"Harry K" wrote in message
m...
(jacktripper) wrote in message
. com...
I have a home with a retaining wall about 8' from the back of the
house. The retaining wall is built with treated timbers and is about
4' high. I would like to build a deck on the second level of the
house, facing the retaining wall. How should I support the deck?

Is it better to set the posts (1) on the higher ground beyond the
retaining wall, (2) on the retaining wall itself, (3) on the lower
ground short of the retaining wall, and if so should it touch the
retaining wall (flush) or not?

Ideally, on the retaining wall or on the higher ground beyond the wall
would be best use of space, so please let me know if those options are
feasible, even if not the best plan. Thanks.

Just my opinion. If the wall has been there for several years with no
signs of movement, I would build on the wall itself. Of course you
have to consider local codes, nosy neighbors...etc.

Impossible to give a good answer without seeing the wall, and possibly
digging around to see what is under it, and how it is tied into the hill
behind. Simple retaining wall is unlikely to have footers deep enough for a
tall deck like that. If hillside slumps (like after heavy rains), or the
timbers rot out, outer edge of deck could easily collapse without warning.
Unless you built the wall yourself and know what is down there, probably
best to go behind it with conventional piling footers. In many areas, a deck
that tall requires a permit and an engineering drawing, since a collapse
could actually kill people (unlike a surface deck.)

Aside from noting that from your description, this proposed deck will make a
big dark damp hole out of much of your existing back yard downhill from the
retaining wall, I'd say you probably need to get professional assistance on
the design from a deck or landscaping company. Codes vary by area, as does
the substrata. Once you have a safe design, you can probably do most of the
grunt work yourself.

aem sends....