Hi
I’m fitting an engineered oak floor in a week or so. I have started looking at the underlay but I’m not 100% which type I want / is best. My options seem to be a separate one piece damp proof membrane and an insulation without a membrane or an all in one insulation/membrane where the membrane overlaps and gets taped.
My thoughts are that a singe membrane is always going to perform better as there are no joints but a taped and lapped joint should also perform well as long as it correctly installed.

Any recommendations on the underlay? ideally around 3mm and I want the best insulation and acoustic properties I can find.

I have seen one called Novostat Comfort gold which is a combined insulation/dpm. is this type any good?

I have only ever done fully glued solid oak before but this engineered flooring came along at a price too good to turn down and should be a quick job which will do until we extend in a few years time.

Thanks

Andy

Another quick question.

How much better is 5mm than 3mm underlay?

I’m wondering if its worth putting 5mm down and taking up the extra 2mm on the door strip. It wont be noticeable.

I was advised to buy a good quality underlay, mine was 5 mm.

On a side note, the remains of the roll makes a great floor protector when decorating.

Whats it going on? floor boards or concrete? how flat is the floor / many bumps etc? is there a dpm in the concrete already? Is there insulation in the concrete? Check the building regs for the year of the house.

I laid our floor over 10mm rigid sheets of blue xps on an uninsulated concrete floor that already had a dpm and it made a massive difference to the room.

More is better than less. But if you already have a modern regs compliant insulated floor then a couple of mill won’t make much difference.

Glued mine down with some brown sludge at 50 quid a tub used 5.Works well with the underfoor heating.

If your floor is uneven and/or you need to run network/speaker cables I would recommend the 5mm. The extra depth helps even out the cables and uneven surfaces. This weekend I installed laminate flooring and used timbertech2 5mm with gold dpm backing. This was on concrete flooring, and so far so good. My laminate was 10mm on top, and the weight of the flooring reduced the overall height by a couple of mm. It is also quiet to walk on. I can’t comment on 5mm vs 3mm but I wouldn’t hesitate to use 5mm again.

I think the house is 1963 so I’m guessing solid concrete floor with no insulation. I’m unsure about how its damp proofed.
The more I think about it the more i’m convinced that 5mm is the better choice.