Subfloor cannot expand and contract. All wood fiber subfloor materials need to be installed with sufficient room to expand and contract as the ambient temperature and humidity changes. TrimJoist provides a wide surface so that framing tolerances may be eased enough to eliminate this problem.
Many contractors use a composite underlayment board in areas that require carpeting.
This underlayment is non-structural, but provides a very smooth surface. More often than not, the underlayment is attached only by nails. Over the course of time, these nails begin to rub against the underlayment causing squeaks. We suggest that the underlayment be attached with both screws and glue with the same care as was taken with the subfloor. Subfloor not adequately attached to joist system Conventional 2x joists or narrow flange I-beam type wood products do not provide sufficient surface for good nailing technique.