The short answer is that radiant heat works well underneath certain types of linoleum,ceramic tile, stone, hardwood, bamboo, cork or carpeting:
- as long as the floor temperatureis not too high,
- the flooring is designed for radiant heat and
- is acclimated properly beforeinstallation.
Most flooring manufacturers require certain conditions prior to, during and afterinstallation of their floors for their warranty to be valid over radiant heat.
Now, the longanswer.
Check the manufacturer's guidelines
First, check the warranty. Not all flooring can be used over radiant heat. In mostcases engineered or floating floors are warranted, but not always. There are some typesof solid wood floors, usually exotic woods, which will work over radiant heat too. Butin every case, you and your contractor need to follow the manufacturer's guidelines veryclosely.
For a floor to be warranted for radiant heat means it must be capable of expansionand contraction without cracking or delaminating.
- For this, it must be designed andconstructed specifically for radiant heat.
- That usually means it is engineered flooring,although certain types of solid wood flooring may work too.
Engineered flooring can be designed for extreme conditions of moisture and drynessby using alternating layers of wood layered perpendicularly one on top of the other.Usually the top and bottom layers are made of the same type or density. In addition,very stable quarter-sawn wood or high-density fiberboard cores may be used along withspecial elastic adhesives and fabrication processes which all contribute to a floor that willaccommodate excessive moisture and excessive dryness
Can the floor's temperature exceed 85 degrees?
Second, check the floor temperature requirement. Most companies say not to
exceed 84-85 degrees F after installation. This is relatively easy to control but takessome experimentation to get it right. If the water temperature in your boiler is, say, 115degrees F, it may end up being 85 degrees F by the time it gets to the second floor. Youhave to test throughout the house. Closer to the source of heat will be hotter.
The danger in exceeding 85 degrees F is to dry the wood out completely. If this happens,it can split the wood.
- All wood is hygroscopic which means it absorbs moisture andthen gives it off.
- This causes the wood to expand and contract which is a natural process.
- However, when the floor is heated too much, it can stress the wood causing it to warp,twist, buckle etc. beyond its normal capacity.
Third, acclimate the flooring properly. Acclimation refers to the adjustment timefor the moisture level in the wood to synch up with its new environment in your home.
- Unlike solidwood products, engineered flooring generally requires very little, and in some cases,no acclimation.
- However, there may be strict requirements for the sub-floor moistureconditions prior to installation.
The drying process is something that can't be ignored as it will definitely createproblems for any type of flooring if the heat is cranked up right from the get go. Mostmanufacturers who warrant their flooring over radiant heat require a gradual increase infloor temperature over a period of several days in order to make the transition to a lowermoisture condition as natural as possible.
Speed is the key here. Going too fast forces too muchmoisture out of the concrete and into the wood which may stress the wood.
Moisture is always the key factor in determining suitability. If the subfloor is damp,it will need to dry out. All new concrete floors are full of moisture when new and needtime to dry out. If a concrete floor has been poured 6 months ago, which is typical, it isassumed that most of the moisture has dried up. This can be true if the weather is hot anddry most of the time. But in some states or times of the year when it rains a lot or it's verycool, concrete can take months to fully dry.
While radiant heat will certainly dry things out more quickly, you don't want yourflooring to be sitting on top of a damp subfloor when this process starts.
Using proper moisture meters or moisture testing proceduresare vital to this process.
- These can be rented from rental companies or purchasedon line. Most experienced contractors have these too.
- Each manufacturer will provideyou with specific details about the proper moisture level for their floor.
- If you don't see itwritten, call them and find out.
- Check Wikipedia's page on concrete moisturehere.
If you ever have a warranty claim, the first question the manufacturer will ask youis "what was the moisture level of your floor and your subfloor". If you don't knowbecause you did not test, then your chances of getting them to accept your claim will beseriously compromised.
Bamboo over radiant
Back to your original question: "Can bamboo be used over radiant?"
Yes, therecertainly are some manufacturers who make products for this purpose and others whodon't.
- The Teragren brand of bamboo, for example, makes several types of engineered floating floors that are alldesigned for radiant heat. Most can be floated over your linoleum floor.
- Kahrs hardwoodflooring is another favorite brand which invented engineered flooring in Sweden where80% of the people have radiant heated floors.
A Radiant Heat Primer
There are basically two types of radiant heating methods: electric and hydronic. Somemanufacturers will warrant their floors over both and others only over hydronic.
Regardless of how the energy is created to produce the heat, both methods are used:
- insideor on top of concrete slabs, or
- underneath or on top of wooden subfloors.
Wood, bamboo, linoleum, cork, tile and carpet all have different R-values from 1-3 andthey typically use an underlayment or pad with an R-value of 1-2. The question naturallyarises whether the radiant heat can get through all that.
Radiant heat is infra-red whichmeans it heats objects and transfers energy through any medium depending upon thedensity, humidity and thermal resistance of the object. It is well known that radiant heatcan and will penetrate just about anything no matter what the R-value. It may take longerto penetrate, but it will eventually get through.
Ideally, the lower the R-value in the floor and underlayment, the better. Some underlaymentsmade from synthetic rubber have extremely low R-values and are ideal for radiant heatedfloors because they allow the heat to transfer through more quickly. SCI DeciBlok is an example of this.
Radiant heat transfers heat through the floor to your feet and eventually your entire body.
Slowly, quietly and naturally the heat moves in all directions unless it is reflected bya "radiant heat barrier."
Radiant heat barriers
Radiant heat barriers are usually recommended to keep the heat from being lostdownwards or through the ceilings or walls of your building.
- These barriers are usuallyin the form of a foil backed bubble wrap material or in the form of tiny glass beadsadded to paint and sprayed on the walls or ceilings.
- Radiosity 3000 is an example.
- Both are highly recommended as a means to keep the heatinside your home.
Radiant barriers can also reflect the sun's energy back outward keepinga house cooler too.
For more information:
Read "We are considering radiant heat. Will manufactured bamboo flooring stand up to the challenge?" a Q&A answered by Lily Livingston.