See the video.
How to Level a Concrete Floor | This Old House (youtube.com)

 

I’ve seen that video. I think the owner was not capable of using mortar so they decided to partition the floor and do it in pieces.
Also, I’d have to use $3k of leveler …

 

I'd call a few places and get them to price you the job.
I doubt you will save too much doing it yourself, and the quality will be better.

 

Yep.
I know this is a DIY forum, but a couple of tasks that are best left to pros are natural gas hook-ups and self levelling compound.

 

You could do a dry-pack mud bed to level the floor. Search on line for "Dry Pack Tile Bed" or "Mud Bed" or "Green Sand Bed" or "Dry Pack Mortar".
It's a little more work than pouring new, but you can be very precise about your leveling. And it's way more fun to do than pouring.

Dry Pack Mud Bed is the tried-and-true method that's been used for over two thousand years. (My mother's house in Italy has tile on dry pack & it's many hundreds of years old. No cracks.)


If you pour, good thinking on using sill seal. I've done it many times. Be sure to seal it to the slab with tape or duct seal so no water will wick up the drywall from the edge that touches the floor (the facing down edge that you can't see).

Be sure to enjoy your project!
Paul

 

Use topping cement in the huge gaps (no less than an inch), then go over with leveler. If you find a very high spot, grind it down if feasible. Don't trust the home depot equipment, their diamond grinders have been beat to ****

 

The minimum depth I would use standard bagged concrete mix is 1 1/4". If you use the sand topping concrete mix, you can use it to fill as shallow as about 1/2". For the rest, you'd need to use a leveling compound.

 

Do nothing!

You're installing the wrong product. If lvp/ lvt is your goal, use a glue-down version and hire an installer. No snap joints to open over the irregular surface. Better yet, install tile, which is vastly superior to any vinyl. A smaller format would allow for irregularities in the substrate, mortar can help too.

 

Tile is very cold on concrete.

 

As is 3/16" thick vinyl, which has zero insulative properties.

But you make a point- another option would be foam insulation, Advantech, then wood flooring. A few different ways to put the system together. Irregularities wouldn't matter here either.

Anything lvp above bottom quality has insulation, hence their suitability to go over concrete.
.

 

.. that's marketing. LVP is thin vinyl, it has no insulation. It's slight padding helps with sound deadening and micro irregularities, like a small pebble, under the floor. LVP's suitability over concrete is due to its composition: plastic.

 

.

 

I've decided to use topping cement for the 1/2"+ areas, then self-leveling cement (SLC) for the <1/2" areas.
I might also use SLC on top of the topping area if my screed is unacceptable.

I plan to install screed guides - 2 per room, cut to match the crazy floor elevations.

My question is what is best way to attach guides to slab? Will be removing screed guides after 24 hour cure time. Could use glue or short tapcons, my preference is glue to avoid 1-2" holes in slab.

 

My question is what is best way to attach guides to slab? Will be removing screed guides after 24 hour cure time. Could use glue or short tapcons, my preference is glue to avoid 1-2" holes in slab.

Maybe do a test with a very weak construction adhesive that has instant grabbing. Loctite Power Grab comes to mind. The boards will be able to be pulled off easily later. But, I don't know how the water in the mix will effect the holding power, so do a test.

If you choose screws, Spax brand T-Star Plus Yellow Zinc Construction Screws hold in concrete & masonry very well. They are much cheaper than Tapcon or Confast, but for interior only. (And different shear & torsion rating)

Paul

 

I'm going to avoid screwing in to the slab or using glue by screwing screed guides to the wall. These will be 2x4s cut down to appropriate height off floor. The screed board will ride on top of these.

Also, since there's only a 10 x 20 area that is <1/2" low (surrounding the highest spot), I'm considering grinding down that area. That would decrease by 1/2" the filler I need in the rest of the house.
The room is empty and there are patio doors and windows and garage door for ventilation. I would have to use smaller grinders, and then chippers, in the sides/corners. I'd probably cover the ground area with SLC, if needed. Otherwise, the underlayment would handle small defects in the ground surface.

Comments?

 

Your plan sounds quite reasonable & more fun than pouring and screeding. It'll certainly cut down your self-leveling compound costs.

Pre-Scoring the large areas with a circular saw and carbide blade will make the grinding go must faster. Set the blade depth & make lines in both directions. The closer together they are, the faster the grinding will go. If water isn't a problem, it is safest to trickle as you cut from a hose to minimize dust.

After grinding, an angle grinder will help finish where the large grinder can't reach.

For the corners & areas that the large grinder or angle grinder can't reach, an oscillating tool with a triangular shaped diamond or carbide "blade" will get all the way to the corner. They are rather inexpensive on places like Temu. (I bought some for $1.00 each and they are still working well.) It isn't a fast process, but works. Photo is below

Please be very careful of the concrete dust. Here's an article you may find helpful: A Guide to Respirators Used for Dust in Construction | Blogs | CDC

If you can rent a wet-grinder, it will cut down the dust (but not eliminate it).
Here's an article about choosing a grinder to rent: Concrete Grinder 101: The Insider's Guide to Concrete Grinding

Enjoy The Project & The Fruit of Your Labors!
Paul