Hi, Timber Framers! I am new to this. I have a circa 1840 TF house in Iowa. I am a woman, if that matters, and I have 35+ years experience in carpentry and woodworking, started in the woodshop with Dad when I was 10 or so. This is my 4th old house.

Here's my question: My house is 24 x24 square, with a 6.5"x 6.5"girder down the center. The girder was cut out at 4" to accept the 2.5"x 6.5" joist. The joist notch isquare, which I have learned from other posts is the worst case scenario.
On the north side of the girder, 3 joists were completely broken, several others were cracked and ready to fail. I removed the subfloor, and the joists, lag bolted 2x8's to the girder, and the other beams rimming the floor, then used joist hangers to support new 2x8 joists, 16" o.c. I used .75" OSB for the new subfloor. This has been installed but not finished, because I am concerned that I need bigger joists to make the floor structurally sound. I am still getting some jiggle and bounce.
On the south side of the girder, I currently have one broken joist, and the others are seriously sagging. The floor upstairs dips almost 3 inches in the center. Someone framed a new dropped ceiling downstairs, using 2x4s that is also failing, and must go. I cut out a small part to see what is going on with the joists, and it appears some were already "sistered", but that, too is failing. I'm not as worried about being historically accurate as I am about having a repair that will last at least a couple more generations. I welcome your ideas and comments. Thanks, Katy

Hi Katy,

We really need to see some digi pics of these failures. It is rare to get so many failures in such a "young" building and so something must be at work here to cause these failures.

Regards

Ken Hume P.Eng.

Yes, pics please. Why the dimensional lumber repairs and hangers? Why not proper timberframing repair(or re-engineering stronger)? If you need to get some new or reclaimed timber beams or joists in there, not too hard to find. Not at your local big box stores granted, but there are plenty of barns coming down locally, you can probably find something locally or order some at good prices if you know where to look. Do you have TF experience? Not too hard to learn techniques.

Welcome Katydid;

About that new floor framing you installed: 2 X 8s @ 16 O.C. should work fine on a 12' span. You mentioned bounce issues still remain... Did you install bridging between the new joists? That will stiffen up the floor considerably. Maybe even two courses of bridging (@ 4 & 8') in the 12' span...

Perhaps the center girder also needs reinforcing (additional posts installed).

Good luck!

Thanks for your reply. I believe the joists failed because the notch was cut square instead of tapered. The joists are cracking at the notch, then splitting out to about 4 feet from the girder, and then breaking. When I get more torn out next week, I'll try to get some good pictures.

Thanks for your reply. I am still learning.. a lifelong process. Didn't know a whole lot about timber framing.. discovered that this house was TF about 6 yrs ago when I had a new roof put on. I bought house from HUD, it was going to be torn down if no one bought it.
When I did the prior fix, it was priority to get something done fast, before someone fell through! I thought I read my span chart right when choosing 2 x 8's. I didn't bridge the joists, and I think I should do that.
It would be neat to redo the joists using TF techniques, and leave them exposed, problem is, the house has been retrofit for forced air heat and electricity, and the ductwork and wiring would have to be moved.

Thanks, Don. I agree, that bridging would be a good idea. The center girder has only dropped an inch and a half in all these years. I have jack posts under the first floor girder (in the cellar)and I plan to take a closer look at the support posts for the second floor when I get the ceiling opened up. I'm thinking it may be a little easier to work on this repair from above, though. But in any case, I have to redo the ceiling, I can't believe they used 2x4s to support it!

Had a thought on those old splitting joists.

A barn restorer I talked to ran into this same situation. He ran a beefy lag screw up from below into each joist to close the splits.
Sounds like you could use a few lags per joist, that is if you plan on keeping things "original." Might even be able to put some adhesive into the cracks before lagging them. Maybe use a jack to close the gap before installing the lags.

And that ceiling sounds like a job... fun stuff!

I guess deciding on going TF or "modern" in this home's restoration ultimately depends on your budget and skill set. Might be a good time to give some TF-tech a try.

HHmmm- Something to think about! I will take a look at that when I get further into tearing out the ceiling. It sounds a lot easier and way more cost effective than ripping it all out and starting over! Thanks for the idea!

Hi Katy

Your joists that have split lengthwise from the end cog, could probably be repaired by jacking the joist up until the crack closes and then apply two steel plates on each side and bolt right through from side to side. It would help if the plates had a shoulder at the bottom to assist and hold the joist together and not allow splitting to occur again.

This is not a repair that could be used if things are going to be left in view but if they are to be hidden it would be ok., it should make them as strong as they once were.

This is just a normal failure, and is predominantly noticed when using certain types of timber that fractures easily is used such a Hemlock, or pine as examples.

My father once built a platform for a drawbridge using an engineered set of plans. He was very skeptical from the start about the failure of the timber due to a similar notch at their ends. Of course the engineer would not give in but in the final analysis when the first truckload of gravel passed over it ended up in the brink! The timbers simply failed lengthways from the bottom of the notch.

I suspect that in your case the original framer used a technique that most of the time you can get a way with but not all the time and this is one of those times.

NH

I have most of the joists exposed now. The joists are 2 foot O.C. The first one (from left to right) is cracked, has been "sistered" with 1x4's on both sides, also had lumber added on top of joist to attempt to correct the sag in the joist. The second one has cracked and twisted, has about 5 different pieces of wood affixed where repair was attempted. The third is broken, but has another 2x6 nailed to it. The whole thing flexes about 2 inches when you step on it. The next 4 have various repairs tried, but are completely broken, have pulled away from the girder, only thing holding them up is the nails in the subfloor, and about a half inch setting on girder. To complicate things further, the main ductwork for the furnace runs parallel to the girder, and will interfere with whatever fix I do. I have had my furnace man in, we are looking at re-routing the ductwork, and I have a structural engineer willing to take a look and offer advice. I love this old house and it is certainly presenting a challenge and an opportunity to learn! I just don't think there's anything there that is worth trying to save. If I try it and it doesn't work, then all that time and $ would be wasted and I'd have to start over and replace it all anyway. I am leaning towards a repair with new lumber, and modern construction.

Wow, that sounds like a hell of a mess!

Someone's about to fall through that floor. Sounds like no parties at Katydid's place for a while :-(

This house, if I remember, is circa 1840 right? ...are the timbers sawn or hewn? You say the joists pulled away from the girder. By girder are you talking center of the building or exterior wall? Is the exterior wall bowing out? That will want to be brought back in if possible (you probably know that anyway).

Those joist repairs sound pretty lousy...did you say 1X4 sistered to one of them (head shaking)? Sounds like you had a hack in there before you, which definately makes it harder for you now.

Are you in any historic area of town?

Do you want exposed original beams/joists? Do the floorboards have character?

If you keep the original framing, you could save money and time in not re-doing / drywalling a new celing. (But you said the furnace ducts are there...not exactly something to show off... perhaps the ducts can be re-routed in the wall or some other area like a closet?)

I'm sure it's tempting to rip it all out, but that may not be the cheapest in the long run. Any broken joists can be replaced w/ reclaimed stuff sawn to size...

Fun fun

Still like to see some pics on this post...so we can better advise and hopefully save you some trouble.