Author Topic: Question of foundation piers  (Read 58609 times)

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Offline MountainDon

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Re: Question of foundation piers
« Reply #50 on: March 09, 2009, 07:59:11 PM »
That drawing was meant as a concept of principle drawing, not a construction plan. It probably would have been better to draw the joists for the side extension lapping on the other side of the central joists, the left side as drawn.

alcowboy, the best thing you could do before building, is get some good drawing paper. Use large enough sheets so you can make a large drawing that is easy to detail and draw in joists and studs to scale. That is what I did for our cabin and everything else I've built or remodeled before. I use 11 x 17" vellum tracing paper that comes in 50 sheet pads. they have a fine grid printed on the bottom side. It's available at good office supply stores. In the pad you can see the lines through the paper as guides and draw in pencil on the top surface. Vellum paper costs more but it is super erasable without rubbing and tearing away the paper surface.

Making an accurate scaled drawing will assist in understanding how lapping the joists at the center will affect the way the T&G subfloor sheets lays out. In making the drawing you will also see and understand how to adjust the joist lengths to account for the rim joist. That is, say the building width is 24 feet; you need to subtract 1.5" off each end where a rim joist will be nailed to the ends of the joists. Little things like that need to be thought out beforehand to avoid niggling problems later on.

The purchase of a good right angle drafting triangle and an architects scale will prove to be very useful. Mechanical pencils with 0.5 mm leads are my favorite pencil; they never need sharpening.

I find that making the drawing helps me understand how all the pieces will go together. I did the walls, the ceiling joists and the roofing all on paper first. I relate well to drawings; some don't, but it works well for me.
« Last Edit: March 09, 2009, 08:51:36 PM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

alcowboy

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Re: Question of foundation piers
« Reply #51 on: March 10, 2009, 04:24:01 AM »
Thanks Don! All it amounts to then is be sure you have all measurements correct and know what the next step will be and how the next "building block" will fit into your current, etc, etc.

That makes sense.  I have already gone one step further than the vellum. I have built a to-scale model of the home and have already seen how some of the "building blocks" should fit together.  I have not done that with the subfloor though. Guess I will be purchasing some vellum this weekend.  ;)

Offline Don_P

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Re: Question of foundation piers
« Reply #52 on: March 10, 2009, 05:54:11 PM »
I've asked a question on the building inspectors website about pier and beam foundations and was referred to the appropriate code sections. To build a code compliant pier foundation without resorting to an engineer a pier and curtain wall foundation type is used. This is a rough sketch of what the minimum foundation for this house would look like using concrete block piers, brick curtain walls, and continuous footings under load bearing walls. It would be prescriptively allowed in non seismic areas. They are attempting to give a generic way to adequately support and brace the structure. To step below their minimums one should consult an engineer. There are other ways to build a well braced foundation, this is about the prescriptive minimum in masonry.


« Last Edit: March 10, 2009, 06:43:18 PM by Don_P »

Offline Beavers

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Re: Question of foundation piers
« Reply #53 on: March 10, 2009, 06:48:04 PM »
Thanks for the info Don.

I've tried without luck to find any code info for pier and beam foundations.  Do you have a link to any online info?

Is the concern racking of the piers? (I think that's the right term) 
Seems like the compressive strength of either concrete or masonry piers are hundreds of times stronger than the weight of the house sitting on them.

I calculated the load of the 14x24, and using 8 piers with 2'x2' footings it seems to me that even with 2000 psi. soil there is plenty of bearing capacity.  ??? 
So would the full perimeter footing would be just to support the curtain wall?

If a house were subjected to winds strong enough to topple steel reinforced concrete piers, wouldn't the rest of the wooden structure be reduced to splinters?

I'm not trying to question your info, or John's designs here.  I wouldn't even pretend to know enough to do that.  I would however like to find out all the info I can though about the foundation of my house, any areas of weakness, and if/where I could beef them up.

Offline MountainDon

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Re: Question of foundation piers
« Reply #54 on: March 11, 2009, 06:20:16 AM »
My County Development Division (high faluting name for building inspectors) routinely approves pier and beam foundations in the mountain area where my cabin is located. Many of these approved plans are not engineered per se, or even drawn up by architects. The office does look at the proposed plan and indicates what changes might be necessary to gain their stamp of approval. From talking with ordinary folks around there as well as some county officials the foundation changes usually revolve around the size of footing, the spacing of the piers or the size of the beams; some folks submit self drawn plans with inadequate footings, too few piers or undersized beams.

So maybe that doesn't meet any prescriptive code. However it is an approved foundation in my county. It is similar to many foundations around there that were built a couple - three decades and longer ago; foundations that still quite adequately support many buildings in this area. In fact my foundation is a vastly more robust foundation than that used for a 60 year old cabin just off my south property line. I've been in that cabin and the doors still open and close, the windows rise and fall and the floor does not sag. Back then it was built outside of any regulations.

So, it's my opinion that a building code that requires a full perimeter continuous footing for constructing a simple cabin like mine, is a building code that is out of touch with reality. More than likely, it is a building code that exists to extract fees simply for the need to justify its own existence. No doubt a cabin built to those prescriptive rules would not be likely to fall down. However, local experience here would indicate that pier and beam construction can be executed with great long lived success.

I do believe that building departments do have their place. Sometimes out of pure ignorance some self builders do truly dumb things, like a neighbor back home who removed an interior load bearing wall in a remodel. However, it seems to me that in the past decade or so, many prescribed changes to the codes are pressed on us because the code officials have run out of real things to do; they need to justify their existence. Many changes are also pressed on us because some special interest group, such as a manufacturer of a product, wants to see his product mandated as necessary to meet code. I believe that it is impossible to protect the citizenry against all possible things that could go wrong and some things are not very cost efficient.

I also believe there are too many government agencies involved in too many aspects of private life and they should butt out, but if I said that I'd be creating more topic drift. I wouldn't want to do that.

On the other hand when someone comes along here on the forum wondering anew about how something can be or should be done with respect to building one of the first things I ask is "are you subject to any building codes or rules?" I suggest that is the place to determine what the local officials require of their subjects.
« Last Edit: March 11, 2009, 07:45:40 AM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline new land owner

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Re: Question of foundation piers
« Reply #55 on: March 11, 2009, 10:51:29 AM »
Sorry guys. I guess I am just stupid. Sorry for the confusion I have caused. Don I believe you have actually answered my question as well as ScottA.

There is no reason as to why 6x6, only trying to keep costs low and thought it would work as well as a built-up beam. Thanks for the drawing Don. It is the THING that brought everything together for me. Exactly what I have been thinking. I am in the middle of the State of Alabama so no biggie threat of hurricanes but there is some.

I don't want to get others, like engineers and government, involved in my project as that would only be someone with a hand out and a big possibility of "I really don't know, $500 please." I knew I could trust you guys to figure this whole thing out. As far as the load bearing wall, I would have to agree the wall between the kitchen/bathroom and living/bedroom would have to be load bearing for that great of span and, yes, there is a beam shown underneath at that point. According to the plans there is no vaulted ceiling.  I am beginning to believe these plans are not true and complete as there is a lot of information missing that you guys keep asking me which I cannot answer. There is even no materials list - which goes back as to why I am working up the plans in BHG.

This conversation has taught me more than I ever thought I knew about doing this - which was nothing in the beginning. I feel like an idiot. Sorry guys.

I bought these plans as well and when you look at the side elevation the roof pitch changes further up the roof that the picture shows.  This may not be a concern for others but I did not like the looks of the "plan" as compared to the picture.  I did contact the seller and they offered to refund my money.

alcowboy

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Re: Question of foundation piers
« Reply #56 on: March 11, 2009, 04:48:02 PM »

I bought these plans as well and when you look at the side elevation the roof pitch changes further up the roof that the picture shows.  This may not be a concern for others but I did not like the looks of the "plan" as compared to the picture.  I did contact the seller and they offered to refund my money.


I noticed the same thing and corrected that using my software. For the price I paid for these "drawings" I cannot complain. I consider them more as drawings rather than plans since they are not 100% accurate and leave off so much information. However, I have managed to reproduce the plans well enough in with the Home Designer Suite 8 that I can get started.  I really need a software that would generate a better takeoff than what I have. I may play around with PlanSwift to see if I can get it to work properly.

Offline new land owner

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Re: Question of foundation piers
« Reply #57 on: March 12, 2009, 01:11:55 PM »
I use Punch software ver 3000.  It make it easy to see what the final product will look.

Here are examples of my plan for a 20 x 32 cabin






Offline Jaltman039

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Re: Question of foundation piers
« Reply #58 on: January 21, 2017, 07:13:19 PM »
I am considering a 32x44 cabin located in North GA Mountains and I'm wondering cinder block pier foundation with wood floor joist. Wall height is 9ft 3in. What should my spacing being on my cinder piers

 

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