Expert: Stephen Major (Owner--Major Design Group) - 7/31/2007

Question
I live in Winchester Virginia.  My home is 24x56 and is made from concrete block. I would like to install metal siding and metal roof. I know i need to fir out the block in order to attach the siding. But, i would really like to insulate it the best i can before adding the siding. I was thinking of using treated 2x4's for furring strips, with the thickest part of the 2x4 attached to the block, 16inchs on center and place foam sheet insulation between the 2x4's. then put plywood or other board over that, then place house wrap on top of that and then attach the metal siding.  do you have any suggestions? in order to produce the best possible job, what should i do? I plan on keeping the house for a long time.  

Answer
Alex,

This is a common retro-fit on block buildings.  An efficient way to do it is to install the PT 2x4s horizontally.  Start at the bottom and install a straight, level course (to a chalk line).  Then lay 1.5 inch, 24 inch wide extruded foam insulation (Dow board or similar), adhered with foam-compatible construction adhesive.  Atop this, install another course of 2x4s, and so on up the face of the building.  Wrap the assembly with Tyvek if you prefer, and then install the siding (assumed vertically).

I would use 2-1/2 inch powder-actuated fasteners with the appropriate loads, to secure the 2x4s.  Then I would go through afterward and install Tapcon screws every 4-5 feet or so, as extra insurance.

Best of luck with this and please let me know if you have additional questions.

--Steve Major