Possibly Overloaded Garage Door Header

[pdickerson]

The interior photos did not turn out. Here is the exterior photo, and I will do my best to desribe the issue. 1959 home. the garage door header is a DF #2 4x12 with a 16' span. The garage has a ridge beam about 21' long, which is supported on one end by a post that bears on the center of the garage door header. I noted about 1/2" to 3/4" deflection at the header when I sighted down it. Live loads for roofs here are 25 psf, and the dead load is probably about 10 psf. Is the garage door header OK? I have my own opinions, but I would like to hear from some others.

[Bruce A. King]

It may have been considered ok back then but not now. It could develop a small crack at a knot and split in half. Snow load could do it in also.

The deflection you see is not a big deal, it would do that with no load at all over time stretched out over 16 ft. Sudden failure is the issue that could occur.

I would recommend and engineer to design a reinforcement or total replacement if access is not too hard. A bolted on steel flitch plate could be the answer from an engineer or double LVL beam.

[Kenton H. Shepard, CMI]

Describe what you see and recommend an engineer. It's a simple calculation and may not even require a visit. It's possible that the 4x12 was installed crown down and has never deflected although if you get big snow loads it could have developed a sag over that amount of time.

[pdickerson]

I described what I saw and recommended an engineer... Then I dusted off the statics book and tried to see if I could remember how to figure it out. beams are sized to resist both the shear loads and bending stress loads. Continuos loads, point loads, live loads, and dead loads must be accounted for. Unless I made a mistake (fairly likely), I made the right call.

[Kenton H. Shepard, CMI]

Originally Posted by pdickerson

I described what I saw and recommended an engineer... Then I dusted off the statics book and tried to see if I could remember how to figure it out. beams are sized to resist both the shear loads and bending stress loads. Continuos loads, point loads, live loads, and dead loads must be accounted for. Unless I made a mistake (fairly likely), I made the right call.

What was your call?

[bdoles2]

Well considering it's almost 50 years old and nothing has happened, I don't see the big deal. 50 years worth of winter snow has not done anything to it, nothing probably will.

Anything is likely to fail after 50 years.

It looks ready for another 50 years in my opinion.

JMO

[Larry D. Kage]

Originally Posted by bdoles2

Well considering it's almost 50 years old and nothing has happened, I don't see the big deal. 50 years worth of winter snow has not done anything to it, nothing probably will.

Anything is likely to fail after 50 years.

It looks ready for another 50 years in my opinion.

JMO

When I hear something similar to this reasoning, I remind people of Mount St. Helens. It was fine for years.

Framing parts can take abusive stress over and over and over and then fail catastrophically.

[Richard A. Hetzel]

If a couple of assumptions I made were correct, the header is undersized by more than 50%. I used a total load of 40 psf, and assumed the garage was 24 feet wide. I also used the old dimensions for a 4x12, which were slightly larger than modern ones. Even if the live load were reduced to 25 psf and the dead load to 7 psf, the header probably won't be adequate...nope, it's still undersized by slightly less than 50%.

Why didn't it fail catastrophically? Because full loads are rarely encountered, and because there is a safety factor built into the structural design values for the wood, and also in the grading rules.

It is definiely an issue for a qualified design professional, even though there is some truth to the contention that it has endured for 50 years with nothing more than excessive deflection and isn't likely to fail catastrophically now.

[Larry D. Kage]

Originally Posted by Richard A. Hetzel

It is definiely an issue for a qualified design professional, even though there is some truth to the contention that it has endured for 50 years with nothing more than excessive deflection and isn't likely to fail catastrophically now.

Would you put your stamp on that, architecturally speaking?

[bdoles2]

We are hired to evaluate the home/garages and their systems (in their current state). We can't predict when an item will fail or if it ever will.

All I would state in my report is - The garage door header is adequate in it's current state - any modifications to the structure of the garage may warrant a professional opinion from a structural engineer. However, building standards of today are much different than those of the 50's - if built today, the header may be larger.

[Larry D. Kage]

Originally Posted by bdoles2

We are hired to evaluate the home/garages and their systems (in their current state). We can't predict when an item will fail or if it ever will.

All I would state in my report is - The garage door header is adequate in it's current state - any modifications to the structure of the garage may warrant a professional opinion from a structural engineer. However, building standards of today are much different than those of the 50's - if built today, the header may be larger.

Without seeing it in person (too many variables) makes it somewhat difficult to call but I would want to describe what I see (sag) and may add:


Garage overhead door header is sagged. Framing does not meet current framing standards/practices due to age ofstructure. Additional framing or reinforcement may be required. Seek advice from framing contractor and design professional.



I would not want to state that the header was adequate, however.

[jkogel]

Don't forget the sheathing, either plywood or shiplap in the 60's, well nailed, plus the siding, forms a big triangular gussett and makes that whole doorway pretty strong, IMO.
But that's not our call to make and I might still suggest getting a professional's opinion if there's a visible sag there. He might come up with a repair like this....

John Kogel
ww.allsafehome.ca

[Peter Doane]

Originally Posted by Richard A. Hetzel

If a couple of assumptions I made were correct, the header is undersized by more than 50%. I used a total load of 40 psf, and assumed the garage was 24 feet wide. I also used the old dimensions for a 4x12, which were slightly larger than modern ones. Even if the live load were reduced to 25 psf and the dead load to 7 psf, the header probably won't be adequate...nope, it's still undersized by slightly less than 50%.

Why didn't it fail catastrophically? Because full loads are rarely encountered, and because there is a safety factor built into the structural design values for the wood, and also in the grading rules.

It is definiely an issue for a qualified design professional, even though there is some truth to the contention that it has endured for 50 years with nothing more than excessive deflection and isn't likely to fail catastrophically now.

Good post!
The Western part of Washington State is in a rain belt, we are blocked in by two major mountain ranges that causes a convergence zone of milder climate but produces A LOT of rain.... and what we are famous for no doubt. How this translates to this thread is we don't get huge dead loads of snow that other parts of the country typically see in the winter time, and probably the reason this garage has not had any "issues" in the past or maybe... it was taken into consideration way back then?
Just my two cents to shed some light on the issue.

[Bruce A. King]

Originally Posted by bdoles2

We are hired to evaluate the home/garages and their systems (in their current state). We can't predict when an item will fail or if it ever will.

All I would state in my report is - The garage door header is adequate in it's current state - any modifications to the structure of the garage may warrant a professional opinion from a structural engineer. However, building standards of today are much different than those of the 50's - if built today, the header may be larger.

Problems with that report example above:

1. You made an engineering determination "adequate in it's current state"


2. You failed to fully disclose basic information (assuming you are aware of it)
when you stated "the header may be larger". I think we all all know that it "would" be larger or a different material or actually both.

3. You failed to disclose the sag or deflection. I agree that the amount of sag as posted is not unusual for that header but if not reported you failed to disclose the current property conditions to the client.

[bdoles2]

Originally Posted by bking

Problems with that report example above:

1. You made an engineering determination "adequate in it's current state"


2. You failed to fully disclose basic information (assuming you are aware of it)
when you stated "the header may be larger". I think we all all know that it "would" be larger or a different material or actually both.

3. You failed to disclose the sag or deflection. I agree that the amount of sag as posted is not unusual for that header but if not reported you failed to disclose the current property conditions to the client.

Don't forget, I'm looking at a photograph. All I am looking at is a pretty blue garage with the door down.