Deck Set on Retaining Wall
 

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.

Deck Set on Retaining Wall
 

Deck Set on Retaining Wall
 

"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....

Deck Set on Retaining Wall
 

On Tue, 20 Jul 2004 03:19:04 GMT, someone wrote:

.... a deck
that tall requires a permit and an engineering drawing, since a collapse
could actually kill people

??? Has the sky fallen yet today, the wall is only 4 feet high,
doesn't seem like a big deal, and the span would only be 8 feet.

I would NOT support the wall on piers behind the wall, because that
soil in turn relies on the wall for support. If you are not confident
in your wall, then you should not rely on posts set in the soil held
up by the wall.

I vote for the wall itself. Next for the soil in front of the wall,
but that requires posts at least as high as the wall so what's the
advantage.

-v.

Deck Set on Retaining Wall
 

"127.0.0.1" wrote in message
...
On Wed, 21 Jul 2004 19:03:00 GMT, (v) wrote:

On Tue, 20 Jul 2004 03:19:04 GMT, someone wrote:

.... a deck
that tall requires a permit and an engineering drawing, since a collapse
could actually kill people

??? Has the sky fallen yet today, the wall is only 4 feet high,
doesn't seem like a big deal, and the span would only be 8 feet.

in many places a 4 foot high structure requires a building permit

OP said deck was to attach to second floor, which implies 8-10 feet below
deck surface to fall. IOW, a 4-foot deck covering a 4-foot pit.

Yes, these do collapse and kill people. I've visited people with decks
bouncy enought to scare me, and had to take them by the hand and show them
what was failing underneath, or underengineered. They didn't grasp it was a
danger, even though it was bouncy with 3-5 people. 30 people at a party
would be risking a lawsuit, and maybe dead friends.

aem sends....

Deck Set on Retaining Wall
 

On Wed, 21 Jul 2004 15:21:26 -0400, someone wrote:

in many places a 4 foot high structure requires a building permit

In many places a structure 1 foot or 1 inch high requires a permit
(i.e. there is NO height threshold for a "structure"). But that
doesn't mean there is a likelihood of death. A remote possibility,
sure, hey kids drown in 5 gallon pails. It wasn't the permit part
that annoyed me, it was the "death" part. You could just as well say
"don't try to cross the street without a police escort, because it
could result in death."

-v.