Simple Solution:

Long spans of porch or deck railing will, over time, start to sag in the middle.
To straighten out the railing, cut a tapered block out of a 2×6 and wedge it under the middle of the railing.
Secure the block to the decking or porch floor with two decking screws.
Listen to the embedded audio clip above to learn more about this Simple Solution!
Read the blog from the April 6 Today’s Homeowner Radio Show and listen to the full broadcast here