Finding and fixing the cause of sweating subflooring is a must to prevent damage to flooring materials above the subfloor, and the growth of mold and mildew in your home. Follow this procedure to stop subfloor sweating.
Step 1 - Find the Source of the Problem
The subfloor may be sweating due to condensation between it and the concrete base, wall condensation that is seeping into the flooring, or sweating around cold water pipes. Identify the cause of the sweating before attempting repairs and preventive measures.
Step 2 - Repair Wall Condensation
If your subfloor is saturated near walls, lift out the damaged surface flooring and subflooring and install moisture barrier insulation in the walls. Place a moisture barrier under the new subfloor.
Step 3 - Lift Subfloor off the Concrete
Use a product such as DriCore (TM) or Thermal Dry (TM) under your subfloor to channel moisture to weeping tiles or a sump. The dimpled, padded membrane of these moisture barriers lifts your subfloor providing air circulation to evaporate moisture. They also keep the floor warmer, reducing condensation.
Step 4 - Insulate Cold Water Pipes
Wrap a thin layer of polystyrene sheet insulation around all cold water pipes to stop condensation and subfloor sweating.