Expert: Ted Barnhill (Principal, Design45 LLC) - 12/5/2009

Question
I live 1 1/2 hours north of New York City. A contractor did a renovation of my home. He removed the old siding, insulation board and original cedar siding. The contractor than put up Tyvac paper and than the vinyl siding. I questioned about he needed to use insulation board and the contractor said "no" that is not necessary since the house is insulated inside. Should he have used insulation board on the exterior? Should I redo the siding?

Answer
Sue,

I'm sorry to hear of your trouble with your siding contractor.  In these times of climbing energy costs and increasing awareness of environmental issues, it's unfortunate to hear of a contractor making your home less energy efficient.  Not only did removing cedar siding and insulation board remove some of your walls' insulation, this insulation had the beneficial effect of eliminating "thermal bridges," that is, cold spots at studs and insulation gaps.  Without opening your wall up it is difficult to know what insulation is inside your walls (in the cavities between studs); if you have original pre-1950s insulation in a 2x4 wall, it has likely settled and is not very effective by modern standards, and you would probably more than recoup the cost of better insulating your home.  If you have newer insulation in a 2x6 wall, it's possible that your home still has decent insulation despite the removal of the insulation board.

I suggest you ask the contractor to explain his determination that your home has "enough" insulation.  What kind of insulation did he find, at what thickness, and what total R-value?  Whether it is worthwhile to remove siding and add insulation depends on these answers.  In some areas, there are programs that provide an "energy audit" of your home with tips to increase effciency; this would be a great help in your situation.  These might be run through your power utility, local government, or an independent nonprofit.

Best of luck,

Ted Barnhill
Design 45, LLC