Over the years we built a few new walls
and repaired some existing walls. I've also attended a half dozen
clinics hosted by companies like Techo-Bloc (thanks Paver Pete!) on
proper wall construction techniques, right down to what type of
gravel to use for the base.
When dealing with the heavy clay
soils prevalent in our part of western Pennsylvania, along with our
typical freeze-thaw cycle that makes soil move, proper construction
techniques are critical for any sort of long term success.
Walls tend to fail.
The force is against them!
Three basic keys for success with
a timber wall include:
1. A good compacted gravel base below the 1st course of timbers.
2. Good drainage behind the wall, including gravel behind the wall
and a perforated drainage pipe behind the lowest course of exposed
3. Deadmen (or tiebacks) to strengthen a timber wall (prevent
'tip-over' like you see in the photo below)
We recently spotted a rapidly failing
timber wall not more than a few years old. Reasons for failure? The
most obvious was no 'deadmen' (tieback timbers
extending back into the soil bank being retained). It also appears no
gravel drainage was used behind this wall.
It's obvious deadmen DO tell
tales, very sad ones indeed!