Download this Stacked Stone Wall article as a pdf - Handyman Club ...

HARDSCAPING
By COnnie bastyr i Photos by tracY walsh
22
APRIL/MAY 2013

This stone retaining wall blends naturally
into the hillside and complements
the bungalow-style home beyond.
No matter how small your yard,
mowing a steep slope can be a
dreadful task. And if you’re a master
gardener (like the owner of this city
lot), you might enjoy grooming a series
of beds rather than maneuvering
a mower on a horrible hill. So when
landscaper Scott Reynolds of Creative
Habitats Inc. in Minnetonka, Minnesota,
transformed this sloping lot with
a series of beautiful stone walls, we
documented the process to show you
how it’s done.
Although building a dry-stacked
stone wall like this one is timeconsuming,
it does not require special
masonry skills, and it can be less
strenuous than working with manufactured
concrete blocks, which are
typically heavier than limestone.
Scott and his crew of two tamed this
bank (with the help of some power
equipment) in a little more than a
week. Though it might take a bit longer,
a handy DIYer can tackle this
project and create a timeless and enduring
structure.
HANDYMANCLUB.COM 23

tech art & design
Getting ready
In this dry-stacked wall, only the top
course is set in mortar; gravity holds
the other stones in place. The cut Chilton
stones vary in thickness and length
but are a uniform 8-in. width. Chilton
is a type of limestone from Wisconsin
that is available at most stone yards;
you could also use other types of locally
quarried limestone.
For any stone wall that is higher than
24 in., drain tile (surrounded by aggregate)
must be installed.
For inspiration, look at stone walls
in your area and check out stone suppliers’
displays to find types of rock
and designs that you like. This wall is
built in a basic running bond pattern
in which all of the stones in each row
are the same height, and the joints are
staggered (strengthening the wall).
Using a scale drawing and the dimensions
of the rise and span of the
hill (see “Design,” p. 26), Scott calculated
the wall’s surface area and ordered
20 percent more stone than
the plan required to allow
for waste. (He also included
the buried base layers
of walls in his calculations.)
Before you begin
designing your wall, Scott
recommends these preparatory
steps:
• Obtain a survey of your property
to be sure your project
fits within the boundaries.
• Dial 8-1-1 to have utilities
marked.
• Tell your neighbors about the project
beforehand; they’ll be more tolerant
of the mess or any inconvenience and
noise if they’re in on the plan.
• Check with your city regarding code
requirements, setbacks, etc., and
about street restrictions for deliveries
of stone and gravel.
•Determine a convenient staging area
for piling extra soil and supplies.
• Know your soil. Is it sand or clay?
• Collect all of the tools and gear you’ll
need before you begin (see “Tool for
the Project,” p. 28).
Laying groundwork
Cut stone is delivered in mixed
lengths and thicknesses (ranging
from about 2 in. to 3 in. thick), but
each course of the wall must be made
of stones of the same thickness. (Aesthetically
and structurally, it’s best to
use the thickest stones for the lower
courses.) To save installation time,
Scott sorts the stones into piles according
to their thickness in 1/4-in.
A
B
Add gravel backfill
as each course
of stone is completed.
This allows you
to completely and
easily fill any gaps
between the rocks
before the row is
covered by the next
course.
A power plate compactor is faster and
more effective than hand tamping, and
you can rent one from most home centers
and rental companies. They weigh nearly
200 pounds but move along easily when
running. Wear hearing and eye protection,
gloves and reinforced-toe boots.
A maul’s top end
is ideal for tamping
down the high
end of a stone or
for packing smaller
areas of gravel. The
tool’s weight and
long handle make
it easy to lift and
drop, and the flat
top works as a mini
plate compactor.
C
24
APRIL/MAY 2013

Digging in
When terracing a hill, always work
from the bottom up. The crew began
by digging a 12-in.-wide x 7-in.-deep
trench along the edge of the sidewalk,
being careful not to disturb the soil
below. They smoothed the base, making
sure it was level with the horizon
(which is typically not parallel with the
grade of the sidewalk).
The next step is to spread a 2-in. layincrements
before starting the project.
The maximum allowed height for a
dry-stacked stone wall is 4 ft. Because
this site’s walls are less than 24 in.
high, they do not require the installation
of drain tile. If they were higher
than 2 ft., they would have needed a
perforated drainpipe under the base
(see illustration, opposite), and the first
12 in. of stones would need to be 18 in.
wide front-to-back.
er of compactable three-quarter-clear
gravel, which is angular and contains
no crushed material. The angled surfaces
of the stones help to lock them
in place, preventing shifting, and the
absence of crushed material allows water
to drain more easily. (Scott says you
can use three-quarter-minus gravel for
this purpose but only if you have sandy,
good-draining soil.)
Pack the 2-in. layer using a power
Cutting stone
For most of the project, you can pick
through the stones to find a good fit,
but sometimes you need a custom
shape or size. You can use these
methods for cutting stone:
• Chisel and hammer (score and tap
along the score line with the chisel
several times)
• Maul (whack and hope to get lucky)
• Diamond-blade gas saw (rental)
• Hydraulic splitter
Get the free stone mobile app at
splitter
Some stones have visible grain lines that http:/ / gettag.mobi
To watch Scott
may indicate where they are likely to demonstrate how
to use a hydraulic
split, but in most cases your results will
stone splitter,
depend on luck. You (and any bystanders
or helpers) should always wear eye
scan this
tag or visit
HandymanClub.
and hearing protection when cutting or com/magazine.
breaking stone. — CB
D
For times when
a stone’s fit is
almost (but not
quite) perfect,
Scott’s crew keeps
a bucket of limestone
chips handy
to prop the gap.
These shims become
tightly affixed
under the
weight of the wall.
E
Stone shim
F
Stone shim
Each row of stones is stepped back (battered)
1/4 in. along the front faces. It’s a
subtle graduation, apparent only when
compared with a level. Battering adds significant
strength to a dry-stacked wall.
Put a stone sliver (shim) in any wedge-shape openings along the back sides; then fill
behind it with gravel. The shim prevents gravel from sneaking through the spaces.
HANDYMANCLUB.COM 25

G
To adhere capstones, mortar is applied along the rear half of the previous row, filling
voids and helping to lock the entire system and to protect the most vulnerable layer
from being disturbed.
Even though the
ends of the return
walls will be buried
in soil (and in
this case, abutted
to concrete steps),
they must have the
same gravel base
and backfill as the
face walls.
I
H
Lucky rock
Fieldstone boulders complement the natural-stone walls and add height and interest to the
planting areas. In some spots, the wall stone is shaped to wrap around the boulder (inset).
J
Wide gaps between
the patio
flagstones allow
for future planting
of moss or
ground cover:
The homeowner
can simply remove
pockets
of the crushedgranite
sand and
add planting soil.
plate compacter (photo A, p. 24), the top
of a maul or a tamper. Add another 2 in.
of gravel and pack again, continuing until
you have a smooth, level 4-in.-thick
base. (The remaining 3 in. of trench
depth allows the first course of stone to
be below grade.)
Regardless of their finished height,
stone walls require an 8- to 10-in.-wide
layer of gravel behind them (photo B).
This site has clay soil, which is prone
to hydrostatic pressure and can cause
any retaining wall to bulge and heave,
so Scott used three-quarter-clear gravel
(not three-quarter-minus) behind the
wall as well to allow rain and melting
snow to drain.
DESIGN
“I always look at the house for patterns
to mimic in the landscape.
It’s important to consider the entire
composition.”
– Scott Reynolds, Creative Habitats
Scott incorporated arcs in the shape
of the wall partially to give the
natural-stone structure an organic,
flowing design, but also to reflect
curves featured in the entrance area
of the house. He used a 5-ft.-radius
cutout for the patio area. (The center
is about 18 in. from the sidewalk’s
edge.) The same radius was repeated
in the two curved walls on the upper
level. Although the patio side of
the design is different from the wall
on the opposite side of the steps, an
overall balance is achieved through
the careful placement of shrubs and
plantings. — CB
26
APRIL/MAY 2013

Tools
for the
project
In addition to shovels and levels, these are some essential
hand tools for this type of project. Although
none are motorized, most of them call for hearing
protection, and all require protective eyewear.
Hand
guard
Pick (pick mattock)
This tool combines an ax
head and a pick for chopping
away at hard soil,
roots and rocks before you
shovel the soil out.
Sledgehammer
Its long handle and 10- to
20-pound weight deliver
great force for packing soil
or gravel or pounding down
a high spot in a stone.
Mason’s hammer
Also called a bricklayer’s
hammer, this tool’s flat
face and chisel-shape
blade help to chip off
edges of a stone.
Wrecking bar
It works as a lever to loosen
and lift large boulders
or adjust heavy stones, or
you can use it as a pick to
loosen hard soil.
Mason’s chisel
To score a cut line in
stone, tap the top of a
mason’s chisel with a hammer;
then deliver a heavy
blow to split the stone.
Setting stone
As with any wall construction, the base
course sets the stage for the rest of the
project. For this first layer, you can use
stones that have odd shapes or different
thicknesses, as long as the top surfaces
are all even and level. Just pound
down any high spots using the top end
of a maul (photo C, p. 24). Check for
level front-to-back and side-to-side. (If
you can’t get it perfect, err on the side
of a slightly higher front edge than
back.) Make each course level before
you start the next layer — don’t plan to
compensate for height differences later.
As you install each stone, flip and turn
it until you have a solid fit. You might
need to try a different one for compatibility
with neighboring stones and with
the base. Set the front face of each new
row 1/4 in. back from the previous row
(photo D, p. 25).
Natural stones’ irregular shapes
sometimes make a slight “rocking”
movement unavoidable. You can compensate
by shimming with a stone chip
(called chinking) under the offending
rock (photo E). Where needed, you can
knock off protruding edges of stones
with a maul. Try to avoid leaving gaps
between neighboring stones, but where
they occur, fill vertical spaces with a
stone chip and gravel (photo F).
Use various sizes of levels to check
each stone as you install it, adjusting for
level front-to-back and side-to-side. Continue
to backfill with gravel as you add
each new course. Scott did not install
landscape fabric because it tends to prevent
drainage and to build hydrostatic Adding outcroppings
pressure — especially in clay soil. If your To help support mounds of soil and
soil is very sandy, you can add landscape plants within each tier, Scott placed
fabric between the gravel backfill and the small boulders as outcroppings within
soil behind it. Do not lay fabric directly the tiers (photo I). Strategically set to
against the back of the wall.
support the greatest elevation changes,
For the top course (called capstones), these rocks are partially submerged in
Scott used the thinner (2-in.) stones, the soil to help them stay in position.
being careful to fit the shapes together (One of these boulders was a lucky find:
well (see “Cutting Stone,” p. 25). Once When excavating the patio area, Scott
the entire top course was in place, he discovered a large rock buried right in
folded back the row of capstones and the spot where he had planned for one!)
applied mortar (photo G, p. 26) before A small patio created along the sidewalk
(photo J) provides room for potted
pressing them in place. To prevent
soil from seeping past the top layer of plants or a small sitting area. The flagstone
floor was laid over a 1-in.-thick
stone, you can pack mortar along the
back of the capstone row as well. ) base of compacted granite sand which,
To allow room for a layer of soil and like the gravel used for base in the walls,
plants, stop adding gravel backfill when is angular rather than rounded so it
you’re 5 in. shy of the top of the wall. You locks together and stays in place. Once
may choose to place landscape fabric on the 1-1/2- to 2-in.-thick flagstones were
top of the gravel before adding the soil. in place, gaps between them were filled
with more granite sand.
Building up
The upper walls are constructed like
the first: Dig a trench, pack in a 4-in.-
thick gravel base and install level
courses of stone with 8 to 10 in. of
gravel backfill behind. Dig the trench
deep enough that the top of the base
course is level with (or slightly lower
than) the capstone of the lower wall.
The return walls (the sections that Get the free Proper mobile app at
Planting
run alongside the steps and into the hill) http:/ / gettag.mobi
To see a planting
need to extend into the soil at least 6 in.
secret from
master gardener
beyond their exposed portions (photo H).
Amy Sitze, scan
The hidden portions must also be supported
with packed gravel and a course
com/magazine.
this tag to or visit
HandymanClub.
of base stone.
28
APRIL/MAY 2013