Author Topic: Stone house - Concrete backing or not? Slipform  (Read 21525 times)

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domwild

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Stone house - Concrete backing or not? Slipform
« on: March 08, 2010, 04:11:08 PM »
Hi,


There seem to be two major ways to slipform a wall:




  1. Stones inside and out on mortar beds,

  2. Stones outside without mortar but later lime grouting and concrete backing on the inside for strength.




Method one seems to be harder for the novice as the stones have to fit better and individual stones are sitting on a mortar bed. The second method seems to rely on the inside concrete backing to hold the stones together and the outside gaps are filled with a more lime based mortar, which also breathes. The gaps between stones are large here.


Anyone with experience in this or the other way of construction?

« Last Edit: March 08, 2010, 04:11:08 PM by (unknown) »

Phil Timmons

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Re: Stone house - Concret , ,
« Reply #1 on: March 14, 2010, 12:31:43 PM »
That is some interesting thinking.  Stone outside, concrete poured and integrated from behind, if I understand your thinking?


Have pondered this for a ICF design, as well.  I guess you are familiar with ICF?  Sort of a sandwich of Styrofoam/concrete/Styrofoam.  Then I guess the stone would be another outer layer for good looks and durability?  But not really tied into the concrete, unless connecting re-bar were used.


Back towards your idea, I guess you have seen tilt-wall concrete walls?  When a stone outer finish is desired for them is to put small river stones in the "bottom," of the form, pour the concrete, and then stand up the wall section, and it has a stone finish on the outside.  Those walls are VERY tough and durable.  

« Last Edit: March 14, 2010, 12:31:43 PM by Phil Timmons »

domwild

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Re: Stone house - Concret , ,
« Reply #2 on: March 14, 2010, 05:32:06 PM »
Phil,


Thanks for that. I have never read of rebar being required to tie the stones to the concrete at the back. During pouring and pounding a bond is achieved. However, at corners rectangular rebar is required for strength.


I have built a small house with tilt-up concrete panels. The panels were 2.4 m high or about 8 foot and about two foot wide. Dry weight of 80 kg or 200 lbs, wet 100 kg or 250 lbs. Bolted together.


The books about slip-forming contain wall building ideas with styrofoam, concrete and stone mixes.

« Last Edit: March 14, 2010, 05:32:06 PM by domwild »

GaryGary

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Re: Stone house - Concrete backing...
« Reply #3 on: March 17, 2010, 07:46:17 PM »
Hi,

Have you looked at Doug's slip form wall article?

http://www.builditsolar.com/Projects/SolarHomes/Doug/SlipForm.htm


You might want to email him the same question.


Gary

« Last Edit: March 17, 2010, 07:46:17 PM by GaryGary »

Phil Timmons

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Re: Stone house - Concret , ,
« Reply #4 on: March 20, 2010, 09:52:56 AM »
The rebar (or other connecting / tie method) would be if you wanted to use ICF (insulated concrete form) e.g., http://www.icfhomes.com/  


That is not really slipform, but is very insulated for energy considerations.  Since the Styrofoam is not suitable as a final outside finish, one may wish to put a stone face on it.  So by layers from the outside inward:  Stone. Foam. Concrete. Foam. Inner Finish.  I was musing the stone should probably be tied to the concrete.  


The ICF options are very low energy use to heat and cool the house, as the concrete stays a very stable temperature between the layers of foam.


I think there are also some "light" admix concrete options with various foams or fillers in the concrete (which may reduce heat transfer).  Since residential walls would not carry a high load, you may want to look into that, as well.  

« Last Edit: March 20, 2010, 09:52:56 AM by Phil Timmons »

domwild

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Re: Stone house - Concrete backing...
« Reply #5 on: March 20, 2010, 05:27:01 PM »
Gary,


Thanks for link. Have contacted Doug with my questions. He has used the method I have described.


Regards,

« Last Edit: March 20, 2010, 05:27:01 PM by domwild »

Ronnn

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Re: Stone house - Concrete backing or not? Slipform
« Reply #6 on: April 10, 2010, 06:54:04 PM »
Stone and concrete are the worst kind of thermal mass you can have. They conduct heat and cold like it was going out of style. Sorry if you knew this. It's easy to remedy if you plan ahead. A straw bale wall of whole or half bales cut longways, on the inside or outside then plastered would be a possibility.

Ron

GaryGary

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Re: Stone house - Concrete backing or not? Slipform
« Reply #7 on: April 10, 2010, 10:42:01 PM »
Stone and concrete are the worst kind of thermal mass you can have. They conduct heat and cold like it was going out of style. Sorry if you knew this. It's easy to remedy if you plan ahead. A straw bale wall of whole or half bales cut longways, on the inside or outside then plastered would be a possibility.

Ron

Slipform walls are normally built with insulation on the outside -- usually rigid foam board.  This way the large mass of the concrete and stone acts as thermal mass for the house reducing temperature swings and acting as thermal mass for passive solar gains.  With the concrete and stone on the inside the thermal envelope the relatively high heat capacity and relatively high conductance are both advantages.

Gary

troy

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Re: Stone house - Concrete backing or not? Slipform
« Reply #8 on: April 25, 2010, 05:49:46 AM »
Internal thermal mass is almost universally a good thing.  The only time it's bad is when you walk into a cold house and want it to warm up fast.

If you live in a cold climate, or a hot climate, I wouldn't settle for less than r-30, and r-40 or 50 is not unreasonable.

Yes, you will have thick walls.

You knew that I expect.

troy

Boss

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Re: Stone house - Concrete backing or not? Slipform
« Reply #9 on: April 25, 2010, 07:53:16 AM »
I built a dual rock sided extension on my house, unfortunately a divorce removed me from the home before I could appreciate the qualities of having tons of rock on a east-south and west wall of a lower level on a two story home.  What I do recall was stone is freakin awesome.
We employed sandstone found on our property here in northern New Mexico.

Although it is interesting how y'all describe working with river rock, I would not have figured that out, I just thought it was impossible or at least  too hard for the effect.

Our family is super lucky obviously to own a couple hundred acres in the mountains, we have a large selection of rock, and a great variety is as important, as a great quantity.
We always hunted for rocks with at least two qualities, two flat edges, at right angles to the front. We chose sandstone because it holds up very well to weather and it is easily trimable with a hammer and coal chisel .
Limestone we have everywhere, but it is brittle and cracks when it gets wet and freezes, Granite is gorgeous, but we are at 7500 feet and  not very much is down here, plus it is literally too hard to work with.

I believe I invented the technique I employed for our double-sided rock wall system, probably not, but I never saw this done so I might as well have.
I like big rocks, which might account for my sciatica, but big rock cover great areas, quick, with hardly any mortar.

Like I said, find lots of rocks with at least one, preferably two right angles, and find a way to stand the rock up on the previous layer or foundation.
I can't think of anything more interesting than fitting rocks together like this. It is so primal, very satisfying.

It takes time, there is no rushing, which I didn't mind when I was young and strong, I had a few buddies helping collect rock, and yes a huge selection it what makes finding the proper rock for each instance work.

I was able on the lower rows to stand 200 pound moss-rock as they are called around here back to back, with a small space between them. After several rocks were in place I wadded newspaper into the spaces between the rocks, laid in any EMT (electrical conduit) and crap loads of rebar, then started mixing concrete with an old cement mixer.

On the lower layers it was easy to pour concrete from the wheelbarrow between the rocks,  the bits of newspaper worked surprisingly well at keeping the concrete in, and with moss-rock it is critical to keep the concrete off the lichen, or it will kill it, yes is a living wall, still is as far as I can tell, I drive past it every day, I never did get around to mortaring the rock, the technique with the newspaper worked well enough that there was really little need, sure there were a few cavities, and if I still lived there I would have done it. Life changes, what are ya gunna do?

In places where the rocks were not balanced well enough to stay in place while buckets of concrete were poured in, we tied the two sides together with metal bailing wire. We got that wall up to eight or nine feet high with this technique, and it sure is pretty, I don't miss the woman at all, the wall however is truly missed, every one ought to build one rock wall, just place it where it doesn't matter so much that it is a heat sink.

And lastly when moving wheelbarrows full of wet concrete to heights of eight feet, one learns how to build sturdy scaffolding out of very large timbers, with ramps wide enough to keep cherished  buddies safe and secure, after being a rock fitter is only one part of rock work

My next rock wall, if this sciatica goes away, will be behind glass, a green room on the south side of the house, then an interior rock wall, interspersed with more glass, so the sun can shine on the rock in the Winter, rock still has a place in the DIY builder's toolbox, sure it can be modernised,
for instance I thought about timber-frame with SIPS and rock facing
Anyway you do rock, have fun

Brian Rodgers
My sustainable lifestyle site http://outfitnm.com no ads, not selling anything either

domwild

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Re: Stone house - Concrete backing or not? Slipform
« Reply #10 on: May 02, 2010, 04:31:25 AM »
Boss,

Sorry to hear of the divorce, but on the other hand you love your wall much more than your wife! I also had this hard to pronounce sciatica. Bought a tractor for a plantation but decided to do the lifting myself (idiot!), after three days I could not even crawl to the toilet and the ambulance had to be called. Enough whinging!

Newspaper is a good idea which I have never read before despite reading all the articles on the net about slipform wall building.

The contributors from cold climates build stone houses with insulation on the outside and a rainfast material. The reason seems to be to stop the cold from entering  the brick work, where any water present would then freeze and crack the solid wall. Here in the SW of Western Australia, we only ever get 0 deg C (32F) rather rarely and are more worried about the heat entering. 

Round river stones would really allow the concrete or mortar to run to the outside as the gaps are larger.