What Kind of Wooden Beam is this

Question

My wife and I recently purchased our first home. We'd like to make a flattened area in our backyard (which is somewhat sloped) for a firepit. My thinking was to dig out a shallow area and fill it with gravel, then place the firepit on top (similar to the picture above) What I'm unsure of is how to safely contain the gravel without it spilling over. I was imagining some kind of retaining wall thing. This picture clued me in on these wooden beams, which I like the look of and I would expect are less expensive than building a stone retaining wall (probably more practical too).

The Question:

What are the wooden beams called in this picture?

Bonus Question(s):

• Do you see any issue with using these wooden beams to contain the gravel?
• Would you expect these Beams to last several years or would you expect them to deteriorate quickly?

Any insights would be greatly appreciated.

BTW, if my question needs to be edited in someway, let me know and I'll edit it ASAP.

Answer 1

"Landscape Timber" or, sometimes, "used railroad tie" - but "landscape timber" is what you'll find at most typical lumber suppliers.

They will typically last several years - if well pressure-treated, longer. It's hard to know if they are really well pressure-treated until they start failing and you look at a calendar to figure out how long it's been.

Concrete "fake stone" retaining wall blocks will last longer, generally speaking. So which costs less depends on how long a time you are considering when judging the total cost.

You probably want a geotextile fabric layer between the soil and the gravel to keep the gravel from migrating into the soil over time.

Answer 2

The answer is RAILROAD TIES.

The timbers in your photo are Railroad Ties. The railroad will change the ties on a regular basis. They are impregnated with creosote and as a result they are very heavy. In Alaska the railroad will give the old ones away for free occasionally. I have built retaining walls with them.

For the purpose of your fire pit area they are cheap and they work, if you do not care about the creosote. Some are in better shape then others.

Treated 6x6 or even 4x6 timbers would also work.

There are more options for this then i care to list here.

Answer 3

Those are railroad ties

They are used in the track bed of railroad track. They are typically either 6"x8" or 7"x9", and 8' long (your photo does a good job of hiding the joints). They weigh 150-200 pounds.

They are heavily laden with creosote preservative, so you won't be doing any organic gardening near them... And using them in a sandbox or around kids is questionable.

They will have a mottled appearance from transferring the weight of railroad trains onto the jagged 2" cut stone ballast used in track beds.

Answer 4

Residential Developer-railroad ties....these are used all across the US for this and other secondary purposes. You will not find these at box suppliers like HD or Lowes.