I e-mailed the Warm Your Floor company where I plan to purchase the SunTouch floor warming system. They are selling the cork insulations that is 1/4" thick and 48" wide and designed to go between the concrete slab and the SunTouch system. They recommend gluing the cork down with a wood flooring adhesive or with thin set. Then you use hot glue or double sided tape to hold the mat to the cork. Then you use thinset over the top to lay the tile. They do not reccomend self leveling cement over the cork and indicate epoxy is not necessary for the grout. I am still concerned about my installation. Using this kind of cork do you think the epoxy grout is necessary and is the above application method going to work? Is the cork really going to cause more problems than I get out of it. The cork is costing me an additional $131.00. Thanks for all your help. Dora

Wood is about R1 per inch, so yes, a thicker plank will have more resistance to heat movement than a thinner plank. But when you're talking about 3/4" for solid strip hardwood versus 5/8" or 1/2" for an engineered plank, that's a differential of R-0.25 or R-0.125, it's not terribly significant. It's not the thickness, but the stability, that's the main advantage that an engineered plank will give over a solid strip hardwood. The ply structure is generally more stable and really does a nice job of minimizing movement. Quarter-sawn, along with choosing a stable species, will be your best bet when going the solid wood route. But in general, an engineered plank will still be more stable than quartersawn. You can get around that a bit by using less wide strips. Example, if movement occurred, an 8" wide plank floor would have wider gaps between planks than a 2" wide strip floor. Going with narrower strips can hide movement. Glue-down is preferable to me over floating. Bostik's is my preferred adhesive. Aluminum Oxide from the factory is more durable than site-finished. There are engineered strips that have a thicker wear layer. Some of the engineered floorings 15 or 20 years ago only had a 1/16th" veneer of "show wood". It took a careful screening to refinish them. So look for a thicker wear layer, it'll resist punctures from dropped items and you can get several screening refinishings or even full-fledged sanding refinishes out of them. Going with solid wood strips, mesquite, teak, wenge, padauk, purpleheart, those are "exotics" that are all fairly stable. Maple isn't. Brazilian cherry can have a bit of movement, though I have installed 5" wide quartersawn BC planks with no ill effects. Much of the success or failure with solid wood over RFH is species choice, flat versus rift or quartersawn, and the overall design of the RFH system. I shoot for a minimum of 3 times the "R" factor underneath the RFH loops that there is above the RFH loops. That keeps the heat going where it's designed and intended to go, and allows for low water temps in the loops.

Mike, it sounds like you're looking for a broad area solution that will cover and heat your entire basement, much like a centralized forced air system would. This approach may not be in your best interests, or even desireable. One of the beauties of electric heating systems is that they allow you to easily create zones. You may have a room that, due to factors such as sun exposure; prevailing winds; uneven insulation; etc., may have a much greater heat loss, and therefore be harder to keep warm, than your other rooms. You may also have a room or rooms that are not continuously or currently occupied. Why waste the energy to keep them as warm as rooms that are occupied? By having a separate thermostat for each room or zone, you can easily tailor your heating as needed, and the result will be much more consistent temperatures from room to room (if that happens to be your goal). Just a thought. :-)

Hi, Suz1023, and congratulations on your home purchase! To answer your flooring question, it depends on the space between the floor joists. If the addition is built with floor joists 16 " on-center, meaning the joists are 16 inches apart (standard for floors), you could run electric heat wires between them. But the amount of heat that permeates up to the floor depends on the material over the floor, and specifically the thickness of the plywood (usually 3/4"). In short, this wouldn't be the way to install the most EFFICIENT radiant heat source, but it may take the chill off the floor. Good luck, and I hope this helps!