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Concrete House questions

Provience

Provience

Kill!
Joined
Jul 8, 2009
Member Number
15
Messages
9,479
Loc
Gatesville, TX
Is concrete not the perfect material :confused: especially given the abusive price of wood lately.

What reference do I need to look up and find for this sort of stuff? Considering a concrete shell that is basically monolithic wall pour (probably done in a few lifts to make forming easier) from footing 4' underground to the roof line.

In my head, i'd like to be able to use standard pre-engineered wood roof trusses instead of concrete and use metal hangers drilled in to the wall to support wood floor span lumber.

is a 4" thick standard rebar reinforced wall enough to do this :confused:

4" concrete -> 4" XPS foam insulation -> 2x4 24"oc hollow interior wall to hold drywall would be about 12" total wall thickness and is pretty reasonable in my head.

So i'm trying to find what the top plate requirement would be for the transition to the roof line and i'm not sure where to look. same thing with the floor joist hangers, not sure if a simpson hanger would be enough or if a pressure treated 2x10 would need to be anchored to the wall all the way around and then the anchors placed into those, but that seems excessive
 
Provience said:
Is concrete not the perfect material :confused: especially given the abusive price of wood lately.

What reference do I need to look up and find for this sort of stuff? Considering a concrete shell that is basically monolithic wall pour (probably done in a few lifts to make forming easier) from footing 4' underground to the roof line.

In my head, i'd like to be able to use standard pre-engineered wood roof trusses instead of concrete and use metal hangers drilled in to the wall to support wood floor span lumber.

is a 4" thick standard rebar reinforced wall enough to do this :confused:

4" concrete -> 4" XPS foam insulation -> 2x4 24"oc hollow interior wall to hold drywall would be about 12" total wall thickness and is pretty reasonable in my head.

So i'm trying to find what the top plate requirement would be for the transition to the roof line and i'm not sure where to look. same thing with the floor joist hangers, not sure if a simpson hanger would be enough or if a pressure treated 2x10 would need to be anchored to the wall all the way around and then the anchors placed into those, but that seems excessive
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Wife's friend is from Romania and thinks its weird for our houses to be made out of wood. I guess their homes are made out of stone and concrete.
 
junkytj said:
If there was a time when ICF house made sense, it's now. Concrete hasn't kept up with lumber inflation.
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Was talking with a concrete company owner recently and he commented that the price has tripled recently and now is not the time to pour a driveway. And that's here in OKC. I'm not sure how the pricing translates to other regions though.
 
Halffastford said:
Was talking with a concrete company owner recently and he commented that the price has tripled recently and now is not the time to pour a driveway. And that's here in OKC. I'm not sure how the pricing translates to other regions though.
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Well, when lumber has went up 600% + it is all relative. He's looking at it from his bubble.
 
Halffastford said:
Was talking with a concrete company owner recently and he commented that the price has tripled recently and now is not the time to pour a driveway. And that's here in OKC. I'm not sure how the pricing translates to other regions though.
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My brother just had some poured and it was about $5 a yard more than what it has been for years. The labor is probably through the roof, but so far the cost of materials hasn't changed much around here.
 
Halffastford said:
You think wood is high, wait til you price concrete.
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my neighbor is getting quotes for a back deck, 16x22 or so.

$7,000 in materials for wood

$8,500 for material, labor and placing for basic trowel finish concrete

$14,000 for installed wood

$14,000 for installed stamped and colored concrete

yeah it will keep itself above wood, but the gap seems to be narrowing. I'm not looking at doing this soon anyways and I think there are many advantages of concrete over wood that help justify the price. The low cost of wood is really woods only advantage, the more that gap narrows, the easier it is to justify concrete
 
junkytj said:
If there was a time when ICF house made sense, it's now. Concrete hasn't kept up with lumber inflation.
Click to expand...
That time was end of last year. Now is a good time for nothing. Steel, wood, concrete... its all full retard.

Hay bales are about the only building material that's still affordable.
 
junkytj said:
If there was a time when ICF house made sense, it's now. Concrete hasn't kept up with lumber inflation.
Click to expand...

ICF, that is a high price that I can't seem to justify over a formed/placed wall style. This would be for a Zone 6 region so it seems the 12" wall of 3 layers would give me just a bit more R value than the standard 6" (iirc) ICF block has
 
This was my estimate about a month ago:


Foundation Specs: 48’0”X32’0”4’0”
  • 160’0” of 8”X16” Footing
  • 160’0” of 4’0”X8” Wall
  • 2-Runs of #4 rebar footings.
  • 2-Runs of #4 rebar bottom of wall a single run of #4 rebar top of walls.
  • #4 Dowels 4’0” on center 2’0” high footing to wall
  • Galvanized anchor bolts 6’0” on center
  • All concrete 3000 PSI
Foundation Estimate labor and materials: $11,785.00

Slab Specs: 48’0”X32’0”X6”
  • 1536 SQFT
  • 6” Thick
  • 27.0 Yards of 4000 PSI concrete
  • Fiber mesh
  • 192’0” of control joints
Slab estimate labor and materials: $10,575.00
Total job estimate: $22,360.00
 
45acp said:
That time was end of last year. Now is a good time for nothing. Steel, wood, concrete... its all full retard.

Hay bales are about the only building material that's still affordable.
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hay is great if you don't mind 24"+ worth of walls :laughing:
 
Halffastford said:
Guess it' regional then. He was telling me it was about 80 a yard, now it's just over 200.
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It hasn't been under $100 a yard here for a decade or more. He paid $129 a couple weeks ago. Its usually $120-$125

I imagine they are just looking for a reason to jack the price up though. so who knows whats happened in the last 2 weeks.
 
woods said:
This was my estimate about a month ago:


Foundation Specs: 48’0”X32’0”4’0”
  • 160’0” of 8”X16” Footing
  • 160’0” of 4’0”X8” Wall
  • 2-Runs of #4 rebar footings.
  • 2-Runs of #4 rebar bottom of wall a single run of #4 rebar top of walls.
  • #4 Dowels 4’0” on center 2’0” high footing to wall
  • Galvanized anchor bolts 6’0” on center
  • All concrete 3000 PSI
Foundation Estimate labor and materials: $11,785.00

Slab Specs: 48’0”X32’0”X6”
  • 1536 SQFT
  • 6” Thick
  • 27.0 Yards of 4000 PSI concrete
  • Fiber mesh
  • 192’0” of control joints
Slab estimate labor and materials: $10,575.00
Total job estimate: $22,360.00
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that all sounds pretty reasonable actually.

maybe 25% higher than "in my head" but my head is wildly far off on everything, always
 
Provience said:
ICF, that is a high price that I can't seem to justify over a formed/placed wall style. This would be for a Zone 6 region so it seems the 12" wall of 3 layers would give me just a bit more R value than the standard 6" (iirc) ICF block has
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I don't sell the shit, so it makes me no difference, but here in tornado alley, there are other benefits. I just finished my house and we went with standard construction, but it wasn't much difference by the end of the build if we were starting over and I would have went that way.
 
junkytj said:
I don't sell the shit, so it makes me no difference, but here in tornado alley, there are other benefits. I just finished my house and we went with standard construction, but it wasn't much difference by the end of the build if we were starting over and I would have went that way.
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that's what has got me leaning more towards doing concrete walls, it's basically ICF except not blocks and not a sandwich, so you get to do more free-form rebar work and typical wall style construction.

high desert with potential for high winds makes the concrete siding appealing, being poured means you can make it finish out looking like literally anything you want, and also means it would be very easy to add color to it while being mixed so that you aren't stuck with gray if you don't want to paint it
 
ICF is apparently the easier search term to use when looking for information on residential grade walls

www.foxblocks.com

How do I determine which size ICF to use?

Typical residential construction will use 6″ or 8″ concrete core size blocks. Project specific engineering may allow for some core thickness to span vertically higher.
www.foxblocks.com www.foxblocks.com

ICFs provide a reinforced concrete wall which is designed to specific engineering principles. Typical residential construction, per the applicability limits in the building code, allows walls 10' (3 m) high or less between lateral supports (floor and roof connections). Below grade walls must have a minimum 6" (150 mm) concrete core. In some regions, an 8" (200 mm) concrete core is the minimum allowed thickness for below grade walls.

The 4" (100 mm) form cannot be used below grade as a foundation wall. The 4" (100 mm) form may be used for above grade walls up to a maximum of 10' (3.0 m).

The 6" (150 mm) form, above grade, is limited to approximately 14' (4.2 m) in height. Walls higher than 14' (4.2 m) must use an 8" (200 mm) or larger form.
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there isn't much reference there, but it certainly seems like some reasonable points. at some point when this project actually gets closer to reality, i'll need to hire engineers and architects and other such and whatnot, but it's still important to have an idea of what is going on. if there is no real need or reason to run an 8" wall where a 4" wall will do, then stick to the thinner and such and whatnot
 

Minimum thickness of bearing walls

A. The unsupported length of a wall is the length between members that laterally support that wall. These members could be columns or other walls perpendicular
www.concrete.org

now we're cooking with gas :rasta:



Minimum thickness of bearing walls​





Q. ACI 318-19, Section 11.3.1.1 states that the thickness of bearing walls shall be greater than 1/25 the lesser of unsupported length and unsupported height. I have a wall that is 31 feet long and 12 feet tall. What does “unsupported length” mean? Does this mean that the thickness of the wall cannot be less than 15 inches?



A. The unsupported length of a wall is the length between members that laterally support that wall. These members could be columns or other walls perpendicular to the wall being considered. Section 11.3.1.1 states that the minimum thickness shall be based on the shorter of either the unsupported wall height or length. Thus, it appears that in the example you provided, the minimum wall thickness is 6 inches. For more on designing bearing walls refer to chapter 11 of ACI 318-19.



References: ACI 318-19
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my boss built an entirely concrete house, well it's more like a compound.
when you build bridges for a living I guess you build everything in concrete.

It has poured exterior walls and is partitioned off into thirds with interior concrete walls. Makes getting wifi everywhere kind of a bitch. It is traditional truss roof. The attic space is all spray foam insulated, I've never been in the walls, and never want to need to be in the walls, but he told me they're all rebar reinforced. It's basically framed inside so you could run all the wires and finish the walls with drywall, so you're still spending money on wood and shit.

the bridge over the little creek is basically a single lane highway bridge, because it had to be sturdy enough for concrete trucks obviously.
 
posford said:
Fuck that. $120/round $10/small square here.... if you can find it!
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Funny memory-

Sometime around 03-05, central/north TX had a bad year long drought. A guy from Dallas was coming here and buying round bales, hauling them back, busting them and re-baling as square bales to sell to all the horse people. I don't remember the markup he was getting but it was pretty insane. 3 months of work and at the time netted what I did in a year. :smokin:

(the guy was either on pbb, or good friends with one of my pbb buddies. My memory sucks)
 
45acp said:
That time was end of last year. Now is a good time for nothing. Steel, wood, concrete... its all full retard.

Hay bales are about the only building material that's still affordable.
Click to expand...
Hay is a crap building material. Straw on the other hand is amazing. Unfortunately, straw prices are through the roof, too. I've attended a seminar for straw bale building and helped on a house. I'd love to build one and live in it.
 
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