Solid Hardwood, Engineered and Laminate Flooring - Subfloor issues to resolve ..need PRO'S !!

I am getting ready to install my first HW floor. I chose vertical carbonized bamboo, I am pretty good with tools, just never did a HW floor B4, and will NOT lay down a grand worth of beautiful flooring and have issues with it... the subfloor MUST be in good shape!!
I pulled up the carpet and pad, and was pretty happy that nothing was glued down, BUT........
The main section of the room is 9'Wx16'L , and there is alot of deflection from level(straight), I ran a string across the floor in a couple directions and I have up to an 11/16" gap in some spots. There is also 2 joists that don't help matters, as they are higher than the rest( clearly evident, and I can actually see it is about a 3/8" or so higher looking from a sunken living room riser)making the floor pitched also.
I have read as many threads in about 4 different forums as I can regarding this subject (using the underused search feature ), but have not seen a clear answer(of course all situations are different, hence my own thread).
The subfloor is nailed and glued to the joists below ( the joists are in good shape, I looked at them in my finished basement- lifted suspended ceiling), so that would be a hassle and a half to fix..
The floor has 2 areas where it will meet other floors(both floors have subfloors that the 5/8" bamboo will meet almost perfect right now), and I want to keep the transition as close to level as possible for obvious reasons (I may have to rip a threshold, but I want it fairly close).
I have thought about using 1/2" (pw)in the lowest areas and stepping down to 3/8" toward the higher areas , then using some auto leveling compound and feathering it to be straight and level, as that SEEMS to me like ALOT of compound without any wood underneath.
I have read on these forums about a product called Ardex(and I have a link to their webpage), and they have numerous products.
My question's to the pro's are:
Would you even attempt to just use auto leveling compound to fix this issue ( seems a little extreme, as there are NUMEROUS areas that need alot of compound, and I do NOT want any issues regarding integrity of anything under the floor).
Do these compounds accept and HOLD nails/staples( I am getting a bostich floor stapler to use for this from my brother, with 2" staples unless a pro tells me not to use this). I don't want to be worrying about nails coming loose, or compound turning to dust after awhile, or cracking etc....

Would the step down idea mentioned be a better idea with compound used also?
I have run a circular saw down the seams(some were slammed against one another with NO gap- and it caused the floor to buckle a bit there,I see that there is supposed to be a gap, so I would THINK that the compound should NOT be allowed in the cracks when I use it (either way),please tell me if I am wrong on this issue ( if I could just pour it and let it go where it wanted that would be even easier- but I have NP filling the cracks with something higher to keep them open). I have also screwed the floor down and countersunk all nails.
Right now I am at an impass as to where to proceed here, and was hoping some pro's would chime in and give me a bit of input to help me along, so ANY help is GREATLY appreciated.
I have also gone to HD and they sell some 50lb bags of auto leveler, has anyone used this stuff (red and brown bags- forget the name), and if so is it any good, or is the Ardex the only stuff people trust(gonna have to look for that stuff). They also sell Henry's underlayment in 25lb bags...

I am going to post this on a few other forums to get as much input as possible, so please don't freak out if you see this somewhere else
Sorry for the long post, I just wanted to give as much info as possible up front.

Thanks alot in advance.

muzz

Alot of views......

I dug into Ardex's offerings, and now I see that they are cement based, and this is a nail/staple down floor.....

I don't see how thats going to work.

Muzz-
You definitely don't want to lay decent flooring on a crummy subfloor. You may need to get someone to determine why your subfloor is in such bad shape. 11/16" is WAY TO MUCH of a "wow". I'm betting that those two joists haven't risen, the rest of the floor is settling.

Get the subfloor problem(s) fixed before you lay your flooring.

Thanks Dave,
I have gone into my finished basement and taken a look, the joists look fine, slight bow from top to bottom on a few and a few stress cracks, but nothing out of the ordinary...
2x10- 15', with diagonal bracing, 16"OC.
I have seen MUCH worse.
I am still looking into what to do at this time, and I appreciate your input.

The floor WILL have a solid and level subfloor to lay on B4 the first board is even nailed.

Thanks Again

m

That "slight bow from top to bottom" may be the problem.

I'm just guessing, but the joists may have been put in with the "crowns" down instead of up. If so, years of traffic has worsened the sag. You can probably fix the problem by jacking the joists back to straight and sistering another board to it with the "crown" facing up.

I was thinking the same thing Dave (crown down), and the bowing has in a sense made them uneven and slightly lower(sitting on a huge carrier at both ends, and they don't move ;) )

I started leveling the floor with some rolled roofing, it's almost finished...
Taper,Taper,Taper.... heheh

Thanks Dave,

m

Well as I stated in my original post.....
This IS my FIRST HW floor AND....................

When I bought the floor I asked the guy if I had to nail it, and he said "yeah we rent nailing guns for a lower rate if you buy here" ( I don't need 1, my brother has one available)......
NOW I find out I COULD have used auto leveler and GLUED it.

The rolled roofing was coming out pretty darn good, but I was STILL a little bit leary because of the amount I would have to nail through, so I kept digging (Like I said I will NOT risk the new floor if I am not CERTAIN of the subfloor), when all of the sudden I find out I can glue it....talk about being %^&(*& !!!!
I could have had this floor done last weekend.

I am now returning the unopened rolls I have and buying auto leveler, a 1/2" drill ( brother has the mixing bit), and some urethane glue ( Bostich is a name highly regarded).

There is my sorry story, I'll let you know how I make out Dave.

m

Sounds like it's working for you. Personally, I would have dealt with the joists first. If they don't sag any more, you're home free, but..................... :(

I don't think they are going to be a problem, I took a good look at them from underneath, and they seem ok.
I would have tried the sistering if the SF wasn't glued down... I almost did until I was talked out of it.

Looked some more and found some cracks........ 1 joist is cracked all the way through.
I am now going to sister 3 joists, as 2 others in there have some cracks, and since I will be jacking up the floor and sistering I am NOT taking chances with the floor settling again and cracking my leveler....

The Joy the Joy......
heheh

Ain't home improvement fun?? :D

Originally posted by Dave_D1945
Ain't home improvement fun?? :D

Absolutely!!!
:D