Replies

1. 
   charlie_sullivan | Jan 01, 2016 01:44pm | #1

   I assume you are talking about the sub-floor? There are plywood and OSB subfloor materials that have extremely low formaldehyde emissions, including the common Advanctech OSB subfloor. But if you want to get away from it completely, it's possible to go back to the traditional pine board approach, laid perpendicular to the final floorboards. It's harder to get it perfectly flat, and I assume it is more likely to develop squeaks long term. It will leak air easily, but if you have a good plan for air barriers that doesn't count on that floor being one of them, that's not a concern. It would also leak water if you spilled water on the floor, so I wouldn't recommend it for a kitchen or bathroom.

2. 
   iLikeDirt | Jan 01, 2016 04:25pm | #2

   One option is a concrete slab, if it's on grade. You can get lightweight precast concrete panels too, if it's above a crawlspace or for a second floor. Another option is a masonry "block and beam" subfloor, which is very common in parts of Europe (example: http://www.farleygroundworks.com/foundations-for-a-house-near-reading-part-4/).

3. Expert Member
   MALCOLM TAYLOR | Jan 01, 2016 06:23pm | #3

   John:
   http://www.columbiaforestproducts.com/library/information/frequently-asked-questions/

4. GBA Editor
   Martin Holladay | Jan 02, 2016 06:28am | #4

   John,
   As Charlie noted, plywood is usually used as subflooring, not flooring. Charlie is also correct that softwood boards make a perfectly adequate subfloor; that's what I have in my house.

   One final point: researchers have looked into the sources of elevated formaldehyde levels in indoor air, and to the best of my knowledge, plywood subflooring is not an important source of such formaldehyde levels. Far more worrisome are cheap cabinets and cheap furniture -- although tightened regulations are addressing this problem.