Planning a shop on steep terrain - thoughts?

[Oaktree]

Dumb question, but how stable is the soil where you live? That would concern me about building anything on a slope that steep.

Moss Road's thoughts in post #14 seem to make the most sense to me.

 

[MossRoad]

Dumb question, but how stable is the soil where you live? That would concern me about building anything on a slope that steep.

Moss Road's thoughts in post #14 seem to make the most sense to me.

If you look at his house, it's two stories built on the side of a hill. A two story shop built into the side of a hill would be almost identical in construction.

 

[joeyd]

I'm no expert but I was able to but a shop up by digging into a hillside it may not be as steep as yours but your house went in on the same slope. Here are a couple of pictures during the construction.

 

[EddieWalker]

My wife definitely wants to increase the deck area towards the slope/water, and expand the house as I proposed. The lower patio where I store my tractor is the entrance to my 'man cave'. The thought was to expand to the right as it would be easy to just add trusses and scab on to the side of the house and extend the deck in both that direction and towards the camera.

Expanding the size of the house will really add to the cost and scope of the project. Do you need the room? For just a workshop, making your deck bigger would be the most cost effective way that I can see, based on your photo's.

 

[dragoneggs]

Expanding the size of the house will really add to the cost and scope of the project. Do you need the room? For just a workshop, making your deck bigger would be the most cost effective way that I can see, based on your photo's.

Agreed! That is what I’ve been telling my wife. The changes she wants are the most expensive as they involve changing existing structure and roof lines.

 

[EddieWalker]

I can easily see where adding on to the house will cost well over ten times as much as just extending the deck and creating a workshop under it.

 

[Oaktree]

If you look at his house, it's two stories built on the side of a hill. A two story shop built into the side of a hill would be almost identical in construction.

The house looks like a lot of it sits on fill. Big difference between that and building into the side of a hill (which doesn't look practical at this location unless there's an easy way to get to the lower part below the clump of trees on the right).
That was the reason for my question about soil stability...especially after the mudslides California's been having recently. I personally would be very cautious about building on a slope that steep, YMMV.

 

[dragoneggs]

The house looks like a lot of it sits on fill. Big difference between that and building into the side of a hill (which doesn't look practical at this location unless there's an easy way to get to the lower part below the clump of trees on the right).
That was the reason for my question about soil stability...especially after the mudslides California's been having recently. I personally would be very cautious about building on a slope that steep, YMMV.

The house definitely does not sit on fill. It is cut into the hill and the foundation is easily 12ft back from where it was cut back. The middle portion of the house extends out beyond that and you can see the posts supporting it and the two decks on either side.

Our soil just under a lot of forest decay is glacial till and quite stable. Take a look at this cut into the bank nearby when my neighbor had a new retaining wall build last year. I am not too worried about a slide unless we have a massive earthquake.

 

[dragoneggs]

I can easily see where adding on to the house will cost well over ten times as much as just extending the deck and creating a workshop under it.

There really isn't enough real estate to extend the basement space towards the water to create a shop unless I also extend to the side. Even then I think I will not enough.

 

[dragoneggs]

I got out side and did some rough surveying just before dark with a theodolite and a telescoping measuring stick. I roughly figured I could get a max 24ft wide road side and about 40ft deep. But that 40ft after figuring about an 8ft set back from the driveway means about a 16ft drop in elevation! That is a lot to deal with. I was hoping it was closer to 10-12ft so my upper level floor would be close to the road level.

Maybe the earth that I cut out for the foundation can raise the grade on the downhill side a little even if the footings have to be a little deeper to hit bearing soil?

I have a old version of Chief Architect software that I should dust off and sketch something out.

 

[dragoneggs]

Here is an orthographic as-is view of the house. I don't have the decks modeled. My thought would be to expand to the right but there is limited solid ground as the slope curves back into the hill. But adding to that side wouldn't be too bad except the wife would like a higher ceiling for more glass for the view.



The 'scab on' to the right bottom floor is an uninsulated shed (outside the bearing wall) and a sun room. These could easily be demo'd to make room for a proper two story extension. Note the cement retaining wall extending further to the right to handle the steep grade change. Would have to move my heat pump that is just below in front of the retaining wall. No big deal I suppose.

 

[MossRoad]

If you add on to the right, won't you be cutting off your drive-around and down access to your current under deck area, and put that greenhouse really close to the house?

 

[MossRoad]

 

[MossRoad]

It would look very nice, though. Like it was there all the time.

 

[ultrarunner]

Lots of hillside construction on the Oakland Hills... very steep lots and they do it 20 to 26' deep piers and a lot of them... concrete and steel...

A nearby build had 150k into steel, concrete and piers... but they did it for a large 900 square foot garage as they wanted to reclaim existing garage as living space...

Start with what you want and then work backwards as you cost it out...

My shop is an elevated Concrete slab 22 x 30 supported on 2x4 framing with my tractor garage under the slab... I have been beefing things up as I do live in earthquake country... elevation drops 8' in 30'

It was built in 1970 when code for accessory buildings were lenient.

Having the elevated slab is like having two shop spaces... a double decker.

 

[dragoneggs]

View attachment 592336

Exactly... the greenhouse would have to go. Sad because I plumbed and wired it and heavily modified the 10ft by 12ft structure to make it a quality structure. Wondering if I could somehow skid it down the hill to relocate it?

The access to the 'other' side would be a challenge but I would keep a wide enough 'easement' for the tractor plus a little but there I would be straddling some unstable soil.

 

[dragoneggs]

Lots of hillside construction on the Oakland Hills... very steep lots and they do it 20 to 26' deep piers and a lot of them... concrete and steel...

A nearby build had 150k into steel, concrete and piers... but they did it for a large 900 square foot garage as they wanted to reclaim existing garage as living space...

Start with what you want and then work backwards as you cost it out...

My shop is an elevated Concrete slab 22 x 30 supported on 2x4 framing with my tractor garage under the slab... I have been beefing things up as I do live in earthquake country... elevation drops 8' in 30'

It was built in 1970 when code for accessory buildings were lenient.

Having the elevated slab is like having two shop spaces... a double decker.

I definitely want to avoid driving piers and the such. I have zero experience with concerte floors above ground. Something I might research a little. My slope is closer to 8ft in 20ft or so!

 

[ultrarunner]

8' IN 30' only works because no snow or ice here...

I did live with steep drives before and might be alright for the family car but backing down with trailer and having the rig slide because the concrete is wet just wasn't for me.

Extending the deck and closing it in would require lots of drilling with re-bar cages automatically here along with many yards of concrete... the curved drive might be tweaked by making the curve wider and more gentle?

I am considering actually reducing the width of my WA deck by a 1/3 to improve the water view.... rather look at nature than a large deck.

I'm guessing side yard setbacks are set and not much would be gained with a variance at the existing garage?

There is something to be said with a separate shop within sight... but deep in a tree canopy causes it's own problems.

On your side extension if you could drop the roof slightly could you tuck it under the existing eve?

This would minimize disruption to the existing... but would you pick up enough square footage?

 

[dragoneggs]

8' IN 30' only works because no snow or ice here...

I did live with steep drives before and might be alright for the family car but backing down with trailer and having the rig slide because the concrete is wet just wasn't for me.

Extending the deck and closing it in would require lots of drilling with re-bar cages automatically here along with many yards of concrete... the curved drive might be tweaked by making the curve wider and more gentle?

I am considering actually reducing the width of my WA deck by a 1/3 to improve the water view.... rather look at nature than a large deck.

I'm guessing side yard setbacks are set and not much would be gained with a variance at the existing garage?

There is something to be said with a separate shop within sight... but deep in a tree canopy causes it's own problems.

On your side extension if you could drop the roof slightly could you tuck it under the existing eve?

This would minimize disruption to the existing... but would you pick up enough square footage?

I think those following this thread are starting to appreciate my predicament. Not complaining because I am lucky (oh I worked for it) for what I have.

I do appreciate all the comments here. When I start figuring costs, the option of #2 vs. #4 might become a lot more clear... as my life employed is now less than a decade. Resale is not as big a factor because I want what works best for me and the wife. If it means a difference of $50K on resale, I won't care... I'll be dead.

 

[goeduck]

My slope is mild compared to yours. I would expand the garage on one level, I do not see doing that subtracting from your street appeal. You are not on a public street and your appeal is largely the house and the view from the house.

I forget what kind of oysters you are growing. Pacifics?