Return to Part I
Go to Part III:
Our Favourite Reference Book on Wood
and Wood Flooring
Wood is Good by Dr. Joseph Lstiburek,
Jeffrey from Climatec Advanced Heating
Technologies knows how to simplify a mechanical room and make it
look outstanding! This pump and control set up is for a
really nice home in PA.
This is a picture of our steam humidifier which
we use to hold constant RH all year long.
Radiant heating and cooling design has really
benefited from software developments. This is a simulation of a
heated floor. This is a useful tool for understanding how floor
coverings like hardwood and radiant work together.
Everybody in the radiant business knows Moses of
New York fame...he does the most incredible radiant heated
Andrew from Radiant Engineering took this picture
showing their heat transfer plate system. These products
make it so easy to radiant floors with hardwood.
This is another shot from Andrew before the wood
strips were laid down.
There are so many great ways of doing hardwood
and radiant and it all begins with working with professional
radiant contractors and professional hardwood installers.
You can learn more by downloading this free
Guide to Hardwood Floors and Radiant Heating
(.pdf slide show)
Other useful resources:
Learn About Thermal Manikins
Learn About Thermal Comfort
Click on the floor temperature graphic to
Click on the climate control graphic to enlarge.
We discuss the details of this systems in our
online forum and in our
Part II : How to Install Hardwood Floors Over
(click here for illustrations of other heated
support visit our
visitor services page.
With advances in heating and insulation
technology, and effective management of wood's natural expansion
and contraction, builders, architects and designers achieve
faultless installations of hardwood flooring over radiant heat.
Parquet floors are readily used in radiant heat
applications. With strip flooring, the wider the board, the
greater the potential for gaps between the boards when they
contract with seasonal changes in temperature and humidity.
Tongue-and-groove strips are recommended and beveled-edge boards
show fewer seasonal gaps.
It isn't recommended to use radiant floor heating
under plank flooring wider than 3". Despite all your
precautions, there is a high probability the user will not be
How It Works
Radiant heat systems use a three-stage process to
convey heated water to its destination. (See diagram).
A water heating system that can be either a
standard boiler, water heater, a geothermal heat pump or
even solar panels.
The heated water is pumped through a tubing
network installed in the subfloor.
As the warm water moves through the tubing
network, it releases its energy and returns to the boiler
system to be reheated.
Good communication with the radiant heat system
designer is critical. Everyone should be notified of any work
pertaining to the installation, especially if specifications are
To ensure a superior end product, pay attention
to the following factors before, during and after installation:
Red rosin paper is the preferred and
recommended choice for a slip sheet. Tar paper (roofing
felt) has been known to outgas in some cases.
Work with the system designer to choose the
subfloor option (see illustrations.) The heat system designer is
responsible for the subfloor installation, but you will want to
be familiar with the choices. Direct contact of the tubing with
the flooring is not recommended. The subfloors shown here are
recommended for hardwood floor installations.
Plywood (5/8") or oriented strand board (3/4")
make good candidates for subfloor materials in radiant
installations. Particleboard subfloors are not recommended by
radiant heat companies.
Provide the radiant heat system designer with the
hardwood flooring dimensions, species, and the desired
temperature of each room. This will give him/her the information
needed to calculate the necessary water temperature.
Consult with the system designer to determine the
tube network layout, so you'll know where the tubes are before
you nail down the floor. It is best to have the tubing spaced
evenly down the joist cavity (between the sleepers). Then you
can nail down the finished flooring onto the sleepers on
eight-inch centers. When the tubing circuits are crossed over
the center of the joist cavity, have the system designer use
nail plates to protect the radiant circuits from being
The following climate controls will minimize
expansion and contraction during and after installation of the
Mechanical Humidity Control: The
heating/ventilation/air conditioning (HVAC) system should have
mechanical humidity control. This will monitor the room and keep
the relative humidity at an even level, which will keep the
equilibrium moisture content of the floor stable.
Heat Transfer Point Control: The system designer
also should install a set point control that will monitor the
wood floor temperature. The set point control should either
reduce the system water temperature or temporarily cycle the
system off to prevent overheating the flooring if equipment
Exterior Thermostat: An exterior thermostat (aka
weather compensator) is
recommended to protect the perimeter of the system from
condensation absorption during the spring and fall when rapid
temperature changes may occur.
Once the subfloor, tubing and climate controls
have been installed, the HVAC system should run for at least
72 hours to bring the house to the desired relative humidity.
Temporary, unvented sources of heat - such as
propane-fired "salamanders" - can add excessive amounts of water
vapor. Avoid them if possible, but if they must be used, leave
windows open to vent the humidity.
Now follow the customary procedures for
installing any hardwood floor.
Republished with permission(c)2001-2005
Hardwood Manufacturers Association
Words of wisdom from the
(see also, NWFA, Appendix H – Radiant Heat
Hardwood Flooring Installation Guidelines) Copyright 2007
National Wood Flooring Association
"Maintain relative humidity planned for building
occupants, and an ambient temperature between 65° and 75°
Fahrenheit in spaces to receive wood flooring for at least seven
days before installation, during installation and for at least
seven days after installation. After post-installation period,
maintain relative humidity and ambient temperature planned for
For unfinished products, open sealed packages
to allow wood flooring to acclimatize.
Do not install wood flooring until it adjusts
to the relative humidity of and is at the same temperature
as the space where it is to be installed.
Close spaces to traffic during flooring
installation and for time period after installation
recommended in writing by flooring and finish manufacturers.
Install factory-finished wood flooring after
other finish operations, including painting, have been
Favourite Reference Book for Radiant Heating and Wood Floors
Suggested reading for consumers and office
How to "ball
park" your budget for indoor climate control.
Built to code: What does it mean for
consumer thermal comfort?
Indoor environments: Self assessment
Comfort: A 40 grit perspective for consumers
Comfort System - The "Un-minimum" System
Comfort: A Condition of Mind
Do-It-Yourself HVAC - Should you do it?
The Cost of HVAC Systems -
Are You Paying Too Much for Downgrades?
Radiant Installations - The Good, Bad and Ugly
Thermal Comfort Surveys - Post Occupancy, Part 1
Thermal Comfort Surveys - Post Occupancy, Part II
support visit our
visitor services page.