pouring concrete over concrete

[sman]

I am going to pour concrete over existing concrete in my garage. I plan to remodel into a bedroom.The question is.Should I be doing something to keep the new concrete attached to the old concrete?

[JC-hatchet]

Two things that I would recommend you do.
1) Rough the surface up first. You can rent a 30# jackhammer or even a corded one and rough the surface up a little.
2) Then apply a concrete bonding agent. Call your local concrete supplier to see what product they recommend for this application.
Hope that helps.

[John Bridge]

If the new pour will be around three inches or more, you won't need to attach it. Just make sure you reinfroce it properly.

[JC-JohnScott]

I was thinking if you should rough up the old surface to gain better cohesion.
Just my 2 cents.

[texas contractor]

if your wanting to do it right dont pour concrete over concrete. take out the old concrete. if something is worth doing do it right.

[ils_ots]

I basically had the same question about pouring concrete over concrete. The way my garage is now the floor and outer course of block are below grade and I get a lot of water flowing in on one side whenever it rains. Subsequently, a good portion of the bottem plates are rotted and need to be replaced. Does anyone see any problems with putting down another course of block and pouring 3-4" on concrete down to get the floor above grade?

[Eggert Construction]

Does anyone see any problems with putting down another course of block and pouring 3-4" on concrete down to get the floor above grade?

Yes, I see a problem because the water that flows into the garage flows from an inadequate graded or designed exterior slab or driveway. If you raise the floor just determine where the water that now flows into the garage goes???

[Guest]

can i pour concrete over old concrete if the new pour is 5+ inches deep and reinforced with rebar?

[Eggert Construction]

Sure, but if this has anything to do with the above water problem you may create another issue.
Make sure water is not getting into the slab area because in say winter, if you have winter, the water has no place to go, will freeze and probably crack the new slab. If there is any chance of water infiltration I would try to provide some cracked areas under the new slab to allow for drainage.

The rebar reinforcement for "most" residential slabs is probably overkill. It is cheap though all in all.

[Sheena]

I recently hired a contractor to pour a walkway and patio. The walkway is 3 ft wide and has a horrible slope of 2 and 1/2 inches over the 3 feet. My question is whether I should demand the contractor jackhammer it up and start over or is there a good fix to level it out? The walkway is 26 feet long and has this slope on about 8 feet of it. Thankfully the patio has not been poured yet. I have lost total confidence in this contractor and am ready to fire him!!

[Eggert Construction]

I find it interesting that this contractor can only pour 26' of walk, then has to pour the patio?
Have'em cut out the comedy slope and replace it with the patio pour.

Good Luck!

[Sheena]

The walkway will be 14 and 1/2" above the patio with a step down. There is also a 20' wall tied in perpendicular to the walkway so he planned to have the pouring done in 2 stages. Thanks for the advice- as they will be out Monday and I definitely want the walkway fixed right before moving on to the patio!!