I’m planning to add a drive-through double carport as part of my remodeling project and I’d appreciate any feedback on the following questions:
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- What size slab would you recommend? (Length & Width – code requires min. 4†depth, 12†at perimeter). I suspect a 22×22 or maybe 24×24. Too <!—-> <!—-><!—->mich<!—-> <!—->?
- I’ll be using a gable roof over the carport and extending from a gable end wall. I’ve often noticed that builders offset adjoining gables. What’s the purpose of that? Should I do that too?
- What kind of supports should I use from the slab to the roof structure? I’m planning to re-brick the house, so I’d prefer brick columns for the carport. Would the brick columns need to have steel posts concealed within them?
- I’d like to keep the area open where the roof spans the entrance and exit of the carport (no center supports between vehicles). Just wondering if you guys know whether a wooden truss would be sufficient to span that distance.
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Sorry to ask so many questions in one post. I’ve never seen an attached carport constructed and I couldn’t find decent info about it with a web search.
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I’ve re-attached a photo of the wall that I’ll be attaching the carport to. Thanks in advance for any help on this.
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Michael
New knowledge is priceless.
Used knowledge is even more valuable.
Replies
HEY! Who stole your chimney?!
As for size....I would try and keep it in proportion to the house. Big enough to accomodate two cars comfortably, but not so big that it overwhelms the main structure.
Offsetting the gables is done for many reasons. Keeping them at the same height can make the overall structure appear to large. Often times there is a slight difference in roof pitches that is not noticed when they are offset. They break up what might otherwise be a rather bland single plane roof.
I would likely use steel to support the framing and then box them in with brick.
I would definetly speak to an engineer regarding structural design as far as beam sizing goes.
All the best!
J. D. Reynolds
Home Improvements
I would just match the depth of the house and match the roofline, continuing the ridge. If it seems too deep, add structure and convienience with a storage room across the back. I always try to make add-ons look like they were always a part of the house, and this would do it.
Steel columns to support your beams would be adequate. You could also use structural fiberglass square or round columns and save some money on steel sub columns and brick surrounds.
22' - 24' width (from the gable end) is very comfortable, even with 14" brick columns at the end. You may need an engineer or local truss plant / beam spec department to spec the beams. We recently built a porte-cochere (drive through carport) on a new home. We stickframed with 24' beams from the house to the end. 3 fiberglass columns / front middle and rear on the end.
A truss could be built to match and continue the existing roof for clear span.
For slab / foundation plan it is best to consult a local engineer.
A picture is worth a thousand words. I did the attached real quick for you.
Thanks for the input.
MichaelNew knowledge is priceless.
Used knowledge is even more valuable.
Really scratching my head here. I know I have to have vertical supports at the farthest end of the carport, but is it also necessary to have vertical supports where the carport roof joins the end of the house? I don't recall ever seeing one built that way, but I have to believe that the building code is going to demand some substantial way of supporting the weight of the roof at the house end. Can someone "splain" it to me?
MichaelNew knowledge is priceless.
Used knowledge is even more valuable.
Pocket your girders within the existing exterior wall, posting to the foundation.
J. D. Reynolds
Home Improvements
Thanks, J.D.. Unfortunately, I'm still puzzled. I'm assuming (I know, I know) that the last structural roof member on the end of the house is flush with the exterior wall. If that's the case, how do I make your suggestion work? Can you point me to a drawing that illustrates what you're describing? I've got a couple of pretty good framing books, but neither one of them deals with this scenario. Attached carports are pretty common here in the south. I've just never seen one during the construction stage, so I'm struggling to imagine how the framing is tied togther at the roof and how the exterior wall is beefed up to support it.
Thanks again for your help.
MichaelNew knowledge is priceless.
Used knowledge is even more valuable.
No illustration handy at the moment.....
The roof framing members are flush with the existing wall.....but the girder(s) they sit on are pocketed, and rest atop posts that continue to foundation. (If the foundation is block, you may want to solid fill beneath posts.)
Clear as mud?
J. D. Reynolds
Home Improvements
"Clear as mud?"
Not yet. Are you saying that the exterior wall which currently consists of a double top plate and wall studs will also need to incorporate a girder that spans the length of the wall and a number of posts that extend beyond the floor and down to ground level? This house has a crawlspace. There is no skirtwall. It is merely blocked piers and brick veneer siding.
Maybe I'm getting tripped up by the terminology. Sorry to be so dense. Can you add a little more water to the mud for me?
Michael
P.S. There's a pic in the original post that might help a bit.
New knowledge is priceless.
Used knowledge is even more valuable.
OK, lemme see.
You are planned on continueing the existing roofline out off the side of the house, yes?
So your rafters for the carport will run in the same direction as the existing rafters....from the front of the house to the back. They will sit on top of girders....one in the front, one in the back. The girders run side to side.....from the far side of the carport (where they will sit on top of either the steel or brick columns) back to the house.
I'm suggesting that the ends that meet the house actually pocket inside of the wall. The rafters themselves will be fine, secured flush to the outside of the wall. But the girders need to pop in through the sheathing, and sit on top of posts. (Just like they are sitting on top of posts (columns)outside, at the far end.) And just like the columns outside will need some type of foundation.....the posts inside must be properly supported. (i.e. continued to the houses foundation rather than sitting atop a bottom plate and possibly between to joists.)
I hope this helps.
J. D. Reynolds
Home Improvements
"I hope this helps."
Much better. I can see that your suggestion was clear all along. I just wasn't grasping it until now.
Thanks, J.D.
MichaelNew knowledge is priceless.
Used knowledge is even more valuable.
No problem man.....I realize I don't always express my thoughts as clearly as need be.
Good luck.
Be sure to post pics when done.
J. D. Reynolds
Home Improvements
"Be sure to post pics when done."
You mean like my last remodel?New knowledge is priceless.
Used knowledge is even more valuable.
LOL!
Love the pink roof!
J. D. Reynolds
Home Improvements
Here's a REAL quick sketch. Hope it helps clarify.
J. D. Reynolds
Home Improvements
I second the right answer from JDRHI.