Construction/Framing - Bringing adjoining floors level with each other.

[MstrCarpenter]

Mound,
O.k., So here's what I'm thinking could be the easiest repair to raise the floor from 0" -3/4" over the width of the room given the following facts.
1) Jacking the floor system and everything above it messes with the ceiling you just fixed, and could cause some cracks and leaks.
2) Vinyl siding; easily removed and replaced if necessary. 
3) You have required clearance between header and slider, but not much extra.
4) Looks like an attached deck outside slider. Let's not mess with that if we don't have to.
5) Access, although slightly limited, to floor framing is available.
6) Raising slider was not presented as required, but my opinion right now is that removal and reinstalling may be necessary anyway.

What this leads us to is that the posts supporting the beams and header must remain in place. The roof doesn't move, so no need to move the walls. We still need the floor to go up so we might as well bring up the floor joists, but the first joist has a deck hanging off it and those posts that remain on top of it. This is indicating a cut-line of the sub floor just inside the shoe on the left wall, turning right at the slider wall, around the post (if protruding), then turning left to the exterior at the slider R.O.. Cut the attachment nails between the sub-floor and ribbon joist between the slider jack studs, then continue the cut line back in beside the jacks, turning left around the shoe then around the post to the "orange" area.

The left ends of the joists will need the framing nails securing them cut or removed, and the top will need a notch so we don't lift the wall above. The right ends just need to be cut free. I would do the left ends one at a time, then add a short stud between the sill and sub-floor to support the wall, but don't nail it to the joist until the floor is flat. Proceed with raising the joists using shims between the joists and sill. The next step is to fill the gap under the slider R.O. so it's flat and level and solid (the glass panels are heavy). This should leave us with two floating sections of floor outboard of the slider R.O.. You'll need to glue and screw plywood of the appropriate thickness to the bottom of the raised sub-floor to be flush with the sub-floor under the walls. Now that they're flush, you can glue and nail another layer, spanning the cut-line, to tie them together. If the floor is where you want it, it's also time to permanently secure those short studs to tie the joists to the ribbon joist and sub-floor under the left wall. 

All that's left is to re-install the slider. If you didn't remove it, then you will still have to make sure it is flat and solid. During the process of raising the right ends of the joists you should have seen a logical place for the cut line. It would be better if the last layer to bring the "orange" floor to plane was glued and nailed to both the orange and green joists.

Also, please don't underestimate the necessity of tying the floor system back to the walls. It is part of the structure. Without it, the walls would be balancing on top of the ribbon and band joists.

[mound]

Thanks for a great writeup!

I do agree on your conclusions for reasons not to jack anything up.

I'm curious though, if I understand this correctly you're basically excising the existing floor structure from its surroundings, raising it and then re-attaching it in the correct plane.

What I had envisioned was removing the sub-floor just as you described, but then leaving the existing structure as is while simply sistering the existing joists with new joists, each offset vertically from the existing joists as needed to bring them up to the correct plane, then attaching new sub-flooring to the "new" joists. Would that not be appropriate? (it certainly uses more material, but doesn't require cutting any existing structure away.)

Or perhaps my ignorance of framing is shining


Also you mention, I think, 2 layers of sub-floor, the top one being glued and screwed to span both the orange and green areas. I think that would need to be a very thin layer, as the offset now between the "blue" and "orange" is shy of 1/4"

Also, do you anticipate removing the sliders would be particularly difficult or is it likely just screwed (or nailed) in place at the sides and trimmed out like you'd install any window..

[MstrCarpenter]

There are may ways to skin a cat; although I never understood why so many techniques are necessary.
What you envisioned and what I described will yield the same results. Either way, you still need to provide support and a structural connection of the sub-floor at the "cut-line". So the difference is basically a personal decision. Is the time and expense to remove the hardwood and sub-floor, sister the joists, and replace the sub-floor and hardwood worth an hour or two with a Sawzall cutting some nails and notches, and installing some short "studs" on the left end; in a totally miserable work area with no lights nor ventilation?

Is there another way? Sure there are; I considered several. A strong contender was to cut the studs and posts shorter and jack the whole floor system up. The attached deck nixed that idea.

Your way would work fine too. When the floor is open, you could glue and screw a "shelf" to the bottom of the remaining sub-floor for the new sub-floor. (Add shims on top of the shelf as required.)

[mound]

There are may ways to skin a cat; although I never understood why so many techniques are necessary.
What you envisioned and what I described will yield the same results. Either way, you still need to provide support and a structural connection of the sub-floor at the "cut-line". So the difference is basically a personal decision. Is the time and expense to remove the hardwood and sub-floor, sister the joists, and replace the sub-floor and hardwood worth an hour or two with a Sawzall cutting some nails and notches, and installing some short "studs" on the left end; in a totally miserable work area with no lights nor ventilation?

Is there another way? Sure there are; I considered several. A strong contender was to cut the studs and posts shorter and jack the whole floor system up. The attached deck nixed that idea.

Your way would work fine too. When the floor is open, you could glue and screw a "shelf" to the bottom of the remaining sub-floor for the new sub-floor. (Add shims on top of the shelf as required.)

oh I see what you were getting at.. never actually removing the hardwoods, and doing it all from within the crawlspace. that point escaped me when reading your instructions, I was envisioning the whole still thing being done with everything opened up. 

Another issue is that there's various ductwork and electrical strapped up to the existing joists. 

hmm.. Gonna have to ponder this. Headed into the mountains for 2 weeks of camping, maybe a break away from the project will help!

[mound]

Well, I pondered the problem (a bit) while away on my camping trip.  Had a professional builder acquaintance come by and take a look too. 

In the end, the consensus was that any sort of jacking up of the house created too many possibilities of bad outcomes, and due to the way the various ductwork and plumbing was configured in the crawl space, accessing the joists with a sawzall from below wasn't possible, unless perhaps I was only 3' tall.  

So I took a 3 day weekend after my camping trip and busted it out. 

Day one I removed the sink/disposal/dishwasher and relocated that kiddy corner (including tying plumbing and electrical into it so we have still fully functional sink/disposal/dishwasher) 

Next day carefully pried up all the oak hardwood (which went well, it's all reusable) and tore up the existing subfloor. 

The "bouncy" part (in the orange area of my original post) was bouncy because the 12' 2x8 joists had no blocking between them, and one of the joists in the center had two large knots on the top edge which had cracked out to the point that any weight on it would cause it to sink well over an inch. So I beefed that up.

Third day, sistered all the joists with new 2x6's as needed to bring it all flat and level and skinned it with new OSB.  
(Yes, I realized I forgot to stagger the seams! I think in this smallish space with all the extra blocking and such below, this won't be any problem.)

I do think the sliders now need to be taken out and raised, probably just with a new 2x6 plate.  

So, a few days of hard work and the problem is solved! Time to move on..

   

   

[Cabinet Monkey]

The "bouncy" part (in the orange area of my original post) was bouncy because the 12' 2x8 joists had no blocking between them, and one of the joists in the center had two large knots on the top edge which had cracked out to the point that any weight on it would cause it to sink well over an inch. So I beefed that up.

Lots of hard work there, looks pretty good.

However ......................your "bouncy" floor wasn't due to lack of blocking
  It certainly didn't help , but wasn't the main factor. Bouncy floor are caused by undersized joists.  Too short/thin relative to their span.   The fact that crap wood was used also contributed to your issue. 

Another glaring issue you now have is your subfloor.  Best I can makeout - almost none of your seams fall on a joist or blocking.  That's a BIG No No.  Additionally, the orientation of the panels is incorrect in the bouncy house section - again doing you no favors for stiffening up the assembly in that section.

If you haven't glued down those panels- I'd STRONGLY advise you take them up and re-lay them properly.    You've taken a lot of time and care in other aspects of this project, It'd be a shame to let yourself down with a poor foundation to save a few dollars and hours of time at this point.   One, that might very well cause you issues down the road.   

[mound]

Lots of hard work there, looks pretty good.

However ......................your "bouncy" floor wasn't due to lack of blocking
  It certainly didn't help , but wasn't the main factor. Bouncy floor are caused by undersized joists.  Too short/thin relative to their span.   The fact that crap wood was used also contributed to your issue. 

Another glaring issue you now have is your subfloor.  Best I can makeout - almost none of your seams fall on a joist or blocking.  That's a BIG No No.  Additionally, the orientation of the panels is incorrect in the bouncy house section - again doing you no favors for stiffening up the assembly in that section.

If you haven't glued down those panels- I'd STRONGLY advise you take them up and re-lay them properly.    You've taken a lot of time and care in other aspects of this project, It'd be a shame to let yourself down with a poor foundation to save a few dollars and hours of time at this point.   One, that might very well cause you issues down the road.   

Thanks. 

The joists are 2x8.. isn't that (supposed to be) sufficient for a 12' span, 16" OC? I did actually add about 2x more blocking to the bouncy side in the time between taking those two pix, guess I didn't take a pic at that point. 
   
There are definitely no unsupported seams. Every seam has a joist or blocking directly below it, glued and screwed to it and none of the seams deflect or move at all when I walk over them or put pressure down with my foot directly over them.  The bounce is gone and everything feels very solid at this point.  It'll have to be good enough, as I've already weaved in 80% of the hardwood flooring!

[mound]

My builder buddy took a look and agreed with @Cabinet Monkey's comments, but also said given the extent of extra blocking and material I put below it, plus all the glue and screws (and that yes all the seams are supported) he agreed with my conclusion that it is in fact "rock solid"..  I had started to worry!


This is now the only room in the house where the floor doesn't creak. The rest of this 60's house (all hardwoods) sounds like a 60's house when you walk around. 

Anyway, just some final pix of the process of weaving hardwoods back in.. I used a spade bit to drill a 1-1/4" hole in each board an inch or so in from each end seam, then used a heavy framing hammer and a cats paw to bang each board out in a staggered fashion. That proved easier than I expected (the old wood was stapled down) and less wasteful than using a circular saw to cut a long section out the middle of each in order to pry them out. In the end, I was able to re-use all the material I cut out by cross cutting away the mangled ends and then I milled a new tongue and groove as needed.. A bit of extra work but saved $$ in material. 

   

   

Since I was weaving back in, I had to honor the already established line which meant very carefully positioning the first course to ensure it went straight out and remained exactly parallel to the last course.  

   

Then it was just a matter of mixing in old and new to weave it all back in, hiding the cutline I hade made to repair the floor. 

   

Normally I'd move to drywall, but timing and such means my hardwood guy (who was shocked I had done this and said "you're hired!") is going to come and sand/finish next week sometime, then I'll lay down Ram board to protect the whole thing and proceed to finish the rough electrical and get that inspected before closing things up. 

The sliders do need to come up to look correct, but remain fully functional, including the screen, so I can get that done at some point, but moving forward inside doesn't depend on that.

[Cabinet Monkey]

The joists are 2x8.. isn't that (supposed to be) sufficient for a 12' span, 16" OC? I did actually add about 2x more blocking to the bouncy side in the time between taking those two pix, guess I didn't take a pic at that point. 
   
There are definitely no unsupported seams. Every seam has a joist or blocking directly below it, glued and screwed to it and none of the seams deflect or move at all when I walk over them or put pressure down with my foot directly over them.  The bounce is gone and everything feels very solid at this point.  It'll have to be good enough, as I've already weaved in 80% of the hardwood flooring!

oK, it just looks like most of them are unsupported in the pictures when referenced against the wall framing and patio door.   I'm not onsite, and pictures often distort sight lines. Keep in mind , x-bracing is not the same as solid blocking when it comes to seams.  

12' span 16"o.c. is within span tables (barely) for structural grade lumber or SPF - SYP .  Ungraded stuff - who knows ???  Yours had knots on the top center which makes me have my doubts about the quality and def. questions the competence of the framer.  The fact that you sistered on additional members has strengthened them to acceptable levels.   You are also using wood flooring - if you were going to use tile or stone flooring, you'd have to rip up the subfloor and start over.  It's no where near stiff enough for that material.

I'm with you on the "too late to re-do" assessment , and both of you on the "it'll have to do or be good enough".   I wouldn't lose any sleep over it, every project is series of compromises all along the way.

[mound]

oK, it just looks like most of them are unsupported in the pictures when referenced against the wall framing and patio door.   I'm not onsite, and pictures often distort sight lines. Keep in mind , x-bracing is not the same as solid blocking when it comes to seams.  

12' span 16"o.c. is within span tables (barely) for structural grade lumber or SPF - SYP .  Ungraded stuff - who knows ???  Yours had knots on the top center which makes me have my doubts about the quality and def. questions the competence of the framer.  The fact that you sistered on additional members has strengthened them to acceptable levels.   You are also using wood flooring - if you were going to use tile or stone flooring, you'd have to rip up the subfloor and start over.  It's no where near stiff enough for that material.

I'm with you on the "too late to re-do" assessment , and both of you on the "it'll have to do or be good enough".   I wouldn't lose any sleep over it, every project is series of compromises all along the way.

Thanks again!
Interesting.  In which aspect isn't it stiff enough?  That whole "bouncy" section, before the walls came down, was a tiled bathroom (12" square porcelain tiles) that sat in a bed of thinset on 1/4" luan which was stapled to the subfloor (the subfloor,  looking back at older pix,  was also running with the long edge parallel to those crappy joists, the way I did it, though their seams were staggered.)

I never noticed the bounce in the floor until the whole thing was opened up. The floor/tiles seemed fine, no cracks.  But I get what you're saying!