Thread: Joist repair practice.

Repairs have been made beneath a bathroom area. Four floor joist have been cut off approx. 4" and new lumber (2X12) pieces 4' long were sistered on to the ends. Nails joining the two pieces were spaced 4 - 6" along the length of the splice.

Is there any problem with this repair?

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Vern,

I see this kind of repair frequently. The joist should be full length between supports. That kind of repair is more likely to pivot or "scissor" and fail. I always recommend correction. If the contractor gives you any guff, have them show you where it is allowed in the code or to provide an engineer's approval.

That PB plumbing is likely to fail, causing a leak that will shpritz onto the joists, causing mold and decay and ultimately structural failure.

Gunner, this is a short sale, no contractor to confront. The 2x12 joist have short span and the floor is very solid to jump on. I have explained to the young prospective buyer that it is not up to code, but I do believe it will hold up if they don't park there SUV in the bathroom. Have you seen this type of repair fail? I believe bolts through the splice would be a good idea to prevent the scissor failure. I will give the standard CYA "recommend further evaluation by licensed engineer" but suspect it will not happen.

Victor, Gloom & Doom! Hey its got the copper fittings and besides no vapor barrier already has organic growth doing very well thank you!

Vern

I like the way you handled it.

Cheers,

Vern,

I would say the adequacy of the repair is dependent upon the joist span. It is my understanding that it is possible to sister a joist without going from support to support (although that method should be foolproof).

A proper sister joist must be a minimum of 1/3 of the span of the joist plus the length of the damage on the end of the joist that is being repaired. The sister joist should have a triple row on nails every 12 inches on center to properly transfer the floor loads from the damaged joist to the sister joist. Bolts are even better, but probably not necessary for the loads involved.

FWIW I'm in trotal agreement with Gunnar. Wrong is wrong and there is no darn way around it.
(I'd love to use stronger language, but afraid of offending Billy's ears.)

Originally Posted by Jerry McCarthy

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(I'd love to use stronger language, but afraid of offending Billy's ears.)
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.
What did I do?
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Not an engineer here, but I don't think that it should extend from support to support. I am not a fan of nails and prefer the use of through bolts (2 sets of 3 for a 2X12 at the beginning of the repair and one set of 3 towards near the damaged end in good wood). If the good wood is at least 3 X's the length of the damaged section and a minimum of 3', I'm good with that also. Of course, the joists need to have been jacked back into place and I list it as prior repairs to the floor joist(s).



Any comments???

Verne & Jon,

You might be right that this kind of repair is acceptable, but I would be unwilling to make that kind of call. I do not have the engineering knowledge to support it. As Jerry Mc will tell you, in CA, everything that I write, I have to think about whether or not it will hold up in court. Because, I will eventually be sued for something. And, I don't want to end up on the stand saying, "Well, it looked OK to me".

Trotal? You arn't hedging on me are you Jerry?

Gunner, I agree with end to end method of repair as being the best practice but don't know if this one is acceptable per an SE. I was hopping someone had seen this type of repair with an SE's blessing. Hence the CYA statement in my report.

I know that I would be comfortable with this repair if I were buying the house. Only real problem I would have is with resale time, which I expressed with the buyer. I have left the ball in his court.

I would still like to hear if anyone has seen this done with SE's blessing.

Originally Posted by Vern Heiler

The 2x12 joist have short span and the floor is very solid to jump on. I have explained to the young prospective buyer that it is not up to code, but I do believe it will hold up if they don't park there SUV in the bathroom.

That is setting yourself up for getting that "fat letter" from the attorney. A "skinny letter" from an attorney has a check in, a "fat letter" from an attorney is asking for a check by return mail, and if you do not ...

Have you seen this type of repair fail?

Yes.

I believe bolts through the splice would be a good idea to prevent the scissor failure.

While bolts will help, they will not "prevent" that from happening.

I will give the standard CYA "recommend further evaluation by licensed engineer" but suspect it will not happen.

That CYA is canceled by you saying "but I do believe it will hold up" in whatever words you said it to your client.

You cannot expect to CYA when you say "Better get that fixed" and "but I think it is okay" - when the judge hears that, you are really in for it. It will not matter how many times you told them to fix it or get it checked - you stated (in whatever words you used) "it is okay" ... you said it ... they heard it ... now it is time for you to write the check and ask "Your Honor, how much did you say I need to make this check out for?"

Originally Posted by Vern Heiler

I would still like to hear if anyone has seen this done with SE's blessing.

Double those joist up with new joists next to the damaged ones. Not part way, all the way.

That is what I've heard the structural engineers say 'bearing point to bearing point ... like the original one'.

Originally Posted by fritzkelly

(apostrophies left out for Gunnar)

Frit'z,

Thank's, I's appreciate's that's.

It can be repaired as shown, but the repair has to be designed. It's a moment connection and will likely need bolts (depending on the load and the span). It's probably easier and more cost effective to simply install a sistered full-legnth joist next to it. The design of the repair would cost more than a new joist. I've designed repairs, but usually only when it's cost effective (for example, a main beam that had to be lengthened a few feet)

Originally Posted by fritzkelly

I'm kind of curious about why the joists needed to be "repaired". How many were like that? It doesnt look like any of the original joists are bearing on the sill plate. (apostrophies left out for Gunnar)

Apostrophes left out? Then whats that little thingy in the middle of your first word? Looks like troll bait to me.

Just thought I would throw out some load calculations for this type of joist repair.

Let’s say the joist spans 14 feet and the joists are 16 inches on center. The joist would be supporting 18.62 sf of floor (14 x 1.33). Multiply this (18.62sf) by 50# per sf (10# dead load and 40# live load) and you get 931# that this joist needs to support.

The load on each end of the joist is half that total or 466 #. If you sister the joist with 16d nails, each nail can carry approximately 100# in shear (total shear load is dependent upon the species of wood, but let’s use a mid-range figure of 100#). If you make the repair with a partial sister joist using the 1/3 span minimum, the joist repair in this scenario would have a minimum of 15 nails (triple row of nails every 12 inches). This could safely carry 1500#, or three times the expected load, a comfortable safety margin.

While a full length sister will also work, there are times when this may be prevented by pipes or other obstructions and a short sister joist may be the best solution.

I see partial sister joist repairs that have been in place for thirty or more years. Most do not have adequate nailing, but almost all of them have supported the floor with no problem. The loads involved are just not that great.

Regarding Vern’s comment re approval by a structural engineer, I have seen engineered rafter repairs using partial length sisters where rafters have been broken due to trees falling on the house. Only nails were used to connect the sisters.

Originally Posted by Lou Collier

Regarding Vern’s comment re approval by a structural engineer, I have seen engineered rafter repairs using partial length sisters where rafters have been broken due to trees falling on the house. Only nails were used to connect the sisters.

And, without that piece of paper signed and sealed by the engineer, YOU are the one standing behind that repair.

There are things I would do, feel comfortable doing, as a licensed GC, but when it comes to 'needing support documentation for structural issues', nothing ... I repeat ... NOTHING ... nothing beats that piece of paper signed and sealed by a structural engineer.

I would personally not recommend a structural engineer to evaluate such a minor concern that can be easily repaired. I would recommend a short 4x6 support beam and two pre-cast concrete piers to provide additional support.

I see partial sister joist repairs that have been in place for thirty or more years. Most do not have adequate nailing, but almost all of them have supported the floor with no problem. The loads involved are just not that great.

I see this type of repair quite often usually in century homes.

Hi,
So many posts get into talking about whether something is up to code or not. Whose code? Where? What edition? I am sure code for Biloxi will be very different from Prince George BC Canada where a basement is almost essential to avoid frost heaving of foundations. We also now use R40 or more in the attic and use 2x6 framing to beef up wall insulation even in the more salubrious area I am in on the southern west coat of BC.

I was taught that true knowledge of all aspects of building code is beyond us. We cannot be code experts on every aspect of a building nor do we expect to see a 25 or even a 5 year old building up to today's code in every system. So code is a moot point for a home inspector.

Sooo the issues become is it safe? will it fail? which we can only surmise from the evidence we see and our experience. This joist set-up looks bad to me because of the shortness of the sistering joists.

Is there evidence of scissoring movement in the area? Any idea when the work was done and by whom and for what purpose? It looks a little damp in the area.

Oddly in Canada the code is written in metric but everyone builds using imperial which can result in some really fine screw ups!

Originally Posted by Jerry Peck

And, without that piece of paper signed and sealed by the engineer, YOU are the one standing behind that repair.

And I would have NO problem standing behind any repair done to the specifications I have listed.

In fact, I did many such repairs during my years as a carpenter and a general contractor. I stood (and still stand) behind all of that work. Maybe my background as a designer and carpenter gives me a comfort level with what works and what does not work that others may not have.

Yes. We always recommend that all sistering be of joist of equal size and extend either the entire length or at a minimum 5' either side of the failure. Also joist should be bolted with 1/2" bolts with nuts and washers 16" o.c and staggared.

Based on the picture, and following discourse the question is: What would it cost to correct the issue and would it negate a purchase?

Originally Posted by Lou Collier

In fact, I did many such repairs during my years as a carpenter and a general contractor. I stood (and still stand) behind all of that work.

As I have done in the past.

However, there is one thing you are not paying attention to ... just a small thing, ... one of those tinsy-weensy things ... as an HI *you are not getting paid as a GC*.

Lou, you're a living example of; "it's better to be lucky than good."
In California one tries to perform home inspections without leaving finger or footprints. There are more state licensed attorneys in CA then the entire country of Japan. Go figure?

Bryan



"salubrious" You are killing me "salubrious" I can't help but repeat the word "salubrious" I have only heard that term once in my life.

"salubrious" Still smiling

WC Jerry,

Fortunately, Virginia is not California.

One thing I’m surprised hasn’t been brought up is the location of the splices.

If Vern’s splices were in the middle of the span I’d be very concerned. That concern is much, much less when the splice is right at the ends, with the potential “pivot” very close to the bearing point. I don’t have the engineering calculus to document this, or even name the forces involved (leverage, tension?), but I’m 99.99% certain that the live floor load required to deform the splice would be a significant order of magnitude greater than if the same splice was at the middle. There’s a good reason notches are allowed to be 1/4 at the ends of joists, 1/6 at the outer thirds but none in the middle.

Vern said…”I know that I would be comfortable with this repair if I were buying the house.” I have to say that where they are, and assuming a good nailing pattern, so would I be. But I’d probably toss in a few carriage bolts anyway.

Originally Posted by Lou Collier

Fortunately, Virginia is not California.

Lou,

Yes, but Virginia is next door to DC and that place has more attorneys than rodents. I'd bet that they sneak across the state line at night.

Can someone point me to a good source of information on the proper connection methods for sistered joists?

(I don't want to play SE, just to improve my ability to spot clearly insufficient/incorrect connections.)

Don't know if this is what you want or not but it is a handy tool.

Connection Calculator

Originally Posted by Gunnar Alquist

Vern,

I see this kind of repair frequently. The joist should be full length between supports. That kind of repair is more likely to pivot or "scissor" and fail. I always recommend correction. If the contractor gives you any guff, have them show you where it is allowed in the code or to provide an engineer's approval.

Gunnar is absolutely right,and from what i can see you have the space to build a support pier under the sister joists. Just bury a 4"x8"x12" solid concrete block directly under the connection perpendicular to it then build it up with 8"x8"x12" block and top it with another 4" or 2" solid block and some 1"oak boards and wedges.
I have always used this method when doable since an inspector showed me that this method will always pass inspection. Good luck