Treated syp vrs NE white cedar

[hawghead10]

Hi everybody
I am at a crossroads here as to use treated syp as apposed to north east white cedar as what timber would last longer in a ground contact retaining wall. The cost is equal.

Thanks
Brian

[VTwoodworker]

Both timbers would be a good choice and probably have about an equal life.  I think the choice would be dependent on the particulars of your project.  Unless you have access to really good EWC the lengths of the timbers maybe limited to shorter lengths than treated SYP.  If the wall is substantial and if the timber strength is a factor then that would favor SYP as EWC is lower strength.  If you are using treated SYP be ready to treat the cut ends as the treatment does not go all the way through and it is more of an envelope.  I have replaced treated SYP after 10 years on the ground due to improper details.

In my neck of the woods folks use a lot of hemlock and tamarack 6x6 for retaining walls.  The life is not equal to cedar or treated timber but probably 1/3 ot the price.  My experience with using hemlock is that if you backfill right behind the wall with 3/4 inch stone the life of the wall can be extended.  The stone is not as friendly to ants and somewhat lowers the moisture content.  I would estimate 15 years for hemlock and probably 25 for the cedar and treated SYP.   Wayne

[Chuck White]

I agree with VTwoodworker! 



VTwoodworker wrote:
If the wall is substantial and if the timber strength is a factor then that would favor SYP as EWC is lower strength.