Originally Posted By: Francisco J. Hernandez This post was automatically imported from our archived forum.
The enclosed pictures are of our new two story house in North Florida. We are concerned of future problems that could arrise from the repairs. The builder said while inspecting the water pressure they discovered a leak somewhere under the slab. They drilled wholes in the slab until they found the source of the problem. Then dug the two big wholes in th kitchen to fix the leaky pipe. While I was taking pictures I noticed two hair line cracks that extended from the two big wholes, one going to the west side of the house and the other to the east side of the house. Is there any thing that we should be concern with??? We are worried about future problems, for ex. moisture, termites, radon and the value of the home etc… Thanks for your help.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
What part of North Florida? I know a good inspector in the Gainesville area.
I am not too concerned about the crack (based on the photos, which is hard to tell what is going on), however, you have other problems.
First, that leak has diluted the termite pretreatment under the slab, and the slab will likely need to be drilled in many areas and the chemical injected through from above.
Secondly, all those holes will need to have proper fill re-installed, will need to be compacted properly, will also need re-pre-treating, will need plastic sheeting (as a moisture barrier), will need WWM (welded wire mesh) installed, will need the patched areas doweled into the surrounding slab. Basically, I doubt if the builder is even aware of everything this needs before they fill the holes back in and patch with more concrete.
Getting back to the concrete cracks. Concrete does two things: 1) it gets hard, and, 2) it cracks. Large slabs will crack. Thus, most slab cracks are nothing to worry about, however, I cannot discount all slab cracks, some are indications of settlement.
Originally Posted By: Francisco J. Hernandez This post was automatically imported from our archived forum.
I am in Jacksonville. the house is in St. Johns County, St, agustine. Is all that extra stuff that needs to be done, to the wholes large and small, a standard repair? What should I insist they do? Thanks
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Real small repairs do not need the WWM or dowels, but they still need everything else. Your photos did not show anything that small.
I would insist on a complete and proper repair, even going to the building department if necessary.
It is important that it be re-pre-treated for termites (not just the dug out areas, but the areas which go soaked from the leak as that dilutes the pre-treatment chemical in the ground), and that it have a moisture barrier, and that it be filled and compacted properly (using "clean" fill, which means no rocks or other sharp objects, as they could create new leaks in the pipes).
Larger patches need re-enforcing (both of itself - the WWM - and to hold it to the surrounding slab - the dowels) to make sure the patch stays put and does not move out of the hole it patched.
Call Frank Nosko of Inspection Plus, Gainesville 352-371-2959. He does not go to Jacksonville or St. Johns, but may know someone good there.
Originally Posted By: roconnor This post was automatically imported from our archived forum.
I agree with Jerry that just looking at the pics the cracking does not appear to be a big deal, but ya have to look at the whole install and get a “feel” for what is going on, particularly in new construction.
You have to consider things like what the soil conditions are, and when that crack occurred. Did it show up right after the slab was poured, or just recently? Is there more than one crack, but just not as visible? Does it run directly across the slab, or possibly run across a corner? These things make a difference.
It's hard to tell, but it does not look like there is steel mesh (WWM) in the slab. Not that it's a huge deal, but it makes packing the soil used to fill the hole and proper patching that much more important. With small holes in thin slabs it is sometimes very difficult to drill in dowels, so sloping the edges inward so the patch acts like a cork can be done.
In addition to the other things Jerry mentioned, it would also be important to adequately patch any vapor barrier below the slab so moisture cant work it's way up ... particularly in areas with glued on tile floors.
Also consider hiring a qualified HI, PE, or RA to perform some periodic inspections during construction for you. It's well worth it, and now would be a good time to bring someone in before the concrete and framing is covered up.
(PS ... put a return between each one of you pics so they line up vertically ... then people can see them and the posts easier ...  )
Just my 2-nickles
-- Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: Larry L Leesch This post was automatically imported from our archived forum.
It appears that you have a post- tension slab as there appears to be a sleeve at the left side of the hole. Structurally, there is no compromise of the slab with this small of a hole. Most often, the plumbers will pressurize the system, cut off the water, and install gauges looking for a drop in the pressure. There was probably less than a quart of water lost during the leak and search for it. With that in mind, there is no problems with the termite treatment. The patch is usually completed using a patch mixture which includes a sealer like Posileak or others. As I see it, the only question you have here is the type of patching compound used. The cracks are drying cracks and are normal. The drill holes need to be filled with a similiar compound as the repair hole.
Originally Posted By: Guest This post was automatically imported from our archived forum.
Today I went by the house and they have repaired the wholes. I talk to the builder and he said they treated for termite, packed, moisture barrier, and did not used use any “rebarb”. He told me that they use a special mixture of concrete with fiber glass, that suppose to be stronger and will not require anything else. Is this sounds right???
Originally Posted By: kmcmahon This post was automatically imported from our archived forum.
JMO here, but that’s a pretty crummy patch job. Joint lines should be clean and strait, and dowels should have been drilled into the ajoining concrete to support the patched area. Rebar or welded wire mesh is not needed in COMPLETE concrete slabs on grade with fibermesh. But fibermesh only for a patch job is not a good practice.
Thin slabs like that are hard to dowel into, so possibly the contractor figured a way to offset that issue as was mentioned above…hard to tell from the photo. It doesn’t look like they angled the cuts to create the wedge effect.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
The reason for the dowels is to keep the patch in place within the cut out hole.
The reason for the WWM is to keep the concrete together when it cracks. The WWM, therefore, has nothing to do with keeping the patch in place within the cut out hole. The fiber re-enforced concrete is designed to replace the need for the WWM.
That puts us back to keeping the patch in place in the hole, the need for rebar. And you stated that your builder said no rebar was used.
Termite treatment, have your builder provide you with a copy of the termite companies treatment certificate (they may lie, but, if they do, they will have problems with their licensing board if anything happens.
Compacted? No way to know how well this was done.
Moisture barrier? Hopefully it is tuck up under the existing moisture barrier.
Sounds like you builder did (said they did) 3 our of the 4 things they should have done.
It is easy to drill and epoxy rebar dowels into a 4" slab, when the hole is still open, but not now.
