The Effect of Moisture on New Construction


We just received a question on the website relating to caulking gaps and openings along joints within a new home. The person asking the question was concerned that these gaps, openings and miscellaneous cracking that was occurring was an indication of poor labor practices or techniques. Based upon that question let me clarify the numerous effects of moisture within a home, especially a newly built project.

  1. Wood as a natural growing product is saturated with water as a growing tree. Water is obviously crucial to the health of the tree as well as its ability to grow.
  2. Once the tree is cut for lumber purposes, the moisture within the tree starts to dry out. There are various processes that enhance and promote this drying of the lumber. However, not all the moisture is removed. This is a physical impossibility especially with the industry expediting the timing of cut lumber to sales.
  3. Depending upon the type of wood, the porosity of the wood and the type of drying that the cut lumber received will determine the amount of moisture that remains in the lumber as it is used within your new home.
  4. Techniques such as minimizing the horizontal stacking of wood members during the construction are used to minimize the effects of any moisture leaving or drying from the wood. For example the stacking of ( 4 ) pieces of lumber would increase the shrinkage by a factor of ( 4 ) in comparison to a structural concept that only has a single piece of lumber. Awareness of shrinkage is key to the reduction of negative impact due to moisture leaving the structural framing.
  5. In some situations the acclimatizing of the wood is performed prior to installation. Wood flooring is a perfect example. The flooring is delivered to the site and stored for a period of time to allow the wood to balance itself with the environment. This will not eliminate shrinkage, but will reduce the negative effects of severe shrinkage.
  6. The use of more stable materials such as fiberglass or composite board is beneficial to the reduction of shrinkage. Trim work that is going to be painted will be more stable if a synthetic material that is not subjected to moisture is used. Wood trim will shrink.
  7. Builders’ awareness of shrinkage is also an important factor in providing trim where shrinkage is minimized. The proper nailing, gluing, doweling or jointing will reduce the amount of gaps, openings and joints that will appear in the trimwork as the wood dries out.
  8. Careful purchasing of wood materials that will be subjected to shrinkage effects is important. As mills try to recover from the COVID shortfalls in production, drying processes will be expedited. It is important that builders understand this and adjust their installations accordingly. Trim that is installed in a new home after the interior air conditioning or heating is completed and started will be less subjected to movement and shrinkage.

The effects of moisture within the framing lumber, the trim, flooring, etc. is an important aspect of home construction. Knowledgeable builders that are both experienced and honestly concerned for their clients, will make efforts to minimize the negative effects of the drying out process. Builders that have no clue will not. This is one of the reasons that taking the lowest quotation for your new home is in many instances not the best decision. A builder that appreciates craftsmanship will take into consideration all of the issues that moisture can and will affect.

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