We have a slope in our back garden that we want to terrace. The rise
is a little over 8 ft, and the run is 20 feet. We're thinking 4
terraces, each about 5 feet wide, with walls about 3 ft to 3 ft 6.

First, what do you suggest to maintain overall stability? And how
about drainage? We get quite a bit of rain, but currently erosion is a
problem (hope terracing will help that!)

Second, do we need building permits to change the landscaping in our
own back yard? And if we don't get permits, what might happen??

Thanks! :-)

wrote:

We have a slope in our back garden that we want to terrace. The rise
is a little over 8 ft, and the run is 20 feet. We're thinking 4
terraces, each about 5 feet wide, with walls about 3 ft to 3 ft 6.

My math says 3 will do it.


First, what do you suggest to maintain overall stability?

I like these-
http://versa-lock.com/

My wall is about 3' high & 25' long- hasn't moved a hair in 5 NY
winters. It is serpentine & I think that adds to both appeal and
strength.

And how
about drainage? We get quite a bit of rain, but currently erosion is a
problem (hope terracing will help that!)

My wall started with a ditch twice the width of the wall & 8"(?) deep.
Tamp. . . tamp. . . tamp. . . lay the first course. Laid a 4"
flexible perf-pipe in a sock behind that-- and carried on to the next
course. Once the wall was done I backfilled with a bit of #2 stone
protected with landscape cloth. BTW- 1/2 of the first course is
below grade. The low side is a paver patio.


Second, do we need building permits to change the landscaping in our
own back yard? And if we don't get permits, what might happen??

That depends entirely on where you live- and who your neighbors are.
*Probably* you can do a 3' wall without a permit. [If it was me, and
I was confident of my ability to engineer the thing- I'd do a 3 foot
wall. Then another. . . ] OTOH- a call to the building dept. is
free and you might get some valuable insight.

What happens if you act without a necessary permit & get caught?
anything from make an apology and buy the permit- to tear it out and
pay a fine.

Jim

wrote:

We have a slope in our back garden that we want to terrace. The rise
is a little over 8 ft, and the run is 20 feet. We're thinking 4
terraces, each about 5 feet wide, with walls about 3 ft to 3 ft 6.

First, what do you suggest to maintain overall stability? And how
about drainage? We get quite a bit of rain, but currently erosion is a
problem (hope terracing will help that!)

Second, do we need building permits to change the landscaping in our
own back yard? And if we don't get permits, what might happen??

Thanks! :-)


I don't know the technical issues, just a few things from experience.
Our local codes address
changes in drainage, removal of trees, using rock for mulch, etc.
Whatever you plan, I would
run it by the building code office. You can probably find code online.

Is slope AWAY from the house? Will the drainage still be downslope as it
is now, or will it be diverted? That would be a major
concern. You don't want the water in a neighbor's yard. Does water
collect?

From work we had done on our seawall, and old problems with soil
washing out from behind the
wall, I would pay special attention to using weepholes, and using
landscape cloth behind the wall
to hold back soil when water drains. Tiebacks to hold wall in place
also something to think about.

We live on relatively flat ground, but have very heavy rains in summer
(Florida). Building design
is such that downspouts pour a huge amount of water out along the
building. We were able to
cure a lot of the erosion that had occurred from that with landscaping.
We planted stuff that
is dense and has tight roots - holds soil AND diffuses the flow. You
can also place stuff like
rock or timbers across the slope to slow down the water.

Thanks for your replies!!

My wall is about 3' high & 25' long- hasn't moved a hair in 5 NY
winters. * It is serpentine & I think that adds to both appeal and
strength.

Jim, that's good to know! I like the idea of serpentine walls too. I'm
concerned, though, that building one wall above another will create
additional issues over and above the construction of one wall--what do
you think?

Norminn, the slope is away from the house and will stay that way. we
have a flood plain easement on our land and in fact the neighbors'
gardens drain into that so, I don't think it will be a problem. Also
we're thinking of putting in a pipe from the lowest terrace to
encourage water down to that area. What sort of plants did you use to
control erosion? And how quickly do they establish a root system
sufficient to have some effect?

wrote:

Thanks for your replies!!



My wall is about 3' high & 25' long- hasn't moved a hair in 5 NY
winters. It is serpentine & I think that adds to both appeal and
strength.



Jim, that's good to know! I like the idea of serpentine walls too. I'm
concerned, though, that building one wall above another will create
additional issues over and above the construction of one wall--what do
you think?

Norminn, the slope is away from the house and will stay that way. we
have a flood plain easement on our land and in fact the neighbors'
gardens drain into that so, I don't think it will be a problem. Also
we're thinking of putting in a pipe from the lowest terrace to
encourage water down to that area. What sort of plants did you use to
control erosion? And how quickly do they establish a root system
sufficient to have some effect?



I'm in Florida.......one good one is liriope IIRC. It is pretty, tall,
dark green grassy stuff and
doesn't spread. I also used concrete edger with rock and landscape
cloth behind it - the edger
stops the water flow long enough for it to soak into the ground through
rock and l. cloth.

The space we had to work is very small, as downspouts are next to patio
and not far from hedges and walks. The hedges were dying because so
much soil had
washed away. Replaced soil. In some spots I used plastic trays that
plants come in,
doubled for strength, placed in ground and filled with rock. I don't
like those concrete
thingies for downspouts.

County extension service or a good nursery can surely give you tips
about landscaping
the area.

The condo next to ours is only about 10 years old and probably doesn't
have 10% of the
lot with permeable ground......huge concrete parking area and most of
the drainage off
the building goes into the lot and then into our yard. Didn't take note
of that until we had
seawall repairs and new erosion came right after repairs. Strange the
things you study
when hubby is the building manager )

Your terrace idea is probably fine, but plants can do a lot of work with
the right choices. The
grassy stuff we used, planted on a slope, would probably do a lot to
slow the flow and hold
the soil, as it is dense and has very strong, dense roots.

On Thu, 13 Mar 2008 04:09:06 -0700 (PDT),
wrote:

Thanks for your replies!!

My wall is about 3' high & 25' long- hasn't moved a hair in 5 NY
winters. * It is serpentine & I think that adds to both appeal and
strength.

Jim, that's good to know! I like the idea of serpentine walls too. I'm
concerned, though, that building one wall above another will create
additional issues over and above the construction of one wall--what do
you think?

In my part of the world- and in my yard- it wouldn't be a problem. I'd
be more concerned if I lived across the street on a big clay hill- or
in some place that gets a lot more rain than we do.

But that's where your local landscape guy, the building inspector, or
the nursery & county extension folks that Norminn mentioned might be
able to help.

Jim