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The screed for a transitional wall (or any transitional
radius) is fabricated in the same manner as an excavation
jig. The standard ratio for most transitional walls is an
8-feet radius. This does not mean 8-feet from the top to the
bottom of the curve. It means 8 feet from the center of the
circle to the outside edge of the circle. See the section on
Drawing a Radius on the Basic
Concepts page for further clarification.
If the area to be poured has coping, the screed must be
fabricated to move and screed 3/8 of an inch to the inside of
the coping. The 3/8 of an inch allows the coping to sit just
proud of the surface of the finished concrete. Pay close
attention, because coping sticking out more than 3/8 of an
inch is more suited to in-line skaters and BMX bikes. Less
than 3/8 of an inch leaves a smaller grindable surface for
skateboarding. The screed should be made so that it can hang
and slide freely upon the coping. To hang the screed use a
metal hanger fabricated from angle steel in the same manner as
the excavation jig. In many instances you can use the same
hanger. When the screed is hanging from the coping, the
bottom of the screed should set solidly upon the lower floor
form. Handles should be cut along the entire length of the
screed near the inside to facilitate pulling the screed along
the concrete. The screed must be very rigid to resist flexing
when pulled. It is important the screed not flex when being
pulled along the concrete. Strengthen the screed by backing
it up with welded angle steel across one side and bolting the
steel to the screed. When fashioned in this manner the screed
will only be about 1-foot wide and fairly lightweight. Using
this method, screeds can be fabricated for any radius and
height. Always perform a test run with the screed before
using it to place concrete.
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