Floor over quarry tiles

[buthowto]

Hello! I need to put a new floor across a kitchen/sitting room. Existing floor is tiles on concrete subfloor. We're definitely not going to dig it up as some tiles on one side have asbestos in. 

We were imagining putting a layer (or roll?!) of insulation and DPM under engineered wood. I'm finding it confusing to work out what insulation might work under engineered wood. I've read about techni board. Would this work? Would the floor need battening around this? We can't go up too much without violating building control re bottom step- I think! We're replacing carpet and underlay so aiming not to increase height of floor too much over this. Any suggestions welcome! 

[Temp]

If Building Control are involved they might lean on you to dig it out to put more insulation in the floor than you have height for. I'm out of date but I think there are/were rules for where things aren't economic or impractical to upgrade. 

 

We have a concrete beam and block floor with 80mm high timber "battens" and 80mm PIR insulation between. Then 21mm thick Engineerd Oak  glued together and secret nailed to the battens. In our case there is also wet UFH with heat spreader plates in/on the insulation. Wish we had fitted more like >120mm of insulation. 

 

I think Building Regs require at least 18mm thick floor boards so beware if you were thinking of using 15mm Engineered flooring - you might need another layer of OSB or ? below it.