Hello. I am new to the forum, but have been reading over some of the material and thought I would post a question that has been bothering me. I live in Central Texas and plan on building a small lake house (24*32 w/ loft), on a somewhat sloped lot (5-6' drop over 32'). From everything I am reading I should drill down half-way to china, place columns half a mile wide, and make sure everything is reinforced with titanium. Like I say, I am in Central Texas, so snow loads and frost heaving just do not exist. I have seen everything from a 2-story house with 16"x16" pads with a couple of cinder blocks sitting right on the ground standing since the 1930's, to a "box house" with 3/4" thick walls that sat on dry stack rocks since the 1890's. Is this need to publish facts and figures way beyond what is needed just a legal out in the event something goes wrong, or are the 50% of the homes in the U.S. ready to fall in at any second? My plan was a simple a 2'-3' hole, 6" gravel, 6"x24"x24" reinforced pad, 12" form tube to make up the remainder allowing the tube 6" above grade to accept a 6"x6" treated post via galv. base, and 3- 2"x10" to make a girder, and overkill my joist to 2"x8" - 16o.c.
You can always find old, old houses with some shoddy construction still standing---but for every one of those you see, there are dozens that failed long ago that are long gone. Soils are highly variable and a single soft spot can wreak havoc. All the building codes are a balance between what the UBC thinks is safe, tempered by big developer lobbies that want to keep cost down. Many of the codes are designed around a 30 year old structure life span, which has made things challenging for fire departments (trusses fail quickly in fires)
As far as your build goes----there are many options for how to do your foundation. Foundations are pretty easy to do correctly and very difficult to repair or upgrade later. As far as depth goes, the rule is 7' to daylight on a slope----There's a discussion somewhere in this forum that describes that better but I have to find it...basically you have to dig straight down so an imaginary horizontal line 7' or more out breaks the surface. Steeper slope, deeper hole
For pier foundations, sinking things deep is to counterbalance the leverage force when putting the weight of an entire house on piers. In frost areas foundations already have to be deep so it is not any extra burden. If you have little to no frost line you can do a full block foundation and perimeter footing cheaper, faster, and safer than a pier foundation. I don't understand the obsession with pier foundations in areas without frost depths.
I have seen many citations to exceptions of the basic rules of building still standing, but in the end they are the exceptions not the rules. What you don't see are the hundreds of houses built on bad foundations that were torn down long before any of us were even born. Houses don't tend to just collapse, they get severely damaged and cost huge amounts of money and time to fix or people walk away from them and they are torn down.
I didn't see if you mentioned a center beam, so a triple 2x10 girder with two clear span floors can span 5'-6" according to span charts. So I would guess 14-16 posts each side. By the time you add up the pt posts, the brackets, the added bracing required, the skirting, and the 2x10 beams, an unreinforced concrete block wall dry stacked with SBC would be stronger and probably faster and cheaper.
Footing thickness for a two story to code is 7".
If you would like to explore other options, I would be happy to write and discuss them with the process, and costs. Due to the leverage, engineering concerns, I cannot give greater input on shallow sunk tall piers.
Not overbuilding; it's building to best practices.
There's some good info, great thinking and excellent advice in the two posts above. In your virtually no frost depth you would be almost certainly ahead of the game if you dug a 12 inch deep perimeter trench, did full perimeter footing. On that either build a formed and poured stem wall or a block wall for a crawlspace. Something along those lines should last longer with less trouble, fewer repairs than anything built on piers, especially for something the size of what you propose.
Let me preface with the fact that I got a lot of great advice on building on piers...from the guys who first tried to talk me out of it. I appreciate the fact that they did that in spite of their "obsession" that this is a dumb way to build.
I agree that a full traditional foundation is easier and more trustworthy. But, in some instances it is not the best choice. When you have a steeply sloped site and do not want a ton of excavation for aesthetic or environmental reasons..or both they fit the bill. And, if you want them, you have to be careful and "overbuild", so to speak. My cabin is likely overbuilt, but I am happy to have done it as the cost and work in minimal if done at the start. Know your soils, build piers correctly, fasten posts correctly and brace correctly. There is plenty of information on all of that...most on this site, so you can build and not be in th dark even though there is no code standard for things.
A house is as much an expression of what you want as it is an engine where I live.eering plan that has everything thought out for you. So, those of you who want (or need) to build houses on piers can relax a bit. Done right they will not crash and they have a lot of advantages in some situations. For me, the sloped site is one...the other is security...nice to above the grade
I've often wondered the same thing.. "does it really need to be like this?" My builder has so rightly said, "It's the extra 10% that's the difference between acceptable and excellent". Plenty of cabins up here on posts/piers, even done to code, leaning or fallen. In the end, it's gonna cost you either way. For something as fundamental as a foundation, I figure, it's worth the extra effort. It's worth the extra cost.
I am not obsessed with post and pier, I am obsessed with saving money and time. ;) To build any solid perimeter means tons of excavation on virgin ground, heavy machinery+steep slope=$$$. I have had it looked at many ways, and I am told 30k for a slab and retaining walls, 15-20k for cinder-block with crawlspace, or 50k for a walkout basement. Now take those numbers and the impact on my beautiful 2 acres of virgin land, and compare them to piers that I can do myself for about 1k and be done in a week. I want to do it right, but I definitely need to go with piers. I am not sure what part of the country some of you are from, but with the exception of bigger cities, every other house in Texas would'nt pass code, and many are sitting on concrete blocks right on the ground, at least in Central Texas. And next time your on the Texas Coast, take a look at the rows and rows of bay houses sitting on 6x6 piers 12' in the air. I understand that a Mercedes is a great car, but some of us have to drive an old chevy. :( I could spend 100k on my foundation, and one day 1,000 years from now it will be a tourist attraction, but I just want a little cabin on the lake that doesn't cost more than a new house in town. Any ideas where to get info on the proper depth, size of piers? Also, I believe I am correct in stating just because it is sloped the sheer force is no different than if the ground where flat, IF the structure is level.
I appreciate the comments of Alextrent above.
In many of the simple plans that I sell on the CountryPlans site I have included several foundation plans - pier and beam, crawlspace, slab, etc. It has been my intention with these to give owners options that they can explore and work out for their local situation. Not all of those foundation options are suited to every site and there are lots of conversations here on the forum about what is BEST!
But best is both local and personal - and not just an argument over codes or "best practice". Best practice, after all, is just an ever-changing collection of the opinions of the "construction industry", commercial builders, engineers and code officials, as to what is most likely to keep them out of lawsuits. Because of this CYA element it is understandably very conservative, but good general advice.
When I once asked my engineer "how long do we have to wait on fill dirt before it can be considered 'undisturbed' soil"? His answer, "after you run a glacier over it." That's good general advice.
I guess I forgot to explain the plan I had so far. The main structure not considering porches is 24'x32', with a loft. My pier layout consists of 12" piers only under bearing walls, so outsides and middle (3 rows of 5). The span between piers will be 8' (actual 7') the bearing length, and 12' (actual 11') between rows joist width. I planned on a 2.5' deep hole with gravel base, 24"x24"x8" reinforced footer, and a 12' pier to make up the remainder, and coming 6" above grade with the pier. My girder would be 3- 2"x10" plywood sandwiched 32' x 3 girders. My floor joist would be 2x8 spanning 11' (carrying only floor load). So I have all my loads directly on the girder and into piers. My soil is 6"-8" of black loam then I hit a rocky hard chalk type layer that seems to go on forever. I have rock outcroppings 4'-5' high all around my build site. I have yet to find anyone who would tackle the job when I did want a traditional foundation, and after seeing all the rock and the hardness of the ground after a few inches I can't find anyone to even dig piers without the use of a huge drill machine that can't even get to my site, not to mention I don't want to disturb this piece of land to that extent. Any ideas on what to do? I feel like I am in some remote area of Alaska, shovel and pick time?
Quote from: Squirl on May 15, 2012, 08:54:51 AM
If you have little to no frost line you can do a full block foundation and perimeter footing cheaper, faster, and safer than a pier foundation. I don't understand the obsession with pier foundations in areas without frost depths.
How do you derive at that? A slope of 5'-6' drop over 32' and you say a perimeter footing is cheaper, faster, and safer? First of all you would have to hire and excavator at 200$ an hour to dig for a day or so, right there your already more expensive, and already slower than a pier foundation. Then you say it is safer, safer how? My pier foundation will not be holding back tons and tons of soil, and my drainage for my pier foundation will be easier to achieve. With a full block foundation I will be not only holding back tons of soil, but also rock and water in heavy rain. My sight, while not the steepest, does show signs of slides, and cedar trees laid over from heavy rains. I want to be safe, do it right, and all with minimal impact. The question isn't why people are obsessed with pier foundations, the question is why when they seem the obvious choice some people won't except that fact.
Most of the quoted price on other types of foundations is labor, not materials.
1k is a little low of an estimate for piers after you add in bracing, skirting, and girders.
A full perimeter footing on a sloped site can be stepped. Here is a picture with UBC code citation.
http://www.naffainc.com/x/cb2/Struct/Footings%20and%20Slabs.htm
(http://www.naffainc.com/x/cb2/Wood/SteppedFootings.gif)
You should dig down a few inches to get past the vegetation layer of the top soil.
Since cost is an issue to you I will run down the other type I proposed.
So a full perimeter foundation for a two story house has to be 12 inches wide as long as you don't have the worst type of soil. With 7" deep and 112 linear feet long that is around 2 yards on concrete. Even if you ordered 50% more at 3 yards for the step areas and overage that would be around $350 of concrete around here. 20 ft pieces or rebar where $7 when I bought them last year. So around $100 more in rebar. So for $450 with almost no digging, as long as you can reuse the 2x8s from the forms for floor joists, you have a full perimeter foundation in a day or two.
Since you won't have unbalance fill pressing on the foundation you can use drystack concrete blocks without rebar or grout.
http://www.sakrete.com/products/detail.cfm/prod_alias/Surface-Bonding-Cement
They were $1.25 last year. Let say you were doing a 6 ft wall sloped over 32 ft. It would take a little more time to plan out, but for rough estimates let's say that is 336 square ft of wall. With the average 8x16 block taking .8 square ft. it would be around 420 blocks. Even if prices increased at to $1.50 that is $630. SBC costs around $15 a bag and should cover 50 square ft. So around $200 in SBC. PT 2x4's and J bolts are cheap. $1.00 a bolt, $3 per 2x4.
Even rounding up for unforeseen costs, I would estimate $1500 -$2000 in materials for a full perimeter foundation. It might even be less work because you won't have to dig much of anything.
A 24x32 1.5 story building is a $30-$40K investment off the bat. If there was a different option that was stronger and was comparable in both time and money, I would take the more stable option.
Nice work Squirl!
Very helpful analysis and estimation calculation.
Also with a full perimeter foundation center beam posts can be on grade even in frost depth areas. No digging.
Sorry, I did not mean just your posting about pier foundations. You are the third or fouth from central Texas that has posted on this. I just thought there were many misconceptions about traditional foundations and misunderstandings, especially in cost/benefit. It appears that you have the understanding that you have to dig a very deep in a no frost depth area. I have read the building code extensively and a few dozen other books on foundations, and have never seen that. If there is a special provision that you have to go X feet deeper because of a slope, I don't know it.
Houses are heavy. At 1500 square ft, I know it will be a cabin to you, but it is the size of a house to me. The more points and wider area you distribute that much weight the more stable it is.
As you can see I am more comfortable telling you something is good practice and OK that has been tested across millions of structures and has passed approval by hundreds of architects and engineers vs. something that hasn't. I'm not saying that your pier design won't work, I am telling you about something else that almost definitely will.
If a step foundation can be poured by hand I am sold. [cool] But like I say everyone I have spoken to will not touch my build, last guy said it would take a crane to pump concrete to the site, and he couldn't get a crane close enough if he wanted to, another said a bulldozer would need to do a weeks work to get to it. This area is restricted, I cannot tear it up, or bulldoze, and I would not want to if I could. Can a step perimeter foundation be poured by hand using sakcrete?!?! I know I want to keep the disturbance to the area at a minimum, last thing I need is someone digging up Indian remains, and my whole build being put off for who knows how long.
If I can hand pour a perimeter step foundation, I assume I could rock that thing :), yeah? That would be awesome! I have been collecting barn, and old house wood, mainly hand hewed beams, some true dimensional oak/pine lumber, and tons of 1"*12" planks. I have a trashcan full of old square nails. My entire cabin is being constructed from reclaimed wood, so a block wall covered with stone would really put the finish touch on it, much better than piers allowing you to see under the house.
My cabin is on a grade as well and I have a full perimeter stepped foundation with a pony wall on the back/low side. I also elected not to even use piers on poured footers under my center beam; instead I used another full-length stem wall with access "cut-outs" to allow access across the entire crawlspace.
As for cost, it sounds like my site is a bit closer to civilization than yours with better access, but I had quotes of 4k-5k for the foundation. They had the site cleared and footings dug and ready for inspection in a day and my site had quite a few trees. After inspection the next morning, they poured the footings. Waited for it to cure and got the forms/rebar ready for the stem walls. After several more inspections and the pour, the framing for the floor started. I recall the foundation taking about a week (2-3 guys), which was mostly dedicated to waiting for the concrete to set up and inspections. They were a great crew - they didn't use a pumper truck and instead "wheelbarrowed" and "bucket brigaded" concrete down to the farthest section to avoid the added expense of calling in a pumper truck. Unreal.
Good luck...
(https://i1186.photobucket.com/albums/z362/metolent/ski%20cabin/09c89155.jpg)
This is a shot of the center stem wall.
(https://i1186.photobucket.com/albums/z362/metolent/ski%20cabin/52333768.jpg)
I like the step foundation idea and see where that could work....sometimes.
But we are still getting lost in the cost ( which is miscalculated in the frenzy to prove "you can build a foundation as cheap" ) and the weight of the house and other stuff that has little to do with what a person wants in a house and what can reasonably be done in a given area. . You need more than an engineer to figure that out.
For a small house, on a steep slope and minimizing the environmental impact (in several ways) pier and post is still the best bet...if you do it right. And, of yeah, it happens to be what some people want. The constant naysayer barrage is getting old and in my opinion is and boring and counterproductive.
Can't speak to building on grade but my 20 x 40 was quoted $5k for post/pier. I paid $7k and went full pwf. Poured was impossible as camp is 2 miles into the sticks. Glad I have the storage and looking back, I'd change nothing.
I'm 2 years into my planning and it seems to change every few months as I talk to more people and engineers- every one has diferent ideas on what works best !
every area is diferent- every soil- angle of the land -frost -rain -water runoff etc etc etc.
It seems that every plot needs to be assesed individually and a suitable design chosen for that land-
a wrong choice of foundation based simply on cost down the road could be a complete faliure.
Perimeter foundations are true and tested - my house in the UK has one- its on clay soil but no frost- its 113ish years old this year
It spreads the load over a great surface area and is mechanicly sound when the walls are added.
Post and beam have issues with height/ soil conditions/ wind load etc etc
The ones you see on the coast of TX often have a perimeter grade beam and 20-30ft deep steel piles below what you see at surface
Fema has a whole bunch of info on pile /post foundations- I have a link arround here somewhere
Footings size, depth and x bracing makes or breaks a pier foundation - lacking in thought on any one may cause you heart ache down the road.
Start with the soil - type and structure- water running through ? bed rock etc
I think I'd start at the loads roof-attic-floor-walls
That will give you the total weight........the position of the supporting beams will divide up that weight
Calculate what beams you need to support those loads
then you have to work out the weights per post
Then you look at what size of piers you need to support that weight.
There are multiple worked examples arround here...if you can find them !
US geological survey gives you basic soils in your area, and provides a free report- that gets you a start on theoreticly what your soils can support
lots of TX is clay- which gives its own problems with expansion due to water
If I have a few mins later I'll point you too one
This one is based on sizing the beams- the software calculated the weights per post.....although you can do manually as well
http://countryplans.com/smf/index.php?topic=10511.0
Quote from: cbrian on May 15, 2012, 12:32:07 PM
.....Texas Coast, take a look at the rows and rows of bay houses sitting on 6x6 piers 12' in the air.
I type/think too slow for UK4x4 :D He beat me on some, but I spent the time so here it is....
Just a FYI, the only comparison that can be made between the typical owner-builder pier foundation and the pilings that are used in coastal areas is that both place the building up off the ground. It is normal for coastal pilings to be designed by an engineer after soil analysis. Owner-builder piers are usually done by a guess. Residential pilings can range from 20 feet to 60 feet in length with considerably more piling below the surface than above. Pilings are frequently 12 x 12. In part these requirements are why coastal homes tend to be uber expensive; it's not worth the foundation cost to build a cottage.
Everybody is right (well almost). Goes to show a lot of ways to skin this cat.
But in making example for or against important to compare same stuff. A beach house on the outer banks of NC with three stories and 4,000 sq feet is not the same as a 600 sq. foot single story in a much less wind threatened area (ok, in this climate, there may be no such thing). But the formidable pilings they rest on are not exactly any prototype for a cabin or a small house, which do with a lot less. Not a bunch of rubble to be sure, but can still be built right. If the soil bearing capacity is worrisome, take a sample and find out...if you cannot or will not do that, likely you are on the road to problems there or someplace else.
TX, lake, hard chalklike layer just under A soil horizon, local contractors quoting high foundation prices.
Caliche
Quote from: Don_P on May 15, 2012, 09:02:05 PM
Caliche
Caliche is actually a 4 letter word, even though it doesn't appear to be at first. ;D ;D
I believe it is used or can be used in the manufacture of Portland Cement.
Quote from: cbrian on May 15, 2012, 01:27:40 AM
Hello. I am new to the forum, but have been reading over some of the material and thought I would post a question that has been bothering me. I live in Central Texas and plan on building a small lake house (24*32 w/ loft), on a somewhat sloped lot (5-6' drop over 32'). From everything I am reading I should drill down half-way to china, place columns half a mile wide, and make sure everything is reinforced with titanium. Like I say, I am in Central Texas, so snow loads and frost heaving just do not exist. I have seen everything from a 2-story house with 16"x16" pads with a couple of cinder blocks sitting right on the ground standing since the 1930's, to a "box house" with 3/4" thick walls that sat on dry stack rocks since the 1890's. Is this need to publish facts and figures way beyond what is needed just a legal out in the event something goes wrong, or are the 50% of the homes in the U.S. ready to fall in at any second? My plan was a simple a 2'-3' hole, 6" gravel, 6"x24"x24" reinforced pad, 12" form tube to make up the remainder allowing the tube 6" above grade to accept a 6"x6" treated post via galv. base, and 3- 2"x10" to make a girder, and overkill my joist to 2"x8" - 16o.c.
Are you originally from Michigan? I love your sarcasm. Best laugh I have had in a long time. :)
I'm also in TX and going post and I beam as well, but going all wood. The only advise I want to lend is to not scrimp one cent on your foundation if you want you building to last. This is the basis for all that comes later, the so make it count, but however you have to do it.
Finally got a chance to speak to an architect, was wanting an engineer, but an architect is who called me back. The architect I spoke with told me that at 3' or so I will hit solid rock. He says that there are many options, but that if I was dead set on piers to dig down to the rock, drill holes in the rock, and epoxy 3/4" re-bar. After that pour a 12" thick x 24" square footer reinforced with re-bar w/ some re-bar exposed to tie in a pier 12" in diameter. He says after tying into the solid rock that the pier would be stronger than going a foot down with a perimeter. The ideal situation would be to excavate to rock and pour a perimeter, but that leads back to the issues of not disturbing the area and cost.
Matthew 7:24
"Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock." 8)
Quote from: cbrian on May 16, 2012, 01:18:46 AM
The architect I spoke with told me that at 3' or so I will hit solid rock. He says that there are many options, but that if I was dead set on piers to dig down to the rock"
Where in central TX are you? When I was looking for someone to drill for my piers I found a guy who was very good cheap with good references, but he was too far away to be cost effective. He has a skid loader with a rock auger, and which will punch those holes in no time.
Rebar epoxied into bedrock adds a lot of stability to a footing. It is a common recommendation I have heard of over the years on shallower piers. If the Architect is sure you have bedrock at 3 ft then it sounds like he has some experience in the area.
I cannot comment on the lateral load of the piers. I can give points on the rest of the design for that route. Since most big box stores carry SPF No. 2 lumber, I use that as a default in most of my calculations. At 40 psf, according to published joist sizing charts a 2x8 SPF No. 2 can span 12'-3". So you should be good on those.
For the girders on the outside load bearing walls on a 24 wide building with 2 center bearing floors 3-2x10s can span 6'-4". If going with 7'-6.5" span (8ft minus the 2.75 inches of half of each 6x6) then I would consider a larger size girder.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_5_sec002_par021.htm
For the center girder, because it has to hold half the weight of the floor it has to be larger than the outside girders 3-2x10's on a 24 ft wide building can span 5'-9" (bottom chart in the last link).
Girder sizing is not a well published and a commonly misunderstood topic. I did a short guide on how to read the charts.
http://countryplans.com/smf/index.php?topic=10511.0
There was a recent topic that broke down the beam calculation math to prove out some of the charts.
http://countryplans.com/smf/index.php?topic=12159.msg156872#msg156872
The solutions are to upsize the girders or down size the spans (more posts). I'll leave the second floor calculations to you. Now you can see all the work that goes into designing a structure for a pier foundation system vs. a traditional full perimeter foundation. This is a lot of the value you get when buying a plan, like the ones sold on this site.
On the perimeter foundation, you can pour it by hand. I assume you will still be using a mixer to mix. I'm not sure about getting a great footing if actually hand mixing the concrete too. Since you are in central Texas you have certain difficulties in pouring concrete in general. My understanding is it hot and dry. You want to keep your concrete moist and not to dry out to quickly. To slow set time, try to use cooled water. Whether you are pouring pads and columns or a perimeter footing you will want to get a wet bond between mixes, slowing down set times will help you achieve that. You will almost assuredly have cold joint somewhere. They make concrete bonding adhesive and sell it at the big box stores for $20 a gallon. It has a greater shear strength than the concrete itself and is pretty cheap, so you should probably give it a try. It a common way pros bond a column to a base. The instructions should be on the bottle.
Quote from: cbrian on May 15, 2012, 12:32:07 PM
And next time your on the Texas Coast, take a look at the rows and rows of bay houses sitting on 6x6 piers 12' in the air.
Sorry, I couldn't pass on this one. It lets me point out my favorite example of the Texas coast.
(http://www.dvorak.org/blog/wp-content/uploads/2008/09/article-1055660-02a87a8d00000578-263_468x7052.jpg)
This house was built exactly to modern building codes on the Texas coast. The neighbors weren't.
1. If you pour piers of normal size for a house...say 12"x12" (with 18"x18" in the lower foot) x 5' there is no reason to have any problems with cold joints because of long times between pours for a single pier. You can hand mix all you need in one throw and do the whole thing in an hour.
2. You won't need cold water..a most unnecessary complication, but do keep the piers wet for a week or so. Just spray water on them morning, noon and night...wrap with a bit of burlap. Wet the hole well before the pour and use wet sand and gravel if it is hot and dry.
3. If you do footings or piers, you can certainly mix by hand and get a good mix. It is done all over all the time. Get you some good help to turn it and work it and shovel it in. Cheap labor...but a mixer is nice too.
Central TX is not hot and dry all the time. Can be cold and wet too. Nothing to worry about with concrete pours of this magnitude in any case, even in the dry season. Just a little water on it as cures is all you need.
Thank all of you for all your valuable input. I have a ton to go over, and looks like a lot of re planning to do. To your question where in Central Texas, I purchased a couple acres on Stillhouse Lake, about half an hour from Fort Hood. I was also told when pouring piers or a perimeter to not use fine sand. Some in an earlier post pointed out that it sounds like I have caliche and they where right. I was told the fine sand would turn the caliche to concrete? ??? Now I am wondering why that would be a bad thing? I have been building for years, but being from Texas everything I have ever done has been on grade slab, I never would have thought this to be so involved. Feel like I am new to the show. I can only imagine moving North and trying to build! d* I gaurantee my first basement would not be waterproof. ;D
Let me know if you want the info for the bobcat guy I mentioned. I found him on Craigslist. I had to throw a pretty wide net to find someone. He's out of Kempner, so he should be close enough.
Quote from: link=topic=12174.msg157096#msg157096 date=1337117383
The constant naysayer barrage is getting old and in my opinion is and boring and counterproductive.
Sometimes it takes me a while to formulate a response to some things.
IMO, the only reason that discussion on piers might seem "boring and counterproductive" is that the subject keeps returning as new members come and ask questions about the subject. Therefore the same type of response is supplied, again. In a similar vein, every time I post the graphic that defines and illustrates the proper placement of collar ties and rafter ties in a rafter assembly, I think to myself, "Here we go again". I can think of a few other questions and responses that get old and tiring as well as they are repeated in some slightly variable form. If a person is reading all the new messages that get posted under all new and existing topics that will occur time and again, and possibly be just as boring. That's the nature of a forum. Ask a question; get an answer. Repeat.
Therefore, I'm going to continue to respond to these type of questions in the same manner I have for some time. It may be "boring" to some readers; heaven knows at times I am bored with supplying more or less the same answers to more or less the same questions. Hopefully though the information, opinions and facts supplied will benefit someone. If not today, perhaps someone who will read the messages next week, next month or next year.
[soapbox:on]
Foundations are unexciting and a lot of work when done in a manner recognized by engineers. You do all that digging, pour a bunch of concrete in the ground and then hide it. What's the sense in that? No wonder so many like to sweep it under the rug, so to speak. {anyone get the subtle attempt at levity?} Who wants to put a lot of time and money into something that no visitor can see, let alone get excited about? Better to put the time, effort and money into some nifty T&G wood walls or floor, isn't it. That brings out the oooh and aaahs, gets the slaps on the back. So if anyone does not like the civil attempts to discuss the pros and cons as something as fundamental as the foundation, please skip over that sort of thing.
[soapbox:off]
sorry for the hijack and rant.
Yeah I would love the phone number, if you know a guy that can dig that hard ground would sure save my back. As far as the picture of the coast, I only used that as an example, and understand the extreme conditions requiring deeper piers. I have been repairing houses for over 15 years in Central and South Texas. Many of the homes do sit on a perimeter footing with piers inside the perimeter (pier and beam). But many of those houses where built in the 1950's and are now in the lower middle class areas of most small towns. When you travel into the lower income areas you run into the homes from the 1920's -1930's then you get into houses sitting on everything from old rocks, tree trunks, and blocks right on the ground. I understand a 50k foundation is better than a 1k foundation. I understand the resell value of the better foundation house is higher, and that foundation will more than likely last longer. With that said, for those that cannot afford that type foundation, there are other options that last for years. To say that for everyone of those right on the ground houses you see 1,000 failed, is based on opinion and nothing more. Entire neighborhoods of what would be considered poorly constructed homes are still standing, and providing shelter for family's decades later. A little tender care some of those look better than the new 150k houses with their press wood moldings, and paper laminated wanna be hardwood floors all mass stacked in a row with a few feet of grass and no tree in site. The point is for those that cannot afford the best, like everything else in life there are other options, and sometimes those other options can give you a more superior finished product, if nothing else the money saved will leave more budget for other parts of the house. In a part of the country with no frost line, and mother nature as tame as a newborn baby, tons of concrete are not always needed, and you will always have someone tell you it can't be done. Best advise research, ask opinions, use your brain, move forward, and hold your head high at your accomplishment.
Not to throw more fuel on the fire, but have you considered a wood foundation? (pressure treated) Sort of a hybrid of the step wall & block foundation, except instead of blocks, use PT wood. You'd still have to pour a cement footing, but I think you'd be able to do that yourself with an inexpensive mixer. Just thinking it might be easier to get lumber to your location than cement blocks.
And I'd agree with your comments about old neighbourhoods and crappy foundations. We lived in a place that was an old coal mining town (in Nova Scotia), there were lots of 80 year old houses made with big creosote treated sills sitting right in the mud. Others, like ours, sat on whatever rocks and crap they could find. In fact, our house had rough 2 x 8 floor joists, 32" o.c., and 3" x 3" wall studs in some parts. Doing renovations, I found most of the interior walls had wallpaper on the inside, facing the studs - meaning it came from another house when built. Some of the wood had fire damage where there was no fire. Yet, that house sat in a severe climate (by the ocean) for 80 years, and at least a couple of those it went unheated and vacant. Mind you, it wasn't exactly "level", and it creaked and groaned in the wind (boy, did we get wind there), but it goes to show you just how much a structure can take. And yes, all the other houses around were in similar state, still standing, with people living in them.
Quote from: cbrian on May 17, 2012, 02:08:13 AM
I have been repairing houses for over 15 years in Central and South Texas.
Exactly.
The better a house is built up front, the less repair and maintenance it needs over the years. A little bit of work and a small percentage of extra dollars or maybe even less dollars can get a better longer lasting result. It is more of a case of knowledge and understanding of the why and how materials work over time.
Say the 3-2x10s vs. 3-2x12s for girders. The house will not fall down with the difference of the two. The house may flex over time and have the floors creak, loosen floor boards and nails, possibly crack plaster, or loosen windows. The difference upfront is $72. But you have the knowledge of books on carpentry, publicly published building codes, and trade organizations that state it will definitely work and be the strength needed to last over the lifetime of the structure. I posted a link to the previous topics of with all the calculations of carpenters, who have built on the thousands of years of carpentry knowledge passed down through the generations as to sizing and spans.
So it is more of a question of building knowledge than cost. This is also a large premium built into the cost of hiring a contractor. I have been rehashing the same basics and topics here for the past four years. Many people are fully willing to go over the math and physics of the why and how things are done a certain way because we have received that help from others and want to pay it forward.
Although post and pier foundations may seem simpler and cheaper from the pictures. There is a lot more physics and engineering that goes into them than a picture can provide. Not all of us are willing to wing it and guess when there are easier, better researched, and more published alternatives.
cbrian, I am glad you have been patient with many of us in our ability to explain the why and how behind building things a certain way.
hhbartlett
I thought about that too. Since cost is such an issue for cbrian, I did not suggest it. But let us explore some of the advantages. If he does go with the perimeter footing he can certainly do PWF attached to it. Since it would all be above grade and there would be no unbalanced fill on each side so he wouldn't need to worry about bracing the interior with a slab.
But since the PWF wood costs so much more per square foot than concrete I did not suggest it. It can also be difficult to source PWF lumber. Regular PT lumber (much cheaper) can be used as long as it is above grade. All lumber touching concrete (because it holds moisture) or within 18" of the ground is supposed to be PT. Although the stepped concrete footing with 2 layers of block and a double 2x4 sill plate would probably be greater than 18" above the soil. He could build a wall out of regular lumber, almost identically metolent's picture. It would save on hauling a lot of blocks, and probably would be close to comparable in cost.
PWF does not require concrete at all. There are methods laid out using compacted crushed rock under the PWF wall structure. LINK near bottom of this page (http://www.southernpine.com/applications_permanent-wood-foundations.asp)
Quote from: MountainDon on May 17, 2012, 10:06:59 AM
PWF does not require concrete at all. There are methods laid out using compacted crushed rock under the PWF wall structure. LINK near bottom of this page (http://www.southernpine.com/applications_permanent-wood-foundations.asp)
As was used in my 20 x 40 at less cost than poured.
(https://i234.photobucket.com/albums/ee314/glennjakobsen/SAM_0650.jpg)
So with a PWF you can actually make a basement? This is new to me, but sounds promising. Any figures on the longevity? I see that they pour a foundation inside the perimeter. I am guessing you could do a joist floor system w/ crushed gravel underneath, just raise the height of the PWF to compensate, and there would be no concrete involved at all. Only thing that worries me, and mind you I haven't read all the way threw the document that was linked, is how is the structure pinned to the ground? Is it bearing weight alone that holds the structure down?
Quote from: AdironDoc on May 17, 2012, 01:04:26 PM
As was used in my 20 x 40 at less cost than poured.
(https://i234.photobucket.com/albums/ee314/glennjakobsen/SAM_0650.jpg)
Do you have any more pictures of the structure. Would love to see more details and the overall build also.
I should have put a footnote on my post.... Like pier fpoundations, PWF don't work in all soils. PWF works best in type 1 soils. Read the entire document.
There's a chance the Web Soil Survey (http://websoilsurvey.nrcs.usda.gov/app/) will have info on the soils in your area. Or ask locally.
Quote from: cbrian on May 17, 2012, 01:57:59 PM
Do you have any more pictures of the structure. Would love to see more details and the overall build also.
More photos of the PWF and overall structure on this thread:
http://countryplans.com/smf/index.php?topic=10791.0 (http://countryplans.com/smf/index.php?topic=10791.0)
A french drain runs around the perimeter of the PWF base, enters a length of PVC which diverts any possible ground water or seepage downslope. Diagonal supports were for support during construction and were left on for extra support against frost heave against the middle sections of the 2x's that make up the wall. Note that as the first floor pushes down with added weight, the diagonals actually create lateral force. Leaving them in was considered overbuilding, but this mechanical advantage was recommended and there was no reason to remove them once in.
Just wanted to add to the pile of stuf to look at----my two O/B projects were built on slopes with bedrock under thin soil. This was my solution---high labor, low cost, should last forever since there are no cold joints and it's one massive piece
http://countryplans.com/smf/index.php?topic=11812.msg151774#msg151774
http://countryplans.com/smf/index.php?topic=11821.msg151922#msg151922
Read all Don's warnings carefully----I went a minimum 30" deep where I could, and epoxied rebar into bedrock where I couldn't. 3 sticks of #5 rebar too
I'm taking the chance you hadn't already looked at this but if you had my apologies
Quote from: flyingvan on May 17, 2012, 07:40:10 PM
Just wanted to add to the pile of stuf to look at----my two O/B projects were built on slopes with bedrock under thin soil. This was my solution---high labor, low cost, should last forever since there are no cold joints and it's one massive piece
http://countryplans.com/smf/index.php?topic=11812.msg151774#msg151774
http://countryplans.com/smf/index.php?topic=11821.msg151922#msg151922
Read all Don's warnings carefully----I went a minimum 30" deep where I could, and epoxied rebar into bedrock where I couldn't. 3 sticks of #5 rebar too
I'm taking the chance you hadn't already looked at this but if you had my apologies
Thank you for the info, I did alittle digging the other day and found rock 6" in some areas, this looks like what I will have to do also.
Quote from: AdironDoc on May 17, 2012, 05:24:40 PM
More photos of the PWF and overall structure on this thread:
http://countryplans.com/smf/index.php?topic=10791.0 (http://countryplans.com/smf/index.php?topic=10791.0)
Cool place you have! Nice views, and you did a great job on your build. Did you saw and draw your own logs?
Quote from: cbrian on May 18, 2012, 12:38:09 PM
Cool place you have! Nice views, and you did a great job on your build. Did you saw and draw your own logs?
Thanks! I had my neighbor who owns logging equipment and a mill prepare them for me. I have yet to clean them up and poly them. Every project I'm at takes 4 times longer than I figured. At this rate the cabin will finished by the time I'm put out to pasture.