Shrinkage in Pressure Treated Post

[ironmon]

I'm working with a homeowner restoring and repairing an old house. In the basement we re-supported the main floor girder with (3)-8x8 pressure treated posts. Another contractor at the site bought up the concern of shrinkage. The posts are about 7 feet tall. I'm looking for info on an approximate magnitude of shrinkage in the longitudinal direction.

Shrinkage for green wood in longitudinal direction is about 0.1% - 0.2% So we are talking about an 1/8". I'm telling the owner, it's a valid point....but not a concern.

Your thoughts, links, opinions appreciated.

Iron-mon

 

[dik]

Shrinkage in the longitudinal direction should be next to nil... possibly in the order of 0.1%

Dik

 

[RARWOOD]

The o.1 - 0.2 figure is from a moisture content of 30 % to oven dry, a moisture content of 0. Generally longitudinal shrinkage is not of a concern. I would not worry about it.

The other question would be is pressure treated wood required. If the basement has a concrete floor by using a steel base plate 1" thick, you probably do not need treated wood.

The use of untreated wood would be a cost savings.

 

[Taro]

RARSWC, that depends where the house is. In some warm climate areas, ALL wood is pressure treated for termite protection.

 

[ironmon]

Location is the Greater Philadelphia Area.
And I do think it is prudent to use either steel (my first choice) or treated wood for posts in basements.