Wood used in construction has usually been dried to some extent. If exposed to moisture it may reabsorb water, causing the wood to swell and its dimensions to increase. This can cause buckling or other problems.



(1) original percent of moisture content

(2) percent moisture content after exposure to water

(3) original measurement in cm

(4) shrinkage value (SV) in percent as the wood goes from green to oven dry. The SV varies with each species of tree.

(5) fiber saturation point (FSP) for the wood, which is usually 28%


increase in moisture content in percent =

= (final moisture content in percent) - (original moisture content in percent)


increase in dimension in cm =

= (original length) * (shrinkage value) * (increase in moisture content in percent) / (fiber saturation point) =

= (original length) * (shrinkage value) * (increase in moisture content in percent) / 28%


final dimension of the piece of wood in cm =

= (original dimension in cm) + (increase in dimension in cm)


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