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View Full Version : Advice request: Concrete work


patteeu
06-07-2006, 07:27 PM
I'm having a concrete pad laid alongside the pad in front of my garage and extending back along the side of my house. I've had a couple of contractors come out and make bids. One of them tells me that he would drill into the existing pad and my house foundation every couple of feet and use short pieces of rebar to anchor the new pad to the existing concrete. The other one tells me to beware of contractors who do this and says that he'd put some kind of material between the old concrete and the new but not anchor it so that the new could float either up or down (relative to the old) if it needs to.

I can understand that letting it float would reduce the potential stress and therefore reduce the likelihood of cracking but I don't really want a substantial elevation difference between the old pad and the new pad either. Which contractor has the better approach?

Thanks in advance for any helpful advice.

ChiefsFire
06-07-2006, 07:29 PM
whenever ive assisted with pouring a porch or add on,we always shot rebar into the exsiting concrete...

HemiEd
06-07-2006, 08:07 PM
Done quite a bit of this and we always let it float. What is your soil like?

jspchief
06-07-2006, 08:40 PM
What is your soil like?Probably the most pertinent issue.

The problem with using rebar to tie it in to existing concrete is that you're connecting concrete that has yet to settle with some that has probably done all the settling it's going to do. If the soil is stable and the contractor does a good job preparing the ground beneath the pad, you may be fine. But if the new pad needs to settle, but is locked on to the other concrete, it may crack or settle oddly.

ChiefButthurt
06-07-2006, 08:40 PM
Wow. DO NOT allow the contractor to "dowel" the new concrete into your garage floor pad. Have them install expansion material at the connection of the new concrete. If the new pad were to move, you wouldn't want the garage floor OR especially your foundation to suffer the same consequence. If you are driving over this new concrete and it sounds as though you are, make certain that it's five inches thick with 6.5 bag mix and wire mesh reinforced. Placed over at least 6 inches of 3/4" crushed limestone. The additional cost should be minimal.

ChiefaRoo
06-07-2006, 08:44 PM
Wow. DO NOT allow the contractor to "dowel" the new concrete into your garage floor pad. Have them install expansion material at the connection of the new concrete. If the new pad were to move, you wouldn't want the garage floor OR especially your foundation to suffer the same consequence. If you are driving over this new concrete and it sounds as though you are, make certain that it's five inches thick with 6.5 bag mix and wire mesh reinforced. Placed over at least 6 inches of 3/4" crushed limestone. The additional cost should be minimal.

Don't forget to to use duct tape and lots and lots of gauze pads. I mean my god man don't you get it?! It's all done with tape and gauze pads these days! :)

plbrdude
06-07-2006, 09:09 PM
Don't forget to to use duct tape and lots and lots of gauze pads. I mean my god man don't you get it?! It's all done with tape and gauze pads these days! :)



tape and gauze pads??? whatever happened to good ole bailin' wire?

prolly should let it float

Iowanian
06-07-2006, 09:42 PM
I agree. If the new pad were to settle after it was connected, it could cause your garage/foundation to crack.

Considering what you're talking about doing....I'd let it float.
If it were a house addition, I might feel differently.


This is a good question for the handyman thread...I'm going to link it.

Probably the most pertinent issue.

The problem with using rebar to tie it in to existing concrete is that you're connecting concrete that has yet to settle with some that has probably done all the settling it's going to do. If the soil is stable and the contractor does a good job preparing the ground beneath the pad, you may be fine. But if the new pad needs to settle, but is locked on to the other concrete, it may crack or settle oddly.