Do I glue my bamboo flooring to the radiant heating pad after gluing the pad to the floor? I'm installing bamboo over a concrete subfloor.
This is 9/16" thick x 5-14/" wide solid Bamboo flooring. The floor is supposed to be glued down, & the radiant heating pad is designed for use under wood. Do I glue the wood to the pad after gluing the pad to the floor? Do I glue only the edges & let the floor float? Should I do this myself if I'm careful & methodical? I'm reading about 20 different ways to do this, and none are the same. I live in the very dry climate of southern New Mexico.
Good questions. Radiant heat can be either carried via hydronic (water tubes) or electric (cables). In both cases it produces infrared heat and most flooring companies set a limit of about 84 degrees F at the floor.
- This continuous heat can cause hardwood to expand and contract quite a bit.
- Some manufacturers allow both types of radiant heat and some don't.
- Be sure to check the warranty very carefully. If it's not in the warranty, then find a different company that has it spelled out.
- Manufacturers usually specify, but if they don't, call them and get it in writing.
Choose the right flooring for radiant heat
Not all engineered floors perform well over radiant.
- Teragren's Craftsman II bamboo, for example, does warrant over radiant but they don't seem to mind whether its hydronic or electric.
- EcoTimber, on the other hand, allows hydronic but not electric. They never say why, but even though the bamboo might look the same, don't assume it is made the same way.
Engineered flooring is made like a sandwich with a layer of solid wood or bamboo on top and bottom both running lengthwise and a different type of wood, bamboo or high density fiberboard running perpendicular in the middle. This makes for a very stable yet flexible structure that can be glued or floated over a wood or concrete slab.
Each company uses different types of bamboo harvested and manufactured differently with various adhesive, finishes and milling techniques. This all adds up to a structure that may be conducive or not conducive to radiant heat.
- In either case you must follow the flooring manufacturers installation instructions precisely.
- Don't ask the radiant heating company as they only warrant their own product and can't confirm it will work with other companies' flooring. Just because they say it should work does not mean they guarantee it.
Gluing is not do it yourself, but a floating floor is
Generally speaking, engineered floors are floated over hydronic heat and not glued down.
- Gluing to concrete is expensive, requires flat subfloor and professional installation.
- We don't recommend doing it by yourself.
Most DIY floors are floated because they are much easier to install. Some are glued side to side on the edges and some click together without glue.
- In either case, they usually require a 1/8" underlayment and vapor barrier to be applied underneath the floor.
- If you have experience with woodworking and have some basic tools, it is possible to install a floating floor by yourself. It can save you lots of money and is very fulfilling.
- Make sure there are step by step installation procedures for radiant heat. If not, consider a different company.
A valuable reference for installing flooring over radiant heat comes from Kahrs. (Read it here.) They are one of the oldest flooring companies in Sweden and they invented floating floors.
- Because a large percentage of people use radiant heat in their country, they designed their floors specifically for that purpose. They have an excellent product and an amazing installation guide.
- Many manufacturers have tried to emulate their products but few do it as well as they do.
- While it is very technical, reading it will provide you with a valuable education on this subject that you won't find anywhere else.
Radiant heat barrier
Another thing worth investigating is a radiant heat barrier. Sometimes underlayment has a foil backing and sometimes it doesn't.
- In your case, you definitely want a radiant heat barrier so the heat reflects back up towards the floor instead of going into the concrete slab.
- Foil may also be built into the underside of the electric radiant heat pad.
If you have further questions, please feel free to call or email.
Joel Hirshberg firstname.lastname@example.org www.greenbuildingsupply.com
For more information:
Read "Can radiant heating be installed under our existing flooring?" a Q&A answered by Brad Hubbell.