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Floor Prep Flatness and Blueprint Request
The area that I am working on is the basement of my house. The floor is concrete and is approaching twenty years old. It was previously carpeted. The carpeting has been removed, the entire concrete floor has been cleaned with a floor grinder. There are only two cracks which are mostly 1/8”. It looks in wonderful condition…until you put a level on it!
I would describe it as mostly two level planes with a ½” difference in elevation. The transition zone can be as short as two feet across as the floor raises/lowers ½”. There are several places where the concrete is slightly wavy in elevation with maybe a 1/8” variance in height and two or three feet between the crests/valleys.
There are also two ½” mounds in addition to the larger planes described above. Both of these mounds have been ground down about halfway by using a floor grinder. (sidenote: painfully slow!)
The plan is to install LVP. While we are open to other suggestions, we are currently leaning towards Flooret’s Modin Signature LVP. It is sized at 9 inches by 6 feet. A picture of a sample piece is included so you can identify what you need to know about it. It would be my preference to install the entire floor without any transitions. LVP flooring is to be installed in all rooms in the drawing. This includes the main L shaped room and both bedrooms with their closets.
There are several items on my wish list:
#1 Guidance on flattening the floor. My perfectionistic nature would like to see the entire floor perfectly level and flat. I understand that unless I want to grind the floor for another six months that is not realistic. I do NOT want to raise the flooring for the northern three doors (tiled bathroom, epoxy floor closet and bare concrete furnace room). The northern end (with the wavy orange lines in my elevation drawing) probably needs Henry’s 549 screeded across it. Simple enough. I started grinding down the two ½” tall mounds in the middle of both legs of the L room. The ½” elevation change transitions between the different planes has no good solution that I can figure. I am trying to achieve the balance between properly supporting the LVP so it will last a long time and looks/feels good while keeping the prep time realistic. How do I properly prep the floor for flatness at the ½” elevation changes between the planes?
#2 Can you expound on what 3/8” variation in 10 feet means in real life? (this is the real question behind the first question) If this 3/8” variation was evenly distributed across the 10 feet then it would just be another flat plane which existed at a slight angle. I would guess the opposite, being a 3/8” instant elevation change like a stair step, would be completely unacceptable. It seems like the relevant issue is the deflection point and how abrupt the elevation or angle changes combined with the height difference. Or maybe how wide of an unsupported distance combined with the depth of the valley. Sorry to describe it so poorly. What is real world “good enough” flatness to properly support LVP?
#3 Recommendation on direction to run the LVP planks, where to start the starter plank and your general advice/blue print.
Thank you very much for the service you provide. Your expertise and advice are very appreciated! Please let me know if you need any additional information.
God bless!
Quinn
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13 Replies
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Thank you, Joe, for your informative reply. A video chat would probably be more efficient. I have an iPhone so probably stealing my wife’s Facebook sounds like the best option.
Picture with level: The level is an 8 foot level. Picture is at an angle because have a stack of lumber in the way. The left 2.5’ of the level is not in the picture and is flat on the floor. Only about 2 inches of the right is missing and it is in the air. To the left what I am calling a flat plane while on the right is what I am calling a flat plane. In between is transition between the planes. In my elevation drawing, to the left would be red while the right would be yellow and the transition would be white.
Outside of the wavy orange lines, there are few “low areas”. It is more like they were pouring the concrete and keeping it level until they had too much concrete and sloped it to a new level area. That sloped area is my white “transitions” between the red and yellow planes. I am considering the yellow planes to be at 0 height and the red to be half an inch higher.
You did correctly identify the location of my two mounds. I rented an Edco TL9 grinder and hooked it to my Bosch VAC090AH dust extractor. For the benefit of anyone else grinding, dust control was incredible. Sometimes the hose gets dust settling in it and you need to dump the dust out of the hose. That seems to be because the grinder is a little too large for the dust collector. Back to the grinder…my local Home Depot does not have that grinder available. Sunbelt had the Edco TL9. Here is a link:
https://edcoinc.com/products/details/magna-trap-r-turbo-lite-grinder
For grinding speed, do you think this is not aggressive enough and I should find something better?
How do we setup a video call?
God bless!
Quinn
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That grinder is good for small stuff but not what you probably need. The one I shared is aggressive. What is a good day and time for you?
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I can be available pretty much anytime today, tomorrow or Saturday. Just let me know what is the best time for you. Thanks.
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Today or tomorrow works for me.
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Today sounds great then. How do we make the call happen?
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Call me and we will talk about using messenger 218 256 8080
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Thank you for your time and help on the call today. Attached is my hand drawing with the measurements.
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Today is the last day I have the floor grinder. Could we please have a video call today to discuss floor prep before the grinder is returned? Thanks!
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Sure can, what time is good for you?
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I am flexible. Could do it in 10 minutes or whenever. Just give me a time!
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Call me – 218 256 8080
