my home was built in 72' and i'm not sure how to go about testing the integrety of my garage floor. i've read on here that these older homes usualy didnt have rebar. my floors dont have any visual cracks. what i want to install is a maxjax but not sure about the concrete. any help would be appreciated.
testing concrete for a lift
- Thread starter mondols1
- Start date
kaffine
Well-known member
I had a engineering firm come out and take a core sample of my slab to test the compressive strength of the concrete. I think it cost around $250. They came out took a sample, patched the hole and cleaned up the mess. 3 days later I got the results. I used a metal detector to check for rebar. I don't know what size the rebar is but I was able to determine it was there and about what the spacing was.
i will probably go this route too, have someone come out to take a core sample. i have gone back and forth over a two post, four post or a scissor lift. i realy want a two post so i can drop an engine from under my car. but i want to go about it safely.
sasquach
Well-known member
Wouldn't it be cheaper to jusr locate where you are going to put the lift then dig out an area to repour the proper pad under the posts ?
Stuart in MN
Well-known member
BuickFarmer
Well-known member
I strongly suspect the floor was poured 4-5 inches thick and out of 2,500-3,000 psi concrete with reinforcing wire. (Which is difficult to determine whether it is wire or rebar with a metal detector) My opinion of wire is that it offers very little strength and all it does is holdthe cracks together. I always use rebar in my concrete slabs) I wouldn't be as concerned as much with the strength of the concrete as I would the thickness. The base of the lift post should be wide enough to spread the weight over the concrete that concrete strength shouldn't be that much of a factor. You can determine the thickness by drilling into the slab and determining when you hit dirt or gravel. If the depth is deep enough for the bolts for the lift then you should be ok.
If not then as sasquach suggested, saw cut out an area and replace it with thicker high strength concrete. This will have to be doweled into the old concrete though which can be a daunting task to do correctly.
If not then as sasquach suggested, saw cut out an area and replace it with thicker high strength concrete. This will have to be doweled into the old concrete though which can be a daunting task to do correctly.
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Full Size 66
Well-known member
Done correctly I would go the route of pouring some new pads. It may cost more but then you know for sure. I spoke to bendpak about this and they said that my new floor of six inches would be sufficient for a two post. I'll be pouring six inches deep with six inch grid for rebar. If I were in your position I would cut some three foot squares and set up forms and get some 5 1/2 - 6 sack mix with rebar tied in to your old slab. Make your pads about one foot deep and you'll be good to go... sure it maybe over kill but you will know for sure you will not have any problems...
BuickFarmer
Well-known member
Sounds good Fullsize, just one question. Where do you use the forms.
Another thing to do in addition to doweling it in (drilling into the old slab 6 inches and epoxying in new rebar) is to dig under the old slab around the sides of the hole 6-8 inches so that the new concrete goes under the old thereby helping to tie it all in.
Another thing to do in addition to doweling it in (drilling into the old slab 6 inches and epoxying in new rebar) is to dig under the old slab around the sides of the hole 6-8 inches so that the new concrete goes under the old thereby helping to tie it all in.
Denee007
Well-known member
I know my husband wouldn't allow tearing up our nice garage floor! Must think Resale and what potential buyers would think, unless they themselves would want a Maxjax!lol
I'm just going to drill a hole and see what comes up, if it's shallow, then I'll have to pursue other lifts~ still remaining optimistic that it's ok.
I think this is probably most peoples concerns! Thickness of the concrete and drilling the concrete~ at least these are my concerns~
I'm just going to drill a hole and see what comes up, if it's shallow, then I'll have to pursue other lifts~ still remaining optimistic that it's ok.
I think this is probably most peoples concerns! Thickness of the concrete and drilling the concrete~ at least these are my concerns~
sasquach
Well-known member
Not unless you can pour a new floor for $250.
Can't pour a whole floor for 250 but I shure as hell can pour 2 pads and reinforce with rebar the proper depth for not much more .
