Author Topic: Which foundation type?  (Read 76985 times)

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Offline Amanda_931

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Re: Which foundation type?
« Reply #25 on: October 22, 2005, 05:31:02 PM »
Some of the thermal mass people would disagree about the thickness of the mass.  I think you're right for fairly conventional construction.  

But I know a house built with no insulation and slipformed concrete, sunk into a hill, from most perspectives way too much south facing glass, etc.

You really can't cool that place down to 48 degrees F--somewhere in the 9 degrees C range) and pop it back to reasonable without a sweater temperature in an hour and a half if you have feet of thermal mass all cooled down.  On the other hand it would take a good while to get that far down if you had, for instance, a green house with a blower that puts anything over 80 degrees F--a bit over 25 degrees C--into the house, nearly solid window walls on the south side (except for that greenhouse.  

The people with that house believe that extensive thermal mass is the only only only way to go, and their house is quite comfortable in the winter, not bad in the summer with minimal air conditioning, and the pergola in front of all those windows covered with vines and awnings.   (People who've had retinal tears in their eyes--or oncoming cataracts--are not going to be terribly happy there, but not for reasons of temperature.)

Ianto Evans says that cob would be terrible house to have if you're wanting to come in once a month for a ski weekend and the only possible windows are on the North side in the Northern Hemisphere, and you were expecting the house to be comfortable without outside heat.  Or if the only windows were on the  South side in Tierra del Fuego--but he doesn't say that.
« Last Edit: October 22, 2005, 05:31:21 PM by Amanda_931 »

Offline Lady_Novice

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Re: Which foundation type?
« Reply #26 on: October 22, 2005, 06:49:49 PM »
Seeing that this thread was active again, I had to report on my experience with my foundation since I last posted.

I'm in cold country with a south-facing lot, so I decided to get thermal mass with a slab foundation.

John and others are right that a slab foundation is best handled by professionals. Besides the extra expense this entails, if you're in a booming building area like mine, good professionals are difficult to find. With a slab foundation this problem is compounded because the work of each professional (in my case, the foundation contractor, the in-ground plumber, and the excavator) has to be coordinated with the others, and each may have to come out two, three, or more times to complete various steps in the process. Because they're so dang busy, with each separate step in the process, you are on the phone begging each professional to now please come and perform this or that step in the process and you may wait a long time for the completion of each step.

So, believe it or not, it has taken three months just to get a slab and utilities in. The snow is about to start falling here, but I can't start framing until just one more thing, the final slab pour, is done. But my highly recommended foundation contractor is dragging his heels again, probably busy with more important clients. I've been leaving him messages for two weeks, and he's been completely ignoring my calls. He did this with the other steps, too, so I think he plans to follow through and complete the final pour, but he can't be bothered to let me know if or when he might do it. I wasn't planning to frame in the snow, but that's now a given.

(Actually, my experience with him has been much better than my experience with the plumber, so I'll give him some credit.) :-)

So if I were to ever build another home, I wouldn't do a slab, or I would hire a general contractor to handle it (in which case, the additional expense of using a G/C could in itself make it a lot more costly than other foundation types?).

In short, I can see the value of do-it-yourself building techniques (such as the concrete or wood post foundation that John has detailed). I have really disliked being dependent on these professionals as I'm under the impression that owner-builders (i.e., people who can't offer them repeat business like a general contractor) are their lower-priority clients?? But I'm guessing here.

But that's another thread, one that I thought about starting, called "Experiences with Subcontractors."
Thanks for listening,
Lady Novice
P.S. If you're a subcontractor, I hope I didn't sound as if I'm generalizing about professionals. I believe my experiences have been unique? I'm easy to work with and very understanding if a subcontractor is under time pressure, but I just wanted them to return my calls, which usually didn't happen without incredible persistence.
« Last Edit: October 22, 2005, 07:58:28 PM by Lady_Novice »

Offline Amanda_931

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Re: Which foundation type?
« Reply #27 on: October 23, 2005, 03:54:33 PM »
People around here are notorious for not showing up.

Maybe the worst of them was a guy who underbid the job so much that he really couldn't afford to bring his equipment in unless he had a job across the street.

Nice guy, probably trying to save me money, but....  Three years later that project, which should have been a half hour job, still hasn't been done.

and I admit to doing a bit of badmouthing.  Especially trying to suggest that if the subcontractor underbids by too much, it will never get done.

Offline Billy Bob

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Re: Which foundation type?
« Reply #28 on: October 23, 2005, 04:59:56 PM »

Then there's the middle of the road, where you get someone who knows concrete work, and you provide the bullwork.
Last slab foundation I worked on (about fifteen years ago) was for a thiry foot square shop.  Three of us took about five hours to pour, screed, and float the thing.  The guy who ran the power trowel spent another couple of hours, and a couple of hours getting a nice edge and setting anchor bolts after pulling the forms.
For the bathroom, we used a variation on glenn's technique by stubbing the drain for the john into a piece of sonotube.  I guess we could have poured concrete in the hole after getting the final placement of the drain, but we just stuffed some scrap insulation in the hole and nailed a half sheet of PT plywood over it for a floor.

It's nice to have a friend/neighbor who knows how to do this stuff (AND owns a power trowel ;))
The other two of us had some experience, and with a pro to direct, it went well.  In addition to the concrete and reinforcement, it cost $100 and a case of Heineken for the professional help.
(The previous job I was one of the guys got the c note and Heineken; is that the going rate or something? ;D)
Bill

Offline pforden

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Re: Which foundation type?
« Reply #29 on: November 05, 2005, 01:01:04 PM »
Hello, All,
We've just joined because we love the Grandfather's house -- my son is a wheelchair user and this plan is so disability friendly.
We are building in central Texas. We have a couple of soil types, both sandy loam and deep sand. We understand there is some clay under each, maybe as deep as 48 " or more under the deep sand. The soil survey site says that both of these soil types in this area are fine for building houses without basements.

Any ideas of which would be preferable for building upon? and which foundation we should use?

Thanks.

Penny and Allen

Offline glenn kangiser

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Re: Which foundation type?
« Reply #30 on: November 05, 2005, 02:06:33 PM »
Hi Penny and Alan.

I am going to copy this to the plans support section since it looks like you are planning on using Johns plans.  You can get there by clicking on Design Build Forum above the choosing plans support.

I will put it under Grandfather's House question.  John checks there regularly for his plan purchaser support.
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Offline Okie_Bob

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Re: Which foundation type?
« Reply #31 on: November 08, 2005, 12:52:49 AM »
Welcome Penny and Allen! Hope you enjoy this forum, there are so many helpful, friendly people on this site. Glen and Jonsey too!

I've just built in East Central Tx, actually about 30 miles east of Corsicana on Cedar Creek Lake. I built a 24 X 50 garage on a slab floor. I too have the sand/clay problem we all have in Tx. As I've heard said, there are only two types of slabs in TX, those that are cracked and those that are going to crack! I figured I'd be smart and start with a 24" deep X 24" wide footing with enough steel in it  that it would never crack, the poured a 6" slab again with way more steel than recommended.  And YEP, within 3 months I had a crack!
I just don't believe there is anything you can do to guarantee a slab around here won't crack at some point. Drout or deludge, clay is going to contract and expand and concrete just won't hold up forever. But, you can usually live with it, if you want a slab foundation.
PS: I'll bet there are more foundation repair companies in TX than the rest of the world combined!
Okie Bob

Offline keyholefarmhouse

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Re: Which foundation type?
« Reply #32 on: November 08, 2005, 02:59:47 AM »
Can't you first put down crushed gravel, or get it below frost line.  I live up in the cold north country and have decided to use a full basement, with the floor below the frostline (four feet) for this very reason.  We also have big clay issues.  A lot of people use floating slabs.  But then our problem might be much worse than in TX.
« Last Edit: November 08, 2005, 03:00:24 AM by keyholefarmhouse »
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Offline glenn kangiser

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Re: Which foundation type?
« Reply #33 on: November 08, 2005, 05:51:22 AM »
Me and Jonesy too----humpf---- :-/  Then there's the normal ones.   I get it, Bob.   ----------Thanks for the compliment. ;D

If you guys weren't getting so rich down there in Texas pumping all that oil out from under your ground, you wouldn't have the subsidence and your slabs would stay together. ;D

Actually you can do anything you want and it doesn't do much but minimize chances of cracking.  If it wants to crack it will.  You won't find one contractor who will guarantee no cracks.  As you say - with proper reinforcing they don't go anywhere or bother anything.
« Last Edit: November 08, 2005, 05:52:50 AM by glenn-k »
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Offline pforden

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Re: Which foundation type?
« Reply #34 on: November 08, 2005, 06:10:44 AM »
Hey, Bob,
Thanks for letting us know how you dealt with this. I am sure a lot of steel goes a long way! I note that virtually every construction in the area is pier and beam, but we have not talked to people who've built recently in the area. There are a lot of engineered foundations, some miles to the southeast, but we are not going to get into that!

We spent a long time finding sandy soil that should be okay for a building without a basement. Where we are has buildable sand down at least 48 inches on parts of the property. But we are going to dig down to the clay if we can to see what we are really dealing with.

We'll keep you all updated. Thanks again.
Penny


Quote
Welcome Penny and Allen! Hope you enjoy this forum, there are so many helpful, friendly people on this site. Glen and Jonsey too!

I've just built in East Central Tx, actually about 30 miles east of Corsicana on Cedar Creek Lake. I built a 24 X 50 garage on a slab floor. I too have the sand/clay problem we all have in Tx. As I've heard said, there are only two types of slabs in TX, those that are cracked and those that are going to crack! I figured I'd be smart and start with a 24" deep X 24" wide footing with enough steel in it  that it would never crack, the poured a 6" slab again with way more steel than recommended.  And YEP, within 3 months I had a crack!
I just don't believe there is anything you can do to guarantee a slab around here won't crack at some point. Drout or deludge, clay is going to contract and expand and concrete just won't hold up forever. But, you can usually live with it, if you want a slab foundation.
PS: I'll bet there are more foundation repair companies in TX than the rest of the world combined!
Okie Bob


Offline glenn kangiser

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Re: Which foundation type?
« Reply #35 on: November 08, 2005, 06:20:50 AM »
I built on bad clay once - the engineer had me put a deep footing around it like Bob's and raise it above the surrounding area --about 2' of compacted fill. 12" wide by about 30" deep footing to seal surface runoff from getting under the slab clay and expanding it.

That building was about 60' x 120' if I remember right.  No major problems over the last 25 years or so.

You can also add fibermesh to the concrete now as additional reinforcement or even in place of some of the steel in many cases.
"Always work from the general to the specific." J. Raabe

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Offline tjm73

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Re: Which foundation type?
« Reply #36 on: November 08, 2005, 09:36:35 AM »
Many years ago now my parents had a small incredibly old bathroom removed from their house to redesign it along with a kitchen remodel.  It was always cold in this bathroom.  ALWAYS.  Liek 15-20 degrees colder.

Their was a concrete shower.  Yes it was concrete.  The contractor brought in his young helper who tried to take it out with sledge hammer.  HA!!  It laughed at them.  In the end they had a jack hammer in the bathroom as the entire room (about 5.5'x6') was setup on top of about a 4" thick concrete slab over wood.  The house is built on 10" diameter trees (it's like 200 years old and the trees still have some bark on them) so weight wasn't the issue.  Kinda funny looking back.  Took them a full day to get that concrete out.  Then they had to build a proper floor and go up from their.  that was unexpected.