advice not taken
16. There's that police guy! Hide!
17. Sometimes it's just a question of semantics and definitions
18. Winterizing homes in San Diego in September
19. What the heck are they cooking?
20. You mean that little jar will hold all that water?
21. A true real estate nightmare affecting hundreds of people
22. You mean our fine, feathered friends do that?
23. If the shower head isn't working, just turn up the water pressure
24. I purposefully burned a bridge yesterday
25. What part of that don't you understand? (Reading 101, English 101, & Spanish 101)
26. If I trip just one more time, I'll have a baker's dozen
27. Out of sight, out of mind, skip the work, charge for it
28. "How much will it cost?" "$399 plus a $100 aggravation surcharge."
29. I'm so tall that some times I have problems seeing the ground
30. In a home inspection, if the thing works, the thing works
31. What do you do when deceit is obvious?
32. Sometimes it really is that simple (electric again)
33. Sometimes it really is that simple (attic)
34. Did you put that on the disclosure form? "Oh, we forgot."