Hetta overlay system with engineered wood floor

[Newbie1]

Hi wondering if anyone has experience with Hetta wet overlay UFH system with engineered wood flooring.

 

We had this fitted by our builder (background we had full renovation done and had wrongly assumed screed system would be fitted, we had specified UFH and engineered wood floor).
 

Work completed in summer and only when cold weather hit did we realise the system was not working well. Temperature in some rooms could not be increased and in smaller rooms no heat coming through at all.
 

All electrical and plumbing fine. Design fine for heat output required.

 

It is an Hetta wet overlay system, pipes are fitted into overlay boards. Problem seems to be the fitting of UFH with the engineered wood floor (which according to Hetta they system is designed to work for).
external opinion says It’s the flooring not in contact with the pipe work below, so poor heat transfer. Pipe work is just heating an air gap above. The floor is very springy and therefore lots of air gaps.
 

Any advice on how to deal with this without having it all ripped out and starting again?

[Jilly]

I love wood floors but someone on the forum spoke of having both stone and engineered wood in their house and the wood room was noticeably colder, so even though it's specified as ok, it still must reduce the efficiency, so that pushed me to a slate floor. I even risked not using the decoupling mats as the plumber thought it would reduce the efficiency of the floor. I suppose the ufh heat has warped the boards causing the gaps. It seems unlikely the builder laid it badly as you would have noticed a problem before?  

 

Someone will be along with a more practical answer, but you are right, it doesn't seem like there is an obvious easy answer. What is beneath the underlay boards? It's very difficult to get enough insulation under the floor in a retro fit, I'm always quoting Steamy Tea's physics lesson about this if you look back at threads. Builders' assumption 'heat rises' doesn't apply if you are heating the ground. 

 

 

 

[Temp]

9 hours ago, Newbie1 said:

It is an Hetta wet overlay system, pipes are fitted into overlay boards. Problem seems to be the fitting of UFH with the engineered wood floor (which according to Hetta they system is designed to work for).
external opinion says It’s the flooring not in contact with the pipe work below, so poor heat transfer. Pipe work is just heating an air gap above. The floor is very springy and therefore lots of air gaps.

 

What thickness Engineered wood?

What is the water temperature being sent to the floor? 

How much insulation under the UFH?

How well insulated is the house in general?

Do the return pipes get hot?

What was the pipe spacing?

 

We have Engineered wood flooring over UFH and 80mm insulation. We have a near two storey window in that room with no curtains. First winter we had similar issue, room not reaching set temperature. Had to crank up the flow temperature somewhat. Since then it's been OK. However other rooms with stone or tile floors have always felt easier to heat. 

 

Turning up the flow temperature is a risk to the wood floor but ours has been fine.

 

 

 

 

[Newbie1]

Hi I don’t have the specs with me but all of these have been ruled out. Flow rate has no impact, input water temp, insulation and soacing all over the spec. for the space it was designed for. The problem we have been told is that the wood is not in contact with the UFH pipe work so it is heating up the air in the gap between UFH heating and the wood floor.