After reading this article, please see this:

Test Series 2: Introduction to Modelling Concrete Foundations with THERM
http://neuralnetwriter.cylo42.com/node/1810

I've spent a long time researching this topic, and hopefully you'll find that interesting

This is the typical design used in New Zealand for concrete foundations and slabs

It is common for there to be no insulation. The result is a cold floor, especially in winter.
The issue of thermal conduction through the concrete & ground is described here:

from this excellent website: www.design-navigator.co.nz

The thread with my conversation with Albrecht:

Options for edge insulation
http://www.design-navigator.co.nz/phpBB3/viewtopic.php?f=1&t=8

The cold air outside cools the ground. Both are in direct contact with the edge of the foundation/slab. The result is a significant heat loss from the concrete and a cold floor, leading to significant discomfort, and a feeling of being colder than if the floor was not cold.

This is the typical insulation solution offered here in New Zealand

This reduces heat loss to the ground below the slab, but it does nothing to solve the heat loss at the edge.

There appear to be very few solutions to this problem offered on the internet.
I found this one, which is the most interesting I have found:

from this excellent website: http://www.toolbase.org/Home-Building-Topics/Affordable-Construction/fro...

This has led me to create the following possible solutions:

1. Edge insulation extending above ground. This would require suitable protection which would be visible.

2. Edge insulation below ground. This would require suitable protection. This is achieved by lowering the brick veneer step.

3. Edge insulation below ground for higher floor levels in areas where flooding is a worry.

4. Edge insulation below ground with lightweight blocks creating a thermal break between foundations and brick veneer.

215mm of Thermalite shield with U=0.15W/mK, gives an R = 0.215m / 0.15W/mK = 1.43 m² °C/W.
This compares with XPS type V, where 25mm gives R = 0.88 m² °C/W.
Thus one course of lightweight blocks is = 41mm of XPS.

Lowering the brick veneer step in the foundations prevents the concrete being poured in two steps.
Instead three steps are required, as follows:

Step 1: Former inside and out, concrete poured up to top of outer former.

Step 2: A Higher outside former is added, and concrete poured to the top of the inner former.

Step 3: The inside former is removed, and insulation and stone is placed. Concrete is poured to the top of the outer former.

Can Extruded Polystyrene Support the Brick Veneer?

It will surprise many, including architects who I have read tend to underestimate the compressive strength of XPS.
My calculations:

Compressive strength of XPS re under bricks:
Bricks: 230mm long x 76mm high x 70mm wide, average mass 2kg
Max height = 9' = 4.25m
Assume 80mm courses -> 53 courses -> 53 x 2 kg = 106 kg.
Area of brick = .23m x 0.07m = 0.0161 m2
Pressure on insulation = 106 / 0.0161 = 6584 kg / m2
100psi = /2.2 -> 45.45 kg/in2.
1 in2 = 25.4mm x 25.4mm = 0.000645 m2
100psi = 45.45 / 0.000645 = 70,465 kg/m2

For those in the US:
230mm x 70mm = 9" x 2.76" = 24.8 in2
100psi x 24.8 in2 = 2480 lb
53 x 4.4 lb = 233 lb

So the answer is yes, the compressive strength of XPS type V is about 10x the weight of one storey of brick veneer.

5. The addition of a skirt. This would reduce the heat loss from the bottom of the foundations.

Interesting discussions

Subject: underslab insulation
http://www.greenbuildingtalk.com/Forums/tabid/53/forumid/14/postid/38934...

Options for edge insulation
http://www.design-navigator.co.nz/phpBB3/viewtopic.php?f=1&t=8

external wall thickness for slab R-value
http://www.design-navigator.co.nz/phpBB3/viewtopic.php?f=1&t=36

Insulated Concrete Slab Conundrum
http://www.ecobob.co.nz/Forum/ForumPosts/3190/Re-Insulated-Concrete-Slab...

Getting realistic temperature gradients and U-factors with THERM
http://www.passivehouse.org.nz/forum/viewtopic.php?id=138

=========================

I've just bought some glasses for my wife online, and saved quite a bit, and got great glasses.
I've written a detailed review. Just click this: