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.

 

[ponytug]

I assume that you have discarded the idea of bulldozing a larger area, so my advice is that with the site chosen, think about how the house plan interacts with the surroundings;

• Where is the access to the house, relative to the decks, and interior layout?
• Where are the views from inside the house? (E.g How is the view from the kitchen sink?)

From that are there changes you want in floor plans, or home orientation? My folks designed a couple of homes with great views from the living room, kitchen and master bedroom. It is what they valued. What does your daughter value? Sometimes a discussion or two with an experienced architect can really help.

x2 on the advice for a whole house surge protector and a real set of lightning rods and grounds.

All the best,

Peter

 

[beowulf]

Ponytug, thanks for info. Actually, we have been planning the build for a couple of years and we have lived here for 36 years so are very familiar with just about every corner of the 90 acres. We have considered just about every aspect of the build over and over and so selected the site, the orientation of the pad on the hill, the orientation of the house on the pad, what trees to leave, what to take out, where everything needs to be (well, power lines, septic, propane, out buildings and more). A very important part of it all was selecting a plan with "view' windows and a deck/porch facing the mountain range and overlooking the valley like area where our home is located. Every plan we looked at had to have the ability to achieve that particular alignment.

There were other considerations - a CalFire compliant road to the site (with adequate turn around) and grade, location of a separate pavilion with a somewhat different view, a second access road, fencing and landscaping considerations (I drug huge boulders near the site using round poles - the Egyptian way), and we have planned for areas for a kennel and more. And, on earlier plans we did check out the view we would have from the kitchen - and wanted to size that window appropriately, but I don't think I rechecked that on the last plan we focused on - will do so.

I am comfortable we have considered most things - and know the alignment of it all - but was not sure how much clearance I should have on the front and back - it looks like I will have about 12 feet on each side after staking it today and remeasuring - that is with a depth east to west of 30 feet plus a 10-12 foot deck/porch. Now that I have thought about it a bit more, whatever plan we choose will be limited pretty much to the 30 + 12 width.

Again, my thanks for weighing in. It is a process for sure, but nice to work on it with my daughter - she is uber deserving.

 

[oosik]

I don't know about any concerns you might have about wildfires. Here it is a MAJOR late summer concern. I have a 200 foot green perimeter around my house. I consider this might give me sufficient time to grab my "go bag" and boogie as a wildfire approaches.

Insurance policies will cover any wildfire losses.

I see the wind causing "fire bombs" being propelled up a quarter mile in front of a wildfire. My puny 200 foot green perimeter would NOT stop any wildfire.

 

[ericm979]

How big a turnaround does CalFire want you to build?

My county wants a 40x48 turnaround, 12' wide roads that can handle a 75,000lb fire truck, and turnounts on the road ever 400'. They keep increasing the requirements. Not long ago it was 32x32 turnarounds and turnouts every 800'. County fire now wants 14' wide roads in some places.

It'd be good to get your plans approved before your county adopts PRC4291. That's Cal Fire's new set of requirements. My county adopted it in draft form. I think they enjoy making it difficult and expensive for people to build. It's been used to deny a number of projects that people thought they could build when they bought the parcel.

 

[2manyrocks]

Is there any software these days that would allow you to visualize what it would look like when her home is completed to your current building plans on this site?

 

[ponytug]

Ok fire risk post: Given the fire risk of a home on a forrest hilltop, have you thought about having a seamless metal roof, with no gutters and/or steel roll down shutters over the windows and doors?

Around the house, I would think about ways to push anything but grass or rock to beyond the pad dimensions, and I would think about removing brush and laddering up the trees below your pad. The house will be most vulnerable when it is incomplete.

How does fire fighting water get to the house under some sort of pressure? A TBN member (@Rip? IIRC) here had a system with a nitrogen pressurized fiberglass tank in his garage that could foam the exterior of the house in seconds. IIRC, he had nearly been burned out in three different fires over the years. I seem to recall that put in a series of concrete vaults (septic tanks?) piped together to provide for rainwater storage and fire usage that also extended the flat area a bit.

All the best,

Peter

 

[beowulf]

Ok fire risk post: Given the fire risk of a home on a forrest hilltop, have you thought about having a seamless metal roof, with no gutters and/or steel roll down shutters over the windows and doors?

Around the house, I would think about ways to push anything but grass or rock to beyond the pad dimensions, and I would think about removing brush and laddering up the trees below your pad. The house will be most vulnerable when it is incomplete.

How does fire fighting water get to the house under some sort of pressure? A TBN member (@Rip? IIRC) here had a system with a nitrogen pressurized fiberglass tank in his garage that could foam the exterior of the house in seconds. IIRC, he had nearly been burned out in three different fires over the years. I seem to recall that put in a series of concrete vaults (septic tanks?) piped together to provide for rainwater storage and fire usage that also extended the flat area a bit.

All the best,

Peter

Ponytug, all good questions. The roof will be metal - I have not thought about what seamless might mean - will check that out. I was also checking out Hardiboard siding or something similar - or some stucco with faux rock facade - we don't want wood. They do want some faux rock as it would fit in well with location and landscaping. I never considered roll down shutters and likely would not do that.

There will be a lot of gravel, DG, and landscaping with boulders and large rocks - we have plenty of those - all sizes. I checked out a rooftop spinkler system (exterior) tied to a booster pump and capable of being operated by a generator - I was thinking about that for my house - but may think about it for theirs as well - and even found a company selling those but it seemed I could make better ones - I think theirs were about $180 each. I was looking at the oscillating rainbirds or misters. Seems doable. I did not get very for with that other than a design. The plan was - if there was ever any fire issue where embers could float in - to turn it on periodically - the local fire guys told me floating embers falling in gutters with dry leaves is one of the major causes of house fires in rural areas. Of course, we would have to be here to turn it on.

Their house is mandated to have a spinkler system - not sure what kind yet.

On the positive side, the local fire department is 6 miles down the highway with no stops in between. When they were out a couple of years ago they said the way I had cleared things out around the perimeter of the main 'compound' made it totally defensible. And they told me my location and the slope of the hills behind us would also be a help with how the fire would run. Again - that was about the main house. We use cattle and goats as well in areas fenced around the outside - two weeks ago we put fencing for the goats around a huge additional area - and now I am extending that farther - had to stop when I could not get more fencing. And I scrape any other areas down to a moonscape. I will have to see what I could do on the hilltop. I am very fire-risk mitigation minded - thinking through what needs to be done every year when things begin to brown up. Last week the propane delivery guy commented how clean the hills had been grazed down, how little the fire risk was here, and mentioned that some places he goes to would go up instantly with tall grass right against the houses.

For their place, I bought two 3,000 gallon tanks with a hydrant plumbed per CalFire specs - so they can instantly connect to that - they require 2,500 gallons dedicated to fire fighting use. The way that the house sprinklers will be plumbed will be so that a booster pump on top of the well pad can be operated either by line-in power, or if that is out, by generator. The access road we cut (one of two) was to CalFire specs - with a required turn out and topside turnaround area - but the grade on one part is beyond 13% so will have to pave that section.

There is still a lot to think about as we get this all done - we will be at it for a long time.

Thanks for responding.

 

[ponytug]

@beowulf That sounds like you have the fire aspects well in hand! That is great. It is really a solid plus to be so close to your fire department and have them sign off on the site, and your maintenance of the area. It speaks very highly of what you have been doing.

My bad! I had a brain fart on the metal roof. I meant a standing seam metal roof. It has more of the roof area smooth, and the seal between adjacent panels is quite broad. With more smooth area, embers, leaves etc. don't accumulate on the roof. I would also try to have as few obstructions (vents, chimneys, dormers), as possible, as they are all places where the slope will change on the roof (valleys), and accumulate litter and embers. Some AHJs allow internal venting of pipes (one way, to the outside), and horizontal exhausts for things like bathroom fans. If you don't do gutters, I think that you will want the roof to extend farther to help keep water away from the walls of the house, and to a lesser extent, given your site, the foundation. But no gutters is one fewer place for embers to land and cause a problem.

I don't know what your water quality is like, but most sprinkler systems around here have used black iron, which gets corroded pretty quickly. A few years ago, our AHJ began to allow the use of PEX (PEX-Al-PEX sandwich) for sprinkler systems which is much more resistant to corrosion and water leaks.

All the best,

Peter

 

[beowulf]

@beowulf That sounds like you have the fire aspects well in hand! That is great. It is really a solid plus to be so close to your fire department and have them sign off on the site, and your maintenance of the area. It speaks very highly of what you have been doing.

My bad! I had a brain fart on the metal roof. I meant a standing seam metal roof. It has more of the roof area smooth, and the seal between adjacent panels is quite broad. With more smooth area, embers, leaves etc. don't accumulate on the roof. I would also try to have as few obstructions (vents, chimneys, dormers), as possible, as they are all places where the slope will change on the roof (valleys), and accumulate litter and embers. Some AHJs allow internal venting of pipes (one way, to the outside), and horizontal exhausts for things like bathroom fans. If you don't do gutters, I think that you will want the roof to extend farther to help keep water away from the walls of the house, and to a lesser extent, given your site, the foundation. But no gutters is one fewer place for embers to land and cause a problem.

I don't know what your water quality is like, but most sprinkler systems around here have used black iron, which gets corroded pretty quickly. A few years ago, our AHJ began to allow the use of PEX (PEX-Al-PEX sandwich) for sprinkler systems which is much more resistant to corrosion and water leaks.

All the best,

Peter

Again, Peter, thanks for the information - all very useful and welcome. We should be able to follow your advice re the roof and obstructions as it is a fairly simple design. I use goats where the tractor cannot safely go to create fire breaks, and basically scrape away the areas around the home area. Some years the cows and goats take it down enough - and early enough - that I don't have to do much of that - other years I jump on it and move the animals beyond where I scrape. Some pics of areas outside of home area I cleared this year.