building a 34x30 garage and need help

[roermo]

Ok for all the wizards of building a large project here is one.
I am going to build a 34ft wide by 30ft deep detached garage in my back yard this late summer or early fall. There are a few problems I need some help with first.

1. The 1st picture shows the location I want the garage. I am pictured there for scale and I am sure you will (at a glance see my worry). I will have to place the garage into the bank in back and on the right. I am thinking it is going to have to be at least 8 ft wall in back and 8 on the right steeping down to 4 ft.

2. The 2nd picture is taken from what will be the back of the garage looking to the
Street and where the new drive will have to be.

3. The 3rd picture shows the back of the house and where the side door would empty to by the back door and patio. We are doing this project for two reasons 1. I need the space for tractor and 2nd car. 2. In years to come we can park in back and not have so many steep into the house, the front has over 17 steps.


My questions are as follows.

1. Is my location feasible? Meaning placing into the hill.
2. I could bring the garage forward but it then would cut off the back yard.
3. I am sick of cutting the hill so I get ride of some of it. Is that worth it.
4. I called the local cement company gave them the measurements they cal. 51 yards
5. I figured 96 ft of 8 ft x 8 inch walls 5 inch slab and footing 32” deep, 18 wide. 5 ½ bag mix. Rebar 5 rows high and every 24 inch left to right. I am thinking that might be light. Does this sound right. 51 yards and 1 ton of ½ inch rebar was $4680.00
6. I leave in North Missouri and we have a frost line about 32 inch or so they say, in recent years we have not gotten to cold but I want to be safe.
Note I know the wall run will not be quite that much 96 ft of 8 ft, but until I get the footing dug and then shoot it I will not know how much I can shut down.
7. I am not a concrete man so I will bid this out, any idea what labor might be?
8. Would it be cheaper to move the garage forward and frame all 4 walls. I think it would have to be. But then I have a steep hill in back of a new garage.
9. I guess I am just looking for help in what I might be missing. Like most of us I
have to watch my pocket book.
9. Plus can a rafter company make a free span rafter 34 ft wide.


I hope to hear from some one even after falling asleep reading this long posting.

Thanks

Roger

 

[bmac]

Roger,

I'm not a builder, but I don't see a problem. In my area, they build houses with what are called "walk-out" basements and they build them excatly as you are describing. On a lot with a slope, they excavate into the hill, dig and pour the footers and then form up the basement walls. In fact, they did excatly that with my home. The height of each wall is dictated by the slope. and one or two walls are entirely framed. The only caveat is that you waterproof the walls that will be below grade and place sufficient gravel and drain pipes in before you backfill.

Good luck and enjoy the new space.

 

[LarryD]

Your idea is completely feasable as long as the costs don't deter you.

You could cut the hill back and use rock as a retainer wall as long as you're not encroching on the neighbors line. I would call at least three contractors and have them all show up at the same time for a job walk. Plans would be good with a written scope of work so everybody is thinking along the same lines. Let them know you're taking bids when you call and you should get competitive numbers. Ask them for a general breakdown of labor and materials to compare and bids, at least two should be within 10% to validate their quotes. Then select you're contractor.

 

[schmism]

ID cut the hill back and pour the back walls out of concreet (at least up to grade) to double as retaining walls.

 

[WVBill]

Roger,

It looks like you have some pretty mature trees in that tree line along the right side of your lot. I'd be concerned that cutting into the hill as much as you need to would cut some major roots and endanger one or more of the bigger trees. You might want to talk to your county arborist about that just to be sure.

Also, if the tree line is your property line, you might want to double-check your setback requirements. Your rope outline looks to be about 5 feet and, in my experience, setbacks in residential areas have usually been 10 feet minimum for side lot lines. (Except when I lived in Southern California where you could almost hand a roll of toilet paper from one house to another. )

WVBill

 

[scott_vt]

Mornin Rojer,
I kind of feel the same as WVBill, those larger trees could pose a problem as far as the larger roots getting excavated when they dig the hill out. Im in agreement with the other guys as far as putting in the concrete walls. That looks like your best bet IMO.

Sounds like a very nice project ! Im hoping to do the same thing in the next couple of years,about the same size, so will be following your thread. I have been looking at putting up a 26'x34' or something close to that.

Good luck

 

[roermo]

thanks folks for the advise. Here in Hannibal MO. the set back is 25 from the crub for the front, and 5ft on the sides and back unless in new sub. In those case it can be more.

The trees are on the next door neighbor, but I took the picture with a wide angle lenns. they are about 15 ft from my walls and some are more. So the largest tree within 15 ft is not more than 8 to 15 inch wide then there is a 100 year old walnut that is oh about 40 ft away. what do you think would they be in dager.

thanks once again.

roger

 

[scott_vt]

Mornin Rojer,
I dont think you would have a problem at those distances ! The picture was a little bit deceptive.

 

[WVBill]

Roger,

I agree with Scott, sounds like those distances should be far enough from the major tree roots.

 

[bugstruck]

I'd do an 8" reinforced concrete wall on three sides and on the front I'd do a 6" or 8" wall to 8" above the slab grade. Wood frame and sheathing infill the front above 8". 6" wall thickness works better at that location as you can frame a 2 x 6 wall with 1/2" sheathing to align inside and out. Much easier garage door frame installation. Also allows for easy siding on the wall facing the street if you desire. I assume that's how you got into the 96 LF of wall range. Your walls will be about 8'-8" at the back and part of the sides and about 10'-8" across the front and returning back to the footer step up. Check your local guys for form heights as that will drive actual wall heights and footer positions. This assumes only an 8' ceiling. I'd opt for more height though so you can do 8' tall garage doors. They get pricey above 7' tall though. I'm sure you plan to step the footers up as you go back into that slope. No need to be that deep for frost compliance with that much backfill. Your yardage is a touch heavy. Roughly as follows:
5 yards for footers
26 yards for walls including subgrade depth.
13 yards for a 4" slab or 19.5 yards for a 6" slab.

Not sure on cost in your area. We are high in Md. Here I'd say:
960.00 footers plus excavation
7,500.00 conc. walls
3,250.00 slab at 4"
Your location should be much less.

Slope the slab towards the doors and don't be bashful. I'd go at least 1 1/2" over 30 foot in depth. No more than 2" is necessary though.

HTH