How to place a mailbox - design problems?

Question

I am replacing elderly people's mailboxes for my Eagle Scout Project. In one area, there are three boxes on a PVC pipe over a large ditch. In order to get the boxes close to the road, there has to be a 4 foot extension from the post to the road. However, I am afraid that the entire structure will be too top heavy and will fall in towards the road. Any suggestions on designs? Thanks.

Answer 1

First of all; not knowing the size of the current PVC; I'd go large/thick wall PVC. 3 inch/ 4 inch. Certainly this could be done with metal pipe, but that would only add stress weight.

I'd "cement" a 90 degree elbow creating an "L" shape.

I'd probably do one mail box per support system.

I'd post hole dig the PVC into the opposing soil and pour concrete. Perhaps even into the PVC to a point that you feel might be at ground level. You might consider this HOLE to be 3 ft. deep.

I might then add another 90 to the pipe breaching the Ditch, add a small section of the PVC and add a collar I could then bolt to the bottoms of the mail boxes.

If you absolutely had to fix multiple boxes to the frame/support; you might go deeper with the hole; proceed to breach the ditch, add a "T" to the end of the breaching piece, and more PVC extending out, then bolt the boxes to that "T"

Certainly in measuring you'll need to determine an appropriate/ or USPS suggested height from ground level, and the weight factor of the pipe, when digging the post hole.

Just one opinion.

Steven Wolf

Answer 2

PVC isn't the best choice for mailbox supports. A wooden post has the best support with the least liability. If you go to your Post Office they will give you their publication outlining the standards for support posts.

In short, you don't want anything that will injure someone if it is struck, such as the previously mentioned iron pipe. No more than 2 boxes are allowed per support, so more posts is better, This is to prevent the 'guillotine' effect. We've all seen the half dozen or more boxes all attached to a board between 2 posts... well if someone were to hit that it would go right through a windshield at neck level. Not pretty.

As far as a cantilevered post to cross the ditch, consider a 4"x4" wood post with a 2"x4" top, but counterbalance it some. Use treated wood or paint it, of course.

Mine is a 5" natural cedar round fence post, I like that look better than square.

Here is a link to USPS.gov with a diagram of what you're looking for: http://www.usps.com/cpim/ftp/bulletin/2007/html/pb22206/mailboxkit.4.7.html#ep1309627

Answer 3

First of all ...Do know anyone that knows how to weld? And where do live? Cold in the winter? Have to put below frost line, possibly 3-5ft in the ground. 4-6" diameter round pipe,filled with concrete, heavy guage steal, 36"-48" above the ground surface the mailboxes will be.... weld another pipe to go across your ditch and witch will over hang the back by about 2ft to counter balance it... and weld a piece of flat stock 6- 10" wide and 1/4" thick and however long your mailboxes will be.... and bolt your mailboxes to that...Good Luck.....