We are installing an engineered floor in new construction. The flooring is 5" plank 1/2" thick. We are using the staple or nail down installation. Currently there is 3/4" osb as the subfloor. I would like to build up the height of the floor. Would it be appropriate to use 1/4" luan or should I get plywood? Do I place the felt above the underlayment or below?

Thanks for your help,
Ted

It looks like no one answered your question. What did you decide to do? The folks in the flooring dept at Lowe's recommended 1/4" luan plywood over regular plywood. It was much smoother and seemingly more ding resistant than regular plywood. You'll just want to be sure that it is completely flat when done.

Luan should be fine. The felt goes under the floor unless the manufacturer recommends otherwise.