Setting your house post

I've got a question about the post. I'm a bit concerned with the weight. I've added the trays to the houses so they really weigh a lot. It has been suggested that I sink the post four feet rather than three. This would be for extra safety. I plan on having at least 15 inches in diameter for the hole. What do you think?

To answer your question, sinking the pole down 4 feet won't hurt anything. Most people set the pole, including myself, at 3 foot because that covers the depth needed to go below the frost line in just about all areas where martins fly. It is also about all the further a person can reach down to clear out the dirt, easily. At three foot, the t-14 has not had any problems with stability other than people worrying about it, nest trays birds and all. Some folks have even converted the house to mount on a 3" pipe for their concerns. It is suggested by some folks to be a weaker setup because steel does not flex as "easily" as the wooden pole and over time, the steel could develop metal fatigue, thus becoming weaker.

If anything, more problems arise due to how the pole is built and how it is set in the ground. Lots of people do not understand the nuances of lumber and how to counteract inherent problems, for example buying wet lumber, bowed or twisted boards and similar characteristics that hamper building a "straight" pole. These problems can be eliminated by choosing good straight lumber, letting it dry completely and then assembling the pole so one twist counteracts another twist and produces "straight". The use of clamps to help straighten things is also simple yet overlooked by many. Glue can also aid in a much stronger lamination just as well as a good paint job can add in sealing out moisture which could, in the long haul, weaken the lamination. As far as setting the pole the instructions work just fine also but, if you feel a need to go a bit more "solid", here is how I would do it.

At the bottom of the hole the diameter is critical only in one way. The bottom of the pole must remain fixed. When you are ready to set the pole make sure it is plumb (straight up and down looking at it from North/South and East/West directions using a level). Take one or two bags of cement mix and throw in the bottom of the hole so that about a foot of the pole is covered. If you have a small diameter hole it may only take one bag of cement. Now add a couple gallons of water and take a shovel or broom handle and poke it around in the cement and the water a little, just enough to introduce the two. This will keep the bottom of the pole from moving. If you add too much water and make the mix muddy, the pole is going to move. If you leave it a little dry the pole won't move and over time the moisture from the ground will set up the cement like rock. Now, recheck for plumb and then fill the hole with "pea rock" or "one half inch white rock and finds" up until you have enough room to fill the rest of the hole with mixed cement, about two bags worth. I would make the top of the hole about two feet in diameter so if you eye ball all this I am guessing your two bags of cement for the top would fill in around the pole and down about a foot or two. It may take three bags of cement if you didn't use much rock. The whole point is to anchor both the top and bottom of the pole in the hole and this will be so strong the pole would have no choice in moving anywhere by any amount of wind.

My pole over the years began to tilt because I didn't anchor the bottom like I should have and because I made the top about 15" in diameter, the cement cracked and eventually loosened up. So, there ya go. If I didn't confuse you, you should do just fine with setting your pole. Good luck :-)

What's a frost line???

If it freezes during the winter the ground develops a frost line, the colder it gets the deeper the frost line. Any ground below the frost line will not move and anything above the frost line expands and contracts with thawing and freezing, respectively, because there is always some moisture in the ground. This is very important when you build things. If you build a house on a slab of cement in Iowa the drywall will crack, windows will get stuck shut, doors won't open and close and you will have a mess in general, because of the "heave", the expansion and contraction from fall to winter and then into spring. Of course we don't build like that in Iowa because of the extreme temperature changes between seasons. We dig down and build foundations and any problems with heaving, are usually eliminated. If you set a martin house pole above the frost line, it would eventually work its way out of the ground over the years. Setting it below the frost line anchors the bottom in stable ground and the "heave" of the ground above just slips by the cement and pole, so to speak. It's not like you can see the heave or measure it but, minute moves over periods of time can create havoc.

Copyright © 1998 to present Jeffry Blair.