DIY conversation in our email inbox: (do you have a question yourself - use this form to ask us)
When installing Underfloor heating systems and deciding on the floor covering on top, many recommend to use Wood-Engineered flooring. These types of boards are more stable and can handle the changes in both temperature and air humidity better than solid wood floorboards (solid design parquet is a different matter all together).
When we received the following question we advised to take care - it is not impossible to install solid wooden floorboards on UFH systems but there's a but....
Random width boards
"This is a new build & we plan to lay solid oak floorboards (random widths) onto a self-levelled screed. There is underfloor heating & the screed is well dried out now. We've been told that gluing is the way to go, but reading thru some comments on your site I'm getting questions ... can we put the glue just into the groove thereby effectively having a floating floor? or do the boards need to be glued underneath? do we need floorboard crampers or could we use some softwood and rubber mallet?"
Words of caution
Thank you for your question. With wooden floors and UFH it is recommended to fully bond the floor to the concrete underfloor to avoid air gaps. For this you should use flexible adhesive that is suitable to be used on UFH.
Word of caution: UFH and solid wood floors are only agreeable when the solid floorboards are narrow. Otherwise there is a great chance the floor will shrink too much during the heating season.
Wood-Engineered floors are better suited in this situation due to their construction, see our Duoplank range page for more details.
"Many thanks for this Karin. Yes of course, very silly of me, couldn't do 'floating' as it would compromise the UFH!
We've had the boards for over 12 months indoors, they look pretty good ie not bendy.
Max width 160mm - would you say?"
160mm is rather wide, it depends on the other sizes and the number of 160mm boards. Try to keep away from installing two wide boards next to each other and leave a wide enough expansion gap all around.
"The widths are 100; 120; 140;160 up to 200mm. The wider ones we'll keep for upstairs to nail.
My other question tho is do we need the crampers or could we knock them 'home' with a long piece of soft wood & rubber mallet? "
100, 120 and 140mm should be ok, as said before, try to avoid placing 2 x 160 or even 1 x 140 next 1 x 160mm and you should be alright.
If the quality of the T&G is good you won't need crampers, just "knock" them home indeed.
I take the liberty to also email you - separate email through our automated system - our special leaflet with how to treat your UFH before, during and after installing a wooden floor.
"Thanks very much for your comments. We have had the solid oak flooring for a few months now. It's getting the time to do it."
Further info - because it's summer
When you install a wooden floor over an Underfloor Heating System in the summer months you often don't have the system switched on (if it is a new system, it will have had its pressure test to check for leaks no doubt). Our special leaflet - see link above - tells you how to start up the system gradually before installing the wood floor.
Doing this before installation when the temperature outside has reach Mediterranean level would be a bit OTT indeed.
Instead, raise the temperature of your UFH system gradually once the Autumn arrives, so your wooden floor (all wooden floors) can adjust gradually to the changes in "climate".