I was thinking that if I pruned a fig tree into a fan shape and plant it against my house, would it be more cold hardy? Since the house will give off heat and it will give wind protection I have 2 Marsellies Black VS and I was thinking about doing that too one of them. Do you think this a good idea. I want to do it like this
***********************not my picture

http://figs4funforum.websitetoolbox.com/post/espalier-figs-in-high-density-planting-6727497 There was also another post recently re espallier but I can't find it right now. ...and yes it does work, makes sense and looks good if done right.

If you did this I would plant the tree on the south side of the house so the tree gets the warmth of the sun and is protected from the north wind.  This would create an excellent micro climate.

Sounds like a promising training system for figs but I wonder of the old adage. 
"Figs are in love with stones and cisterns" in Italian it sounds better.

Point is that fig roots have an uncanny instinct to search out water and can be a problem if planted too close to a house.

I would love to try this myself but is it safe to my foundation or should I do this along a high fence.
 

http://www.readsnursery.co.uk/fig-trees-for-gardens-and-greenhouses/

What could I use to block the roots from going into my foundation? I really want to this idea and grapht many cuttings onto this tree

Could I use a piece of tarp? or hard plastic?

Ekierk,
Planting a tree in a "Micro Climate" doesn't make it more Cold Hardy, It just creates a warmer area around the tree. A large fan shape may expose the higher branches to the winter cold, which could cause dieback if left exposed especially in colder zones.

There has been some documented info on the forum of trees being planted next to foundations without causing damage. Several large trees that I have found growing in NYC are planted next to foundations and have also not caused any damage, but I have had no personal experiences. Good Luck.

Italian Honey NL Growing against a South Facing wall Bronx, NYC

I could be mistaken but common figs don't have the rock breaking roots that other species of figs have, but again I could be wrong.  I have seen pictures of figs being grown like your picture in france next to houses etc.  It would be wise to have it on either south or north side of the building so it can get all day sun.  South could make it prone to south west injury in the winter and north could block some sun in the fall.

        I have limited ideal space in my yard. I have a 2 story wall facing south, where my vegetable garden is so I have to plant the fig tree flat against the wall so it doesn't effect the sunlight to my vegetables.
        Then the rest of my yard is too shady or is facing north. I was thinking of planted the fig tree as a fan shape so I could graft many varieties onto it so I can have 1 large fig tree instead of a lot of small ones.  
    OR I was thinking about do in espalier and making each branch a new variety.

I would think it is a roll of the dice. Meaning, if you already have cracks in the foundation anywhere the roots can get to, then they will search like roots do and enter the cracks. Eventually making the cracks worse. If you have no cracks, the roots cannot split concrete on their own. Unless you have the wall bare in the basement where you plan to plant, you can never know.

Depending on how cold your winters are you might still have to cover it with a blanket and a tarp for some insulation

I'm in zone 6a, with the micro climate behind my house I think it would be zone 6b/7a. I plan on having Marsellies Black VS or Florea in the ground, grow it into a fan shape and then graph hardy cultivars onto it.