Infloor Infloorboard - Manual (Page 28)

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Infloorboard™ may be used under traditional strip wood flooring in several ways. A con-
ventional nailed and hardwood type system may be used directly over Infloorboard™, with
nailing long enough to penetrate sub-floor and with controls as described in the previous
section. There are many advantages to this method; they include quick response, lower cost
of installation, higher heat output due to lower resistance of flooring, and a quality control
that brings the flooring through temperature changes gradually and accurately, which also
increases comfort.
Optional floating methods for use with traditional strip wood flooring: 2 layers of 1/2-inch
plywood may be floated on top of the Infloorboard™ and strip flooring nailed to it, as
shown below in a method recommended by the National Wood Flooring Association. This
method has the advantage that it allows the wood flooring system to float independently
from the Infloorboard™, but has significant disadvantages in that the 1” extra thickness of
wood limits the output of the system. For example, two layers of 1/2” plywood with 3/4” of
strip oak flooring has an R-value of about R-2.3. This limits the output of the floor at 150°
F water temperature to about 26 BTU/Square Foot. A careful heat loss analysis must be
done to see if this method will produce enough heat. If not, another method should be cho-
sen or provisions made for backup heat. A hydronic control strategy that gradually adjusts
water temperature going to the Infloorboard™ with a reset curve is recommended but not
required with this method.
Clip style floating strip flooring systems must be installed directly over Infloorboard™ such
that clips will never come in contact with the tubing.
The use of a floating engineered wood is a preferred method. This product should have a
specific warranty for use over radiant floors. Many manufacturers of these products have
such a warranty, as well as having extensive experience both in Europe and North America
with radiant heating applications. Edge glued floating engineered wood flooring systems are
preferred, since they are dimensionally stable and expand independently from any thermal
mass. Infloorboard™ should be installed such that the hardwood runs perpendicular to the
majority of the tubing runs.
Glued down wood flooring systems are not recommended unless a layer of plywood is first
screwed down to the Infloorboard™ and the wood is attached to the plywood according to
the flooring manufacturer’s recommendations for installation over radiant heat.
FLOORING COVERING INST
ALLA
TION
Finished flooring assembly of strip wood
flooring and plywood “floats” independently
on top of Infloorboard™
Plywood laid diagonally to
first layer attached with 7/8”
screws on 6” grid pattern
First layer of plywood is
“floated” on Infloorboard™
Wood flooring nailed to
2 layers of plywood
NWFA DOUBLE PLYWOOD FLOATING METHOD
OTHER APPLICATION OPTIONS –FOR WOOD FLOORS OVER
INFLOORBOARD™: