"John D'Errico" wrote in message
...
Our house has vertical, rough sawn cedar siding, and
an attached treated wooden deck. (We live in upstate
NY.)

The problem is the way they attached the deck to the
house. They nailed a treated header directly to the
cedar siding, then ran joists off the header to support
the 1x6 decking. Several times a year I am forced to
carefully clean out this joint with the house, to get
any junk and leafy detritus out. Otherwise It stays
wet and we get carpenter ant problems. I use an air
gun from my compressor to blow out the mess from the
cracks. This takes a fair amount of time, and almost
killed my 4 gallon compressor last time i did it
because the compressor is running almost full time
for over an hour.

I do have access under the deck, where there is
between 1-8 feet of clearance around the house. The
deck butts to the house for about 60 feet around
one side.

My thoughts are to:

1. Run a temporary support down to the ground under
the deck joists for about an 8-10 foot section.

2. Remove the section of deck board immediately
above this area.

3. Cut off (using my sawzall) the joists from the
header, exactly one inche from the existing header,
and making the cut parallel to the header. This
might take some care with a sawzall to do accurately.
(The joists do not butt to the header at a 90 degree
angle.)

4. Once the header is no longer connected to the
deck, pull this section of header from the house
wall.

5. Nail vertical pieces of Trex to the house, one
inch thick, by say 2 inches wide, at a spacing of
16 inches apart.

6. Slip a new header up between the Trex strips
and the joist ends. Nailing it to the Trex strips
and reattach the joist ends with joist hangers.

7. Replace the deck board in this section, cut
back to reveal a one inch gap between the deck
and the house.

Repeat steps 1-7 around the house until it is all
done.

I'd use Trex spacers to minimize the transmission
of moisture to the house in the future.

Any comments? Any better solutions?

Thanks,
John D'Errico
Facing similar challenge, where the deck boards had only a zero to 1/8 inch
space (bad) between siding and deck, I removed the first 2x6 board, ripped
off one inch the length of the boards, then crafted a z-flashing to fit
under siding seam, letting the lower two angles cover header and header
face, making a flared drip edge so the water drips away from the wood
itself. Used sheet metal shears to cut slots for joists to sit in, leaving
the cut tabs running out on the header a little ways, and folding 1/4 inch
over each side of joist, caulking and nailing tab to joist top. Jeez, I need
a diagram! I like the prior responders text effort but cannot quite suss out
the drawing....
Main thing when your finished is you have a broad, quick-dry slot, that is
easy to watch, and to clean with broom or hose.....