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_
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_