Patios and pathways, driveways, outdoor ‘living rooms’ , retaining walls, stairs steps and landings –
its all HARD scape
the flat part underneath your shoes,
the vertical thing holding back the hillside,
the big stylish boulder
all HARD, not SOFT (like most plants…)
for this essay, we will focus on gravels n rocks and pebbles,
save wood and chips for another day
Lets go
First you gotta be able to identify concrete, stone, and brick
and tell em apart
well concrete is a more or less uniform industrial product
made of cement, gravel & sand ( together called aggregate), air and water
looks like this, kinda crumbly gritty evenly holey
sometimes though they do a real nice job finishing the concrete
troweling and floating the cement to the surface, buffing it sanding it down what have ya
work it good and long with a vibrator to get all the air out
and it ends up like this, super smooth and polished stone like, almost
its still concrete, just a bit pricier cause it got special treatment
you like wowwwwww
yeah me too
it gets trickier
in the old times concrete was just gray, boring gray
easy to identify
I mean, theres literally sidewalks and buildings and bridges full of the stuff
nowadays they color it, or stamp it to look like stone, texture it, make it in different shapes
and make em into pavers that look like bricks
sometimes they even call em brick pavers even though they are concrete but in the shape and size of a brick
heres some of those examples of concrete that can confuse you if you dont pay attention to the details
here is stamped and colored concrete, yes concrete!
Tell tale is to check the joints and their depth…
heres pavers – not brick or stone, concrete!!!
Alright enough of concrete for now
move on to stones and rocks
rocks in general are more expensive
its usually dynamited out of a mountain quarry then cut and transported for use
sedimentary rock is usually softer and got layers, real distinctive
sandstone, limestone like that fancy italian travertine, bluestone, brownstone, all sedimentary
got lines like eons of dead shells, dust and clay all settled out
This one here’s trade name is antique black, it is also a sedimentary rock
thats the bottom you are looking at, grooved for easy mortaring or gluing and sticking:
One more really red really pretty sedimentary rock:
Theres a few metamorphic rocks to get to know too
maybe you are not a rock hound or interested in any of this geology earth minerals stuff
and it dont make no difference to you if its sedimentary or metamorphic or igneous
but when you are cutting or installing that stone, hardness matters to the saw and the operator
as does how the stone might crumble or break or flake apart and such
slate is one such metamorphic rock also used in mostly old times for roofing tiles
nice color:
Dont worry too much bout the term flagstone
its one of those generic catch all words for a bunch of different kinds of layery rock used for landscaping
Last but not least you got igneous rocks, cool rocks from lava and magma and volcanoes
in landscaping we see mostly granite, basalt, and lava rock
granite we see sometimes as like cobbles or boulders,
its super easy to know cause of the white and black speckles, plus its super hard
meaning if your metal blade is dull and you dont have your file or sharpening stone
you can get a decent edge on that bevel just running it back and forth on the rough granite
you probably care about this one too if you are one of those sticky shoe wearing
rope hauling belaying rock climbers
here it is:
and where you park the cars on the curb there it is again:
we will get back to basalt and lava rock later when we discuss smaller sized rocks and pebbly things
With stones and selection, you can go geometric squares and rectangles almost like tiles, or go au naturel with uneven asymmetrical shapes in the garden
the clean boxy look:
Or the more messy natural look: (thats the one I prefer)
Heres a lil detail that’ll make you seem like a seasoned pro
take a look at how the stones are cut
makes a difference in price and ‘clean edgieness’
not sure it really makes a difference once its sitting on the ground covered on the edges with gravel and plants but
some people with really sharp eyes notice and care about these things
the roughest cut, kinda hand chiselly, is this one called ‘rockface’ cut:
next up is ‘snap cut’, kinda like how you’d cut foam board for a school project, or cut tile with of those manual cutters
not quite as rough, but not super fine either:
Then its the ‘saw cut’, well, cut with you know what:
After the cutting, some stone is ‘tumbled’ to get that nice soft rounded edge:
Another thing that matters quite a bit in stone selection is the thickness of the stone
it comes thin, medium, and thick
from about 1/2″ – 3/4″ or so to 2-3 inches
thin:
medium:
thick:
from a clients angle
you thinking
whats cheaper?
whats more durable? whats not gonna snap and break?
will it be even and level enough to set a table atop it,
and have a dinner party outdoors with lights and dancing
from a contractor angle
you thinking
what base am I gonna lay this stone on top of?
compacted rock and sand, or a concrete slab?
am I gonna be able to lift the really heavy pieces through the house without breaking em
(cause some san francisco houses have no side gate or easy backyard access)
do we need to rent a crane?
can I make more money on the thicker or thinner stone?
and so on
Other stone considerations might be:
is algae and moss gonna grow on the stone?
is it going to be slippery when wet?
is it easy to clean and scrub?
Thats all for now for stone, onto bricks
bricks are made of clay that has been fired in a kiln
its one of those very ancient materials with a classic lineage that is warm and comforting on the eyes
i love bricks, they remind me of hearths and pug mills and gas kilns and happy country places:
it is not so good in our earthquake prone area for tall buildings
but its fine for short walls, fences, patios and all that good stuff
theres a lot of different kinds of bricks
baked and fired from different kinds of clays with varying amounts of iron, silica, and so on
I remember falling in love with a clay called black mountain, real dark bodied clay
bricks got a lotta variety from a kinda rustic old timey feel to very crisp sharp edges and solid colors
typical standard brick size is 8″ x 4″ length by width, 2.25″ high
actual dimensions closer to 7.625″ x 3.625″ length by width, 2.25″ high
in the landscape, well installed, they look like this,
this example is a “basket weave” pattern, two up down, two sideways on down across the patio:
This pattern is called “herringbone”:
Stylish eh
so far we’ve mentioned concrete, stone, and brick,
they are the kinda larger building blocks for a garden hardscape project
how about the little pebbles and gravels and sands?
they are important too
for a few reasons
one is as a mulch or top dressing, to cover up the earth
so no or fewer weeds grow, or cause you like the desert dry ‘look’
something like this:
or this one:
Or maybe something a lil bigger, a lil rounder, a lil more ‘riverbeddy’:
The second use for the lil hardscape type pebbles and gravels is as a pad or as a fill underneath a brick or stone or concrete paver patio or driveway or path
they help the drainage somewhat
and form part of this massive hardscape foundation that is more stable over time
moves as one cohesive unit
keeping the bumps and uneven contours and movement at bay
so you dont get dips and warps and sinking and things like that in your 40,000 dollar patio
well theres all sorts of ways to install a patio, from the DIY to the professional
from Southview Design
Do you use 1″ of sand or 1″ of 3/8″ gravel beneath the pavers as pad/base?
Use concrete sand or decomposed granite or olympic sand or polymeric sand or silica sand or beach sand or?
Do you use the foam paver panels or not?
Are you in a cold frost and freeze prone area or not?
Do you use weed cloth or not?
Will you be actually planting the spaces and joints where the stones meet up? with thyme or tradescantia or babys tears or?
and the questions go on and on
then ask ten different contractors, see what they say, what are their experiences?
who is telling the ‘truth’, who is scamming and making it up, who is knowledgeable and speaking from a lifetime of observations?
lets just stick to the materials and discuss their intrinsic properties instead
to better understand their characteristics and differences,
and plan a common sense practical way forward
We will start with rocks with a relatively jagged angled shape, in the 3/4″ size
These all 3/4″ sized rocks, mostly used for decorative top dressing:
Two of the bags are lava rock – that is
igneous rocks from magma, but unlike granite which is born deep in the earth and cools slowly
lava rocks are made above ground when lava reaches the surface
basalt is similar but a specific type of ‘lava rock’
yeah basalt like the Giants Causeway in Ireland
Organ Pipes in Namibia, or the Devil’s Post Pile in California
or those fashionable hollowed out basalt fountains:
from the Pond Guy
The Tuscan Gold and Black and White (B & W) are a lil heavier
lava rock has a light porous feel from its quick cool volcanic origins
you also find it sometimes in a smaller size as pumice in potting soils
or we might use it to mound and give drainage to cactus or cycads we are growing in the ground
This next picture, on the left is 3/4″ crushed drain rock, on the right is base rock:
aside from a slight difference in size
what is the main difference that you see?
if you say one is clean and open and full of pores for drainage
and the other is filled with all sorts of sized aggregate and sand for dense packing and compaction
you would be correct
for a trench or a french drain, which would you use?
for under a concrete paver patio, which would you use?
and from mother natures angle,
what happens over time,
to all the open pores in the earth, as rain falls and ground waters flow?
Heres the same set of rocks, with the addition of 5/8″ dolomite
dolomite? isnt that a mineral supplement some folks take for magnesium and calcium?
Questions
are these rocks all more or less interchangeable, in terms of basic function in the landscape?
what is likely the cheapest rock here?
what is it about angular rocks that makes them especially good for a base that is compacted? (hint: Schlage, Master, Yale, Kryptonite)
The next size down are similar angular rocks in 3/8″ sizes, and one sample in 1/4″:
Questions:
Besides color and cost, functionally, do these materials all perform similarly?
which would you like to have as a mulch in a garden bed?
which would be somewhat okay to walk on as a path material?
would any of them feel okay with bare feet walking atop it and a cup of coffee and bagel in hand?
which is likely the hardest rock(s) in this set?
could you use any of em as a sand substitute for the layer right beneath the paver or brick?
hmmmmm
Switching gears to rounder rocks that are more pebble than rock
rocks that likely come from a dredged river somewheres
worn down by the creek or river waters
take a look, most of these are used just for top dressing mulches
too round to walk on or tamp down
nice to use a variety of sizes if you are trying to mimic natures variety and diversity
whether for a water feature or dry river bed or what have ya
those salmon bay pebbles from Alabama have a translucent glow to em that light up when wet
and pami from Montana with the red purple hues is quite charming too
hard to beat a rock with a sweet name like ‘button’
Lastly we go to the fine grains small specked hardscapes
useful for paths and tree wells
good for the pad/base layer between the paver or flagstone on top and the angular foundation rock below
as an addition to some soil mixes that like drainage and dont mind the weight
for stucco masonry mortar
playground sand, and more:
‘Fines’ is another way to say decomposed granite, or DG
comes in a variety of colors
think its just the small screened bits, not sure why its called ‘decomposed’
guess its easier and better sounding than ‘eroded’ or ‘weathered’ granite pieces
‘stabilized’ means its got some kinda binder stick-stick-particles-together in it
it can be a more natural type glue or a more plastic resiny type glue
Questions
which one of these samples is the cleanest, with minimal dust and fill and tiny matters?
which ones if wetted down and compacted, will likely stick together the best, over time?
which ones have probably a more angular shape, and which ones are more rounded?
Well, if a particle of sand was bigger, they would call it gravel
sand is small, and has a range of sizes from about .05 mm to 2 mm
if you look close, it is many colors, very beautiful stuff
the whole universe is there
Okay
next up is recognizing patterns in hardscapes
we already presented the ‘basket weave’ and ‘herringbone’
In this next picture, check out the concrete retaining wall
the name is ‘weather mosaic mojave’
Never mind the top row of blocks which are the capstones
Questions:
Do you see the rectangular pattern made of four blocks that repeats over and over again in a staggered pattern?
How many different sized blocks are used to create this pattern?
Now try this one:
How many different sized blocks are used to create this pattern?
The following picture is one of the most basic patterns, it is called ‘running bond’
sod is laid in the same way, staggered for strength
Once you order your hardscape materials
you may choose to bring it to the clients house in your truck
or you may have it delivered
around here that usually means getting a palette of rock and blocks or a pile of granite in a parking space or driveway in front of the job site:
Questions:
what day of the week is street cleaning day? Do they ticket for stuff like this?
do you have the people power to move it all inside to the back yard right quick?
before the rains or thieves come and the wind picks up?
can you do it in small loads to prevent injury? in buckets? does a wheel barrow fit through the house? ramps?
do you gotta lay down plywood or plastic over the carpets and flooring inside the house?
how is your stamina and endurance and joints?
Something clients, contractors, designers and architects forget time to time
is that they are dealing with Mother Nature
and it is she who calls the shot
by Mother Nature I am not only talking about the wind and rain and rivers and streams underground and scorching UV rayed sun and material expanding heat and sweating humidity and bone chilling contracting cold
but also her frequent helpers allies creations like algae mold gophers ground squirrels rats mice dandelion cats tongue bermuda grass and all the rest who are all constantly rummaging around even whilst we are sleeping or eating
they can all wreak havoc on our hardscapes and our ideas about control and management
so….
What happens if you lay down gravel mulch, but forget about maintenance?
If you dont plant something in the open dirt, who will?
Cute design and all, but who is going to move in asap?
How do you clean up the leaves and dust that falls atop the pebble gravel mulch? Do you use a blower or a broom or a rake or?
maybe you want to just resin/polyurethane/clear coat the whole darn yard? just plastic coat everything
‘nothing moves, nothing changes, nothing lives without my permission’
Who can crack and break up a nice thick and strong layer of concrete and uplift that hardscape?
Who grows in the tiniest cracks in hardly any space at all?
besides reaching for that bottle of herbicide, can you figure out any other solutions to this problem?
thats about all for now
heres a couple of pictures to close it out then
thank you for reading all the way to the end
and thanks to Broadmoor Landscapes for the samples and supplying our local landscapers
whew
Mission Azul 