Creating slope in a level garage slab - prep before tile...

[cavediver]

Hi Gang,

I am still considering the porcelain tile route in my workshop, and will probably be tackling it later this fall. In preparation, I am trying to develop a game plan, and prepare myself (mentally?) for the task at hand.

The shop is 20x30 with a concrete slab that was poured 6" or better with 6'x10' pads that are 16" thick for a two post lift. This was poured early last summer and shows some minor shrinkage cracks but nothing significant. Unfortunately, it didn't turn out exactly how I wanted it to so I have a little more work to complete before laying tile.
The floor was poured level, the front (West - garage door), and the rear (east) are essentially at the same height - this is the 30' length. I would like to prep the floor so that I have the existing height at the garage door (plus the Schluter Reno Ramp transition to tile), and approximately 1/8"/ft slope to the east end (30' away). So that's 3.75" to be raised at the far end.

I have 12'6" ceilings and can afford to loose the 4" along the east wall in order to gain the water shedding benefits (I have puddles and constantly wet areas from the cars defrosting this winter in the shop).

So I need a Game plan:
I was thinking of ripping some 2x4's down with a taper that is 1/8" per foot and attaching them temporarily to the existing floor as a guide to screed "something" to the final slope. I was thinking of placing the "2x4 ramp guides" about 4-5 feet apart. Then when the "something" sets up, pull the ramps out and fill up the remaining channels with more "something".

What product should this "something" be? Will normal concrete be resilient enough for this application? Should it be thinset from the 0-->2" section and then concrete or mortar mix from the 2"-->4" areas?

Location is in Central Ontario, so consideration for moisture and freezing temps is important.

Thanks for your input - John

 

[LXCam]

Where my shop is now was never meant to be for a building. It was meant to be a exterior slab adjacent to the building with a 24W X 40L awning over it. That slab has a 1/8" of fall per foot. I flipping hate it!. That's a fair amount of fall for a exterior slab, but for a interior slab it's a mountain. As long as you have some slope to the door or a drain, it doesn't take much to accomplish your goal. I'd suggest dropping it down to a 1/16" per foot. But getting that critical is very difficult. If you're going for perfect you'll need to rip down some material and complete fill sections in maybe 4ft widths. It's the only way you will get it perfect.

Good luck, I think your making a mountain out of a mole hill and will not be happy with the results (expense and finish quality).

 

[Dakota00]

You can do 0-->3/4" in thinset, from the 3/4"--> 4" section you use dry pack.

If you're planning to do this part of the job yourself, (it's not easy work) invest or rent a set of 6ft and 8ft straight edges. This way you can place the ramp guides further apart and lay down more material and get the job done faster. BTW, you'll need the help of 2-3 other guys, for mixing the materials and carrying it over to where you need it.

 

[toplessHO]

you cant use concrete in that thin of thickness.
Aggregate is where the strength is and you wont have anything but sand that thin.
Perhaps some of the floor guys can offer some help but I use epoxy for high strength
in thin areas. You can get by with more since your covering with tile.
Did you permit for this? If so Code says it should be sloped to promote drainage so you wont have an ice skating rink.