Q: We’re moving into a 1950s Eichler home with the original (still functioning) radiant-heated floor system. It’s a great place, however, the marmoleum floor installed by the previous owners doesn’t match our taste (it’s a little too close to circus stripes). We’re wondering what options we have to replace the floor that won’t defeat the radiant heating.
We’re aware of cork, and laminate floors products, but are also interested in engineered hardwood options. Is there a maximum thickness we can go with for engineered floors? Do you have any advice or product recommendations for radiant-heating floor coverings?
Thanks for your help 
– Joe
A: The method of installation for your project will matter on the type of subfloor you have under the marmoleum. If you have a concrete subfloor (which is my guess here based on the type of home) install a floating product. If you have a wooden subfloor you can either float or nail through the marmoleum to the subfloor. You can also glue down to the marmoleum, but you will need to rough up the marmoleum and then use a urethane based mastic adhesive. Certain adhesives, such as plastic based adhesives will not adhere well in this situation.
With a floating install, keep in mind that underlayment is important. 3mm cork can work here as far as a premium underlayment is concerned, but you will lose about 3 – 5% of the heat output from your floor. Sound 6 Barrier is also a great option here.
Product wise you can look into floating engineered hardwood, laminate and cork. In regards to the engineered, thickness is not a matter but I would suggest something with more plies in order to reduce expansion and contraction possibilities from the heat. You should be ok with a 5 to 7 ply product here as long as it is better quality. Products with thicker plies and species layer such as Bellefloor, BR-111, Kahrs and Westhollow are good choices here.
With cork you will have a reduction of about 5 – 6% in the heat output of your radiant flooring system. Beyond that cork is a viable option here and I would suggest looking into the floating cork tiles from APC or Westhollow.
To sum up – a floating installation will be best here and if you look into an engineered product keep in mind that 5 plies or more will perform best.
