Week 28 – Service Cavities

December 7-13, 2015

The sheathing (OSB) on this house is on the inside and forms the air tight barrier and the vapour barrier.  All the seams are taped which makes the house super air tight.  Unfortunately, I haven’t done a blower door test on the house yet because I haven’t been able to find one locally.  However, to meet the passive house standard, the house must have an air tightness of 0.6 ach (Air Changes per Hour).  A typical new construction home would leak about 3-4 ach.  So since this house is super air tight, the last thing you want to do is start drilling holes everywhere for the electrical and plumbing.  So in this type of house, you build a “service cavity” on all the outside walls.  I used 2″x4″ lumber for this cavity to allow room for standard electrical boxes.  Originally, I was going to use 2″x2″ ‘s for this purpose, but this would require shallow electrical boxes which don’t allow enough wires in them to wire multiple outlets/switches etc. together).  Also, trying to pass water lines and electrical cable through a 2″x2″ would be difficult.

Anyway, the electrical and plumbing all passes through this cavity leaving the air tight barrier untouched.  The really not fun part was creating the service cavity on the ceiling.  I think Pete needed a trip to the chiropractor after screwing ~200 2″X4″ ‘s to the ceiling.  His head now seems to be bent at an unnatural angle permanently looking upward.  Oh well, he likes to watch airplanes flying overhead anyway 😉

Sadly, this is my Dad’s last week here until spring.  He and my Mom are leaving for Arizona in a few weeks.  When he left, he told me to throw out his workboots.  Hmmm, I’m thinking I might have worked him too hard!  Anyway, Pete and I will have to keep going on our own.  It has been great spending so much time with my Dad.  For the last 12 years, I have lived about 600 km away from my parents, so this has been really nice.  He is an unbelievably hard worker and very smart.  It was great to be able to pick his brain when we were stuck on something (which was often).  You are the best, Dad!  I love you.  Thanks for all your help.  We couldn’t have done it without you.

Dad and Pete building the ceiling service cavity.

Dad and Pete building the ceiling service cavity.

Exterior wall service cavity.

Exterior wall service cavity.

Me working on the front wall service cavity.

Me working on the front wall service cavity.

Pete, Dad and I.  Another day done!

Pete, Dad and I. Another day done!