Basement wall Structural problems 3

[scoopgh]

The basement walls were poured using forms. The pour began on a HOT August day in one corner filled to the top sloping down at about a 45 degree slope to the bottom of the form on other end of house. Then moved to the opposite corner of house doing same. The next day the forms were removed. We can see a crack (or maybe it's called a seam) on both sides of the wall exactly where the first and second pours came together. If you draw a square and put a diagonal line from one corner to the other you get a better idea what IM trying to explain. Structural problems is our first concern, second water entering the homes basement living areas.


First pour started here
 |                           |  
 |                          \ / Second Pour started here
-\/--------------------------
| \     Second          |   
|   \        Pour          |
|     \                      |
|       \                    |   Basement wall
|         \                  |
|            \              |
|First pour       \       |
-----------------------------
    

 

[Qshake]

What you have is a cold joint. It appears to me, that this is a result of shoddy workmanship but probably normal to the residential construction industry.

When we place concrete, we start at one location and proceed to the finish point. Furthermore, the concrete is thoroughly vibrated at locations where lifts (different segments within the same pour) are placed. Apparently, no one did this for your basement wall.

Take plenty of pictures before this is covered up and note all the conditions etc. It is likely that water will penetrate the wall later on thus leaking into the basement. In the winter, if you have temperatures below freezing any water inside the joint/crack will freeze and expand thereby opening the crack more.

Unfortunately, I don't know a good solution other than epoxy-injection which looks like hell especially on a new home. Ultimately, to potential buyers/lay-people, it will look like your foundation has settled indicating a long term problem and one that will reduce the value of your home.

I'm sure that the contractor will not want to remove and replace the wall. Although, this is what he should do!

Good Luck.

 

[Ginger]

I agree with JAE that you do have a cold joint and yes it will leak as he has described. As for repair methods, there are a range of solutions available. There are all sorts of injection preparations used (acrylic based sealants are probably the most effective at present). Alternatively, the contractor could cut out the joint back to the rebar and mortar up the gap with epoxy based repair mortar. A third option is to seal the external surface with a sealant (not really the best option in the long term) but is cheap. I doubt that this will be the cheapest in the long term as you may still be left with a leaking crack. Bad practice has caused this problem. You need to better supervise the contractor, (or educate him).

Regards Andy Machon

 

[JAE]

Andy: all credit on the above post goes to Qshake...not me

Also...agree with Q that the structural leakage, integrity issue can be solved.....but the bigger issue is the future buyer (assuming you sell someday) as so many people are ignorant of concrete wall behavior and may shy away from a wall with a cold joint, even if its been repaired. The outside wall surface will probably be mostly underground, but the inside is in full view unless you furr out and cover with gypsum board or some other wall surface.

 

[Ron]

scoopgh...you heard the guys before me...they are exactly right, as usual..

I have one point to add, that being with the epoxy injection that Qshake mentioned. That is the appropriate repair for this condition. If the cold joint line is clean, with well consolidated concrete on either side of the line, then you will just need to have the contractor route the joint, then inject with epoxy. I suggest SikaDur 32 Hi-Mod epoxy. After injection, have the contractor "scabble" the joint and then place a skim coat of polymer modified mortar repair (Sika has one of those also...I'm beginning to sound like a commercial for Sika! I've just had good results from their products so I usually specify them). If the cold joint line is not clean (honeycomb near/crossing the joint) the process is a bit more difficult but still a similar repair process is appropriate.

As Q said, someone down the road will think major structural problems occurred. Document everything and fully disclose if you sell. It will keep the panic down and save you lots of trouble.

Good luck.
Ron

 

[Qshake]

As always, Ron, your right on the point about the disclosure. That can be turned in an opportunity to benefit you; its an opportunity to educated the buyer about the situation and that once corrected will not likely be a problem at all.

 

[scoopgh]

Due to the integrity questions of the concrete. We were able to negotiate with the general contractor to have a structural engineer take a core sample and have a look at the cold joint. I ll let you know the results. You can follow my other concerns at the below link on this website. Thanks to everyone!

http://www.eng-tips.com/gviewthread.cfm/lev2/26/lev3/72/pid/592/qid/9603

We are also looking into a waterproofing method for the exterior of the basement walls, and would welcome any input. The contractor would like to use the asphalt mopping. He claims to use it all the time with no problems. We have read that the uncured chemicals in concrete will break down the asphalt or it becomes brittle underground. We plan to live in this home forever so a lasting product is key.

 

[Qshake]

SCOOPGH,

In regard to waterproofing please refer to the following thread in which RON has responded with excellent advice.

"Concrete Foundation for a Basement" Thread194-2989

Good Luck!

 

[dik]

In addition to the bituthene repair mentioned by Ron (little pricey, but works really well), there are proprietary systems such as Miradrain that consist of a polyethylene sheet with 3/4" 'dimples' that have a non-woven geotex material; there is a cap flashing that attaches at the top. These are relatively inexpensive and provide an 'air' gap between the wall and soil to help ensure that no water is adjacent to the wall. In addition because of the lack of moisture, it reduces heat loss through the basement wall to the soil (northern climates).