Cutting a section out of the garage door header

[Cabin Fever]

Our 30' x 50' pole barn has a 10ft wide sliding door on one end. The header for this door is 9' 5" above the concrete floor and made of two 2x10s. 

We are considering the purchase of a Class B motorhome that is 9' 8" in height (to the top of the roof-mounted A/C unit). I would like to store the RV in the pole barn.

I'm thinking I could cut a section out of the header that is approximately 3" high and 36" wide. If I did this, how should I bolster the header?

I was thinking of nailing a 2x6 to the posts on either side of the door opening and placing a third 2x10 (with a 3"x36" cut out) on the new 2x6 uprights. Nailing the new header board to the existing header boards. The lumber I would add is shown in red in the side view below.

Would that work? Is it overkill? Other ideas?

[Ozarks Tom]

3"? Let some air out of the rear tires.

Your idea of adding a 2x6 across the header should easily carry the apparent 10' span. I'd liquid nail heavily the new board to the existing ones also.

[Cabin Fever]

Mar 22, 2021 17:30:27 GMT Ozarks Tom said:

3"? Let some air out of the rear tires.

Your idea of adding a 2x6 across the header should easily carry the apparent 10' span. I'd liquid nail heavily the new board to the existing ones also.

Or, I could bust out the concrete and make two lanes for the tires.

[fixitguy]

A friend of mine had a pulling truck. The truck would not fit in the small door opening with the pulling tires on. He went to the junk yard and got 4 donut style spares, cut the centers out and welded in the bolt pattern needed for the truck.
But I would just cut the header and reinforce. I would cut a 1/4 steel plate, or angle iron and bolt it in place.

edit, The header at my garage was rotting when I bought the place. Instead of replacing, because there a 6-8 courses of block on top, we built a new header. 
Framed out the up-rights 3 inches thick x 30" wide on each side, and ran 2x8's across the top. I think we have 16 2x8's stacked, running across the top. lol
My engineering buddy's like to over build stuff.

[fordy]

.................Just cut a piece of 3 inch channel iron and insert it in the cutout and then install several 3/8th's bolts that go all the way through the channel and both 2x10's ! , fordy

[sawmilljim]

Yep I would go with the plate steel on both sides with the notch in the steel too. Bolt in place then cut the notch out.

[Cabin Fever]

I am being told that the header is not weight bearing, and therefore, maybe I wouldn't have to do anything? All the trusses in the shed are clearspan 30'. Here's a photo, if that helps.

[sawmilljim]

Correct until it snows then it gets weight bearing. Just a ounce of prevention now could offset a pound of cure later on. In case of truss rafters even plywood around the notch would do the bracing.

[farmrbrown]

I think that's correct, the picture is worth a 1,000 words.
You can just cut what you need as long as it's below the bottom 2x6 (?) of that truss over the door. The truss is carrying the load and spreading it between the two outside walls.
Also without seeing how that center column 4x4 in the front is attached - but if it does bolt to the center of that same 2x6 truss bottom, then that will also help carry any extra "load".

If you did want to be extra safe about it, look up 'flitch beam'.
That's what sawmilljim  was describing, putting plate steel sandwiched between wood.

[Cabin Fever]

Not to beat a dead horse, but the only load on the header is from one 2x4 that extents to the roof rafter (see yellow arrow below). Of course, the header supports the entire weight of the sliding door, too.

[sawmilljim]

Yes the design of your marked 2x4 it to equal to load of the roof. It will have a ratting of so many pounds per square foot.

That door not so much weight but your trusses a designed for top loading not hanging loads also the vibration of that door rolling isn’t figured in either. My thing is if it’s a easy fix you might have never needed but later you notice something amiss now it’s a simple precaution.

Murphy is a resident at my house so if possible I try to out pace him.

[Ozarks Tom]

I have a tendency (compulsion?) to overbuild everything. Heck, you could park a tractor on either of our decks. I think your original thought of an added 2x6, then cutting out the needed height will work fine. If it's not needed, well, it didn't cost much but the peace of mind is priceless.

[farmrbrown]

Mar 24, 2021 20:54:46 GMT Ozarks Tom said:

I have a tendency (compulsion?) to overbuild everything. Heck, you could park a tractor on either of our decks. I think your original thought of an added 2x6, then cutting out the needed height will work fine. If it's not needed, well, it didn't cost much but the peace of mind is priceless.

Yep.That's what I originally went looking for when Cabin Fever, first asked this - Would 3 or 4 2x6's equal the same strength as a double 2x10 header.
I found several discussion and answers that indicated "yes" but nothing official like a building code/engineering link to post.
Basically the consensus was a 6x6 beam (3 2x6's is the same thing) would cover a 10 ft. span so I'm confident he'll be fine too, particularly if he takes advantage of that center column in the middle by nailing another stud to it to support the additional horizontal 2x6 he wants to use to beef up the original header.

You and I talked about too much reliance on "licensed professionals" versus first hand practical experience of us "amateurs" on another thread.
About all I can say is I tend to over build things too and when I'm finished, it always looks like my stuff will still be standing even if the rest of the structure gets flattened by Mother Nature.

[joebill]

I would vote for the 2x6's also, but since I would almost HAVE to know if they were really doing anything, I would measure from header to floor, then add the bracing, cut the notch, measure again.

If the gap has shrunk any at all, the bracing is helping, if not, it is just eye candy....Joe

[sawmilljim]

Mar 28, 2021 2:16:41 GMT joebill said:

I would vote for the 2x6's also, but since I would almost HAVE to know if they were really doing anything, I would measure from header to floor, then add the bracing, cut the notch, measure again.

If the gap has shrunk any at all, the bracing is helping, if not, it is just eye candy....Joe

I would look at it in a different way. If the gap stayed the same I would say my brace held it in place. If it were a less gap it would be time to get out the jack and do a real brace job.