Subfloors should be clean, flat and dry. Failure to make sure this is the case can lead to a host problems, like loosened planks, squeaky joints, deflecting boards, uneven surface etc.

So, the first thing to take into consideration is moisture content as discussed under "check moisture” and make sure wood is dry. Then you need to secure clean surface, meaning all debris and dirt must be cleaned and removed from the subfloor so as nothing interferes with the adhesive when it´s applied. Finally, the floor must be flat prior to installation and we mean to industry standards. Finally, it is crucial to make sure surfaces are clean, flat and dry and moreover, get this done right the first time!