new construction - crack in foundation

I recently purchased a newly constructed home. I've been living in the home for about a month and 1/2. In the first couple of weeks, I've noticed some hairline cracks in the basement floor. As time has gone by, more have developed. I've heard this is normal, but I'm concerned. A couple of weeks ago during a heavy rain, I noticed a puddle of water on the basement floor coming in from a crack in the foundation wall. There is blanket insulation on the basement walls, so I didn't notice it until a puddle had formed. The crack is also on the outside of the foundation, but does not go down as far as the crack on the inside. My builder sealed the crack from the outside and the inside (with cement sealer and then tar on top of that), but he was puzzled as to why the crack on the outside did not go down as far as the crack on the inside. We are having more rain/snow today, and there is still a little water seeping into the basement...no puddle, just a few drops at the bottom of the basement wall. I'm afraid that something is seriously wrong with foundation because of all these cracks. Is this something that happens in new construction often?...or do I just have a bad foundation?

 

yes you should be concerned. settle that is this extreme should takes years to form to this extent and with water coming through there is a huge concern. get a home inspector/engineer asap!

Rochester, NY - Your Way Properties - Property Management - Home

 

I disagree. Most concrete cracks are due to shrinkage while curing. That's why joints are placed in concrete...to control this cracking. Walls have no joints so they crack in random places. Any crack you see goes all the way thru the concrete. That is, it's not just on the surface or extending halfway through the depth of the slab. It's ALL THE WAY THROUGH.
As you know, water will take the path of least resistance and will seep through the tiniest of tiny cracks. It's the nature of water.
In addition to cracks going all the way through the thickness of the slab, they usually go all the way from one end to the other as well. They may be wider and more visible at one end, but they may be so narrow as to be almost invisible at the other. For this reason I doubt that the crack goes down farther on the inside than the outside. It's just more visible. Did they adequately waterproof the wall before they backfilled it? I'm guessing a breach of the outside waterproofing at some point, and water will find the tiniest breach.
I am amazed that EVERY basement doesn't leak. A tiny bit of moisture, in my opinion, is no cause for concern at all, especially after periods of heavy rain. Even moderate amounts of water can be expected, which is why they equip basements with sump pumps.

 

Thanks for the info. That makes me feel a little bit better. When I showed the builder the cracks in the floor, he was surprised that they didn't go straight across the floor. He said the guy who poured the floor must not have put the joists in.

When the builder looked at the crack in the foundation from the outside, he said it didn't go all the way down as far as the crack on the inside, but I was skeptical. I had a feeling that he had a problem digging down any farther, so he couldn't see how far the crack went down. They waterproofed the foundation with black tar. I'm not sure if they did anything else to waterproof it. They backfilled with the dirt and rocks that were originally dug out. I just hate having a new house with water seeping in. It makes we wonder about the rest of the basement walls, which I can't see because of the blanket insulation.

 

New house, understandable being worried. Mine is quite new and they did nothing beyond black tar also and backfilled with what they dug out. You'll read about ideal backfilling with gravel and all that, but a lot of homes simply don't get it and, probably, simply don't need it.

If you posted a picture somebody like pecos could probably offer advice specific to it. If you continue to be concerned you could get an engineer out, just find a good/well reputed one.

What is your warranty like? Is the builder going to be around for a while? Many if not most new homes have a structural warranty for a while (although technically it only is good for pretty severe issues) but you probably don't have to rush on this. Best thing you can do is document (and with pics) what's going on so that you can create a history of it over time.

You will get cracks in concrete slabs and the most will be in concrete block walls, too, even small ones in many mortar joints.

 

If you have moisture is your basement, you have water under or around your foundation.

Do you have the most common sense use of drain tile (interior, exterior or both) leading to daylight or a sump around the foundation? It is very cheap to install during planning and construction, but very expensive after there is a problem. A basement is just a concrete tub sitting in a hole collecting water, especially if the surface drainage is not good.

I have a friend that built several thousand homes and not one without both interior and exterior drain tile from the start, no matter what the soil conditions were because he never wanted a problem and it was easier to do it on every home.

Most home builders are not that concerned or educated. Tar is always an obvious visual solution, but it does not last as long as the foundation will.

Dick