Leveling a floor... maybe

If this is a double post, feel free to delete.  I got all the way through posting, then the site went down when I clicked "post."  Grrr.

First, a pretty picture for you.  This was a sketchup I did for a fireplace design which I am installing currently.

For the sake of numbers, the framing is 52" wide and 22" deep.  The slate you see in front is an additional 16" to catch embers, so a total of 38" to the end of the slate.  So far I've done the wall framing, but not the box framing.

The plan is to lay 1/4 backer on the floor for the full 52 x 38, then framing, then slide in the fireplace, then tile.  Then the whole room is getting 1/2" hardwood so, the tile (1/4" backer + 1/4" slate tile + a wee bit of mud) will be level with the hardwood (1/2" + a wee bit of vapor barrier).

Problem is, the floor on the right side of where the box is going is a strong 1/2" lower than the left.

Option A: lay a 1/2" piece of 1/2" something on the right to screed some leveling mud under where the box goes, then more mud to taper off the the right for a while.  This is probably the better way to do it, but I'm afraid with only about 6' off to the right of the fireplace, I'll just be trading one unlevel spot for another.

Option B: screw down the backer as-is, make the framing 1/2" taller on the right, (to make the mantel level) shim up the fireplace to level it, and deal with the fact that the tile won't be parallel to the fireplace.  This one would be easiest, but probably not the best.

I know that doing it "right" means to level the floor.  I don't really think that is an option short of removing the entire subfloor and joists and starting from scratch.  The joist framing is late 1800s/early 1900s, so it is a mixture of rough-hewn 4x6 or 4x8, some rough-sawn 2x10, and all of it was made to work with what they had, so joists meet at a beam where they don't make a straight line, there appears to be an old access hatch in the framing, and it is generally just 125-year-old farm engineering.  It is ridiculously strong and very well supported, but not something I can just alter without serious alteration.

Any thoughts?  How might you go about tackling it?

If the subfloor is that strong, use floor leveler to level the whole room.  

In one room that had a 3/4" slope i used 1/4" luan paneling to contour it flat.  I worked from 3 layers at the deep end up to one layer.  Then it took less "mud" to smooth out.   Or, use a floor sander to smooth the edges of the luan.

So, I did some more measuring.  Your suggesting is very logical.  It appears that most of the floor is relatively flat, but not level.  I don't mind a wee bit of not-level, but it needs to be flat.  The problem is, I'm trying to correct one high spot.  Using leveling mud would mean I'm bringing 300 sf UP when I think it makes more sense to take the 50 sf DOWN.  I'm also dealing with 82" ceilings which would cause me to re-engineer a custom entry door, find a way to transition to the bedrooms, and otherwise make more work than necessary.

I pulled a few boards up.  Looks like the rim joist and associated beams/joists in that area point up.  I suppose I could pull up a large area and try to shave those joists?  Just seems like a crapload of work.  I could lower the support beam at the risk of causing structural damage, but I don't know how the rim joist is attached to the foundation.

In case it helps, the bare floorboards near the top of the picture are the original structure which was built around 1900.  The white floorboards are an addition which was likely done in the 20s.  This picture shows the highest point in the floor which is near the left of the fireplace "box" in the first photo.

Bringing 300sf up is much much much easier than taking 50sq ft down uniformly in alomkst every situation.

The floor leveling part, yes.  The three custom interior doors won't be bad, but the new threshold/frame/entry door, not so much.  That gets really expensive.  Plus, the transitions to the bedrooms and kitchen might get hairy.  When you have 82" ceilings and everything is custom built for it, raising a floor can mean thousands of extra dollars that I don't have.  I opened this can of worms so I have to deal with it, but raising the floor is just not an option.

One day soon I'll have the rest of the carpet torn up and I'll map the rest of the floor so we have a better idea.

Fook it, it's an old house with old house character.  Put the fire box in level, floor to the floor, make a little black trim to cover the wedge that matches the firebox.  IE cut a quarter round and spray a couple coats of duplicolor bedliner on it

In reply to Patrick (Forum Supporter) :

I like how you think.  I've resigned to having the floor not be level for the fireplace's sake, but 1/2" in 52" is not healthy for the custom maple hardwood I'm putting down.  THAT part of the job I need to do right.

Ok, so I mapped it all out with a rotating laser.  It's kind crappy, but I think it's salvageable.

From the laser down to the floor I get a difference of over 2" from the highest point to the lowest.  2.25" to be exact.  Raising with leveling mud is just not going to be an option.  The nice part is, most of the perimeter (with one exception that might get a little mud) is within about 1/4".  It seems like if I can drop that one beam about 5/8", I can get the entire area within 1/4" of itself and fill the rest with luan or shingles.

Tell me if this plan sounds like something do-able.  I'm going to remove floorboards that are above the one beam and attempt to lower the highest point by trimming the bottom of the beam.  I could dig out the dirt below the concrete, but disturbing 120-year old dirt isn't probably a predictable choice.  If that doesn't do the trick (because there is another beam under the joists, I'll just rip all the subfloor out and chalkline the joists and buy more sawzall blades?  Might be kinda nice to just replace it all with OSB T&G glued and screwed.

Over 2 inches different is rough. Definitely do not dig out the dirt underneath the concrete.

How is the beam held up? Depending it could just need a floor jack to hold the beam up and trim a post.

I have taken up sub-flooring in order to level beams.  Especially when the crawl space was too narrow to crawl under.

It will be interesting to see if you notch the beam so tht it would drop, how long it takes to actually drop.  Sometimes they take a set.  But, they do drop.

If you decide to put in new 3/4' sheet sub-floor it is possible using your laser to glue shims on top of the floor joists to get the deck level when you screw it down.  Been there, got the T-shirt.

Gotta love old homes....

So, after getting about 1/3 of the subfloor torn up, I had to pause.  A rather large colony of leaf-cutting wasps had taken up residence in my wall.  How they got there is a puzzle.  So last night I set off some bug bombs and stayed with SWMBO.

The good news is that the front section of the room was constructed over what used to be a concrete patio.  There are 2x6s sitting on some 1x with a 1/2" shim covering the top.   That part will be easy.

The far corner (where the 2" sagging is) I noticed is um.... floating.  The subfloor is not sitting on a joist, nor is the wall sitting on the subfloor.  Glad I made the decision to replace the subfloor as I have a feeling that corner of the room needs structural attention.  I suspect old termite damage.  I knew that the house used to have termites and I negotiated some money when I bought because they inspector found some damage.  Both the inspector and the pest guy who came to treat each said that it looks like very old damage, but it was treated anyway to be sure.  I'll tackle that corner when I get to it.

As far as the main part of the floor, I have a bit of a challenge.  The beam is sitting on the edge of the concrete patio, so I'll have to trim the whole thing.   The additional supports are timbers sitting on concrete blocks with spacers of varying constructions.   One is on a chunk of 4x4, another one has a couple 1x stacked on it.  Should be easy to correct by just stuffing whatever thickness in there I need without disturbing the concrete or dirt.

Antihero (Forum Supporter) said:

Over 2 inches different is rough. Definitely do not dig out the dirt underneath the concrete.

 

How is the beam held up? Depending it could just need a floor jack to hold the beam up and trim a post.

The beam is sitting directly on a concrete block and spaced up with varying thicknesses of lumber.  The crawl space is only about 8" lower than the joists.  PIcs to follow.

Blue arrow shows how far the concrete patio goes.  Orange arrow shows where the berkeleying bees were living.  The wall indicated by the orange arrow was the original exterior of the structure, so fortunately the rim joist on that wall is just a sill screwed to the foundation, not a structural part of the house.  I think I can slide a sawzall blade behind it and zip the screws, or I could just chalk a line and trim it.

The 1/3 of the floor over the concrete is leveled and ready for new subfloor. I got anal. It's all within 1/16" of level.

Nothing to add but this is cool. 

I wish I had the skills to do something like this if needed.

When it comes to house stuff, I'm always afraid I'm going to berkeley it up so bad the cost to fix will be multiples of what it should have been had I not messed with it.

Glad you went with leaving the original framing/slab yadda yadda ......ripping lumber on the table saw is my go to MO to compensate for uneven situations(plus it's therapeutic for clearing ones mind.....watch yur DAMN finnerz).....Hey left yu a PM on the poncho cha cha.....late

z31maniac said:

I wish I had the skills to do something like this if needed.

When it comes to house stuff, I'm always afraid I'm going to berkeley it up so bad the cost to fix will be multiples of what it should have been had I not messed with it.

Being a theater tech director, everyone always asks me to do house things, like building a deck, or fixing a roof.  I have dabbled in that sort of thing, but I'm not any good at it.  I'm used to building things that LOOK like real stuff and don't fall apart during a 2-week set of performances.  I'm sure that what I'm doing will be safe and sturdy, but it won't be done "right."  I'm sure if a contractor walked in, they might have a heart attack... or laugh.

759NRNG (Forum Partidario) said:

Glad you went with leaving the original framing/slab yadda yadda ......ripping lumber on the table saw is my go to MO to compensate for uneven situations(plus it's therapeutic for clearing ones mind.....watch yur DAMN finnerz).....Hey left yu a PM on the poncho cha cha.....late

The part I have leveled was the easy part.  Shim here and there.  The rest of it.... yikes.  Not sure what I'm in for.

I think I will get OSB tomorrow and lay a couple sheets by the door... only because I have nowhere to put my couch while I tear out the rest.

Nothing much to add except one more tool for your arsenal should be a surface planer.  It take off a bit of height far more easily and consistently than a sawzall.

https://www.amazon.com/PORTER-CABLE-PC60THP-6-Amp-Hand-Planer/dp/B00PSPUWV4/ref=sr_1_20?dchild=1&keywords=surface+planer&qid=1597414399&sr=8-20

Something like this.  Mine came from the hammer store 20 years ago and still works "fine" for the sort of jobs I need it for (about every 5 years or so).

I might actually have one at the theater. If I use that one, then all of the nails I hit won't be damaging my tool 

Curtis73 (Forum Supporter) said:

I got anal.

minor win thread?

In reply to AngryCorvair (Forum Supporter) :

Laughing out loud.

The more I tear into this subfloor, the more I am happy I chose the hard way.  I pulled up a floor board and most of the joist came with it.