http://iso-slab.com/en/index.html#tab-3
Looks like it would be an interesting way to form up a garage slab what are your thoughts.
Looks like it would be an interesting way to form up a garage slab what are your thoughts.
Thoughts on this foundation system
- Thread starter Tduby
- Start date
tjdux
Well-known member
Looks pretty cool. Im no enginer but it also looks a little weak compared to standard building practice.
I guess i would be constantly nervous my big buikding investment may fail due to that pad moving or sliding or freeze heaving.
Maybe in 50 years when that has been around a good long time but what a gamble. But if i was building tomarrow, im going with foundation concepts that are proven.
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I guess i would be constantly nervous my big buikding investment may fail due to that pad moving or sliding or freeze heaving.
Maybe in 50 years when that has been around a good long time but what a gamble. But if i was building tomarrow, im going with foundation concepts that are proven.
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GYPSY400
Well-known member
X2
My garage is built basically the same way as this but without all the pre- formed pieces.. and I have rebar in the thickened perimeter. It looks like it should work long term, but may or may not be cost effective depending on how much the kit would cost.
My neighbor just built this year using ICF around the outside and spray foam in the center ( which is code now ) when I built in 2013 spray foam wasn't code but 2" sheeting was.. the spray foam is a lot less labour and it looks like the cement would " grip" it better because the top surface is not totally smooth.
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jack stand
Well-known member
If your looking to avoid the cost's of building traditional 'frost wall', look into a frost protected shallow foundation.
http://www.finehomebuilding.com/2010/11/11/frost-protected-shallow-foundations-2
RobSmith
Banned
So the whole poured slab sits IN a styrofoam tub on uncompacted gravel ! That structure will rely on its own weight to stay put. good luck with that !
it is a similar system to using geofoam. the only benefits of a " floating" slab are isolating from poor soils conditions. ( bad compaction, etc )
in places where frost is an issue, you still need your base to be good bearing.
I understand the concept for brown field sites, other than that never made much sense to me.
in places where frost is an issue, you still need your base to be good bearing.
I understand the concept for brown field sites, other than that never made much sense to me.
For reference.
The following provides further technical detail over an ISO-SLAB 14" installation
A.
Natural soil without vegetation and leveled.
B.
6" of 3/4" gravel for drainage.
C.
ISO-SLAB 8" expanded rigid foam (R32).
D.
Concrete slab (12" perimeter and 6" center) with wire mesh.
E.
ISO-SLAB 14" module.
F.
ISO-SLAB insulation skirt for frost protection.
G.
Topsoil and turf.
The following provides further technical detail over an ISO-SLAB 14" installation
A.
Natural soil without vegetation and leveled.
B.
6" of 3/4" gravel for drainage.
C.
ISO-SLAB 8" expanded rigid foam (R32).
D.
Concrete slab (12" perimeter and 6" center) with wire mesh.
E.
ISO-SLAB 14" module.
F.
ISO-SLAB insulation skirt for frost protection.
G.
Topsoil and turf.
jack stand
Well-known member
Rob, I'm not sure if you have any cold regions in AU, but the OP is in an area where the frost can be 4' deep or more. Traditional methods with these frost conditions (for a slab on grade) are to excavate down below the local frost depths, pour a footing, then form & pour a wall on the footer up to slab level. This means 3 concrete pours, footer, walls, then the slab. This particular method look's like someone's idea to sell some custom formed foam parts that would eliminate some of the perimeter formwork other methods (like Gypsy & Thumper mentioned) would require. I don't really understand the 8" of foam in the "field".
The link does not really explain the "why" of it, wether it's a for a special soil condition like fill.
No where does it say uncompacted, I see a gravel base and standard construction practice would be to compact in lifts.
I can see this being a useful way to build, much like using ICF's.
If the cost of the styrofoam forms are close to the cost of styrofoam by itself then it would be a no brainer if you are building a frost protected salb.
No extra time tearing off forms.
That was my understanding hire one guy to clear site and provide a level compacted gravel base. The diy the rest. I like that by using this form system you know exactly how much concrete you need I would think with other methods could result in being off and when the concrete plant is far away being short or over could get expensive. I am sure this form system will be cost prohibitive.
Orionrising
Well-known member
more concrete is cheaper than foam... though I fail to understand why foam is so freakin expensive.
ex 2 foam board from the local box box when converted to cubs yards costs 150 per yard.
ex 2 foam board from the local box box when converted to cubs yards costs 150 per yard.
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n20junkie
Well-known member
I am of the mindset that a traditional foundation, with walls down below frost depth sitting on a footer is the way to go.
But thats just my opinion.
But thats just my opinion.
Orionrising
Well-known member
hmm by that diagram your walls are on a insulated footer that is also insulated from a true floating slab, rather then a monolithic type pour
matt_i
Well-known member
My guess is detail "E" is a pre-cast concrete piece set with a crane (etc).
As above the rest would appear to be frost protected-shallow foundation. Although the center insulation, 8" thick @ R-32 seems more serious than what I would expect.
As above the rest would appear to be frost protected-shallow foundation. Although the center insulation, 8" thick @ R-32 seems more serious than what I would expect.
That's true, the design with the insulated footer is an evolution of the OP's (I guess OP's diagram is based on a foam based L), it stops energy leakage from the radiant floor since the footer isn't a part of the floor.
Here is a heatmap of the two different designs:
