Floor Strength...

[merlinpro]

Hi Guys...

Quick question...

I had my floor poured this morning after waiting because of weather. It was poured @ 3500LB and reinforced (fiber mesh I believe?).

I will be ordering a HD 9 4 post lift in a day or two, and the place that the lift will be comming from (once floor was poured then that was the go to order lift!) said to have at least 3000LB.

Just checking with the floor experts to make sure I ended up with the right stuff...I know, the floor is poured....but does the fiber mesh make it a little stronger?

We were going to go with 5000LB at first, but ended up at the 3500LB+ fiber mesh, and builder said more than strong enough to hold a 10 wheeler truck.

OH, should say that the concrete is between 4-5" thick.



Thanks. Dave.

 

[pattenp]

You're good to go with 3500. I don't think it's an issue with a four post, but a two post requuires the concrete to be cured for 28 days to make sure the anchors hold properly. The fiber reinforced concrete helps with controlling cracking. Doesn't add the strength that wire mesh or rerod does.

 

[6768rogues]

I agree with pattenp. The compressive strength of your concrete mix is considered to be its strength at 28 days of typical curing time. After 7 days it will probably be around 2500 lbs.

 

[FakeName]

I have an existing concrete slab in my backyard on which I'm considering a two-post lift. How do I know if the concrete is to spec? House/slab was built in 1962. I was a very young child. An infant, really.

 

[ezrak8885]

I hope that it's ok if I ask my question here, since we are talking about floor strength. I found this online article about hardwood flooring and was wondering if it would be a good idea to use that concept for my garage at least partly. Does anyone have some information about hardwood flooring in general or any experience with two different kinds of flooring in his garage? Any information is appreciated.

 

['the epoxy floor guy']

I have an existing concrete slab in my backyard on which I'm considering a two-post lift. How do I know if the concrete is to spec? House/slab was built in 1962. I was a very young child. An infant, really.

I would tell you there is ONLY an UNSCIENTIFIC 'guess' way to test the concrete without cutting out a piece and having it 'tested in a lab.

I would take a Cold chisel (or large flat screwdriver) Giving it a Solid Whack with a 2# hammer in an inconspicuous spot on the floor. If you dig into the floor more than 1/8" the floor may be 'of poorer' quality.

In General if the floor is 'solid' and not 'flaking off' generally sound and passes the 'whack' test, I would feel safe.

When drilling the Expansion bolts I would pay CLOSE attention to how DEEP the concrete is in EVERY hole.

We have learned a lot about concrete installation in the last 50 years. Major problems exist when the base is not prepared at an even thickness. (cement truck leaves giant RUTS in the sand or gravel base) Drill ALL your holes and test the thickness of the concrete before 'committing' to use those holes.

If in doubt, Break out a 3' x 3' area Dig it 12-16" deep. Bring a couple 55g barrels to the redi mix plant and ask for a 1/4 yard of concrete. Place in your spots and let cure.

Then you KNOW what you have.

 

[ddrewyor]

You could look into a rebound hammer type test (P or N, I think). There is a correlation between the rebound of the "hammer" and the compressive strength of the concrete. It will not tell you the thickness of the pad, but you can come close to the strength of the concrete and then just drill holes to find out the thickness where you are going to place the equipment. Take care and good luck
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