The attic - with its cathedral ceilings

So this is what the attic looks like these days.  It will have 2 bedrooms (one on either end),  a 2-piece bathroom, 2 closets and a study/lounge area.  One of our trades thinks this will be the best space in the house --like a little retreat in the trees.

This is the lounge area to the left with our middle daughter's room in the back.

This will be the small 2- piece bathroom with a skylight over the sink.  We could only do so much with this space because of the sloping ceiling.

This is our middle daughter's room -- an addition on top of an existing flat roof.  The ceilings are much higher in this room (compared with the rest of the attic) because the house is wider in the back than it is in the front.  So we built this addition with a roof that spans the back of the house so that it wouldn't look cock-eyed from the outside.  There is a little jog in the roof-line, right in the middle, that will be filled with cedar shakes to match the gable ends of the roof.  Our engineer came up with this design and it has worked really well.

The only downside is that our oldest daughter's room in the front of the house has much less grand ceilings (we like to try and keep things even).

So we pushed her knee walls back to 2 feet.   This will give her at least a bit more floor space to try and compensate for the lack of ceiling height.  And I guess we'll have to get her some low furniture! 

A big problem we're facing with the attic is insulating the cathedral ceilings.  Attic insulation is extremely important to making the house energy efficient, since heat rises.  In fact, the building code wants us to put in a minimum of R-32 in the attic ceilings -- my dad and I would like to see R-40+ which is recommended by Eco-Energy Canada.  We have two choices to achieve this kind of  R-value.  We either double up the size of the ceiling joists (which would drastically reduce the already low ceiling height) and use either Roxul or Ultratouch, or we use spray foam insulation. 

I was not happy to hear this, since I am not altogether comfortable using spray foam because of offgassing, its permanence, and the toxic gas it emits when on fire.  But we are in a really tough spot with the attic, so we have decided to go ahead and foam the cathedral ceiling.  One small bonus of spray foaming this area is that we don't have to vent the roof.  But I will put up a strong and tight vapour barrier to prevent as much offgassing from entering the living space as possible.