Building Pad on hilltop - perimeter clearance

[beowulf]

I have discussed other aspects of this before (daughter building a home on our property)- now, a different question:

We have graded and compacted a pad on a hilltop. We are looking at mountain-style home and checking out plans she likes and I raised the question about the width and depth of the footprints of those plans relative to our pad size and orientation. The front of the home, for the view and other reasons, will face east. The pad is about 54' east to west before a berm begins (see pic), with slopes on east and west starting at perhaps 62 feet, and no issues with length north and south (120 feet at least).

I understand that builders/contractors/county want at least 5' beyond the footprint/foundaton for drainage, and erosion issues - hilltop or flat ground.

Remember this is a hilltop, and a bit beyond the 54 feet (i.e., to the ground well packed to that point) there is a slope front and back. If I go right to the edge, the east-west depth would be about 62+ feet+ before any sloping begins, but am using 54 feet as what I consider the solid pad area - centered - and before a perimeter berm begins. Dirt is hard throughout - need a sledge to pound anything into it. I know that does not necessarily make it suitable for all purposes.

Anyway, I am thinking if have a footprint that is at least 5' back from the front (east) and 5' in from the back (west), I can have a home with a footprint of 44' deep (east to west).

BUT I am wondering if this is enough perimeter clearance (even with the additonal ground up to 60' or so) as it would seem that the builders - subcontractors would like, or need, more than that for their equipment, unloading trusses and such. There is unlimited access to the pad/foundation site on the north and south - using different roads to each side.

Anyway, as we try to decide on a home plan footprint size - front to back - I thought I should get a handle on any perimeter clearance issues first. Thanks in advance - any advice will be much appreciated by me and by my daughter. BTW - we have found home plans that would fit into my 44' deep scenario, and some even a bit less deep - or which can be modified to suit. . . I am just wondering - as we look at plans - what my permeter clearance target should be. A plan we like is 40' deep including a front deck of 12'.

A couple of pictures may help assess the slope issue. The first is looking somewhat west, the second one is approaching from the north.

 

[2manyrocks]

Standard scaffold frames are 5x5 so you'd need more than 5' if you anticipate ever using scaffolding.

If there is any question about the soil giving way or eroding around the site perimiter, 5' isn't much of a safety buffer, IMO. If it washed, how would you get access to repair it?

 

[ericm979]

People build houses on stilts with 20'+ drops on one side. So it's possible. It'll just cost more.

 

[2manyrocks]

That's not enough access for a dump truck when doing a future shingle tear off job if shingles are used.

My neighbor started his house build with a nice looking pad like that. Then the rain washed it and he had to rebuild the sides, but at least he had access for his CTL.

 

[Rustyiron]

It's going to cost you extra for probably the;
Foundation
(Excavating & concrete pump, possibly twice)
Framing
(No forklift access for handling materials)
Exterior finishes
(Access in general)
Here in the east, $100k+ telehandlers have replaced unavailable manpower and are relied on heavily. With everyone seemingly busy your access is going to be a strong negative on today's construction site.
I hope I'm wrong for CA builders (and you and your daughter).

 

[beowulf]

That's not enough access for a dump truck when doing a future shingle tear off job if shingles are used.

My neighbor started his house build with a nice looking pad like that. Then the rain washed it and he had to rebuild the sides, but at least he had access for his CTL.

Good point. I think we are okay with that though as roof will slope north to south and full access on those sides. We are looking a 40 wide plan - about 12' of which is a front deck.

 

[Diggin It]

Am I reading that you're talking about a 40'+ house on top of a 50'-60' flat-ish spot ?

I hate mine. I'd move if I could.

10' out my front door is 3-4 feet below. 30' out to the mailbox is 10' or more below. Back and sides are worse --- a LOT worse. I have virtually NO flat space other than the pad in front of the garage. I can barely move around if the ground is wet from a heavy rain or has a couple of inches of fresh snow. If it ices over, I can NOT walk outside safely.

Tractor is in a shed 6-8 feet below the driveway and in snow or ice, it stays there as it's impossible to get up the slope.

If I were ever able to find the resources to move, I'd insist on at LEAST 100' of nearly level ground in any direction from the house.

 

[Carl_NH]

Well Digginit said it well, but there is no snow/ice to be concerned with in the CA foothills I presume.

But, a longer, narrower house layout would be better, 28' or 32x60 for example (deck not included) would give you 12' on both sides as long as you have access to north and south sides. Just give yourself 10-12' minimum around the house outside the roof line.

Then the foundation aspects, given the mudslide potential, are you planning driving pilings into the ground to support the foundation - I have no idea what the local regs are on this?

 

[beowulf]

Thanks for the responses. I appreciate it all. I can clarify a bit - in response.

It appear that the home (mountain style cabin with loft) will be 1727 square feet including the loft. Footprint - just checked - would be 30 wide (the depth -front to back) and 52 feet long. That width does not include a front deck - 10 wide. So within the 54 to 62 foot pad 'width' we would be situating a 30' wide cabin with a front deck added = 40'. There is no issue with the other sides - the graded part of the pad is at least 120 feet but you can go beyond that on one side for another 200-300 feet mostly level, and on the other side with a slight rise and then again level.

The pad has been there for some time and no erosion from the rain.

We have had a soil test done (county requirement) and they found no issues. They drilled five holes at various points.

Snow is not an issue. We do get snow - some years anyway - usually less than 1-3 inches and 1- 2 times a year and gone within a day. Rarely do we get more but we have had about 6 inches a few times over 30 years - and rare that it stays long.

The location is unparalled for the views - thus its selection - when my daughter was about 5-6 she picked it out as where she wanted her home - who knew? There are houses scattered all over the hills up here on pads cut into or on top of hills.

I agree with Diggn It, that flat land around the "compound" as I call it, is important. The main house, where we live, has several huge flat areas - some up rises. We never have real issues getting anywhere due to weather. There, on a flat piece - we have our house, a guest house, a barn, garage, tractor shed, pool, pool house, corals, kennel and more. I have to go up to another flat area to take care of the goats, and down to a flat area where the pool and court are, but no real issues. A key point I guess is that when my wife and I are gone the daughter and SIL plan to move down here to our house - where everything they enjoy is, and then airbnb the hilltop cabin. Until then, for them, it will just be a home where they need space for all that I have down below.

And there would be full access to the north and south ends of the home - flat for probably 50-60 feet on the north and for 200 feet on the south - for concrete deliveries and more.
And it appears - as I staked it out this afternoon - that there would be at least 10-12 feet on either side of the front and back side - I easily drove the pick up outside of the stakes on both sides with the footprint staked in the center. Outside wheel was just inside the berms - though the pad narrows at one end - that is an end beyond where we will build.

Finally, the local guys - those grading, digging septic test holes, drilling the well, putting in pump etc, and cutting the roads, have all commented on what a great site it is - so far no one has expressed concerns - they are the regulars for the periferal stuff - but not the home builders.

I have been trying to get a particular builder up here but he is seriously busy. I will talk to more than one. And I could have the pad lowered I suppose - and thus made wider - but that would negate the soil test - but doable. I could gain, I suppose, another 5+ feet especially on the less steep west end. I prefer not to do that, but will ask the grading contractor about that when he is up here next month to widen and recut one of the access roads.

Again, Thank you all for taking the time to respond. It really helps me think things through.

 

[2manyrocks]

My mom's house is at the top of a hill pretty much out in the open. Lightening struck the house once. After that, she was pretty nervous about thunderstorms. My Dad installed some sort of device on the electrical box that was supposed to dissipate the effect of a lightening strike. That's something I would be thinking about if I were building a house on the pinnacle point of a mountain.

The other thing is just having easy access to bring groceries into the house from the car.