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Levelling wood floor

6K views 13 replies 6 participants last post by  buletbob 
#1 ·
I'm sure there are any number of threads on this subject- and I do know the basics of what I plan to do to level my slightly sagging floor. But I do have a site-specific problem I have to work out.
My floor sags slightly toward the center of the house(where there is a chimney) in the front room (large living room)
The 1912 house was originally built without a basement, and in 1957 the house was jacked up, a full basement installed (7' from slab to beams!) and an oil furnace installed. The front half of the house, from the chimney to the sill, is supported by a steel I-beam, with a pier and post on the chimney end. The rear half (shorter distance) is supported by a wood beam and a pier and post. However, where the furnace is, the steel I-beam stops short of the chimney to make room for what was originally two floor grates, but is now a single duct upward to upstairs wall, which houses two wall grates. The floor was boxed around the earlier floor grates (which have now been patched with new wood floor upstairs, but the underlayment is kinda haphazard and not the ideal shiplap that the rest of the floor underlayment is.
My problem is that this boxing is not as strong as the original floor joists, and that's why it is sagging. Someone has since installed a 2"x2" square steel tube beam supported by 2" lally columns (If they even make them that thing, I'm thinking it is just plumbing pipe!) to one side of the furnace area to support the floor joists in that area. What I'd like to do is put a 4"x6" wood beam alongside the chimney, parallel to the steel I-beam and the other wood beam, to "bridge" the gap made by the furnace and chimney, and pour a couple piers and support it on posts like the other beams. I DON'T want to build any kind of load-bearing wall, which is one idea I was given by a friend. I'm trying to retain the open feeling of my slab basement.
Now that I've written a novel, I'll get to my problem-
If there was a joist that was split to make the boxed areas, I would simply sister another joist alongside it, and run my support beam and posts. Unfortunately, there is no joist there! The joists are on 16" centers, and the joist at the front side of the chimney is resting on the end of the steel beam, so it is supported. The next rearward one is exactly where the furnace ducting is (the reason for the split joist) and the next one after that is where the chimney is. What do I do in this situation? Do I take out the cross beams that create the box (perpendicular to the joists) and put in some kind of joist halfway between the two split joists? If I do, I have to figure out how to get a 22-23' 2x8 joist downstairs, and get it mounted up onto the sill at each end. Is there any way to put a shorter joist in between the two split joists, and box that joist to the joists on either side of it, creating a stronger box using the already well-supported joists?
I hope I have verbally created a good enough visual picture of my situation. If really necessary I can take some pictures from all angles of the underside of the floor and the joist situation.
thanks,
gomi_
 
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#4 · (Edited)
OK- these pictures should help.

First, here is a view that illustrates the location of the chimney, the I-beam support on one side, and the wood beam support on the other side. The board that comes through the middle is a short board, part of the "boxing" of the floor, and it where I would think I would need an actual joist- since the joist to it's right is split by the chimney, and the joist to the left is split by the furnace duct- you can see in the foreground of the picture where they are located relative to the chimney and the furnace. If you look close you can see how the next beams over are supported by the steel I-beam and the wood beam, repsectively. So in essence, I have two joists that are really not supported- though this end pictured does not seem to sag visibly, it may for all I can tell- upstairs of this is a busy area with closets and walls. I may have to erect a support beam on this side of the chimney as well.



This second photo is the view from the opposite side (you can see the thin metal "beam" held by non-code lally columns in the foreground) Again you can see where the joist ends at the chimney, and that the next one to the left is supported by the wood beam. I want to put my new support beam across this section, parallel to the other wood beam, going through the gap you can see between the furnace intake and exhaust ducts. That double set of short joists that boxes around the chimney is where I think I would need a longer joist, basically it is midway between the joist that is split by the furnace, and the joist that is split by the chimney. The joists are on 16" centers. It is about 11.5' from each wall to the center support beam. I also realized that these are old growth 2x6, not 2x8.



This last one is where I want to run my support beam. Again, you can see that the last complete joist is supported by the end of the steel I-beam, and then the next two joists are those beams that box in the chimney area.



Thanks for your ideas on this project.
gomi_
 
#6 ·
That's what I'm saying- the house originally had no basement, so all of these joists was full length- but when the basement was installed under the house, those two joists were cut, and a "bridge" installed from the two joists to the side, to support the ends of the cut joists. It's not nearly enough to support the floor above it- it simply distributes the weight to those other joists, and makes them all sag slightly.
I think what I need to do is add two beams- both parallel to the other support beams- that will bridge on each side of the chimney and support the ends of these cut joists. But they cut them short almost 2 feet away from the chimney to allow for the floor vents that were originally there with the older furnace. I'm wondering if the best idea is to sister joists to them, but extend them all the way up to the chimney so I can install the bridging beams there. Maybe on the split beams I would sister on both sides with bolts through, and glued, and possibly sister the other two end joists just because they have likely been weakened by supporting this weight for so long.
gomi_
 
#7 ·
they problem I see with what you want to do will not bring these floor beams up and level, or straight. these beams have been sagging for years, they have there shape now. if you install a new floor joist along side the one that the single header is nailed to your not going to to get that straight either, maybe a little, the new joist will take the crown of the new on also.
your best bet would be to install a header under the existing single and have it run past each side about two floor joist. they will be down slightly also because of the subfloor pulling on it also. then install two of those adjustable zip columns. (Lolly). once installed raise the floor a little at a time until you reach your desired height. BOB
 
#8 ·
I'm a little confused as you seem to use the term "header" for two different things in this situation. Are you calling the beam that runs transverse to the joists, that transfers the load of the split joist to the joists on either side a "header"? And then you say to install a "header" (what I have referred to as a "beam", supported by pier and posts) under the split joist and also under the joists to either side (which is what I said I wanted to do, on either side of the chimney, supporting the two split joists and also running under each of the non-split joists on either side. I just thought that once I raised the floor to where I want it (slow process of lifting over weeks of time) and then settled it onto the beams, I would want to sister a reinforcing joist alongside each of the split joists. I'm not going to use any adjsutable lally columns- those are a temporary fix (and what is currently there, and it looks like temporary crap), I am planning on cutting into the floor with a diamond blade, installing a rebar cross, and pouring piers that extend a couple inches above the floor slab for the posts to rest on- matching the existing posts that currently support the beams that bridge the house floor. Keep in mind that this is MY house, I'm not simply doing a half-assed repair to flip it to a new buyer.
gomi_
 
#9 · (Edited)
The adjustable posts are to take up the height to level, very slowly, could take months. Once you get it level then put a permanent post in. Do all you mentioned then Gorilla glue it, run 100 srews in it, weld in an I beam. Beef that baby up to the max. Don't get so defensive. Have a beer on the Dorf Dude.
 
#11 ·
That's what I am intending- I've seen the limit of 1/8 inch per week. Im planning on hanging the beam to the joists with joist hangers to keep it in place while jacking, and use pole jacks to jack it, but my plan is to have piers in place before I start, and posts ready to place when I am done- lifting higher than my target height, then lowering it onto the posts. I think posting on here has simply served to help me narrow down my process more than anything.
gomi_
 
#12 · (Edited)
I'll defer the expert advice to the experts, but the rational seems good. I'd be worth an hour of proffessional advice though.

A couple of parallel steel I-beams and greased screw jacks on pads would probably help reinforce the hole in the support system. These could be hidden with fake columns from a big-box store, or a hollow split-able wooden column.
Without removing/relocating the chimney that might be the only option available.

One thing that might help would be to do a quick blueprint of the main support skeleton of the house. A lazer level and a measure will help with finding the most movement.
-Does the same problem exist on the first-floor ceiling, and the second floor? How is the chimney boxed there?
-Do the second floor load-bearing walls fall directly on top of the first floor walls?
The additional basement beams will probably create the best effect when directly under the first floor bearing walls. Gambatte.
 
#13 ·
I only have a single story. As for lally columns, IN MY OPINION (is that better?) they don't look finished- and in a hundred year old house, they are going to look like they are holding something up that is falling down. I don't know of many places where adjustable columns would meet code. I'm going with what I already have in place, which is solid wood beams, supported by wood posts on poured concrete piers. As for expensive homes, you can't buy a home in Seattle proper for under $250k, so I would say there are plenty of "expensive" homes held up with lally columns- doesn't make it an acceptable practice. Funny how people get their panties in a bundle over someone calling things like they are. Unfortunately, contractors have a bad reputation among the general public (just like my profession, car technician at a "stealership") but you gotta do things to counteract that opinion, not reinforce it.
gomi_
 
#14 ·
I only have a single story. As for lally columns, IN MY OPINION (is that better?) they don't look finished- and in a hundred year old house, they are going to look like they are holding something up that is falling down.
****** Yes they are better, In fact there better then what you have there now, there not going to rot. and secondly THEY ARE !!!! HOLDING SOMETHING UP. that is what they are designed for.:yes:

I don't know of many places where adjustable columns would meet code. I'm going with what I already have in place, which is solid wood beams, supported by wood posts on poured concrete piers.
***** back in the day that would of been alright. but today!, its not code putting a wood support post directly onto concrete. :jester:

As for expensive homes, you can't buy a home in Seattle proper for under $250k, so I would say there are plenty of "expensive" homes held up with Lolly columns- doesn't make it an acceptable practice.:censored:
*****When was the last time you saw a new home built with wood columns resting directly on concrete holding up the house.?? because THATS not an acceptable practice by code.:no:
Funny how people get their panties in a bundle over someone calling things like they are.
****** Unfortunately the term panties does not apply to my gender.:laughing:
Unfortunately, contractors have a bad reputation among the general public (just like my profession, car technician at a "stealership") but you gotta do things to counteract that opinion, not reinforce it.
gomi_
******Not all contractors have a bad reputation!!! And I resent that. there are many, many contractors that are good then those that are not. :thumbup:good luck. BOB.
 
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