Once moisture has entered the exterior siding, moisture barrier, and inner walls exponential damage has started. Evaporation and condensation cause soaking of structural lumber promoting rot, twisting, swelling and uneven expansion and contraction. Most builders and painters use a one pass mentality and inferior products when it comes to sealing flashing, siding, window and door trim. The smallest hairline crack in caulking or brick mortar on a horizontal or vertical run can start the destructive process. Improperly installed step flashing and gutter systems can also be the culprit. Another aspect to consider is the load distribution of the building. If one section of wall framing becomes soaked and rotted this distributes the weight of that load barring wall to other areas of the foundation causing undue stress and the appearance of foundation problems. In 2003 our company performed over 1500 separate siding, door and window remodeling jobs. Itís disturbing to say that approximately 75% of them were directly related to improperly installed or substandard moisture barriers and a lack of Preventative Maintenance in regards to painting, caulking and mortar.