Why is back priming recommended?
Frequently today’s homes are wrapped with a vapor barrier, i.e.; Tyvek or foiled faced insulation which does not allow large moisture droplets to flow through. This coupled with the fact that siding is often times not vented; the moisture is trapped behind the siding. Back priming natural wood siding helps control rotting, mold build up, cupping and movement in the wood, ultimately giving your siding and your stain finish more longevity.
Now, if you are like me, you are wondering where is the trapped moisture coming from? It occurs either when heated or air-conditioned air from the house radiates out and meets the cold or hot outside air. When the dew point is reached, moisture is formed in various sized droplets. On fall mornings, this phenomenon is evident on your car window. The temperature inside your car is warmer than the outside temperature. When the dew point is reached, dew in various sized water droplets is formed on your car’s windshield.
The chance of moisture collecting on the backside of siding increases in the summer, when the humidity is high. Add in the high temperatures and you have a mildew growth and deterioration at its greatest rate.
Protect new wood siding and natural exterior finish before it is installed by back priming with one coat of NatureColor® Base Coat or NatureOne® 100% Acrylic.
This article courtesy of Jan at Structures Wood Care
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