Two Post Lift, Premix or mix your own?

[cthulu]

I have everything ready for the pour (finally!) that will be the base for my two post 9k lift.

http://www.revolutionlift.com/RTP9-9000-Pound-Capacity-Two-Post-Lift-P1C3.aspx

It has a 6in key around every edge and is 4ft by 15ft and 10in deep.

I live in the Seattle area and the professional cement workers are on strike in a lot of places. Getting a truck to come in and pour was hard enough before hand with how busy everyone is but not it's basically impossible.

I have a friend of a friend that works concrete for a living that is willing to help me get the two pallets of premix along with about 10 bags of concrete and get it in the floor for 300$ + materials and my help.

He's been doing this a long time and has pretty precise care and feeding instructions for the concrete after we pour it but says that there is a good chance I'm going to get surface cracks afterwards which made me nervous.

What does everyone think? (Note: rebar work is done, was taking progress pics)

 

[lakeroadster]

Get it from a mix plant. Too critical an application for hand mixing.

More data here: Going To Pour Concrete Slab, How Will I Know I Got The Strength I Wanted?

 

[Walter_TA]

I am with lakeroadster

 

[edcantu9]

It should be fine. Of course there is always the optimal optimal way of doing this. But the price is right and it should work.

 

[LX-Markham]

I deleted my original response, and also on board with Lake.
Besides, mixing by hand *****.

 

[jaysberman]

around here we have trucks that mix what you need on site and then pour it, Pa.

 

[73RR]

I found 7 listings for 'mobile mix concrete in seattle'..........

 

[cthulu]

I found 7 listings for 'mobile mix concrete in seattle'..........

Try calling them and scheduling something, all the union guys are on strike or are booked up 2-3 months out due to demand.

 

[garagelogician]

Get it from a mix plant. Too critical an application for hand mixing.

More data here: Going To Pour Concrete Slab, How Will I Know I Got The Strength I Wanted?

Ditto

 

[jdsac]

excerpt from Mohawk
DO NOT install any Mohawk lift on any surface other than concrete, conforming to the minimum compressive strength, aging, reinforcement, and thickness stated in the table above. DO NOT install any Mohawk lift on expansion seams or on cracked or defective concrete. All ¾ inch diameter anchors must be a minimum of 6 inches away from any expansion seams, control joints or other inconsistencies in the concrete. All 1 inch diameter anchors must be a minimum of 7 ½ inches away from any expansion seams, control joints or other inconsistencies in the concrete. Refer to anchor manufacturer specifications for specific information concerning edge distances and bolt to bolt distance requirements. NEVER, NEVER install a Mohawk lift on hand mixed concrete. DO NOT install any Mohawk lift on a secondary floor level or on any ground floor with a basement beneath without written authorization from the building architect and prior consultation and approval from Mohawk Resources Ltd

They are adamant about not using hand mixed concrete

 

[cthulu]

Ditto

Guys, getting a truck to pour in the Seattle area is not an option unless I want to wait 2-3 months.

The main question is do I want to use premix, or mix it myself.

Again, getting a truck for the pour is not an option due to worker strikes and demand.

 

[LX-Markham]

He's been doing this a long time and has pretty precise care and feeding instructions for the concrete after we pour it but says that there is a good chance I'm going to get surface cracks afterwards which made me nervous.

He uses too much water in the mix then, or does not cure it properly.

 

[73RR]

Try calling them and scheduling something, all the union guys are on strike or are booked up 2-3 months out due to demand.

...and yet Burien Concrete can have it ready next Wednesday...no, they are the high priced leader. If you are near Auburn then Cascade Mobile mix can have it for you on the 24th.
It would appear that you really haven't bothered to actually call any of the mobile mix companies.

 

[polizei1]

Guys, getting a truck to pour in the Seattle area is not an option unless I want to wait 2-3 months.

The main question is do I want to use premix, or mix it myself.

Again, getting a truck for the pour is not an option due to worker strikes and demand.

Then wait 2-3 months...you're talking about a potentially bad mix and your life. Not worth it IMO, but obviously it's your life to live. This is almost as bad as the guy a few threads down complaining about hearing loss after never wearing ear protection. ROFL, what do you expect? DO IT RIGHT, or don't do it at all.

 

[cthulu]

...and yet Burien Concrete can have it ready next Wednesday...no, they are the high priced leader. If you are near Auburn then Cascade Mobile mix can have it for you on the 24th.
It would appear that you really haven't bothered to actually call any of the mobile mix companies.

Burien sand and gravel are able to come out and I scheduled a load next week. All the other places I called gave me delay and sob stories so I gave up.

Appreciate the advice man.

 

[Leaflessshadetree]

Not sure what you are referring to as pre-mix since you also say it requires 10 bags of concrete.
I have gone to a gravel pit and bought sand and gravel or sometimes "con-mix" (where the have mixed the sand and gravel). Then I buy cement and make my own concrete.

For that size pour I'd be calling for a truck. Even if it is 2-3 months. Being an indoor pour you might get lucky and weather may allow you to pour on days when others can't.

 

[Diesel Dan]

Glad to hear you are going with truck delivery.
I've done 1.5 pallets of premix bags before, not fun and wasn't for a lift either.

 

[brownbagg]

oh my god, please dont do this,

 

[sberry]

Take a deep breath,, don't panic.

 

[Majordisorder]

Batch plants are notorious for combining loads. In other words, they send a truck out with extra (1.5 yards in your case) and after the truck makes it's first delivery, they stop by your job. Not good, especially if the first drop had difficulties or added extra water.

They will tell you they never do that sort of thing but try to take delivery early as possible so it can only be their first job of the day, and be prepared to pay extra for a short load.

 

[lakeroadster]

Batch plants are notorious for combining loads. In other words, they send a truck out with extra (1.5 yards in your case) and after the truck makes it's first delivery, they stop by your job. Not good, especially if the first drop had difficulties or added extra water.

They will tell you they never do that sort of thing but try to take delivery early as possible so it can only be their first job of the day, and be prepared to pay extra for a short load.

Good points. So what you must do is hold them accountable, hold them to their word... Trust But Verify. Specify that they provide you with a mix sheet and have a local testing lab take 5 samples the day of the pour and perform mechanical tests at 14 days, 28 days and 56 days.

 

[cthulu]

Good points. So what you must do is hold them accountable, hold them to their word... Trust But Verify. Specify that they provide you with a mix sheet and have a local testing lab take 5 samples the day of the pour and perform mechanical tests at 14 day, 28 days and 56 days.

I saw your post on testing cement PSI lakeroadster, cool stuff I've done similar things with oil before. Found a place that does it for about 320$

Also, how would you bring it up to the mobile mix place? The only time slot I could arrange is 3pm so now I'm worried about getting a bad batch. Luckily I'm still going to have the friend of a friend on hand to help out with leveling and surface finishing, my hope is he'll be able to identify if anything is askew.

Burien sand and gravel said their trucks only hold 1.5 yards each, and I need 2.25 (ordered 2.5 just in case we needed a little more) So I'm not super worried about leftover mix, but would still like to get it tested.

 

[sberry]

Thousands of these are installed on untested cement all the time. 5 samples, 3 different post pour tests,, wtf,,, the local installer comes in and bolts it down to almost any existing cement without question and a rudimentary verification of thickness.
This is a classic case of some knowledge misapplied if there ever was.
Mohawk talked me in to an install, could have cared less and sent an installer only barely competent, not a big deal to them but now 8 fuggin tests are needed? Where did you learn to do this work?

 

[lakeroadster]

I saw your post on testing cement PSI lakeroadster, cool stuff I've done similar things with oil before. How would I got about doing it for cement? A cursory google search didn't turn up good results. I'm not sure what kind of lab to even look for on this.

Also, how would you bring it up to the mobile mix place? The only time slot I could arrange is 3pm so now I'm worried about getting a bad batch. Luckily I'm still going to have the friend of a friend on hand to help out with leveling and surface finishing, my hope is he'll be able to identify if anything is askew.

Burien sand and gravel said their trucks only hold 1.5 yards each, and I need 2.25 (ordered 2.5 just in case we needed a little more) So I'm not super worried about leftover mix, but would still like to get it tested.

I just googled "concrete testing lab seattle washington" and found "Mayes Testing Engineers". I'd suggest you contact them, if they can't help you, ask them who can. My experience is these testing folks are typically pretty helpful.

As for the mobile mix place, simply tell them you want mix sheets for each load and you will review the sheets before the product is poured. Also tell them you will be having testing done and ask them to recommend a testing company. If they balk, find another company.

 

[lakeroadster]

Thousands of these are installed on untested cement all the time. 5 samples, 3 different post pour tests,, wtf,,, the local installer comes in and bolts it down to almost any existing cement without question and a rudimentary verification of thickness.
This is a classic case of some knowledge misapplied if there ever was.
Mohawk talked me in to an install, could have cared less and sent an installer only barely competent, not a big deal to them but now 8 fuggin tests are needed? Where did you learn to do this work?

If you don't want verification that's fine.

Legit concrete companies are used to these tests. They happen every day.

Where did I learn to do this work? I went to the local concrete company and talked to their QA guy. They were fine with it.

That, and I made a living as a QA Inspector. For every task, there is a verification test.

Trust but verify.

 

[BoostedOne]

As others have mentioned, this is your life at stake here. If you have to wait 2-3 months, well, how long have you lived without a lift already?

When I did mine, and granted I planned this into the slab pour in the first place, I went overkill. Where the lift would be, its a min 8" deep. There is also a 1x1 foot gridwork of 5/8" rebar supported by the tails of the bars at ~4" depth.

Necessary? Maybe not. But the extra depth of concrete and rebar may have set me back $150.. BFD.

 

[sberry]

This company sends a guy has trouble drilling a straight hole and knows absolutely nothing about concrete, now we got one with someone taking good care, with 5 times the rods, 1/3rd thicker, it needs and we are worried to tears and want 8 tests on 2 yards,,,, this really should call for a double wtf.
This isnt a pre stress post tensioned bridge deck, I can only imagine the laugh they would get after this phone call or the bill that would come with this should someone insist.
BTW,, when you make the call be sure to tell them someone on the internet told you to do this.

 

[sberry]

Went to the concrete company and talked to the QA, sure they were fine with it, its going to be better than it needs to be. This is a slab in a common garage. While we are at it call and get a quote for this.

 

[cthulu]

This company sends a guy has trouble drilling a straight hole and knows absolutely nothing about concrete, now we got one with someone taking good care, with 5 times the rods, 1/3rd thicker, it needs and we are worried to tears and want 8 tests on 2 yards,,,, this really should call for a double wtf.
This isnt a pre stress post tensioned bridge deck, I can only imagine the laugh they would get after this phone call or the bill that would come with this should someone insist.
BTW,, when you make the call be sure to tell them someone on the internet told you to do this.

The bill is 320$, with the friend of a friend helping level and finish, getting a mobile mix to pour it's still 400$ cheaper than the lowest price contractor I could find.

I look at it as good insurance to make sure the mobile mix pours what they say they will, and if they don't..then good evidence if I have to take them to court over **** cement.

 

[sberry]

They pour these every day without samples. Most residential garages are done this way.

then good evidence if I have to take them to court over **** cement.

Aint even done and we jumping to conclusions already. 300 to test 300 $ worth of concrete in a simple garage floor,,, so you can take someone to court in the event its not going to make a grade where it will already be at least 1/3 better if it doesn't come out of the chute like chicken broth.

 

[73RR]

...yeah, tend to agree with sberry....

For a 4' x 15' by 10" deep plug I would use a min 6 sack mix and not be overly concerned other than keeping the water/cement ratio low....below 0.45 range. Yes, a ******** would be very handy to have on hand as it will be stiff.
Also, the width-length ratio will demand expansion joints or it will crack where it wants to. I would divide the slab into thirds. The 10" depth will require that the joint, either saw cut or tooled, be at least 3" deep.

 

[sberry]

As others have mentioned, this is your life at stake here.

A little dramatic here. 1000's of these are bolted to existing floors every day by company installer with no test. None. Don't we think if it was that critical they would insist on it? Not one or 2 of these done this way but 1000's,,, and some more thousands and some more before and after those.

 

[GMCGarage]

Man, someone got out of bed on the wrong side. Sometimes folks like to do projects correctly and have verification items are what they paid for.

 

[BADSIX]

A little dramatic here. 1000's of these are bolted to existing floors every day by company installer with no test. None. Don't we think if it was that critical they would insist on it? Not one or 2 of these done this way but 1000's,,, and some more thousands and some more before and after those.

2x Sberry, people get a little dramatic here sometimes.
Jay D.

 

[sberry]

Man, someone got out of bed on the wrong side. Sometimes folks like to do projects correctly and have verification items are what they paid for.

This is fine but we don't need to leave the impression that its all done this way or death is a certain outcome when that's not the case. The OP did a fine job to prep it, got it well above the design requirement which is cheaper than testing it.
there are 2 reasons for testing and engineering. 1 is to meet the requirement and the 2nd to make it economical. In a case like this a little extra is easier and cheaper than the cost of cheapening the design. A little extra concrete, a little better mix, some extra rods which was noted above is a minor matter.

 

[GMCGarage]

This is fine but we don't need to leave the impression that its all done this way or death is a certain outcome when that's not the case. The OP did a fine job to prep it, got it well above the design requirement which is cheaper than testing it.
there are 2 reasons for testing and engineering. 1 is to meet the requirement and the 2nd to make it economical. In a case like this a little extra is easier and cheaper than the cost of cheapening the design. A little extra concrete, a little better mix, some extra rods which was noted above is a minor matter.

then just say that, dont come here posting 5-6 times with WTF and 2x WTF

 

[Itsjustdirt]

Just curious, why no doweling into the existing slab?

 

[cthulu]

Just curious, why no doweling into the existing slab?

I was going off the engineering docs for the mohawk two post lift specifications. They call for a 6in key or doweling, since the slab is close to 3in in some places I didnt want to risk cracking the existing slab.

 

[lakeroadster]

"Went to the concrete company and talked to the QA", sure they were fine with it, its going to be better than it needs to be. This is a slab in a common garage....

How is supplying a product and verifying to your customer that they got what they asked for "better than it needs to be".

It's not a slab in a common garage. It's a slab for a 2 post lift.

While we are at it call and get a quote for this.

For the record: I used the procedure I outlined on my slab that also has a 2 post lift. My contractor and the mix plant were fine with it.

The concrete testing was free, didn't cost me a dime.

 

[Diesel Dan]

I ran off concrete guys just by asking how wide was their biggest float. Can only imagine the reactions if I started requesting material testing post pour. Even the redimix plant had a hard time recommending someone local.

While we are at overkill where is the mounting cage?
Take 8" J-bolts, laid out to the lift mounting pattern, welded together and wired to the rebar, poured in place. No drilling or worries of wedge anchors coming loose.