Buying or building a shed requires time and money, so when you finally purchase or build your shed, the last thing you want to happen is for it to be damaged by the wind or by freezing temperatures. To make sure your shed can withstand the weather, the best thing to do is to anchor it to the ground.
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Do you need to anchor a shed?
Yes, generally, a shed should be anchored. An unanchored shed is vulnerable to wind and freezing temperatures, which can damage the shed and its foundation. Also, some municipalities require sheds to be anchored before granting building permits. So to protect your shed and get a permit for your building, it is best to anchor it.
How to Anchor a Shed into Gravel
A gravel foundation is considered to be one of the cheapest options for a shed, as well as being very practical. Gravel is inexpensive and provides better drainage than concrete, which is why gravel foundations are the most common shed foundations we install.
If you are interested in installing a gravel foundation or have already installed one, you will need to anchor the shed into the gravel. To be more specific, you will need to anchor it into the ground below the gravel or onto concrete piers. The gravel itself, no matter how compact, will not be able to anchor a shed.
Concrete piers are one of the most permanent and secure ways to anchor your shed into gravel. Also, concrete piers will generally meet the foundation regulations of your local township/municipality if you live in an area with significant frost levels in the winter.
1. Mark out the shed’s pier locations
The first step to installing concrete piers is deciding where to place your shed. After that, mark out the corners of the shed and where you will put the piers.
2. Determine the grade of the site’s slope.
3. Excavate holes for the concrete piers
Digging pier holes can be accomplished in several different ways. When we at Site Prep dig concrete piers, we use an auger attached to a skid steer, but a power auger also works well. There is also the option of using a post-hole digger and digging them by hand.
4. Add forms for the piers
Once the holes are dug, insert concrete pier forms. Since the shed pier forms come in 48” sections, you can cut them to length with any saw.
5. Pour concrete into the pier forms.
You can mix the concrete for the piers by hand with a concrete mixer, in a wheelbarrow, or directly in the pier hole. Consider buying the concrete premixed and having it delivered by truck to your site for a larger project.
6. Cure the concrete
Let the concrete cure for a few days before placing your shed on it. It takes around 28 days to cure fully, but it has much of its structural strength within the first week. After the concrete is cured, cut and remove the visible parts of the concrete forms. Backfill dirt around the piers and ensure the ground is tamped down well.
7. Add Gravel to Your Foundation
After your shed foundation piers are installed, you can build a gravel shed pad around them.
8. Install anchors.
Now we come to the part of actually installing the anchors. There are several kinds of shed anchors that you can use to anchor your shed, but we recommend using L-brackets installed into the pier with a concrete bolt or large Tapcon® and a lag installed into the shed runners. Install this style of anchor after you place the shed on the piers.
The alternative is to embed concrete anchor straps into the shed piers while you pour the concrete in step 5. However, this requires you to know exactly where the shed runners will fall in relation to the piers (to an accuracy of about ½”).
If you want an in-depth explanation of installing concrete piers, read our article: Shed Foundation Piers: The Ultimate Guide.
How to Anchor a Shed Without Concrete
Although concrete piers are one of the most secure ways to anchor your shed into gravel, concrete can be expensive and time-consuming. Fortunately, there are inexpensive and quick alternatives to concrete piers that can securely anchor a shed into gravel.
Bullet or Arrow Anchoring
One of the simplest ways to anchor your shed into gravel is to use an arrowhead or bullet anchoring system. With both bullet and arrowhead anchors, the head is driven into the ground, and the cable is connected to the shed.
Photo credits: American Earth Anchors
Bullet anchors are especially useful in tough, hard soil. They have a pullout resistance of 350 lbs if anchored into loose, fine, uncompacted sand and 2,000 lbs if anchored into hardpan or asphalt.
Arrowhead anchors are available in several sizes, and the larger the size of the anchor, the more pullout resistance it has. A 3” arrowhead anchor has a maximum pullout resistance of 2,000 lbs, while a 10” arrowhead anchor has a maximum of 14,000 lbs. Both bullet and arrowhead anchoring can withhold 1,700+ lbs if anchored into gravel.
How to install Bullet or Arrowhead Anchoring
Most bullet or arrowhead kits come with the following:
- arrowhead or bullet anchors
- galvanized aircraft cables
- cable clamps or a thimble loop
You will need the following:
- a driving rod
- a sledgehammer or demolition hammer.
- To install the anchor, fit the driving rod into the back of the anchor and, using a hammer, drive the anchor into the ground. You should drive it into a minimum depth of 24”.
- Remove the rod.
- Wrap the cable around the drive rod and pull up on the anchor. This will cause the anchor to turn and “lock” in place.
- Take the opposite end of the cable and loop it around a structural member of the shed.
- Secure the cable’s end with a clamp or thimble loop.
Use the cable clamps to secure the loop. Note: The U-bolt should go over the dead end of the cable
Bolt the thimble directly to your shed or use it to tie off your cable.
There you are, a complete guide on how to anchor a shed into gravel. If you are considering installing a gravel foundation and concrete piers for your shed, consider letting us do that for you! We offer professional foundation installations in most of the northeastern and Mid-Atlantic USA.