I’m trying to remodel my house. I pulled the plans for my house, built sometime before 1953, only to find that the filed plans are not of my house. I can tell because nothing matches. The garage is on the opposite side, the fireplace is in the center rather than the left side, and well, virtually everything else.
There was an addition added on the back half of the house. The foundation seems very solid and built reasonably sensibly. I do not want to re-lay the foundation because this would be outside my budget. This is not on the plans, and I’m wondering if I can detect rebar in the foundation. If found, I can drill through the foundation and see how thick it is and the thickness of the rebar.
If I were to buy this Walmart metal detector, could I detect 1/2" rebar buried 2" below concrete?
There are companies that scan concrete. It’s often done as a safety precaution. Some home construction slabs used post-tension cables and cutting into one of them can seriously injure a worker. They can also evaluate the slab for hidden voids or other defects.
This is a company in my state. Every state will have similar companies.
http://groundpenetratingradararkansas.com/concrete.html?gclid=CKblv5Kg9MECFc1_MgodhnEAWg
I haven’t got any quotes from the scanning companies. The cost shouldn’t be too bad. Deciding whether to replace a big house slab requires these scans. A lot of money can be saved if a slab is ok and doesn’t need replacing.
If even the cheapest metal detector can’t detect 1/2" rebar two inches away it is broken
But that isn’t the same as locating it. Your cheap metal detector won’t tell you the depth or give you a good enough fix to be able to find the rebar in the concrete. It will simply tell you whether the concrete is re-enforced or not.
For actually locating the rebar you need a rebar detector or a cover detector. Not cheap. Rental is a possibility, or as above - get a professional to survey it. Depending upon your local building codes and liability issues, getting a professional assessment may be mandatory anyway.
Even it the rebar is not under stress (the cutting of which causes the rebar to whip around with tremendous force), even cutting it will destroy the structural integrity of the slab (as in breaks, crumbles, etc.).
Do it right - and make sure the folks before you did it right.
If you ever decide to add a story, make real certain exactly how much of what is in the footers.
It’s not clear what your plans are. Are you intending to rebuild on that slab? Are you concerned about it’s conditions? Do you need as-built plans filed? Unless local code requires it, or you intend to greatly increase the load on that slab it shouldn’t be much of a concern. None-the-less if you are making any significant change you need a pro to assess this.
As stated above a small metal detector will tell you there is some rebar in there somewhere, that’s about it.
You are concerned about making sure the foundation is properly done but think maybe checking with a Walmart metal detector would be good enough? Those two things really don’t belong together.
Why not talk to a local foundation specialist or actual engineer? Don’t you think the city is going to want something better than ‘I checked it with a metal detector’ before they even give you a permit? I don’t know where you live but here if I had to do something major enough to worry about the foundation they would want an engineer’s letter.