Cold Joints?

[shawnboy]

http://networthyinc.com/personal/images/cold_joint.jpg

I'm wondering about the significance of a cold joint in the foundation walls of my house. My builder says it's nothing to worry about. He's planning to put asphaltic tar on for sealant. I've heard from others that a cold joint will leak. However, in this case, the joint is situated higher (not lower where the water pressure would be more), and there will be an 8 foot covered porch in front of the main wall. Should I worry about this and possibly use a better sealing method there, or is my builder correct that it isn't anything to worry about? See photo at above web address.

I don't want to be paranoid, but I also don't want to be foolish and have a leak there sometime in the future.

--Shawn

[JohnScott]

Cold joints present two problems. The first is water related. That can easily be fixed by using a number of different methods.

See Link #1
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Link #2
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And you can also seal the cold joints in the concrete with tar. <- My favorite.

The other issue with cold joints involes structural integrity. This wads the main issue with many tunnels built in Japan for the bullet trains. The stregth of concrete relies on "monolithic integrity". That is to say, if the concrete is not monolithic, then it suffers from gradually reduced structural integrity. The more seams, cold joints, and cracks it has, the more it resembles the structural integrity of a pile of gravel.

For the most part, cold joints do not significantly reduce the structural integrity of the concrete due to the rebar.

In the end, each case has to be evaluated case by case.

[Eggert Construction]

I would bet money on it that there is no rebar in that wall??
The wall itself appears to be properly constructed compared to some we see, and the cold joint itself looks better than most. Was there a particuliar reason this happened, delivery, miscalc of amount? Although it looks like a good "joint" if we word it that way, they could have tried a vibrator, if it wasn't way to late?
Did they insert any dowels between pours, or was this done when no one was around? Also what type of footing drain
The term asphaltic tar is a little dated. Have the contractor use a waterproofing sprayed on membrane for you below hydraulic protection. Use one that is appropriate to your locale. I doubt that water will be an issue that high up on the wall.

[JohnScott]

Just looking at the picture, is the foot-high, 8 foot long section in the foreground another pour? How many pours did it take to get this where it currently is?

[nevada94]

If that is a walkout wall Water is not to big of a concern in my mind because the water pick up is higher then the cold joint. If that isn't a walk out wall then you might have problems. I would say a peel and stick ater proofing with my old stand by a drain mat system on top of it. This take the pressure off the concrete and moves it to a waterproofing that is a little bit more forgiving.

To address that rebar if there isn't there should of been.

[I.C.F. North]

I would have to echo Jim's commments exactly. The joint seems good with no visible signs of graveling or honeycomb that I see. It's the re-bar issue that needs a look at, is there any bars extending up between the 2 pours?
If there is, then no worries- I would also proceed to waterproof with a membrane system, preferably sprayed on if available or a primer/peel & stick would work fine. If there is no steel in that wall, then I would take extra precautions while back filling along the "fault line" so as not to knock or dislodge or push in any portion of the top of the walls.

It also wouldn't hurt to brace & shore up the inside walls prior to back fill if it looks like the situation warrants it, and place marks along the wall to see if there was any movement. Lastly- if there are any voids along this seam large enough to stick your finger in, you may want to consider using an injection epoxy mix to give a little more peace of mind.
hope that helps...

[shawnboy]

Thanks to everybody who has given their input on this for me.

To answer some questions:

1. There is both horizontal and vertical rebar in the wall(s), although I couldn't tell you exactly how much.

2. Neither my builder nor I was able to be present at the time of the pour. I would love to know the reason for the cold joint in the first place. I suspect it was poor planning which led to running out at the last minute.

3. The 1'x8' section you see was obviously poured separately but I don't know exactly how or when because I wasn't there. I know my builder insisted on that section being concrete because he didn't want to backfill against wood. They had to use a makeshift form to accomplish that section.

4. The only place there is any exposed gap or void is a small area (you could maybe lay your finger across it) on the end/corner of the short wall on the walk-out side (it's hard to explain better than that without a picture).

If I'm understanding everyone correctly, it sounds like there shouldn't be structural problems, especially since there is rebar.

What I'm still not completely sure of is whether I should insist on a better sealant than what he had originally planned to use. I don't have experience with this, so I can't tell you very specifically exactly what sealant he's talking about. All I can say is that he calls it "asphaltic tar" and he refers to brushing it on manually. Should this be good enough, or should I insist on some better form sealant?

[Eggert Construction]

I know exactly what he is proposing to use and the product was fine in years past. However, there are better products available instead of a laborer troweling on "goo" from a 5 gallon pail. The costs are not so incrementally costly to defer their use.

I don't know where you live, but the design shows or calls out a walk-out basement. That to me is "liveable space", not storage. The typical requirements under the CABO and IRC2000 codes "require" waterproofing for below grade liveable space. Waterproofing is rarely effective when provided by asphaltic trowelable compounds for long periods of time. It will work for the typical 1 year builders warranty. The main problems are the compound does not dry, in a sense, so the backfill material constantly is attempting to migrate thru it, especially during the backfill period. Is the contractor providing a drainage board to protect the troweled on material for the backfill stage? What provisions are there for drainage? Is any additional cant placed at the footing/wall juncture?

In theory the asphaltic product works; its practical life expectancy is the 1 year warranty. In my mind, because I no longer use these types of materials, it's pennywise and pound foolish! Read your specs as to what you are being provided, then apply the proper word interpretation to understand what you really bought; not what you think you bought!