How-To Anchor Down Your Tiny House

How-To Anchor Down Your Tiny House

by andrewodom on May 21, 2011 · 1 comment


I am sitting here literally in the midst of a tornado watch. With nearly 700 tornadoes on record from the past two weeks and over 100 having touched down just last night, my mind is wandering through a number of issues.

Just two days ago as a guest on Backyard Poultry with the Chicken Whisperer I was talking about having just come out of a month filled with doubt, second thoughts, and clouded judgement. With Crystal being 19 weeks along with Tilly Madison (the Tiniest r(E)volution, mind you), our budget getting thin, and time waning on, it has been all I can do to stay focused on our real passion of simple living via minimalism and our tiny house. At times I have actually said to myself, “Maybe we should just get a sticks ‘n bricks and call it a day. Why go through all this? We could afford it….I guess.” And then I remember that Rome was not built in a day and that the pioneers spent years developing their small homes and plots of land. Something inside of me will not let me look my wife in the eyes and say, “I quit.”
The sky has become pretty dark right now and the rain seems to be blowing in sideways. I haven’t seen any hail but the birds have disappeared altogether. How then are we going to handle these situations in tiny house? We are an hour from the most active hurricane coastline in America and while we have built a windblock on our property we are fair game living atop a platform with wheels. Perhaps the most wise strategy is to be prepared. We will not wait until a storm is upon us to think about safety.

If building officials recommend that mobile home owners check their tie-downs — the system of steel straps and anchors designed to keep the home firmly in place — at least once a year then we will check twice a year. Once just before the hurricane season and once just after it. If repairs are needed we’ll make them despite expense. Safety known no price parameter sometimes. But I am getting ahead of myself a bit. Let’s first talk about an anchoring system.

There are three parts of the basic anchoring system:

  1. The anchors, or steel rods several feet long that screw into the ground. Only a few inches of the anchors should be above ground level; otherwise, they won’t have the holding power they’re designed for. We’ll be inserting ours into the wet concrete as it is being poured for our pad.
  2. Steel straps. They fasten around the frame of the trailer and are attached to the anchors with adjustable bolts.(NOTE: It’s hard to guess how many straps your tiny house should have, because the numbers have been set by engineers and changing state standards during the past 20 years and are for sticks ‘n bricks homes, to boot.)
  3. The piers that the home sits on. They’re usually made of concrete blocks stacked on a concrete pad, although a few homes may be on solid concrete piers, especially if they’re elevated several feet above the ground. We have welded scissor jacks onto all four corners of our trailer for extra stability. We are planning on removing the tires once our tiny house is in place and then adding some sort of pier in their place.

Let me point out that the purpose of anchoring is not because the trailer may or may not be stable but rather because in heavy winds the gusts can get up under the trailer/house and literally lift them up. To avoid this you need to anchor your home down. According to most mobile home manufacturers a trailer up to 40ft. (our is, if you remember, 30ft.) should have 2 diagonal ties per side and 3 vertical ties per side.

Types of Anchors

Anchors are available for a number of soil conditions including concrete slabs. Auger anchors are what we think will work best for us and are designed for both hard soil (think Georgia clay) and soft soil. Rock anchors or drive anchors allow attachment to a rock or coral base (think Western Carolina mountains). This type of anchor is also pinned to the ground with crossing steel stakes. If you will be pouring a concrete base, you can install a concrete anchor first.

You need to know your soil type to select the right anchor. Soil classifications usually include: rock/hard pan, heavy, sandy gravel, heavy sand, silty gravel, clayey gravel, clay, silty clay, clayey silt, uncommitted fill or peat/organic clay.

Remember, auger anchors (screw-in anchors) can be installed manually by inserting a metal bar through the top of the anchor for added leverage or with a machine designed for this purpose. It’s important to screw this type of anchor in. Do not dig a hole to install. It will not function properly.

How To Install

  1. Level tiny house. Make sure your trailer is level before anchoring it to the ground.
  2. Determine soil type. Merely looking at the ground under your home isn’t enough. Some types of anchors need to be installed five feet deep. If you will be attaching your tie-downs to a concrete foundation, make sure it is at least 4 inches thick.
  3. Select anchors. Talk to a supplier or installer for advice. Your soil type will determine the type of anchor.
  4. Select hook-up. Depending on your tie-down system, over-the-top or frame, select the appropriate hook-up and tensioning device. Make sure the entire system is certified to a 4,725 pound capacity.
  5. Install anchor. As with most thing there should be very specific instructions with your anchors. For a vertical tie-down, the anchor is installed vertically. For a frame/diagonal tie-down, the anchor can be installed to the same angle as the tie-down – at least 40 degrees. The anchor can be installed vertically if you also install a stabilization device to keep the anchor from moving sideways. A metal stabilization device can be attached to the top of the anchor and buried in the ground. Another option is to pour a concrete collar around the top of the anchor. The collar should be at least 10 inches in diameter and 18 inches deep.
  6. Adjust tension. Alternating from side to side, adjust your tie-downs to the appropriate tension. Don’t do one side of your tiny house and then the other.

Have you ever anchored down a tiny home or a similar house? Do you have any tips or tricks? If so, please share. And if you enjoyed what you just read please share it on Facebook or link to it on Twitter. More great information is available on My Great Home. Both images reposted courtesy of My Great Home.

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