New construction or older house? Soffet and high vents?

 

Has soffet and 4 square vents on the back side 1915 home

 

So it is not a vapour barrier like you might think, but on a house that age most walls are open from the crawl space or basement to the attic which is a fire hazard and the should be blocked.
All hole from the house to the attic should be blocked off plumbing pipes, vent ducts, light fixtures, chimney.
and an attic hatch that will seal. You want to stop any air from the house from getting to the attic.
Any Knob and Tube wiring that needs to be changed out should be done before insulation.

 

So it is not a vapor barrier like you might think, but on a house that age most walls are open from the crawl space or basement to the attic which is a fire hazard and the should be blocked.
All hole from the house to the attic should be blocked off plumbing pipes, vent ducts, light fixtures, chimney.
and an attic hatch that will seal. You want to stop any air from the house from getting to the attic.
Any Knob and Tube wiring that needs to be changed out should be done before insulation.

Hi yes it is balloon framed but the 2nd and 3rd floor was gutted to the studs and r13 insulation installed. All know and tube is removed. The only thing I didnt insulate was the attic (4ft tall). I want to spray fiberglass in but want to know if I need to add a vapor barrier since the blueboard is about 13 years old with plaster , latex paint and I was hoping that would be enough of a vapor barrier

 

Spray away, remember everything is harder to work on after the insulation goes in.

 

Basically, no you do not need a vapor barrier where you are. Far north and deep south, but all of us in the middle do not need one.
But here is some related reading: BSI-073: Macbeth Does Vapor Barriers (Double, Double Toil and Trouble)*

Been awhile since I read that link top to bottom so if you have questions let me know and i will review.
Bud

 

Insulation Upgrades - Massachusetts Home Inspections

The most important rule is that you want to fully insulate any surface that divides inside (conditioned) living areas from outside (unconditioned) spaces.

homeinspectionmassachusetts.com