Greek Revival in need of joist repair
Hi everyone. I’m a long time reader and long time restoration carpenter. I may step out of my wheelhouse and buy and restrore an 1823 Greek Revival, The house was raised and put on a new block foundation in 1980. At this time they also tore off the roof and rebuilt it. New framing and everything.Why at that time they didn’t address the floor joists I’ll never know. Basement floor is still dirt and about 7’6 to joists. They are all log of varying sizes all hewn flat at top. With the help of at least a dozen steel posts the did take much of the bow out of th 1st floor. The real problem is the 2nd floor. Plaster ceiling on main floor looks actually fairly flat. This is probably due to very thick plaster at edges and very thin in center. The floors upstairs show everything. All rooms[3] and hallway have visible slopes. The worst is probably a dip of 5in across 12ft. I dont have a problem removing the flooring. I would if possible save the plaster.Any suggestions . I may be crazy but the house is all original and could stand for a 190 more years with a bit of TLC and craftsmanship. Thanks Randy
Replies
Randy
Could they have redone the ceilings-furring them at least flat and then replastering? For the floors to be that far off and the ceilings undecernable seems unusual.
Are your plans to "level" or flatten the floors while maintaining the ceilings below?
Is the framing of the 2nd floor so undersized that it is the cause of the sag, or does this somehow work it's way down to the cause of the problem?
What's the condition of the wiring and do you expect to run into that in potentially sistering the joists?
If you level out some areas upstairs, will this compound or create a problem at doorways and stairs?
thanks and best of luck.
Authentic (Original) Bow
Plaster is very unforgiving of movement, so I have to assume that the it is not a case of the joists being that seriously undersized to have that much sag without having the bounce of a trampoline which would start breaking up the ceiling the first time someone walked acrossed it.
I would guess that the way the logs were hewn to create a flat side also created a nonsymetrical cross section of the log which caused it to warp as it dried. They may have gone in green and flat in 1823, by 1824 there was a pretty good sag to the floors which was totally set in place by the time they dried completely. At some later point in time, they brought in a plasterer to level out the first floor ceilings.
The historian in me says that this is part of the original character of the house. It will be seeing its third century soon. It sounds to me that if a good roof is maintained over it, it probably has a few more centuries left in it. As a bonus, when you drop something, you know exactly where it will roll to. I don't think I would change it unless I found the condition unacceptable for livability, the same way that you most likely have central heat and electricity even though they required some damage to the original character.
A crazy idea if my assumption that the floors have the necessary structural strength, and you want to straighten the floors since you will not be able to sister to the round face of a log and likely there is no sill plate or rim joist to build a new flooring structure in between the existing log joists, you might effectively "shim" the floor. Remove the flooring. Set up a level string or lazer level above each joist, measuring down from the level line to the joist every couple inches along the length of the joist. Subtract off the shortest distance (at your highest point on the joist). Transfer these measurements to a 2x6 or whatever board that is at least as wide as the greatest measurement of sag. Cut along the line formed by these points and you should have a custom "shim" to relay your floor on. If you want to save your ceiling, need to be careful to keep vibration to a minimum. This probably means screws rather than nail whenever possible. And of course, don't step off a joist onto the ceiling.
If the floor needs to leveled in both directions (not only to correct for the sag in the joist, but also to correct for some joist ends are higher than others) you will need to set your level lines for each joist at the same height as each other and the high point you subract off your measurements must be the highest point of the highest joist.
I certainly would not guarantee that the ceiling would survive this type of work, no matter how much care is taken. The flooring may be restraining various stresses set up when the joists dried which will be released by removing the floor boards
Floor bow
Thanks for your input. Upon further consideration I may have to fix the ground floor also. The basement is really unusable now. If I tackle this I may need a complete new joist sysem for the house. As much as I want to save the history of the house, It needs to fit todays needs to make it 200 more years. In 1980 they gave it a solid foundation and roof. It has a new furnace but still is gravity heat. Plumbing and electrical both need upgrades. The basement joist are notched into the top f the beams. Could I assume[i know I know] that the 2nd floor joists are notched or morticed into a beam that has been flattened toward the inside of the house.All main beams in basement are flat 4 sides. I'm Thinking of joist hangers mounted to this. It's a big project, but everyone needs a hobby.Mine may be insanity.