Pier foundations vs other type

[chrisser]

Hi all,

New to the board.  We're thinking of building a cabin in some rural, remote and difficult to access property in WV.

I would prefer to use a concrete pier foundation because I can do most of the work myself, and because the cost to improve the driveway and easement to our property sufficiently to support a cement truck and other heavy equipment would likely cost more than the cabin.  Our property is in a hilly valley, based on Google Earth, it's a 500' elevation drop over about 1/2 mile from the nearest county road down to our place.  I'm sure I can get heavy equipment and trucks in - I'm not so sure about getting them back out unless the ground is very dry.

My wife found a small house plan she really likes in one of those floorplan books.  Unfortunately, all it is is a floor plan - no construction plans are available.  It's basically two 16x32 "wings" spaced around 25' apart and connected by a 25x10 hall across the back 10' giving a protected courtyard inside the "U".  It's a single story, which we also like because we expect to retire there and the local terrain will be bad enough to climb without having stairs in the house.

Even though it's a bit larger and more complicated than I originally envisioned, I like it because I could build the two 16x32 wings one at a time using commonly available plans, and we'd be able to live in the first one as soon as it was completed.  Later, when both were finished, I could connect them by the hall structure.

But as I look around at various plans, it appears that larger structures nearly always specify a crawlspace or full basement rather than concrete piers.  I'm wondering if there is some practical size limits to a pier foundation.  Eventually this structure will have a footprint around 32 x 60, even though it won't have that much floor space.

Our county just mandated a permit system, so I'm not really certain how much inspection is going to be required or, more importantly to me, what sort of resources will be available from that department.  From my reading, it sounds like the county is being forced into the permit system and is intent on generating revenue from it, but I'm not sure they've invested in a staff that knows the building code, is able to interpret it correctly, and can assist home builders in complying.    I do legally have to comply with WV building codes (which I don't have a problem with), although up until now there was no county enforcement, so there's no history of how it's all going to work.

I do plan on getting some professional help drawing up the plans and the county will probably require soil testing (we tend to have a fair bit of clay and rocks), but I don't want to bother if, for example, there's some sort known size limitation to a pier foundation that we're exceeding. If that were the case, we could just start from scratch with the ideas.

The traditional foundation in this area up until maybe the last 30 years has basically beams over stacked rock piles or something similar to a rubble trench, but the county may be trying to change that too.

[Don_P]

 
I like the idea, pretty much a dogtrot.

A pier foundation by code requires engineering, that is why you are seeing most houseplans drawn with a prescritive, code compliant, foundation.

After having to empty the first truck into drums and buckets in the back of a 4wd pickup I had a dozer and chain here to pull up the trucks.

[Redoverfarm]

  from one Mountaineer to another.  Where exactly are you going to build?   Personally I like block piers but to each his own. One of the main reasons is that it does not require a continuous pour and can be done as time is permitted.   I would say as long as your foundation is done correctly and will support your build I really don't think you would have much problem in your permits.  Keep us in the loop as it sounds like an interesting project that we would like to follow.  Good Luck.

[chrisser]

Thanks for the welcomes.

Our place is in Wirt county between Elizabeth and Grantsville a ways off 5.  Very close to Burning Springs.

We bought about 4 years ago as a place to eventually retire, but a possibility is in the works of us moving down their sooner if all goes well.  We're in NE Ohio now, so it's a 4 hour trip down and we can only do that on vacations and long weekends.

I haven't yet found a reference for the frost line in our part of the county.  I'm guessing going down 36" would be plenty, but I've seen significant variation in climate from our place vs 20 minutes away due to topography, wind and hill shading.  We're surrounded on all sides by hills and some parts of the property don't get any direct sun during the winter because of that.  But that also shelters us from some of the high winds our neighbors see - they have to chain down their porch furniture.

I have a tractor on site - an older IH that's about a size larger than a Ford N.  The effort to mix and pour concrete for a pier would be offset by being able to dig a hole with a 3point post hole digger and set a sonutube vs digging a hole large enough for me to get down and mortar, but that depends on how deep I need to go vs the length of my arm 

We have picked a gentle hill as a preferred building site.  Has good drainage and view and far enough from large hill and woods to minimize those downsides.  Also way above any water table. But we really love the topography and I'd hate to have to bulldoze the top flat and dig a huge gash in it if I don't have to.  I do see the structural advantages to a perimeter foundation.  I don't suppose there's a way to pour a footer myself in sections?  The biggest obstacle is getting a cement truck in and out.  Second biggest would be getting heavy equipment in and out, although a mini excavator might be enough and that would be more doable.

It's difficult to really figure anything out from 4 hours away.  I can't find any engineers or architects in the county, although there are some large firms in Wood around Parkersburg (over an hour away).  I think I can rent a mini excavator in Pburg, but if it has to be delivered, I anticipate a hefty fee.  Neighbors may have some leads on equipment owners, but nobody has a clue how the new permit process is going to work - people have just built what they wanted and lived with the consequences of their decisions, good or bad, for as long as anyone can remember.  There's no fire service that would arrive on time to do anything other than offer condolences and 2 ambulances in the whole county - assuming they have drivers that day.  Nearest cement is in Grantsville - 30 minutes away.  They may have gravel, but if not I'd have to go to Ravenswood or Parkersburg to get it, along with any building supplies - both over an hour away.

I did find this 1970 USDA soil survey of the county.

http://www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/west_virginia/woodwirtWV1970/woodwirtWV1970.pdf

Unfortunately the "detailed map at the back of this survey" referenced in the text didn't make it into the PDF.  I'm trying to find a complete copy of the document.

[chrisser]

I don't know if this is of any use, but the USDA has a web soil survey online.  Not the easiest thing to use but I finally figured it out.

The area on which we'd like to build is classified as "Vandalia Silty Clay Loam, 20 to 30 percent slopes"

Here's the description:

"Wood and Wirt Counties, West Virginia

VaD—Vandalia silty clay loam, 20 to 30 percent slopes

Map Unit Setting

National map unit symbol: k8k3
Elevation: 180 to 430 feet
Mean annual precipitation: 34 to 47 inches
Mean annual air temperature: 43 to 64 degrees F
Frost-free period: 161 to 192 days
Farmland classification: Farmland of statewide importance
Map Unit Composition

Vandalia and similar soils: 100 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Vandalia

Setting

Landform: Hillslopes
Landform position (two-dimensional): Footslope
Landform position (three-dimensional): Base slope
Down-slope shape: Concave
Across-slope shape: Concave
Parent material: Silty and clayey colluvium derived from interbedded sedimentary rock
Typical profile

Ap - 0 to 5 inches: silty clay loam
Bt+BC - 5 to 43 inches: silty clay
2C - 43 to 72 inches: clay
Properties and qualities

Slope: 15 to 25 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.57 in/hr)
Depth to water table: About 33 to 42 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.8 inches)
Interpretive groups

Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Other vegetative classification: Fertile Loams (FL3)"

Is this of any use in determining what sort of foundation options I have or is that more site-specific?  I was surprised to find they have different classification areas for different areas of our 30 acre parcel.  Didn't expect that sort of resolution.

[Redoverfarm]

I know about where you are.  I used to live at Parkersburg and drove through Ravenswood a good bit.

The frost depth should not be anymore than 24" and that is pretty well standard in most the state.  I live in a cold region and it is sufficient even here on the south eastern part of the state.

If you are intent on poured piers then you might try to find a mixer that will work on your 3-pt hitch.  If not I am sure you can find one locally that utilizes a gasoline motor rather than electric.

I have a friend that lives in Elizabeth.  I will try to drop him a line and find out about equipment rentals.

Here is a google site of Wirt County which may help you out some.

https://www.google.com/search?sourceid=navclient&aq=&oq=Wirt+County&ie=UTF-8&rlz=1T4TSNA_enUS401US438&q=wirt+county+wv&gs_l=hp..0.0l5.0.0.0.6725...........0.ytdLRlTKK5E

[Redoverfarm]

Bodley Rental in Parkersburg is the closest.  There is no rental company in Elizabeth.

[chrisser]

Thanks for the info on the rental place John.

What part of the Mountain State are you in?

[Don_P]

In the course of living there you will improve the road, no time like the present to begin. The next time you are there get someone from the concrete plant to come look it over and see if they can get in. I do that sometimes, other times we don't give them a chance to chicken out  My drive is about 25% but we had to bring them in backwards, I've had them come up forwards on those kinds of grades. You can also move concrete in the buckets of tractors, backhoes and bobcats.

Structurally the intent of the code is to build a structure of braced wall lines. Piers are normally an unbraced short story under an otherwise braced building. Pier and curtain wall is about the lightest masonry foundation prescriptive in the code. The curtain walls can be as thin as 4" between piers on a continuous footing. A footing can be poured in sections, I'm doing that now. We run the rebar out the end of the footing form about 2' to develop an adequate lap with the next section's rebar.

A permanent wood foundation is also prescriptive, a gravel trench with treated wood and plywood walls to form a crawlspace.

A house doesn't need to be on the crown of a hill, just over the brow can preserve the flatter ridge for yard, parking or other uses and can be more protected.

[chrisser]

I appreciate all your advice.

I'll know what's going to happen sometime early next week and then I'll either be shelving the cabin idea for later, or starting a 6-8 month period of semi-controlled chaos.

[Redoverfarm]

Thanks for the info on the rental place John.

What part of the Mountain State are you in?

Sent you a message.  Check you message box.