Building on piers or full foundation

[grover]

Building on piers or full foundation.  That is what I'm trying to figure out now.  Tell me what you did and why.  Would you do it differently if you had it to do over again?  Costs of each? 
For instance...Is it harder to keep your pipes from freezing with piers vs full foundation with a crawl space?  I would have some sort of insulated skirting around the cabin.
My plans are for approx 24 x 28 with 12/12 pitch roof and a loft. 

If I do piers I would probably use the bigfoot system or some version of that.  Three rows of columns with 3 beams of three 2 x 12's sandwiched with some 1/2 inch ply.  Cabin site is pretty level so they concrete pillars would be about 18 inches out of the ground and about 30 inches down depending on if I hit rock or not.  Columns would be about 6 ft apart so about 18 columns total. 

If I do full foundation I would have to hire someone to dig out the crawl, pour footer and lay block. 

Tell me what you think. 

[BassLakeBucki]

This has alrady been discussed pretty extensively on this site. I would search through the previous discussions for more information.

[MountainDon]

Yes, this has been bashed about many times.

I'm going to let others chime in before saying anything more.

But, in the meantime here's a link to something related that I completed on our cabin this summer.
http://countryplans.com/smf/index.php?topic=2335.msg164063#msg164063

[grover]

Sorry

[MountainDon]

nothing to be sorry about. 

[flyingvan]

Not piers.  Perimeter with crawl space is so doable---like others have said,  it's been discussed.  Mine are formed with fabric and it works great

[alex trent]

How level is almost level?

That would be one consideration.

The other would be now much are you willing to tear the place up for a foundation dig out.

Piers are so doable and present their own set of benefits.

[MountainDon]

Just because piers are easy to do, does not make them a great solution.  If tearing the ground up is such a big factor then perhaps nothing should be built on the site at all. 

[John Raabe]

Long term, I think a full perimeter foundation is a better investment for most sites, if only that it is more likely to be valued higher by appraisers and future buyers.

In addition it anchors the home more firmly into the soil and adds inherent strength to better survive earthquake, high wind and other such disasters.

With modern materials and fasteners a pier foundation can be built better and stronger than ever, and there are thousands (millions?) of long standing homes with such a foundation. But of the two things that you can do to upgrade a house when extra money is available I would list a reinforced concrete foundation as one. The other would be more and better insulation.

[alex trent]

Just because piers are easy to do, does not make them a great solution.  If tearing the ground up is such a big factor then perhaps nothing should be built on the site at all.

I am not sure EZ is a big factor...certainly was not mentioned by me as a reason.  Perimeter foundations are not all the difficult anyway.

You are right...some site are better left alone, no matter how great the view...or whatever makes them the "site".  But sometimes the site is the site and if piers can work and make them a LOT less intrusive on the land, that is good....or at least better

And then, there is the fact that some of us like pier and posts. The looks, the feel, a place for the dog to sleep as he guards the house.  I happen not to like the look or the feel of a walk out one bit. Others might (do) feel the same way, so let's think about personal preferences too.  I though that was one of the objectives of the site..let people express themselves .  Even on relatively flat sites piers can be a good choice...especially if that is your style.  Let's keep style in mind, not just earthquakes, where most perimeter foundations are toast anyway. and wind...naaaa,  mine will stand with any of them. Roof may come off, but it is not getting knocked off the piers.

As for more value at selling, I do not believe that one bit.   There is so much more to the worth of a house than that.

If you need insulation that is a differnet story and piers are way behind in that regard.

I am currently building a 25x25 on a perimeter foundation, so I do believe in them too, Each has a place.

[MountainDon]

Maybe it's just me, but "so doable" more or less translates into "easy". If it doesn't necessarily mean that to you; my error.

Yes, the forum is a place to express opinions. However, I also see the forum as a place to promote the best and safest construction practices. Best and safest means, to me, the best and safest while building and then later while living in and enjoying the product.

Personal opinion on what anyone likes, or the aesthetics of something should, IMO, never take precedence over good design and proper engineering. Sound engineering should never, IMO, take a back seat to some personal sense of style. Engineering and the associated costs can be avoided by using and following the IRC.

[BenB]

Very much enjoyed gringo's viewpoint and thoughts as well as others here.
I'm becoming more and more of a pier fan as more and more builds done this way I am seeing. maybe its more me looking for them and noticing them now?
Anyhoots - the frost line around my place is 48" so my very first thoughts were full basement to insulate and keep my tootsies warm. 
Then I started taking notice of all the pier builds and started asking around and .... well, many are on old log homes dating more than 100 years ago and they boxed and insulated in the plumbing and such, some used rock and masonry cosmetic walls underneath the floors, all addressed in the manner they desired for appearance mostly. And danged if all don't love the results with one exception. His was issue that may indeed be related to some fracking being done miles away he thinks.....the whole lot has undergone some changes/settling he feels. (?)
I'm planning more of a cash and carry and hope to avoid financing so my issues, if any, will be in my head and with the local building inspectors. They are PITA around there so I am anticipating some problems in general. If not I will be thrilled !
Happy Election day at ya all 

[MountainDon]

BenB, before you too far along in your planning you owe it to yourself to talk to those building department officials who may be handling the permit and inspections that may be required. From what you said about inspectors in your area it sounds like a building code is probably used and enforced. I believe that MN uses the IRC, version 2006 last I knew, but that could have changed. When talking to them it also helps to know what code is in use. I find it hard to make any arguments unless I know what I'm up against. Knowing the facts to the best of one's own ability is the only way to know if anyone is snowballing you.

G/L and keep us informed; we're all curious.

[BenB]

Will do MountainDon and as always appreciate your insight and thoughts.
Across the way 2 lakes over a guy is building a 30x30 log home on piers and has same inspectors. The issues are usually with the electrical, plumbing AND the folks who handle septic related or thats what I always hear of. The stick guy uses code and common sense and adaptability to location mostly they say. Guess I'll know when I am there at that point and yep - you will be in the loop and leaned on for advice.
Cheers and have a great night!   

[alex trent]

This is a real question, not an argumentative one.

If IRC has nothing about building with/on piers, how does this get approved to build in areas like this where they have good code enforcement?  Do you need an engineers sign off on it?

I never dealt with inspectors in the States, but after reading on here, it is one of the first things I would do. Not just to build relationship but to run the whole idea by him.

[MountainDon]

If IRC has nothing about building with/on piers, how does this get approved to build in areas like this where they have good code enforcement?  Do you need an engineers sign off on it?

There's no "if" about the IRC having nothing about building with/on piers. The IRC does not list piers as a prescribed method.  The IRC is a prescriptive code; it lists tables, charts and methods or techniques that, if followed, do not require an engineer. It does not state anywhere that there is no other way to do things. There is the provision for the project owner to use alternate methods as long as there is an engineers approval supplied. That is how truss roof and truss floor joists are used and approved. The manufacturers engineer supplies an engineering report that states the roof or the floor will support the required loads. That piece of paper is the missing link when it comes to pier foundations as we see them used here.

Not even what is probably the best of the pier systems, Bigfoot Footing Systems, can or will supply an engineers stamped approval with the sale of their product. I have asked them and after dancing around the question in a series of emails they responded with a "No, you will need an engineer to approve the foundation".

So, IMO, you will likely find the piers we see have either never been approved or seen by an inspector, or they are located in areas with lax to non existent building code enforcement. There is sometimes a large gap between there being a building code adopted by the state and the local government enforcement. That's wrong, not right.




I was reminded today of Marcus Vitruvius Pollio. Who you ask? He was a Roman writer, architect and engineer, active in the 1st century BC. Vitruvius is famous for asserting in his book De architectura that a structure must exhibit the three qualities of firmitas, utilitas, venustas – that is, it must be solid, useful, beautiful. Note that in his opinion, the beauty of a structure follows it being solid or soundly designed and constructed. IMO, he makes perfect sense; no reason to build something beautiful if it is not solid enough to last long enough to be enjoyed my many. Building solidly also makes perfect sense from a standpoint of good use of materials. No sense building something that may deteriorate prematurely. IMO, of course.

[Ndrmyr]

Sometimes the site dictates the foundation choice.  Sometimes it is a matter of economics (often!), or, availability of materials and equipment, or, of the builders skill level.  Sometimes we change our minds.  I accumulated tube bases and sono tubes, planning on post and pier, before deciding on a seawall and slab.  Despite the expense of 47 yds. of concrete, in the end, it was the right decision for me.  It withstood a 100 year rain and flood the following year, and erosion might have been a threat to the post and pier.  Of course, now I am the proud owner of tube bases and sono tube, but hey.....anybody in the midwest building post and pier?

[alex trent]

To MtnDon's point about Bigfoot (or others) not supplying an engineering stamp, my impression is that would be only part of the requirement even if they did. Still need the other components to be vetted...bracing, post attachments, etc.   

So back to my question, if you want to do this "legally/the right way" do you hire an engineer to do the plans, and if some components like the Bigfoot lack engineering stamps, can that engineer work through that to come up with a plan that passes muster?

[MountainDon]

So back to my question, if you want to do this "legally/the right way" do you hire an engineer to do the plans, and if some components like the Bigfoot lack engineering stamps, can that engineer work through that to come up with a plan that passes muster?

I thought I made the answer clear with...

There is the provision for the project owner to use alternate methods as long as there is an engineers approval supplied.

But again, if the method or technique is not in the IRC then an engineer is required to approve the design. The engineer would look at the entire package from roof down to ensure a strong design and that a permit could be obtained. Neither an engineer nor anyone else can design a proper foundation without knowing what is being built on top of it and what the ground conditions are.

[John Raabe]

Finding an experienced local engineer who has practical solutions for local loads and local code intrepretations is always the best route to a safe and solid house. The engineer looks at the house as a system not as isolated IRC issues. When it comes to pier foundations the engineer will take into account wind and earthquake loads, the site characteristics, bracing and fasteners. This will be tied into the walls above and he will "engineer" the worry-free solid construction Don is urging you to do. Doing such "whole house" engineering is more and more often required as natural disasters pile up make all builders and inspectors more cautious. This does not need to be expensive, my engineer always charged the same when I was designing smaller custom homes - $300. He called this a lateral bracing analysis.

And just so you know, my part of Western WA is over a fault line and has sever earthquake bracing requirements. This small house has a locally engineered pier foundation that was very
sturdy and cost effective:

More here: http://countryplans.com/Alt-home.html


If I were doing an owner-built home today I would consider this not only a good investment, but well worth the price when compared to having to study such a boring book as the IRC and then trying to argue my interpretation with the plan checker and inspectors. Life is too short! 

[UK4X4]

In different areas- engineers cost more !

1 letter to the permit office saying that yes he had read the soil survey cost me $300 !

the HOA required stamped foundation plans


I drew my own plans- did my own calculations- drew the plans and supplied him with digital autocad files and the calculation sheets from the software

he made two red line changes to one drawing and checked the loading distribution- ref the foundation design.

Total bill was 2750usd which included two site visits and an 8 hour round trip each time

One to check the scarification ground prep- then again to check the re-bar placement before the pour.

This is after another engineer charged me 3000 for putting his name on my dwgs...........

In colorado its seemingly a good way to print money !

[John Raabe]

UK4X4

Maybe I can put my engineer in a box and ship him to you... That's a very expensive small house engineering project!

[alex trent]

John's comments were the gist of my question.  An engineer at what seems to be some small relative cost does away with all the jibber jabber about is this good enough, etc.  Looks at the plans and says do this or that and it will work.  This is a safe bet even if you do not have to deal with inspectors. I would have gladly paid $300 to get that done on mine.

Since then i have found some people who appear to be qualified to do this and just for the heck of it am going to have one look at my place and "reverse" approve it. It may reveal a thing or two that needs fixing an that can be down.  My guess is I am fine...but we shall see.

I had the local county engineer up for something else and the only thing he really cast a bad eye on were the connectors from post to pier, which have always been my idea of the achilles heel of this. If you notice on my cabil, the back row of piers have no posts...beams are right on the piers...my way of putting in a bit of safety factor..east to west as that is the main wind direction. I have no illusions about a quake and this place.  Since I found the plastic sleeves to protect the posts (which are not treated) I will avoid that by putting the post in without piers and the attachment weak link.