I've read about your drunken contractors. Well they've struck again. The concrete floor flaws (no cracks) were hiden with carpet. There are no cracks on the exterior and no major cracks on the interior walls to account for foundation failure. I still don't know how it escaped my notice - it's just so gradual and probably the only area that I didn't check.

My wife and I intend to install bamboo over our concrete living room floor. Our problem is that there is about an inch rise almost exactly in the middle of the 25' wide room with no cracking to account for it. One side of the room is about 1 inch below this rise and the other is about 1-1/2 inches below. The base of the two opposite walls are almost level with each other but the floor slopes up to the center of the room about an inch. The rise ridge only extends about 1/2 way into the room and gradually levels out for the other 1/2.

Should we grind the center ridge down? Add mud or leveling compound to raise the floor to it's highest point? A bit of both?

If we grind we'll loose some of the vapor barrier as my wife and I DID put down some vapor barrier compound a couple of weeks ago before we noticed the rise (but I can live with that). We might cut some of the vapor barrier away from the center ridge and then let the final adhesive's inherent vapor barrier to just be enough in that area. Cutting away the vapor barrier in that area might lower the center ridge area by about 1/8 to 3/16".

If we raise the floor at the edges such a small amount we might run into slight tripping hazards when entering the living room from bedrooms, kitchen and front entryway.

I hope I've given you enough information.

Thanks for your attention and advice.

Can you get a picture? That would help.

Yes, there are some things you can do, but if you can attach a pic, it would be easier to help you out.

Okay, photo and diagram on their way.

For the photo I am standing at the top of the diagram image looking towards the bottom of the diagram. The ridge area has some discoloration due to some sanding but that serves to highlight the area.

The high ridge begins roughly at the center of the angled kitchen wall (kitchen has floated laminate with which we've not noticed any problems) and continues out to about the "v" in Living Room. Above the words "Living Room" the room is fairly flat as the ridge slowly goes away in that direction. The largest difference is from the bottom left of diagram (top right of photo) to the middle of the right diagram wall (left of photo). Those two floor levels are almost identical but rise towards the sanded area.

Pardon the cat toys and vacuum cleaner although they do give some scale. Those bamboo boards in the right background of the photo are 38" long.

I hope this helps.

Thanks

I forgot to say that we intend to place the bamboo at a 45 degree angle to the room. That would start at the bottom left and extend to the top right of the diagram. That would mean that the planks would lay perpendicular to the ridge area.

And, don't be fooled by the wandering light gray area on the photo. That was just where I (yes, I - not my wife - the areas she did were perfect) went back over the vapor barrier with a toothed trowel and raised it a bit not realizing how much it had cured. So, after it cured I sanded it down to match the surroundings.

Based upon the data I gathered from running a string level across the room at the most offensive spot and measuring down from the string every foot, I came up with this rough diagram of the ridge area. The scale is skewed for emphasis. The vertical scale is inches, whereas the horizontal scale is feet. Otherwise the vertical wouldn't hardly show.

It sure looks like two different workers trowled to the middle from each side and then smoothed over instead of starting over. Maybe I need to be "on" whatever they were in order to do this floor to match.

I have two contractors coming out to take a look over the next few days. One works with a group that "turns" houses and is a friend of a neighbor. He has already suggested grinding but will come out to look. The other's business name indicates a preference for filling in voids with a polymer of some sort. It will be interesting to see what they advise.

I priced the My-something polymer at Lowe's Hardware. To fill a 1" void, one $28 bag will only do 6 sq. ft.. Tomorrow, I will look into grinder rentals just to get a price in mind.

I would be interested in your opinions and advice.

Thanks

Another thought:
One thing I've considered is leaving the floor alone and modifying some of the boards by cutting grooves underneath so they will more easily bend ever so slightly over the ridge. I'm thinking the groves would be every 1/4 to 1/2 inch or so, about 1/2 way through the 5/8" thick boards, the cuts would be parallel with the ridge (perpendicular to the board length) and only on the boards that ride over the ridge.

If the house had hardwood floors and then settled the resulting floor would have a similar effect I would think. Any opinons on that idea?

"modifying" boards is not the answer.

It looks like you have quite the span. My only suggestion would be floor leveler. They have self leveling. Yes that is a bit spendy when you look at the price tag, but works really well. So labor and cost of product?

When you switch flooring, you are likely to have different levels of flooring and to combat that, then you change out your transitions. You could level out the floor as much as possible without a complete level. BUT, if your floor transition is going to be an inch higher, that is a rough on the toes.

Perhaps grinding part way down and meeting with leveler up would be the answer.

Well, I came up with a solution:
I added a design element of marble tile.

Marble tile is 3/8" whereas the bamboo is 5/8".
I'm laying down the bamboo up on both sides of the rounded hump area. Next, I will level only the 2' width of the hump with the appropriate mortar for marble tile. Finally I will lay the tile and level it out with the top of the bamboo on each side. The marble, being shorter, will level out the rise and meet the edge of the bamboo (with a 1/16" gap for colored caulk).

This is the least expensive solution and it will introduce a unique and interesting design element (the whole thing is a stylized fire-work so the new element will be a stylized rocket trail). It will add some time to the process but I think it will be well worth it.
I'm well on my way with the bamboo installment. Once I get the bamboo and tile down I'll send a photo. And a year or so from when I finish I'll let you know how it is holding up.

Thanks for all of your advice.