Need some help!

Inspected a house yesterday that was not finished and was being sold "As Is"
The bottom floor is a raised slab that has not had the carpet or flooring installed yet. The question was that there were several cracks in the foundation floor in addition to the normal expansion crack that would be found. These were migrating within the interior in almost every room. The question from my client is; Is this going to continue, Should this be happening this early and what is the remedy?

The pictures show the patterns of the cracks.


Jim Murphy

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Jim,

In my opinion, those cracks look significant enough to recommend a SE.

Are they going to continue? Probably so with my experiences.

What is the remedy? Probably foundation repairs.

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Rick Hurst_Home Works Inspection Co_Rockwall TX
In the words of Mike Tyson.... "Everyone has a plan until they get hit inda mouf"

To be safe, you could go with a structural engineer.

Concrete does two things:

1) it gets hard

2) it cracks

I always look for cracks in the places where I would expect them, i.e.,
- long narrow area will typically crack across the narrow width
- 'L' inside corners will typically crack from the inside of the corner into the slab at a 45 degree angle or thereabout
- large areas will crack depending on where the pressures build up
- that's why control joints should be cut into the concrete
- control joints *do not stop the concrete from cracking*
- control joints simply try to "control" where the cracking will occur
- sometimes mother nature will comply with the control joints
- other times she thumbs her nose at them and cracks where she wants to anyway

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Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

Not that I am questioning you but Raised slab? Could you give your definition of a raised slab.

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Ted Menelly
"Castle"
Home Inspection Services

Concrete block perimiter wall about one to two blocks high filled with soil, wire and poured with concrete. It is above the ground rather than at ground level.

I think if you pulled the carpet back on 90% of all slab (on-grade or stem wall) homes you'll find cracks that make you do a double-take.

Just an observation...

Well at a closer look at the pics the foundation/slab has serious issues. Being a raised slab with that amount of serious (not hair line) cracks the compaction below was extremely poor. the amount of settling that has taken place with all those cracks is far beyond what one would see with any slab.

The reason I asked about the raised slab is that they do pour slabs in place with the post tension cable an all installed and there are several piers in place that the slab is cranked up off the soil and is literally a raised slab. They do get cracks in the slab but would be hair line and the post tension cables pull it together from all sides.

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Ted Menelly
"Castle"
Home Inspection Services

Ted,

What Jim means, I think, is 'slab on compacted fill', versus a 'raised structural slab'.

Jim is just stating that it is not 'slab on grade' in the sense that it is 'raised up on fill' within the foundation stem walls.

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Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

And, when there is tile instead of carpet, those cracks transmit up through the tile as 'cracked tile', and (in most cases) you can follow those same crack lines the slab by following the crack lines in the tile.

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Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

Thanks fellow,

Great job as usual. Love this site

Speaking of "raised slabs" does anybody remember back in the 50s when they began using hydraulically raising what they called "lift slabs?"

In certain soil conditions (think fill) concrete slabs installed on caissons is common and so are “raft-slabs” which are reinforced 8 inch thick slabs. We have many such types in the SF bay area and although they do well in seismic events they have a tendency to emulate the Titanic sans the iceberg.

The old 4 inch slabs, actually 3-1/2”, have major problems in that they used 6X6 wire mesh and/or ½” steel rebar reinforcement and punctured the hell out of the pitiful 4 ply plastic vapor barrier while pouring the slabs.

I don’t have to tell you that moisture quickly infiltrated through that membrane, attacked any metal reinforcement, cracking and heaving began, and the home owner law-suits grew exponentially. Most of the old timers who worked in the SF Peninsula are familiar with the saga of Foster City.

PS: How many are familiar with electric cathodic systems?

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Jerry McCarthy
Construction Consultant
www.expertbuildingconsultants.com

What's the remedy for something as shown in the photos?

Thanks,

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If nothing is moving structurally, and it is likely that nothing is, then no remedy is needed.

I say "it is likely that nothing is" moving structurally on the presumption that both sides of the crack are fundamentally at the same height (one side of the slab did not drop noticeably in relation to the slab on other side of the crack).

Another thing which causes those slab cracks is that the footing is poured, the fill brought in and compacted (even when compacted properly), the walls of the house are constructed over the footing, the roof framing is installed bearing on those walls. Then the walls and roof finished, with all of those loads being transferred down to the footing and none 'to the slab' in the wide open areas (by design, that is the intent), the footings then compact the soil under the footing *just the tinyest, itsy-bitsy amount, the slab flexes over the unloaded fill in the center, and ... well ... as I said "concrete does two things: 1) it gets hard 2) it cracks" ... so the concrete cracks.

That may, or may not, be what is the cause of those cracks.

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Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

Yes, but my point is that there are a large number of "undiscovered" cracks that preclude reporting explanations & SOP disclaimers/definitions, because they are concealed, yet still exist. Carpet, laminate, vinyl, engineered wood, tile- over-crack-suppression membranes, etc.

Many, many such cracks out there. Very few slabs go uncovered beyond initial construction. The issues are typically documented only after, or during, a remodel, or other floor covering replacement.

Dom.

Thanks Jerry, good info!

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Dom,

I was agreeing, just expanding on what you said, then went into a related direction where those slab cracks 'could' be seen.

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Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

And I was agreeing with your "agreement", just wanted to add some additional notes for those folks that don't see as many "post-inspection" conditions.

Sorry if I wasn't clear.

We live in crack heaven out here so to say we have serious amount of experience with concrete cracking is an understatement.

Those are not just hairline cracks. They are open and certain areas have settled and other followed or the edge of the cracks would not have the concrete chipped off of them. Yes concrete cracks but for a brand new home that is serious cracking that if things were prepared properly would not have happened.

My opinion it to have an engineer take his measurements and observations for evaluation to stop further movement and for possible fix for what is there now. At that stage already and more than likely future movement you could not consider tile work. More movement could have consequences to plumbing and out of square doors and cracks above and below windows and over doors and possible cracks in ceilings.

Again. The home is new and your client should be aware that if it moved that much all ready it will move more in the future. Cover you and your client with a recommendation of an engineer.

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Ted Menelly
"Castle"
Home Inspection Services

.
The Home maybe Brand New ( vacant for how long ? ) couple of years ?

Does not mean the slab is Brand New. Poured a couple of years before framing ?

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It Might have Choked Artie But it ain't gone'a choke Stymie!
Billy J. Stephens HI Service
Memphis TN.