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gone around all the walls and drawn a line at your finished
height. A day or two in advance, you might need to go around
and
fill any holes, voids or low spots with a damp clay -sand mix,
maybe even tamping a bit with your nice tamper. When dry you
should be able to sweep up any loose debris. It's a good idea to
mix up your material a day in advanc e. Now, do your math.
Calculate your square footage then your cubic footage and add
about 30%. If your room is 10 ft x 12 ft, then 10 ft x 12 ft
equals 120 sf. Multiply this by 0.0416 to get cubic feet.
(0.0416 is 1/24th of 12 in.) 120 x 0.0416 = 4.99 cubi c feet.
[ For metric calculation: 3m x 3.6m = 10.8m2. 10.8m2 x 13mm =
0.14m3]
Add 30% more material. 4.99 x 0.3 = 1.49 for a total of 6 1/2
cubic feet. We add 30 % due to the fact that we will be
measuring our materials dry so there is air space. Once wett ed
and applied, the material gets compacted by the toweling
process and we lose volume. You will need a container to store
all this material. A simple tub can be made out of a frame of
straw bales set on the ground and lined with plastic or a tarp.
You can also buy large kids' swimming pools. The color of your
floor will be the color of your dried clay. You can add concrete
liquid or powdered colorants. It is always a good idea to do a
few 3 ft x 3ft.90cm x 90cm samples to test for shrink, cracking
and colo r, also a good way to practice your applying
techniques.
How to apply
Again one of those concepts that is best shown during a workshop
training session than through trying to write about it, but
here it goes. Ahead of time make up a few 1/2 in. x 1/2 in./1
3mm x 13mm screed sticks. These are also the thickness guides,
four per person. Vary the lengths, 12 in. to 36 in./30cm to
90cm. Also make some wooden pool trowels out of the 1/2
in./13mm thick concrete wood floats from your building center;
they cost arou nd $3.00 USD each. Keep one square for
corners.
Plan your route of attack so you will be able to work your way
out of the room. Begin by setting down some pre -wetted wood
sticks - trowel lengths apart, shovel down some material and
start working in the mat erial between the sticks. The trick is
to
make sure the material is compacted well, no voids. Do a few
square feet leaving the sticks in place to run your trowel over
thus establishing the thickness. Don't spend a lot of time
making it look good right now. Slide out the sticks, you now have
a
square groove that needs to be filled. First, take your trowel
and press the sharp sides and ends down to form sort of a vee,
now add small amounts of material in the vee and trowel it flat.
Any voids or air pockets wi ll leave a spot for cracking so
compress well. The tendency is to put too much material in at
one time; instead use a small amount frequently rather than
large amounts all at once. Keep your guide sticks clean, wash
frequently so as not to add buildup crea ting a thicker and
uneven floor. As you progress along placing material and
removing sticks, go back over the previous areas with your trowel
to
smooth and even out your floor as far as you can reach back over
what you did. Sounds easy? Hopefully you worke d this all
out in your 3 ft x 3 ft (90cm x 90cm) test samples.
Sure looks good doesn't it? You're not done yet. More steps
involved as the floor begins to dry. A word of caution about
drying, it's important to get even drying. If the sun shines in
a window or door, these must be covered up. Air circulation
helps to remove the moisture and speed up drying but again you
need even flow.
Hard Troweling
Now it's all about timing. On hot days/in hot climates, we find
it best to apply the floor early in the mornin g so that
hopefully by late afternoon or early evening we will be able to
get back on the floor with kneeboards and steel pool trowels,
or apply late in the day and hopefully you are back on it first
thing in the morning. Miss this window of opportunity an d your
floor will be too hard to steel trowel. If you were so good
applying the material with the wood floats and you are happy
with
the results, then one can skip hard troweling so your floor will
be a little more course.
So your floor is drying, time to hard trowel on kneeboards - 3/4
in./20mm plywood, 18 in. to 24 in./45-60cm square or 2
in./50mm foam blue board works well. Make sure to wet your
kneeboards, otherwise they stick and pull up your material.
Almost like hard troweling a concrete slab. Steel troweling
tightens up and flattens the surface. We use pool trowels and
basically just go over the whole floor again, pushing hard with
two hands in big sweeping motions.
Once your floor has completely dried, it's time to seal and fill
the floor with Linse ed oil.
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Now, weeks later after your floor is 100 percent dry, it's time
to seal and fill the floor with Linseed oil. Here in the Sout h
West our floors can dry in a matter of a few weeks but in humid
climates error on the safe side.
Materials:
Linseed oil. We prefer raw linseed oil, less petroleum additives
then the common boiled linseed oil but the boiled works if
you are not concerned about petroleum out gassing. Even raw
linseed oil has carcinogenic warning labels. Ask for an MSDS
sheet. Linseed oil is made from flax seed. Citrus Solvent
(thinner) or mineral spirits, again petroleum out gassing
We are still learning how to estimate coverage and quantity so
I'm not sure how much material is needed for your size floor.
Maybe buy 2 gallons each for starters; you can buy linseed oil
in 5-gallon lots.
Equipment:
y 4 inch paintbrushes, natural bristle is always best but
priceyy Electric hot plate or gas camp stovey Large pot or kettley
Approved vapor masky Safety glasses or gogglesy Fan for air
circulation/expelling fumes if you feel this is necessaryy Rags,
Gloves
Prep floor:
Sweep or vacuum any loose debris and dust. You might want to do
a light mopping or sponging. Give yourself time for the
moisture to dry before applying the oil.
Procedure:
Heat the linseed oil to almost boiling (do not boil). We are
just trying to heat the oil to aide in soaking, absorbing in.
This
must be done outside with caution, flammable. Another option is
to pour the oil into a large deep baking pan, cover with a
piece of glass and let it sit out in the sun. Leave an air gap.
With either method start with a small batch to get the hang of
heating and applying.
Transfer the oil into a suitable container. You can paint the
material on or if you are quick, you can pour some onto the flo
or
and swoosh it around with the brush. The only risk here is that
you will not get an even distribution of material. Try it. Be
consistent and watch how the floor is absorbing. If more than
one person is applying, then you might get varying results but
by the time you are done it shouldn't matter. Use up your first
small amount then decide how much more (a large batch) to
heat for your next go at it. For reference keep track of how
much material you use for each coat and offer this info to
others.
The floor will soak up this first coat and there should not be
any pooling of the oil on the surface. Plan your route of
attack
so you end up working yourself out the door, window or hallway.
You should be able to go back to the start and do a second
full strength coat right a way. Remember your shoes will be
picking up dirt and dust from the outside so take steps to
minimize this. There are disposable booties one can buy to cover
their shoes.
What we are trying to do is seal the floor but think of it more
like filling the fl oor. Filling all the little air voids between
the
sand and clay particles with oil.
The floor will dictate the timing and how much material. Watch
how the material soaks in. You might be able to continue
with more heated, thinned coats the same day, unless you are
tired or sick from the fumes and not wearing a vapor mask.
Diluting:
The first two coats can be applied full strength. For the third
and fourth coat combine 75% oil with 25% thinner, heat and
apply. Watch the absorption, watch for pooling or puddling but
also give the material some time to soak in; you just don't
