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Remove sag from second story floor joists

Amy41706's picture

Hello everyone! My husband and I purchased an old 1860's farm house. When we purchased it we noticed the floors were slanted and bowed on the second story. We had a structural engineer inspect the house and he reassured us this was ok. Now that we have begun remodeling, we have discovered that the floor joists are old 2x6 lumber spanning about 16' on average. I know the engineer said it was fine but it makes me very nervous since I have two young boys that like to jump off their beds and it causes the whole house to rumble.  What I'm wondering is can I put one beam across the center of my living room and kitchen that would support the floor joist and make the floor joist span 8' instead of the 16'? If so should I be looking into regular lumber or would I need a metal I beam? And if this will support the weight, could I also use this new beam to slowly jack the bow out of the floor or would that be too much weight on the beam? 

Sagging floors pretty much (post #216221, reply #1 of 4)

Sagging floors pretty much come with old houses. You could install a beam and make the floor stiffer but I would suggest you not try to jack the sag out. Doing so would put terrible stresses on the house and it probably wouldn't work anyway. You could also pull the ceiling down or the second floor up and install new joists flat and level but in an old house you'd probably have to do all the floors to make the rooms consistant.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

There are several different (post #216221, reply #2 of 4)

There are several different ways to deal with this, but they all have complications.

The biggest factors in determining a "fix" are in the amount of headroom you can give up in the room below, and the available structural elements to support a cross beam or the like.

Also note that very likely portions of the foundation have sunk, leading to much of the slant you see.

For an 1860s home the "2x6" pieces are very likely full-dimension lumber and may well be of a more substantial wood than ordinary doug fir, so the pieces are likely about 50% stronger than stuff you'd buy at a lumber yard today.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

If it were me, I'd add a (post #216221, reply #3 of 4)

If it were me, I'd add a 4x8  3/16" wall steel box beam flat under center of joists - vertical I-beam if you have 10 ft ceiling

Cover with old barn wood to make it look original to the 1860s house.

Footing at the ends will be the biggest engineering challenge.

158 years old....just (post #216221, reply #4 of 4)

158 years old....just guessing it has seen plenty of boys horsing around...and there is always the option of instilling a little discipline into the house....