Attach Stud To Concrete Floor

[DoubleARS]

I have to fasten some 2X4's to the floor to build a shower pan. I believe I have a post-tension slab (my first) according to the inspection report when I bought my home. I have done similar things many times using both anchors and Tapcon screws but I was cautioned against drilling into this slab. The rotted boards I pulled up were attached with what appeared to be cast spikes.

Anyone have any experience with post-tension slabs or is there a site/forum you frequent for these types of questions. I have Googled this question but I find conflicting information.

Thanks C5 crew.

[SirMike]

Originally Posted by DoubleARS

I have to fasten some 2X4's to the floor to build a shower pan. I believe I have a post-tension slab (my first) according to the inspection report when I bought my home. I have done similar things many times using both anchors and Tapcon screws but I was cautioned against drilling into this slab. The rotted boards I pulled up were attached with what appeared to be cast spikes.

Thanks C5 crew.

Same here. I have a post tension slab and my builder said the same thing. NO DRILLING INTO THE SLAB. In fact it is stamped in the slab (garage floor).

I am sorry I do not have an answer for you. I would also like to know though. I would think there has to be a way to do it safely.

Good luck OP and sorry I am no help.

[AirManFL]

Originally Posted by DoubleARS

I have to fasten some 2X4's to the floor to build a shower pan. I believe I have a post-tension slab (my first) according to the inspection report when I bought my home. I have done similar things many times using both anchors and Tapcon screws but I was cautioned against drilling into this slab. The rotted boards I pulled up were attached with what appeared to be cast spikes.

Anyone have any experience with post-tension slabs or is there a site/forum you frequent for these types of questions. I have Googled this question but I find conflicting information.

Thanks C5 crew.

Somehow, you need to see if you can get the shop drawings for the post-tensioning cables. Perhaps they have copies at the municipality building department?

Rob

[jmaynard]

Not a problem, you can shoot the nails in using a nail gun rented from Depot. It uses .22 cal shot to drive the nail in and woint mess with the tension lines.

Have you done your own shower before? I did my last one 3 times :0

Make sure that you use a liner with no breaks and that it goes up the wall at least 8". I also recommend that you use wonderboard and seal that with a tar based paint product before laying any tile.

Now for the 'real' advise, and what my wife would recommend; pay someone who knows what they are doing. It's not that it's really that hard, but if you miss any step, and I missed a few, you have to tear is all down and start again. Pros get it right the 1st time. So it basically costs about the same, unless you hit it perfect the 1st time.

[DoubleARS]

Originally Posted by AirManFL

Somehow, you need to see if you can get the shop drawings for the post-tensioning cables. Perhaps they have copies at the municipality building department?

Rob

Thanks for that. It just occurred to me that the last homeowner left a binder with some info on the house. It turns out the whole slab blueprint was in it. Bad news is that I had attached some studs to my patio. I thought it was added on. It appears it is part of the main slab and there are cables running through it. I used ancors and they were pretty deep. I hope I didn't mess anything up.

Originally Posted by jmaynard

Not a problem, you can shoot the nails in using a nail gun rented from Depot. It uses .22 cal shot to drive the nail in and woint mess with the tension lines.

Have you done your own shower before? I did my last one 3 times :0

Make sure that you use a liner with no breaks and that it goes up the wall at least 8". I also recommend that you use wonderboard and seal that with a tar based paint product before laying any tile.

Now for the 'real' advise, and what my wife would recommend; pay someone who knows what they are doing. It's not that it's really that hard, but if you miss any step, and I missed a few, you have to tear is all down and start again. Pros get it right the 1st time. So it basically costs about the same, unless you hit it perfect the 1st time.

I have not done a shower before. I bought some of these things called pre-pitch, quick-pitch, and kirb-perfect. I've also watched quite a few videos. The best lesson I have learned is that I should not do it the way the idiots did it before me. They nailed and screwed the liner on the inside of the shower pan as low as 1/2 inch up. They didn't put any slope under the liner. They used only 12 inches of backerboard behind the tiles with the rest being drywall. They had the weep holes filled with mortar.

I have hope that I will do better. Wish me luck.

Originally Posted by SirMike

Same here. I have a post tension slab and my builder said the same thing. NO DRILLING INTO THE SLAB. In fact it is stamped in the slab (garage floor).

I am sorry I do not have an answer for you. I would also like to know though. I would think there has to be a way to do it safely.

Good luck OP and sorry I am no help.

I wish they had stamped that notice before screened in my patio.

[Ivas]

No one's attachin' me to no floor, and thass final, hrrumph!

[Dieseldoug22]

Can you use Liquid Nails on it? I've used that before on other projects and that stuff holds like a mother when dry. And it won't rust or rot. And since you won't really have any lateral movement on it, it will be strong.

[DoubleARS]

Originally Posted by Dieseldoug22

Can you use Liquid Nails on it? I've used that before on other projects and that stuff holds like a mother when dry. And it won't rust or rot. And since you won't really have any lateral movement on it, it will be strong.

Not a bad idea. I will look into that.

[Ocikat]

Gluing the 2x4's to the floor is your best option, the problem in attaching anchors to a post tension slab is twofold, one is drilling into the tension rods and damaging them in the process, which would compromise the structure, this can still be done if you can accuratly locate the tension rods with a metal detector or Xray, ( a stud finder is not the right tool for this ) ( Your building prints will help if they are available however most construction companys don't always build exacltly to the architects drawings) . there is still a probem though, you cannot use a screw, or expansion type device as these will impose a lateral stress on your flooring and it will eventually crack and again this will compromise the structural integrity of your slab. the proper way to install a stud in this type of flooring would be to core drill ( after properly locating the tension rods ) the floor and install the studs in a bed of structural epoxy. kits to do this are available from vendors such as Hilti. you would really only need to do this if your attaching something like a lift or other type of machinery on the floor. The cast spikes you mentioned were placed in the floor during the concrete pour so there would not have been any compromise or lateral tension from them. hope this helps