In August of 2023 I dug a hole in the ground to put my radio tower in. I’m not always the most physically capable person, but I have my days. When I did this I had decided I would try “Secure Set” expanding foam from GRA Services. I ordered a utility pack and had contacted the company to determine the volume of the foam in question. It’s been a few years, but I believe the package I ordered was roughly 12 ft³. I thought I would do a blog post with the “2 years update” on that, since it’s a question I sometimes get. I also thought I would include some retrospect tips I thought I would share if I ever had to do it again.

So, first of all, I had to decide how big of a hole to dig. If you know me, a large hole isn’t something I dig every day, so, I’m honestly still impressed I did it to this day. I decided on a 24-inch diameter, and I knew it had to hold 12 ft³ of material based on what I learned from the company… Time for math. I ended up with my graphing calculator and Google, but if you try this project, there is a hole depth calculator linked on the top of this page, you may use that. One thing I will say, dig the hole a few inches deeper than the calculator says. Maybe 6 inches even if you can. I didn’t and there’s a small mound of foam sticking out of the ground. When I say I dug it to approximately 46 inches exactly, I’m not kidding you, and I don’t think that 12 ft³ is an exact science.

Empty Hole

As for putting the tower base in the hole, brace your structure before you pour, and make sure it’s level. Like, really make sure. When my good friend who’s a tower climber comes to help me with adjusting equipment on the tower, we always joke how I bought a bent tower, but it’s in the ground crooked at just the right angle to make it straight. I would recommend avoiding that if you can. But once you’re sure it’s right and won’t have any regrets—because you get one try to mix and pour your foam.

On the topic of pouring the foam: once mixed and poured, your first thought will be, “Crap, did I order enough?” Don’t worry — it expands. It really expands. Over the next five minutes you’re going to go from that to, “I hope it stops soon.” After this, just let it sit — it will set up over the next hour or so into a solid chunk of foam. Once you’re done with that, it’s a standard tower build. You can find better experts on building towers than me.

Hole Filling

So, the question on everyone’s mind: how does it hold up… Two years later is it still solid? Yes! Yes it is. No regrets, and if I had to put in another tower I would do that again. I think if I had to fill that hole with concrete I would not have been able to do it myself, and it worked out well. It’s still solid, and the Secure Set is a good product. If you’re going to set a base for an amateur radio tower, I think it’s a good option. If my 88-year-old grandfather and I can do it, you have a pretty good chance of doing it too.

Hole Filling