Well,
I have completed the Roxul insulation on my 'not-so-super-insulated'
house and thought that I would share my experience of doing so.
My 9
foot tall wall construction is, from outside to inside:
Fraser
Evolution Series horizontal '1x6 bevel with ship-lap' wood siding
(http://www.fraserwoodsiding.com/en/...ood-siding)
1
x4 vertical strapping
Tyvec
2”
Roxul Comfortboard IS (R-8) (
http://www.roxul.com/products/build...tboard+cis
)
7/16
OSB
2
x 6 at 16” OC
5
1/2” Roxul ComfortBatt (R-22) (
http://www.roxul.com/products/build...omfortbatt
)
6
mil Vapor Barrier
1
x 4 horizontal strapping
1/2” sheet rock
Installing
the 2” Roxul Comfortboard IS:
Around
the perimeter of the walls, at the top & bottom, I attached 2x4's
(ripped to 2 inches) to provide a strong nailing surface for the 1x4
strapping.
Around
each of the two doorways, I attached 2x4's (on the flat) and added
1/2 inch OSB to bring them out to 2 inches in thickness.
I
'tacked' the 2 foot by 4 foot Comfortboard
panels to the OSB, in a
'brick' pattern, using 3” plastic
cap, ring shanked nails
(example:
http://www.carsonsales.com/nails/pl...ring-shank
)
Although you can use a bread knife with a serrated blade to easily cut the
ComfortBoard, I found that using my table saw did a much better job
giving straight, precise cuts which allowed me to re-use the cut-off
pieces elsewhere in the wall, reducing the overall waste.
After
the Tyvec was installed, I attached the 1x4 vertical strapping with
5” screws, doing my best to hit the 2x6 studs.
This
was the part that I found difficult because the ComfortBoard will
compress under the strapping if the screws were driven too deeply –
this could cause an uneven base for the siding. (read: ugly, wavy
siding) A carpenter provided the solution:
Over
drive the screws and then 'back them off' so that a 'straight-edge'
held against each 1x4 strap was perfect from top to bottom. He
fashioned a straight-edge from a perfectly straight 10 foot 2x4. He
drove a 4” nail at one end which was used to hook the straight-edge
to the top plate. This system proved to be 'the way to go' –
simple, accurate & fast.
I
strapped all the inner & outer corners with 3/4” x 8” plywood
to provide sufficient nailing surface for the siding & the siding
corner trim.
Now,
I will explain the mistake that I made. I used the 1x4 strapping to
'frame' the rough-openings, over the ComfortBoard, around all my
windows – I should have framed them with 8” x 3/4” plywood. In
my case, the 1x4 strapping did not provide sufficient nailing surface
to attach the window trim and the siding! I had to add additional
1x4's around each opening – stupid mistake, especially since 'Bob',
on this forum, recommend doing so. I simply forgot.
Installing
the 5 1/2” ComfortBatts:
This
was a breeze! The ComfortBatts easily, and very snuggly, fit between
the 16” OC studs. Each batt is 15” wide by 47” long, but the
cavity in my walls is 103”, due to the 9 foot ceilings. This meant
that each cavity required 2 batts plus 9”. In actual practice, due
to fitting the batts snuggly, I used 2 complete batts plus 10.5”.
Some
of my studs were not 16” OC. When I had to cut a batt to the proper
width, I used my table-saw 100% of the time. (I had to pass it through twice Again, this gave me
straight cuts which allowed me to use the cut-offs easily. For
'length' cuts, I used the bread knife 100% of the time.
For
any cuts that I made, I added about 1/2” to my exact measurements
to allow for a tight fit. When the width of the cavity was less that
about 8”, I added only 1/4” to my measurement so that I would not
'over-compress' the batt when installing it.
I
have got to say that using this insulation was very easy and very
rewarding. It completely filled each cavity and did so, very, very
snuggly. If I inadvertently 'over-compressed' a batt when installing
it, I simply inserted the thin blade of my bread knife between the
stud and the batt, compressed the batt inward and drew the batt out
to the edge of the stud.
It
took me about 2 days to place the ComfortBatts – 2 “Rob” days.
I am not a very fast worker. I placed all the full batts that I could
first, then I did all the pieces that were full width but needed to
be cut to the proper length. Next I did all the full length batts
that needed to be cut to the proper width and, finally, filled in the
areas that needed to cut in both width and length. This way I was
able to reduce waste. My 'mutinous crew' said this wasn't a very
efficient way to do it and suggested that I start at one end of a
wall and work around the perimeter of the house. I ignored them, yet
once again.
The
perimeter of the walls is about 160' and it took 18.5 bags of Roxul,
or, 148 batts. I had all the window & door headers spray foamed
as well as a couple of places where the studs were less that 4”
apart.
The
cost of the Roxul was:
2”
Roxul Comfortboard IS (R-8): 33 packages @ 45.00 = $1485.00
5
1/2” Roxul ComfortBatt (R-22): 19 packages @ 36.20 = $687.80
Rob.