Possibly Overloaded Garage Door Header

[pdickerson]

A little more information on local weather patterns. We rarely much snow around here, and then it melts fairly quickly. Only half a dozen times in my 40 years has there been more than 8" of snow... But one of those times we got a full two feet of snow, and then in rained on top of that for a day. Lots of roofs collapsed around the region. Structures don't get load tested very often around here, but when they do, they need to be built to take it.

Here is the verbiage from the report

Some deflection was noted at the garage door header (approximately 1/2"), likely resulting from the point load from the ridge beam that bears on the header. The beam may be overloaded by today's building standards and may be subject to failure under an extreme snow load. Recommend further evaluation by a structural engineer.
This is how I structure most of my comments. Briefly describe the issue, describe what can happen if it is not dealt with, and direct them to the proper licensed professional for a fix.

[Richard A. Hetzel]

Yes, I would seal my opinion. The primary part of my opinion is that the header is woefully inadequate. However, the chance of it failing catastrophically is very small, given its history. That being said, the verbiage in the previous post says all that an inspector should say, and says it well.

[dbucknavich]

If you are going to call the 4x12 inadequate, then what would be an adequate size? Get my drift? If you are going to call an existing structural member inadequate, then in my opinion I'd want you to know what the adequate size should be. At least I would if that was my house I was trying to sell.

And anyway, 3/4" deflection in 21 feet? I'm not sure I would make a issue of that at all. I like the "installed with the crown upside down" comment.

[pdickerson]

Dylan,

I don't get your drift. Are you saying that if you found an under-sized beam on an inspection, you would indicate to your client how the beam should be sized to adequately bear the loads on it?

It is certainly within the scope of a home inspection to call out a structural member that appears to be too small. It is way outside the scope of an inspection to specify the size of the replacement. In fact it is illegal in this state.

[Richard A. Hetzel]

Practicing architecture or engineering without the appropriate license is illegal in most states.

[Bruce A. King]

Originally Posted by dbucknavich

If you are going to call the 4x12 inadequate, then what would be an adequate size? Get my drift? If you are going to call an existing structural member inadequate, then in my opinion I'd want you to know what the adequate size should be. At least I would if that was my house I was trying to sell.

And anyway, 3/4" deflection in 21 feet? I'm not sure I would make a issue of that at all. I like the "installed with the crown upside down" comment.

Even with the crown "up", this size beam with that span will sag over time at that span. The weight of the beam itself is too much for that span.

[Greg Veal]

Lots of good comments.
I try to follow the advice of one of my past instructors...it's not what you say, but how you say it.
I always try to give as complete a picture of a condition, as found here, but without crossing the expertise line. I would never be specific about undersizing, structual soundness, lifespan, etc., if making that statement elevates me to an expertise level I can't backup in court. I would always defer to the expert, in that particular catagory of concern. I think that's what my Client is paying me to do...make good judgement decisions on his/her behalf, AND C Y A.

[dbucknavich]

This appears to be a close call, and the beam has been functioning for quite some time. Not trying to stir the pot, I'm just saying if you know that the size of the beam is too small, then shouldn't you know what the correct size is? How do you know it is too small then? With a close call like that, just make sure your not making mountains out of anthills.

On the other hand, maybe you're right not getting in too deep. Just call out a concern and get an engineer to evaluate. But I see it as a catch 22, being able to say it is too small without knowing the adequate size, which was the case here. The reason question this a little is because it is a close call, and the age of the home, and the design techniques utilized then, and the fact that the support is functioning as intended. Who knows? Ahh, the power of discussions.

[Mark Thorman]

Just a thought, if collar ties are persent inside the garage at the top plate would that not transfer most of the bearing wieght to the end walls and not the gable over the garage door. I also doubt it's a 21 ft. garage door opening.

www.mauihomeinspection.com

[Richard A. Hetzel]

The original post specified that the garage had a ridge BEAM supported by a post which was in turn supported by the header. No, the door may not be 21 feet wide, but the garage may be, and therefore 10.5 feet of the roof load, divided by 2, is coming down on that post and being transferred to the center of the header. If it had a "ridge beam", presumably it has no collar ties.

[pdickerson]

You are absolutely correct, Richard. Also, the garage door header span is 16', as stated in the original post.