Wood in dirt

August 6, 2021 11:30 AM

I'm trying to build this address sign. The instructions involve putting an untreated 1x4 into the dirt. Seems bad. I'm not into pressure treated lumber, so I'm deciding between a redwood 2x4 or a metal sign post.

Redwood is easier -- just screw the surface panels right on. Will this work?

I'm not quite sure how to attach to that metal pole. Those holes are big, so it seems to require fat bolts with unsightly (to me) bolt heads, so I'd probably attach vertical 1x4s to the pole (just the above-grade part) and then attach the horizontal boards to that? Complicated. Maybe I'm missing something obvious?

Advice?

posted by Spokane to Home & Garden (15 answers total)

What if you don't bother attaching it to the metal and just build it as instructed but with thicker inside boards that are cut level instead of sticking out? Then pound in the metal posts and just slide the sign part over it so it rests on the ground. You'll still need wood that's appropriate for ground contact, or to treat it with something that is, but it's not as much of an issue as actually having it buried. Or you could even put a bolt/short threaded rod through the post at ground-level to prop the wood up on. In any case though, it doesn't seem to me that there's any particular need to actually attach it unless you think someone's going to try to take it otherwise.
posted by teremala at 11:42 AM on August 6, 2021 [2 favorites]

The holes in the metal post are 1/2", so yeah, the bolt heads would be fairly big. But they also sell square tubing without holes so you could just drill smaller holes. You could also screw in from behind so the front face is unaffected. You's probably want to glue a vertical strip down to the back of the planks and then you could screw into that.
posted by jonathanhughes at 11:48 AM on August 6, 2021 [1 favorite]

Yeah you can get some aluminum tubing with no holes and it will work great. Aluminum is much softer than steel, so you can use regular drill bits to drill holes in it (watch out for spalling and wear goggles!!!) You can also probably hide the bolt heads as jonathanhuges is suggesting.
posted by goingonit at 11:56 AM on August 6, 2021

Response by poster: Okay, thanks! So let me see if I understand this plan.

- Get aluminum tubing without holes (that link look right?)
- Use vertical 1x4s to hold the horizonal boards together without having to make that many holes in the tubing. (Or could I skip this step? I liked how thin the other sign looked.) I'd screw it to the horizonal boards from behind for the front panel.
- Attach the tube to the vertical piece. I'm assuming I'd screw through the full square of the tubing, not that there's some magic way to come in from the center, right?

The sign is double sided, so I could screw in the front panel from behind and then have visible screw heads on the back, which is fine.

Thanks! Appreciate all the help. teremala, I'm not confident that my weather treatment would hold up well to ground contact for similar reasons, but you make a good point that I'll consider if I can't figure this other approach out.
posted by Spokane at 12:14 PM on August 6, 2021

You don't have to fill the holes in the metal pole in this application merely run screws/bolts thru the holes. So you can use whatever size/style of screw you find asthetically pleasing.
posted by Mitheral at 12:14 PM on August 6, 2021

Response by poster: Mitheral, there are wood panels on both sides of the tube so would I have to get nuts down into the tube somehow? Oh wait, suppose I screwed in from the back panel (visible screw heads are fine) but then didn't come out the front of the front panel. That sounds like it might work! Being screwed into the front panel would keep the screws from pulling out of the holes.

Okay, that's the new default plan -- anyone see a problem or have tips about that one? (It saves me a trip to Home Depot!)
posted by Spokane at 12:25 PM on August 6, 2021

You could fix your perforated 1" square steel tube to the 1" inside edges of your vertical 1x4s before assembling the horizontal pieces onto them, using lag screws with washers under the heads. You'd want to pre-drill holes for the screws into the 1x4 edges so as not to split the wood. That way all the heads would end up completely boxed in and you'd never see them.

You could even paint the steel tubing black before doing that, so as not to have little flashes of silvery metal peeping out between the horizontals.
posted by flabdablet at 12:29 PM on August 6, 2021

Didn't follow, from the directions for the address sign, how the builder thought the redwood would survive being buried in dirt. Uneven wetting and drying practically guarantee warping. I'd make sure that the bottom of the sign had an inch of clearance above the ground, so that it dries evenly. For the posts, I'd set them in concrete rather than in the dirt.

If you go with metal posts, you'll still want the wood of the sign itself to be well out of the dirt. And while you might not need to give them concrete "feet," I'd do that just to ensure that the sign stays upright. (Lowers the center of gravity and the "feet" provide lateral support against tipping.)
posted by SPrintF at 1:02 PM on August 6, 2021

how the builder thought the redwood would survive being buried in dirt

To be fair, it probably would survive long enough to get posted on Instagram.
posted by flabdablet at 1:05 PM on August 6, 2021 [10 favorites]

You didn't ask about this part, but I've seen enough mis-aligned house numerals it might be worth pointing out: if you have both rounded and straight-edged numerals, you can't just align their bottom or top edges to a straight line or it will end up looking slightly wrong. Rounded numerals need a small amount of overshoot beyond the baseline and cap-height that you'll need to figure out by eye. Regardless, with this type of numerals the difference would be small enough that at least there's no chance of ending up like the BE^_ST BUY that drove me nuts for years.
posted by stopgap at 3:00 PM on August 6, 2021 [5 favorites]

Personally, I would bury something like this with just an inch or less showing above the ground, and I would stick to the plans as listed, mounting these to sunken chonk(s) of concrete, affixing the 1x4s to the metal bracket. Depending on your paint and the exact metal used on the bracket, you might want to spray-paint primer on the bracket and then paint it.

"Fence post bracket" is what you want to search for, with your desired dimensions. 4x4 fence post will give you the widest variety of options (to sink into dirt, concrete, whatever) but other fence posts exist.

Cedar does not have the anti-rot properties its reputation has been earned on; that reputation was largely gained by older growth stuff that is not readily available to purchase these days (thank bog). Go pressure treated (with drainage!) or metal sunk into the ground. Otherwise you're gonna redo it in 3-4 years.
posted by furnace.heart at 6:08 PM on August 6, 2021 [2 favorites]

I like your first instinct, but would use carriage bolts and acorn cap nuts to give a sleeker, less industrial look than you'd get with hex bolts and standard nuts.
posted by kate4914 at 6:24 PM on August 6, 2021 [2 favorites]

You could use Trex or other plastic lumber for the vertical pieces or even colored Trex for the whole sign. It will never rot. Just use small headed brads or deck mounting clips to attach the horizontal pieces to the vertical.
posted by Marky at 7:44 PM on August 6, 2021 [2 favorites]

get 2 of these:

https://www.homedepot.com/p/Grip-Rite-3-4-in-x-18-in-Round-Stake-STKR18/202090775

.. drive them into the ground, and screw your wood to it (the stakes are full of holes just for that).
posted by the Real Dan at 9:51 PM on August 6, 2021

Another way to do this, without leaving visible screws on either the front or back, would be to use dowels.

You'd need to drill holes in the hidden sides of the outer wooden planks, stopping short of the outer surface. These would need to be marked up so that they line up with each other and the holes in the metal sign post, or whatever else you use in the middle.

Then you just put dowels of the necessary size through the whole sandwich, with a bit of wood glue on the ends.
posted by automatronic at 3:22 PM on August 7, 2021