[hobbzilla]

I am doing a shower remodel. I am having to extend the plumbing and by doing so will need to break up/trench some of the slab.

I _do_ have post tension cables.

How worried should I be about these? I can't afford $500 to have a firm come and locate them for me with GPR or X-ray. It will obviously be more work, but if I tred lightly with a chip hammer vs. using a wet-saw & jackhammer will I be okay?

I have read that these things are torqued to 30k psi and if broken, could sever a person in half!

[Milo Dolezal]

We frequently work on slabs with post-tension cables installed. You do this:

1. plan where you want to cut and trench
2. cut slab about 1 1/2" deep ( score it )
3. take demo / jack hammer and start carefully chipping concrete

Do not be afraid. Cable won't break that easily. If you run into cable, keep chipping around it. Check outside wall. If you see end plug indicating end of the cable, do not chip too close to that plug - or it will snap at you with lots of force. I happened to us before and it is very dangerous situation.

Depends on the house, tension cables can be 4' , 6' or 8' away installed in a grid like design. Chances are you may not even run into it at all.

[hobbzilla]

Milo,

Thanks for the reply. I must say I am very concerned but not detered!

My greatest concern is that I will be breaking up the slab about 2 feet in from the exterior. If in fact I come across a cable that runs perpenicular that close the end of the slab, what are the chances that a 5' x 6" trench that close to the end of the slab would allow the cable to pop under the release of tension?

I have walked around and taken measurements of the places I have found that indicate a cable end and tried my best to overlay a grid on the floor and where they are most likely to be giving myself a 6" high-probability sector.

I plan on going at it slow and using an 30lb chipping hammer vs. a jackhammer. I do not have anything currently to score the concrete. Since I didn't plan on doing anything other than scoring the slab, I did pondered the idea of getting a diamond blade for my circular saw and having a helper keep the concrete wet with a pump sprayer and clean up in small sections with our shop-vac (perhaps taping a plastic bag around the motor housing? ). I have been informed that if I make our house a dust bowl, my wife will be taking the kids and moving out!

Thanks in advance!