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Old 12-09-2009, 08:41 AM   #1
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Sagging Ceiling Joists


We recently bought a rental (~900sq ft) next door; vintage 1920 Northern Ca house. The ceiling in the small hallway joining the kit to the bedroom area has sagged ~1". Likely due to a masonry chimney hung on the wall/ceiling that was customary at the time(now removed). The kitchen is 12' across w/ 2x4 ceiling joists. Most of the kit ceiling is flat to ~1/2". In the hall however, the ceiling joist span approx 17' and have a 4' lap joint with another joist...this is where the sag is ~1". Thinking about shoring up the hall to the right height, running 2x12 in the attic perpendicular to joists resting on walls, then connecting old work joists to new 2x12 with clips. What do you all think?
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Old 12-09-2009, 08:55 AM   #2
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Sagging Ceiling Joists


Usually a 2x4 is addd to the side of the strongback to stiffen it in the horizontal plane:


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Old 12-09-2009, 09:58 AM   #3
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Thanks Michael, really appreciate the schematic. the one thing i will probably change is using a metal strap and screws to hold the joist to the strong back. Excellent advice, thanks!
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Old 12-09-2009, 10:07 AM   #4
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Nice detail. I like the idea of using straps (Simpson or similar) to connect the old joist to the strongback, much more positive than using nails in direct pullout loading. If you use Simpson or similar, you can use the Simpson approved nails rather than screws if you choose, since the straps will allow the nails to be used in shear rather than in tension.
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Old 12-09-2009, 10:15 AM   #5
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Yes, simply nailing down through the 2x4 is no longer accepted practice, and I should have noted that - that happened to be the only link to a strongback I had handy. Back in the day it was also common - at least here in Chicago - to attach to the joists via vertical pieces of 2x4 sized to the depth of the joist + the strongback.

Current practice is to use an engineered connector, and some modern carpenters feel that the 2x4" was added to act only as a nailer, not as a stiffener, and is not necessary, but back when I still did this sort of work I preferred to install it even when a better method was used to perform the attachment to the joists - it helps to stabilize the edge-on member against tipping, which can be an issue on longer spans even if it's restrained at both ends.
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Old 12-09-2009, 10:48 AM   #6
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One thought was to use Simpson HTS (14 gauge) strap tie with their Strong Drive Screws instead of 10d nails..though i may predrill since the 2x4 are pretty dry. Simpson has some lighter gauge options also LTS, MTS. Here is the url http://www.strongtie.com/products/co...TS-MTS-HTS.asp

My leading approach however is to use a 6x6 for the strongback, then adjustable joist hangers and eliminate the possibility of splitting the old joists altogether. Since the ceiling is lath and plaster (all plaster already removed) i can simply remove a few pieces lath and thread the joist hanger through. URL for adjustable hangers http://www.strongtie.com/products/ca...angers_pt.html
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Old 12-09-2009, 12:25 PM   #7
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Your last hanger is not at right angle to the beam. If room is broken = 4'x17' and 8'x12'--------- the beam would carry the middle portion of the total load-- 4' wide x 8'span and 8' wide x 6' span= 32+48 = 80sq.ft. x 26#ll+dl = 2080# 6x6 doug/fir will carry 1775# 2x12 d/f will carry 2000# 2-2x10's d/f will carry 2300# which I would go with. Add 2x10x24" blocks at ends to prevent rotation and load straps uniformly varying sides.
Be safe, Gary
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Old 12-10-2009, 08:17 PM   #8
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The ceiling in my living room was sagging about an inch. 14 foot span for 22 feet of length. We bought an engineered beam, jacked up the joists and clipped them on with Simpson ties. The most difficult aspect of the process was getting the beam up into the attic.

Here's something we found. If we jacked up the joist one inch and screwed it with the clips, it would settle back down when we took the jack out. So we had to jack them up about an inch higher than where we wanted them.

We put the beam up higher than the joists (ends on blocks), with a straight path from the end points to the earth.

It worked really well though.
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Old 12-11-2009, 10:48 AM   #9
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Excellent advice from the forum.
Gary, thanks for reminding me to "do the math" and i appreciate your example. Pyper good thought also on how to prevent hysteresis. I hope to get to this project this weekend and will likely use a 4x12 (left over header) to span the ~4' hallway where the sag occured.

The 4x12 will land on the bathroom wall on one end, and a header (4'span) that opens the space between a hall and the living room on the other. Both will become bearing and i will need to put footings under the walls to connect posts to earth. if anyone has a calc method for the size of the footing, i will appreciate that. The house has 2x6 floor joists on 4x6 girders every 4'. Subfloor is diagonal decking.

To join the two or three sagging ceiling joists in the hallway, i will cut away the lath and use a 4X hanger to capture the two joists that were originally sistered together, then affix with simpson screws to the 4x12 mounted on blocks as Michael explained.
thanks again for all your help.
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Old 12-12-2009, 10:23 PM   #10
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Quote:
Originally Posted by Steve Burke View Post
Excellent advice from the forum.
Gary, thanks for reminding me to "do the math" and i appreciate your example. Pyper good thought also on how to prevent hysteresis. I hope to get to this project this weekend and will likely use a 4x12 (left over header) to span the ~4' hallway where the sag occured.

The 4x12 will land on the bathroom wall on one end, and a header (4'span) that opens the space between a hall and the living room on the other. Both will become bearing and i will need to put footings under the walls to connect posts to earth. if anyone has a calc method for the size of the footing, i will appreciate that. The house has 2x6 floor joists on 4x6 girders every 4'. Subfloor is diagonal decking.

To join the two or three sagging ceiling joists in the hallway, i will cut away the lath and use a 4X hanger to capture the two joists that were originally sistered together, then affix with simpson screws to the 4x12 mounted on blocks as Michael explained.
thanks again for all your help.
you're over-killing this poor ceiling Steve. if you're only supporting the ceiling, and no roof is posted to your ceiling joists, simply put your strong-back in and tie the old stuff to it.

personally, i would yank the offending couple of ceiling beams and replace them with something straighter.

you don't need footings to carry 3 boards of sheetrock and a hi-hat.
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Old 12-13-2009, 01:31 PM   #11
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Quote:
Originally Posted by ClemS
you're over-killing this poor ceiling
thanks for the reality check. I put together a revised picture and calc based on the feedback you guys gave me. Please take a look and let me know what you think -- revised calcs also added now that gary showed me the way.
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Old 12-13-2009, 02:37 PM   #12
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My calc's were for the center of the living room spanning 12', carrying the full load there. Sorry if I wasn't clear enough. At the 4' span, 2-2x4's d/f will carry 980#.
Be safe, Gary
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Old 12-13-2009, 05:18 PM   #13
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Originally Posted by Steve Burke View Post
thanks for the reality check. I put together a revised picture and calc based on the feedback you guys gave me. Please take a look and let me know what you think -- revised calcs also added now that gary showed me the way.
waste your money on an uber dishwasher for the old lady straighten the ceiling out to where it isn't an eyesore, and move on.

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