| Pressure treated southern yellow pine is one of the | | | | timbers are rated for outdoor use at .25 retention |
| most popular woods used in fence building. It is | | | | level. The landscape timbers are not treated to be |
| readily available, inexpensive, and has a long life span | | | | put in the ground around constant moisture. This will |
| if installed properly. Most southern yellow pine lumber | | | | cause the timbers to rot and become brittle, and |
| is treated with Alkaline Copper Quaternary. The | | | | eventually break at the ground's service. Pickets and |
| process of "pressure treating" involves immersing the | | | | 2x4's need to be rated for outdoor use, or .25 |
| lumber in the chemical and placing it in a pressurized | | | | retention level. |
| chamber. The pressure causes the chemical to | | | | Since they will not be below grade, this rating is |
| penetrate the wood. The wood is then given a | | | | suitable for their use. You may want to raise the |
| retention level. A retention level simply means how | | | | pickets an inch off the ground when installing them |
| much of the chemical is retained by the wood. | | | | so they are not in direct contact with the ground. |
| The higher the retention level, the better resistance | | | | This will prevent the picket from soaking up moisture |
| to the elements. Different outdoor projects call for | | | | from the ground which results swelling and rotting. |
| different retention levels. Marine grade lumber, used | | | | Although you need the proper retention level, there |
| for piers or boat marinas in salt or brackish water, | | | | is no need to over do it. .25 retention for the central |
| has a retention level of 2.5. Ground contact lumber, | | | | area of NC is fine for pickets and 2x4's. There is no |
| or lumber to be put in the ground, has a retention | | | | need to spend time hunting down lumber with a |
| level of .40. Outdoor use lumber, such as 2x4's and | | | | higher retention level and paying more for it. In some |
| pickets, has a retention level of .25. It is important | | | | cases, over doing it can cause violations. The EPA |
| you select the lumber with the proper rating for your | | | | mandates all marine grade lumber, or lumber with a |
| project. When installing a wooden fence, it is very | | | | retention level of 2.5, must be placed in salt water or |
| important that all posts are rated for ground contact, | | | | brackish water. If it isn't, they can give you a fine. |
| or .40 retention. | | | | The chemical level is too high for normal use and can |
| It has happened more than once that someone, a | | | | pollute the soil and nearby water sources. |
| home owner or even a professional, has gone to the | | | | When building a wooden fence, make sure you get |
| lumber yard for fence posts. He or she sees the 4x4 | | | | lumber with the proper retention levels. The key |
| posts for about $7.00 each, and right next to them | | | | word is "proper", not too low and not too high. The |
| are landscape timbers for about $3.00 each. The | | | | retention levels in this article are suitable to the |
| lumber looks about the same and it seems like a | | | | Raleigh area of North Carolina. If you live in a |
| good way to cut down on material costs. This is a | | | | different part of the country, you may want to |
| big mistake! If you look at the retention levels, you | | | | check the local building codes for retention levels in |
| will see the 4x4 lumber will be rated for ground | | | | your area. |
| contact at .40. You will also see the landscape | | | | |