A comprehensive educational community devoted to trim carpentry, finish carpentry and architectural millwork. Hosted by nationally recognized author and finish carpentry specialist Gary M. Katz.
 
     
  Durable Exterior Trim: Equilibrium Moisture Content  
 
 

Moisture Content vs Relative Humidity

Relative Humidity
Moisture Content
0
0
25
5
50
9
75
14
80
15-16
90
20-21

*Taken from: Understanding Wood, by Bruce Hoadley;
calculated at 70 degrees F

For Flat-grain Softwood: every 4% change in MC = approx. 1% Change in Size



 
Shrinkage Values of some Oregon wood species based on their dimensions when green          
(values are in percentages)        
 
Dried to 20% MC
Dried to 6% MC
Species Radial
Tangential
Radial
Tangential
Incense Cedar
1.1
1.7
2.6
4.2
Port-Orford Cedar
1.5
2.3
3.7
5.5
Western Red Cedar
0.8
1.7
1.9
4.0
Douglas Fir (coast)
1.6
2.5
3.8
6.1
Western Hemlock
1.4
2.6
3.4
6.2
Ponderosa Pine
1.3
2.1
3.1
5.0
Redwood (Old Growth)
0.9
1.5
2.1
3.5
Redwood (Second Growth)
0.7
1.6
1.8
3.9
         
From Wood and Moisture Relationships by J.E. Reeb; EM 8600, June 1995        
         
         
         
 
 
 
 
 
 
     
     
   
     
  Supported by corporations who care about education in the construction industry.  
 
 
     
  Andersen Windows  
     
  Festool  
     
 
 
     
  Mastering FInish Carpentry DVDs