Folks who’ve been reading JuicyMaters for any length of time, especially the ones who focus on my posts about my yurt, know that I have a hydronic radiant floor for heating during the winter. As I’ve written before, I am very happy with having made the choice to use radiant floor heat.
With that said, as with anything else, there is room for improvement over the way I designed my floor the first time. I am tweaking that design in the bedroom yurt I am adding to my “main yurt”. Let’s talk about how to take a good system, a radiant floor, and make it better.
In the main yurt I have two kinds of finished floor. The half that is the kitchen area and the bathroom are 12×12 ceramic tile while the other half…the living/dining/sleeping half…is hardwood. Not engineered wood flooring like Pergo, but rough cut 1×6 oak that I cut to exactly 6 inches wide with a table saw then planed to one inch thick with a power planer.
If I had it to do over again (and what I am doing in the new bedroom yurt) I would do things slightly different on both the tile and wood floor in order to improve the ability to heat my home.
The first three layers of the floors…both in the existing yurt and in the new one, are identical…2×8 white pine floor joists on 16-inch centers, with one inch composite tongue-and-groove subflooring on top of the joists, with 12 inch by 8 foot strips of 19/32 C/D plywood with 3/4 inches of space between them for the runs of 1/2 inch Pex tubing. This will not change, but everything above it is different…on the new tile floor in the new yurt and how I would do wood floors if I were doing them again.
Tile floor…how I did it, how I will do it differently.
Above the subflooring, a properly installed tile floor consists of two layers. First you install some form of backer board, usually a cement or cement/fiber composite. These backer boards do two things. They level any irregularities or unevenness where the subfloor panels (or the tubing layer is installed in a radiant floor) meet and they provide a surface that is all but inflexible to prevent cracking the tiles and the grout between them.
Then, above the backer board, you install and grout the tile.
If I had it to do all over again on the original yurt, I would choose a different type of backer board. What I used was a 1/2 inch thick cement/fiber composite backer board. What I should have used, and will in the future, is a 1/4 inch thick cement only backer board.
The reason for both changes is to improve heat transfer from the Pex tubing to the surface of the floor. The reasoning behind using the 1/4 inch rather than the 1/2 inch board is obvious… There is less material for the heat to travel thru, thus, less time for the heat to dissipate. The change from a composite to a solid backer board is to move to a denser, less insulating material. The composite backer board is a mixture of cement and a filler material that leaves air spaces in the board that act as insulation, thus inhibiting the transfer of heat.
Wood floor… How I did it, how I will do it differently.
The changes I would make in installing a wood floor again are similar to the tile floor changes, with the exception that you only have one layer above the subfloor, the finish flooring itself, rather than two layers (backer board and tile).
As I said earlier, my wood floor is rough cut 1×6 oak that I sawed to an exact, consistant 6 inch width and power planed it to exactly one inch thick. It makes for a beautiful hardwood floor.as I had expected it would.
What I should have considered but didn’t is the considerable insulating properties of wood. Wood is basically a collection of air pockets encapsulated in cellulose. This cellulose accounts for approximately one third of the wood mass. The rest of wood is air pockets surrounded by the cellulose. One way to visualize wood would be to think of layer on layer of bubble wrap with cellulose replacing the plastic.
That makes for a very insulating material…not what you want in a material that is expected to transmit heat as a radiant floor is.
In the new yurt I am installing ceramic tile flooring (as described above) so I won’t be trying the following, but I do think the following are viable ways to have beautiful wood floors with essentially putting an insulating blanket, the inch thich wood, on top of a very (otherwise) efficient radiant floor.
Probably the second most efficient material for a radiant floor that looks like a hardwood floor would be to use one of the engineered wood flooring products, like Pergo. They are durable, dense (for efficient heat transfer) and thin so heat doesn’t have far to travel, averaging about 1/4 inch thick. I know, I know…there are two drawbacks to engineered wood products…cost and material toxicity. Frankly, I had looked at these products when building my first yurt and cost was what drove me away. The cost factor is something you will just have to look at and decide for yourself if you want to spend the money.
As for the toxicity of the flooring materials, that is an extremely important consideration, especially since the heat from a radiaant floor is even more likely to release VOC’s than a floor that is a more “normal” temperature.
With that said, many manufacturers of engineered flooring use glues and other materials that are not toxic. Pergo, for example, uses non-toxic glues and other materials. (No, that is not a paid link.)
One other possibility.
If you want maximum efficiency ceramic tile over a 1/4 inch solid concrete backer board provides the densest floor reasonably possible. Some people want the beauty of wood while also wanting an efficient floor…and I have finally found a solution. Ceramic tile that looks like wood!
I know…it has been around for a while, but what I have seen in the past did a VERY poor imitation of wood. I would look at it and say, “Gee…they want that tile to look like wood…and they failed miserably!”
A friend from high school, Alex W., is in the process of remodeling his condo in Florida and I saw some pictures of his finished floor and was blown away! At least from the pictures (and Alex’s confirmation) the pictures look just like the actual finished floor. I really thought it was wood…but it is ceramic tile, making it the perfect flooring for someone wanting a “real wood” look along with the heat transmission properties of tile.
I don’t know where to get it, and I don’t know how expensive it is (woulda been rather rude to ask, don’t ya know), but he sent me a picture of the box, and with a little Googling I’m sure you can track it down.
So there you have it folks: A hydronic radiant floor that is more efficient than my earlier design. Tell me what you think in the comments below, and don’t forget to sign up for the JuicyMaters eNewsletter…click on the newsletter banner at the top of the sidebar.
One last thing…Y’all come back now, ya hear!?