Agnes T-H Aug 7, 2011:

@Peter So constructibilité is "Am I legally allowed to build a house here"

Constructabilité is "Is it possible to build a house on this plot due to the nature of the land, where it is situated OR because the "COS" only allows me to build a hut"

Viabilité is "Are water supply and electricity available on the property or immediately outside the property OR it is the way a house already built makes it pleasant to live in (I.e someone on a wheel chair will think the viability (viabilité) is OK if they can have access to all the rooms with their wheel chair. If not they will say that the "viabilité" is not good) or it is the access to the plot that is being questionned (i.e immediately close to an avenue where you need to make an impossible U turn, etc...) or its situation (i.e close to a high traffic highway or an airport where the noise starts at 4AM waking up everybody in the house)"
Now it is your call..... (LOL)

Agnes T-H Aug 6, 2011:

Since it is construction related... Making a plot of land "constructible" means that the mayor & the city (parish) council decide to include one area in the group of plots of land where building is legal(instead of pasture only) ACCORDING to the zoning regulations.
Hence, a plot of land is "non constructible" OR "constructible" .
BUT in the later category the plot ratio applies (coefficient d'occupation des sols or COS) Which could go down to have technically the right to build... A garage! This could be a reason why the client not happy about the buildability of this plot of land. In this case you want to translate by constructAbilité in French or best"Coefficient d'occupation des sols (COS)".
I.e: "Dans une zone commerciale importante, un terrain de 5332m² avec 140m de facade et une constructabilité de 2200m²" ( COS= +/- 40%)

"Viabiliser" the same plot of land is different. It means bringing up to the limit of the property: water supply AND electricity &/or sewer system.

Now IF the text talks about a steep craggy plot of land where, due to the nature of the land, nothing can be built u want to use constructabilité

Peter LEGUIE (asker) Aug 6, 2011:

It is indeed strictly related to construction.

Agnes T-H Aug 6, 2011:

@Peter Hi,
Is this related to finance and banking? Because "viabilité" would probably be more commonly used in construction, building, housing, etc