Want to build a detached carport...Did we budget enough? (Hilo: house, tile) - Big Island - Hawaii (HI) -The Island of Hawaii - City-Data Forum

Tamianles808 · 03-26-2018, 08:11 PM

I bought my grandparent's house in October 2017. They have a hot house in the front that measures 30'x30' (but the county website says it's 1080 sq ft). It's falling apart and needs to be torn down soon . Thing is, I'm not sure if we budgeted enough money for this. All we really want to do it to build a detached carport. It won't be enclosed, but we'd have to pour a slab and build from there.

I was thinking we could just pour the slab and put maybe put up a privacy wall (sorry, I don't know what it's called) on one side and leave the other sides open. Has anyone built something similar recently? What kinds of costs did you encounter? Were there unexpected costs? I just don't really know where to start.

Thanks in advance to anyone who could help me here.

whtviper1 · 03-26-2018, 08:19 PM

I've had garages built - but not carports, but I'd be surprised if a very simple - emphasis on very simple, would run much more than $3,000 give or take assuming a single wall - no electric, etc....

TGPILOT · 03-26-2018, 08:39 PM

Just for comparison in a way. Here in MT., last fall I built a new deck with concrete floor, about 20 X 20 with a roof made of tin that is about 10 X 22. It cost me right at ten grand to have the ground leveled, gravel hauled, concrete poured, and the roof put up. Had it been a bit longer and wider, it could have been a great car port.

hotzcatz · 03-26-2018, 09:32 PM

If it were my project and the hot house is a permitted structure, I'd repair it and use it as a carport. If necessary do a 'change in use' to carport. If you demolish and build new, you'll have to follow the current codes and it will cost you a LOT to build even a carport. As part of your repair, perhaps you could pour a concrete floor and put in new posts and rafters, etc. Although technically, you're only supposed to repair a certain percentage of a structure before you have to bring it up to current codes. Can you repair the hothouse by putting in new posts, rafters and roof and then pour a floor later?

You've got about 14 'roofing squares' (100 sq ft sections) for a roof of that size, if you can get tin roofing at $150 a square, that'd run over $2K just for the metal roofing. Add in posts, beams, rafters, purlins, assorted Simpson hardware, and then a concrete pad. Concrete pads need to have gravel underneath, rebar inside, welded wire mesh, termite treatment and a plastic moisture barrier plus they now have some really thick edges. A 30' x 30' pad is gonna chew up $3K? 5K? I'm guessing you might be able to do the carport for under $6K - $8K, but you'd get to do a lot of the work yourself?

whtviper1 · 03-26-2018, 10:00 PM

Interesting. A full blown nice garage in my experience runs $30K in my experience. I figured a simple carport he was describing would be roughly 10% of the cost. I guess I didn’t really read it as a classic carport more just a slab of concrete and a single non-covered wall.

Tamianles808 · 03-27-2018, 01:54 PM

Quote:

Originally Posted by hotzcatz

If it were my project and the hot house is a permitted structure, I'd repair it and use it as a carport. If necessary do a 'change in use' to carport. If you demolish and build new, you'll have to follow the current codes and it will cost you a LOT to build even a carport. As part of your repair, perhaps you could pour a concrete floor and put in new posts and rafters, etc. Although technically, you're only supposed to repair a certain percentage of a structure before you have to bring it up to current codes. Can you repair the hothouse by putting in new posts, rafters and roof and then pour a floor later?

You've got about 14 'roofing squares' (100 sq ft sections) for a roof of that size, if you can get tin roofing at $150 a square, that'd run over $2K just for the metal roofing. Add in posts, beams, rafters, purlins, assorted Simpson hardware, and then a concrete pad. Concrete pads need to have gravel underneath, rebar inside, welded wire mesh, termite treatment and a plastic moisture barrier plus they now have some really thick edges. A 30' x 30' pad is gonna chew up $3K? 5K? I'm guessing you might be able to do the carport for under $6K - $8K, but you'd get to do a lot of the work yourself?

Thanks, Hotcatz! Yes, this is pretty much what I was looking at, especially in your 2nd paragraph. Concrete foundation is going to have to be built. We have some roof we can already use for most of the carport.

I just didn't know what kind of cost I was looking at. My friend did a super simple extension from their garage that probably measured about 20' x 20' and it cost them $20k! To me it just looks like they did the roof, no foundation, and just some posts and beams.

hotzcatz · 03-27-2018, 07:59 PM

There is the option of just repairing the existing roof and having a gravel floor. Save a ton on concrete costs.

If you wanted, you could get a 90# bag of cement, a load of gravel and a load of sand (back of a pickup full at Glover's or the other concrete place in Hilo) and pour the floor in smaller sections. Maybe 4' x 4' or something? Poured in place but tile by tile. That's small enough that you could mix it by hand and make them one after another. I think it's one part cement, two parts sand and three parts gravel? Mixing concrete isn't rocket science and it doesn't all have to be done right away, does it? You'd possibly still be able to use the carport while adding in the tiles.