Concrete work - Slab foundation - InspectionNews

Dave Hahn · #1 (**permalink**) 11-06-2007, 10:18 PM

Would you say that having the exposed aggregate like this is (a) poor workmanship but does not affect the integrity of the slab, or (b) defective materials that can/will affect the integrity of the slab, or (c) fill in your own (practical) response ??

This is brand new construction.

Dave

Aaron Miller · #2 (**permalink**) 11-07-2007, 03:36 AM

Dave:

The phenomenon you are seeing is commonly referred to as "honeycombing". Honeycombing can be recognized by exposed coarse
aggregate on the surface without any mortar covering or surrounding the aggregate particles. The honeycombing may extend deep into the concrete. It can be caused by a poorly graded concrete mix, by too large of a coarse aggregate, using unclean form boards, or by insufficient vibration at the time of placement. Honeycombing will result in further deterioration of the concrete due to freeze-thaw because moisture can easily work its way into the honeycombed areas. Severe honeycombing should be repaired to prevent further deterioration of the concrete surface. Most engineers recommend repair with an epoxy-resin patching material or "grout".

Aaron

David Banks · #3 (**permalink**) 11-07-2007, 05:00 AM

EXTERIOR FOUNDATION:
: Exposed aggregate noted on foundation wall. Recommend parging. Parging may not be absolutely essential but wall is more vulnerable to water penetration and consequent deterioration. Mason recommended for repair.

I like Aaron's comments also.

Dave Hahn · #4 (**permalink**) 11-07-2007, 08:53 AM

Great info guys.
Thx

buddy brault · #5 (**permalink**) 11-07-2007, 09:59 AM

dave before you recommend the specialist( Mason) make sure you can determine the depth of this honey comb concrete. this is a monolithic slab and could effect structure above. may need to refer them to a foundation specailist or engineer. I know that sounds extreme but just throwing it out there.

Dave Hahn · #6 (**permalink**) 11-07-2007, 10:21 AM

Thanks Buddy.
Ironically, this was in Rock Hill where I see you are based.

What insight you don't provide in your message is what the significance would be for different depths (i.e., if only 1/16th inch then no biggie, but if 3/16th's then get the structural eval.). If you know, please share.

Dave

buddy brault · #7 (**permalink**) 11-07-2007, 04:08 PM

Dave I didn't put numbers because too many variables. Here's how I would look at. How far would you allow the bottom plate of a load bearing wall to extend past the edge of the slab before writing that up as needing structural evaluation. If the honey comb is surface only parging more than likely will be ok. If you are not comfortable about it error on the side of caution. Write it up. Refer it to a specailist! (ie licensed individual. contractor. engineer, or a foundation specailist.) This way you have met the standards and your covered.

Vince Santos · #8 (**permalink**) 11-07-2007, 10:57 PM

I read a post a while back where an inspector was in hot water with a client due to the fact that he did not point out this defect and note the possiblilty of water entry into the basement, which did happen.

Chad Fabry · #9 (**permalink**) 11-09-2007, 04:18 AM

It's a slab, not a wall.

The honeycombing is likely just at the form interface and proves that the contractor didn't over wet the mix.

I've never seen anyone bother to vibrate the form boards on a slab.

Freeze thaw cycles aren't much of an issue in North Carolina and even if they were, a simple parget coating would fix the problem.

Parge isn't a word. Neither is parging.

There is no mortar in concrete. It's cement. What fills the void between coarse aggregates is called paste.

If you recommend an engineer look at that slab, you should be prepared to pay for his/her services.

John Arnold · #10 (**permalink**) 11-09-2007, 05:28 AM

Quote:

Originally Posted by Chad Fabry

Parge isn't a word. Neither is parging.

Chad - You might get some disagreement about that, but not from me, because I found the much-more-interesting phrase "bughole-induced outgassing" while checking out "parging".

Bughole-induced outgassing - Wikipedia, the free encyclopedia

Jerry Peck · #11 (**permalink**) 11-09-2007, 06:29 AM

Quote:

Originally Posted by Chad Fabry

Freeze thaw cycles aren't much of an issue in North Carolina and even if they were, a simple parget coating would fix the problem.

Parge isn't a word. Neither is parging.

From the IRC.

R1001.8 Smoke chamber. Smoke chamber walls shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete. Corbelling of masonry units shall not leave unit cores exposed to the inside of the smoke chamber. When a lining of firebrick at least 2 inches (51 mm) thick, or a lining of vitrified clay at least 5/8 inch (16 mm) thick, is provided, the total minimum thickness of front, back and side walls shall be 6 inches (152 mm) of solid masonry, including the lining. Firebrick shall conform to ASTM C 27 or C 1261 and shall be laid with medium duty refractory mortar conforming to ASTMC199. Where no lining is provided, the total minimum thickness of front, back and side walls shall be 8 inches (203 mm) of solid masonry. When the inside surface of the smoke chamber is formed by corbeled masonry, the inside surface shall be parged smooth.

R406.1 Concrete and masonry foundation dampproofing.

Except where required by Section R406.2 to be waterproofed, foundation walls that retain earth and enclose interior spaces and floors below grade shall be dampproofed from the top of the footing to the finished grade. Masonry walls shall have not less than 3/8 inch (9.5 mm) portland cement parging applied to the exterior of the wall. The parging shall be dampproofed in accordance with one of the following:

From the IBC.
1807.2.2.1 Surface preparation of walls.

Prior to application of dampproofing materials on concrete walls, holes and recesses resulting from the removal of form ties shall be sealed with a bituminous material or other approved methods or materials. Unit masonry walls shall be parged on the exterior surface below ground level with not less than 0.375 inch (9.5 mm) of portland cement mortar. The parging shall be coved at the footing.

Exception:

Parging of unit masonry walls is not required where a material is approved for direct application to the masonry.

parge

One entry found.

parge
Main Entry: parge
Pronunciation: \ˈpärj\
Function: transitive verb
Inflected Form(s): parged; parg·ing
Date: 1701
: parget

parget

2 entries found.

parget[1,transitive verb]parget[2,noun]
Main Entry: 1par·get
Pronunciation: \ˈpär-jət\
Function: transitive verb
Inflected Form(s): par·get·ed or par·get·ted; par·get·ing or par·get·ting Etymology: Middle English pargetten, from Middle French parjeter, literally, to throw out, from par- thoroughly (from Latin per-) + jeter to throw — more at jet Date: 14th century
: to coat with plaster; especially : to apply ornamental or waterproofing plaster to

Main Entry: 2parget Function: noun
Date: 14th century
1 : plaster, whitewash, or roughcast for coating a wall
2 : plasterwork especially in raised ornamental figures on walls

Quote:

There is no mortar in concrete. It's cement. What fills the void between coarse aggregates is called paste.

And there is no cement driveway, it's concrete. Concrete and mortar have portland cement in them. The "paste" is cement and water, even the fines (like sand) are "aggregate". Concrete is "plastic" until it sets up (hydrates and cures), then concrete is no longer plastic.

Concrete does two things: 1) it gets hard; 2) it cracks.

Chad Fabry · #12 (**permalink**) 11-09-2007, 06:48 AM

irregardless

Main Entry:
ir·re·gard·less Listen to the pronunciation of irregardless
Pronunciation:
\ˌir-i-ˈgärd-ləs\
Function:
adverb
Etymology:
probably blend of irrespective and regardless
Date:
circa 1912

The fact that someone bastardized a pronunciation long enough for a word to make it to a dictionary does not prove it's a word.

Google "Masonary"

Aaron Miller · #13 (**permalink**) 11-09-2007, 07:15 AM

Quote:

Originally Posted by Chad Fabry

It's a slab, not a wall.

Parge isn't a word. Neither is parging.

There is no mortar in concrete. It's cement. What fills the void between coarse aggregates is called paste.

If you recommend an engineer look at that slab, you should be prepared to pay for his/her services.

Chad:

According to Webster's, American Heritage and Oxford English Dictionary the term parge, which is indeed synonymous with parget, has been in accepted use since 1701. Running a bit behind the times there in NC?

According to the American Concrete Institute's publication, "Cement and Concrete Terminology":

paste, cement

— binder of concrete and mortar consisting
essentially of cement, water, hydration products and
any admixtures together with very finely divided
materials included in the aggregates. (See also

cement paste, neat

.)

So then paste does contain mortar and is not the term we are looking for is it?

Again to the same publication:

grout

— a mixture of cementitious material and water, with or
without aggregate, proportioned to produce a pourable
consistency without segregation of the constituents;
also a mixture of other composition but of similar
consistency.

Now that sounds like what we want to fill voids, right? that's why we use grout to parge foundation edge honeycombing.

I have referred engineers to so many jobs that I've lost count years ago, and have yet to pay a single fee. NC must be a very strange construction experience . .

Aaron

Nolan Kienitz · #14 (**permalink**) 11-09-2007, 07:55 AM

Quote:

Originally Posted by Jerry Peck

... Concrete does two things: 1) it gets hard; 2) it cracks.

Bottom line ... that's it.

I won't carry those two comments beyond this post, but Jerry did provide me with a setup ...

David Banks · #15 (**permalink**) 11-09-2007, 07:58 AM

It's a slab, not a wall.

The honeycombing is likely just at the form interface and proves that the contractor didn't over wet the mix.

I've never seen anyone bother to vibrate the form boards on a slab.

Chad Fabry, Rochester, NY
StructureSmart Home Inspections, Inc.
New York Home Inspection StructureSmart The Rochester NY Property Inspector

Chad. While your being piled on I will join in.

While you may not see many people vibrate the form boards most good concrete finishers will tap the outside of the forms with a hammer to stop this from occurring.
Here we use the word "Rat Hole" instead of honeycomb. I like it better.
By the way you are probably correct that the contractor did not over wet the mix. If you place concrete wet you probably would not get this.

Jerry Peck · #16 (**permalink**) 11-09-2007, 11:25 AM

Quote:

Originally Posted by Chad Fabry

The fact that someone bastardized a pronunciation long enough for a word to make it to a dictionary does not prove it's a word.

You don't think that being around since before

Date: 1701

is not long enough to make it "a word"?

That it is only "a word" if it has been around since:

Date: 14th century ?

In that case, you'd better throw out *ALL* code books, because I'm guessing there are *A LOT* of 'not-real-words' in them.

Chad Fabry · #17 (**permalink**) 11-09-2007, 02:10 PM

I'll concede parge to an extent. I have 17 different dictionaries. It appears in three. I must have only checked the other 14.

Aaron, cement is in mortar, mortar isn't in cement. Mortar is a mix of portland cement, hydrated lime and clean sharp sand. The cement to lime ratio determines the type of mortar.

I agree, tapping on the forms may have filled the voids. The reason they're at the form interface is there were no other irregular shaped objects to fill them: forms are flat, aggregate isn't. It's HIGHLY unlikely that the voids are elsewhere in the slab.

I'm not in NC, the poster of the question is in NC. I'm in Rochester, NY. We have freeze thaw cycles. Here, I'd suggest filling the voids to avoid an improbable, but possible issue.

In NC the issue is entirely cosmetic.

Billy Stephens · #18 (**permalink**) 11-09-2007, 03:19 PM

[quote=Chad Fabry;23869 I'd suggest filling the voids to avoid an improbable, but possible issue.
In NC the issue is entirely cosmetic.[/quote]

It's Ugly!