UFH underlay for one side of open plan kitchen/diner

I’m planning on laying electric UFH in the kitchen side of an open plan kitchen diner and then finishing with 14mm Engineered Wood Flooring. The UFH is 2mm and the underlay for it is 6mm (minimum), will it make a noticeable difference if the on diner sider the underlay is only 5.5mm (probably fibreboard)? If so would it make sense to use 10mm UFH underlay in the kitchen and double up on the fibreboard on the diner side so there’s only a 1mm difference?

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Answer;-

To address this question about underfloor heating (UFH) and flooring levels, let’s break down the key points and consider the options:

1. Current plan:
– Kitchen side: 2mm UFH + 6mm underlay + 14mm engineered wood = 22mm total
– Diner side: 5.5mm fibreboard underlay + 14mm engineered wood = 19.5mm total

2. Potential issue:
The difference in height between the two sides would be 2.5mm, which could be noticeable, especially in an open plan space.

3. Proposed solution:
– Kitchen side: 2mm UFH + 10mm underlay + 14mm engineered wood = 26mm total
– Diner side: 11mm fibreboard underlay (doubled up) + 14mm engineered wood = 25mm total

This solution would reduce the height difference to just 1mm, which is less likely to be noticeable.

My thoughts on this approach:

1. Minimizing height difference: Reducing the difference to 1mm is a good idea. It will create a more seamless transition between the two areas and reduce the risk of tripping hazards or visual disruption.

2. Thermal insulation: Using a thicker underlay (10mm) for the UFH could provide better insulation, potentially improving the efficiency of the heating system.

3. Consistency in feel: By using similar total thicknesses on both sides, you’re more likely to achieve a consistent feel underfoot throughout the space.

4. Installation considerations: Ensure that doubling up the fibreboard on the diner side won’t cause any issues with the flooring installation. Some engineered wood flooring products have specific underlay requirements.

5. Alternative option: Instead of doubling up the fibreboard, you could look for a single layer 10.5mm or 11mm underlay for the diner side to match the kitchen side’s total height more precisely.

6. Door clearances: Remember to check that the increased overall floor height won’t cause issues with door clearances in either area.

In conclusion, your proposed solution of using 10mm UFH underlay in the kitchen and doubling up the fibreboard on the diner side is a sensible approach to minimize the height difference. The 1mm difference that would remain is unlikely to be noticeable in most cases.