[justincaseme]

We're removing the ceiling in an old house I bought and we need to replace several ceiling joists. Some of the joists were sagging due to water damage, but we're replacing several more to increase their size from 2"x8"x18' to 2"x10"x18'. We're also changing them from 24" OC to 12"OC and adding blocking (Douglas Fir #2, Grn). That's slightly above code in my county, but the 2x10s were a better choice due to some issues with how the gas pipes are laid out, and where we want to store boxes in the attic (not relevant here).

What I'm concerned about... one end of the ceiling joists sits on an exterior wall top plate and we have to cut the joist ends to match the angle of the hip roof slope. The Hip slope is only 4:12 (3.875:12, or about 16 degrees technically). The actual depth of the 2x10 joists = 9". We have to cut 6.667" off the joist ends to make them fit on the top plate under the roof. The codes say not to notch more than Depth/4. That's only 2.25" off the top here!!!There was a similar situation with the old 2x8"s, but it just seems really odd. Is this safe? Is there some special step I should take on the joist ends?

Here are some pictures...





* See Los Angles County Building Code 2008, Wood Frame Residential, PDF

[amsteube]

The reason they say that is obviously because of the bearing point on the wall. The problem that you are going to run into is if you pulled a permit the inspectors will never pass that. Other than that I don't have much of a suggestion for you. Maybe contact a local engineer and pay him the outrageous fee they charge to come look at that kind of stuff.

Sorry I couldn't be more help.

Aaron

[justincaseme]

I appreciate the input Aaron. I'm not too worried about the inspection aspect, just the general stability of the joists. In the worst case, is this any less stable than what was there before? What techniques have people used in the past to handle this situation? Some kind of thicker joist? A steel connector?

[amsteube]

Well first off it is definitely not less stable than it was before. The main purpose of ceiling joists is to keep the walls in. Meaning that the weight of the roof wants to push the walls down and out. If you are increasing the joist size and decreasing the spacing to 12" o.c. than it will be structural stronger than it was before.

Also I noticed that you have the joist nailed into the top plate and the rafter. From a structural standpoint it looks fine to me.

The only other thing that you could do is notch the top plate. To do this you would have to move the cj's into the middle between rafters because the birdsmouth on the rafters rests on the ceiling joist.

Personally I would probably just go with what you are doing. Looks oversized in my opinion honestly.

Aaron

[InspectorDan]

Interesting problem. You are right to be concerned. The 2x4 rafters make it a somewhat difficult problem. Will the inspector 'pass' the 2x4 rafters when he comes back? Are you in the Los Angeles area or are you somewhere where snow load has to be considered?

A few possibilities for 'beefing' up the joist/rafter assembly come to mind. One is to add a ledger to the double top plate in order to increase the bearing area that is available to the joist at the joist/plate/rafter connection. If you screwed and glued 2) 2x4's to the top plate it would increase the bearing area but the glue/screw connection might not have the shear strength required for a structural load.

Since the main job of the ceiling joists is to prevent rafter spread (in addition to apparently supporting your drywall ceiling/insulation/whatever) you certainly want a better framing connection than the sparse nails that are there now. If you want to be absolutely certain that you have a good solid framing system and if you don't mind taking the risk of over-engineering then you could do the following:

1) Double up the existing joists so that there is a joist on either side of each rafter tail.

2)Cut and install fillers of 2x4 lumber so that the space between the twinned joists is filled at the bearing ends.

3) Connect the joists to the double top plates of the wall with hurricane ties.

4) Use through-bolts to squeeze the twinned joists/rafter tails/joist fillers all together.

That should be pretty solid.

Good Luck!

[amsteube]

1) Double up the existing joists so that there is a joist on either side of each rafter tail.

2)Cut and install fillers of 2x4 lumber so that the space between the twinned joists is filled at the bearing ends.

3) Connect the joists to the double top plates of the wall with hurricane ties.

4) Use through-bolts to squeeze the twinned joists/rafter tails/joist fillers all together.

Most of these suggestions are overkill.

#1 is probably a valid suggestion but if you are going to do this I wouldn't use a 2x10 as it will become extremely expensive since you have already doubled the number of joist.

#2 you gain nothing in the way of bearing area or anything to prevent any sort of deflection in the ceiling joists. Also you will have to install drywall backing at the tops of the walls where joist land anyway so kind of a moot point.

#3 This may actually be a viable solution although hurricane ties are designed for short, high force loads not long term static loads

#4 Could work I suppose. Although you need to make sure that drilling holes through the rafters is not against code where you live and also that it won't leave such a small load area as to actually increase deflection.

Most of these suggestions are extremely over designed for what you are trying to do. I do enjoy the apparent sarcasm at ceiling joists being used to hold the ceiling finishes and insulation.

Aaron

[shoproland]

I applaud the remedies by Inspector Dan and Aaron, and I agree there is a bit of overkill there. If it were me, I'd just lag those joists to the rafters near the center of the rafter/joist mating area and call it good. I believe that would alleviate the outward pressures on the top plates. Good luck and Godspeed.

[justincaseme]

All good suggestions...

They get me thinking, what if I came back from the wall about a foot or so, where the joist is full depth, and attached a steel strap to the rafter above (every other rafter technically, since the rafters are 24" OC). Would that be an effective way to help transfer the load to the top plate while bypassing the thin end of the joist?

[shoproland]

If the steel strap is 1/4" steel plate then that would alleviate that outward pressure, but it's still a bit of overkill. If your roof is comp shingles, I would just lag those puppies together and call it good, but if you have tile up there then I would consider some sort of steel gusset system as you mentioned. If it's comp shingles run with a pair of lag screws on every joist to rafter joint. I've been in this business over 20 years and I would feel confident with lagging those together unless the roofing material is concret tile. Good luck and let me know if I've helped. Have a great day... Roland

[amsteube]

Another thing you could do is just add some collar ties in the rafters

[MasterFramer]

Go to your local lumber yard and look through a simpson strong tie book. They carry something for everything. Looks to me like the old way worked for a long time so it should work now