Creating a Solid Foundation: Best Practices for Anchoring a Manufactured Home

Determining the Proper Anchor

Two factors must be taken into consideration when determining which anchor is best suited for your manufactured home: wind zones and soil conditions. Manufactured homes require proper anchoring for stability and safety, especially in locations where high winds are more common. The soil conditions surrounding the home determine which anchor is necessary to ensure this stability even further. Thus, built to comply with the requirements of one of the three wind zones and designed to be securely fastened based on one of the five soil classes within the designated wind zone, your manufactured house must be anchored according to its specified zone and class to adhere to the Manufactured Home Construction and Safety Standards as outlined by the HUD code.

When it comes to wind zones, where you are located within the U.S. is the determining factor. Covering the majority of the U.S. interior where hurricanes are not common, homes in wind zone I need to withstand horizontal wind loads of no less than 15 psf (pounds per square foot) and net uplift loads of no less than 9 psf, which is equivalent to 70-90 mph wind speeds. Within wind zone II, the home must withstand up to 100 mph wind speeds. This is designated for areas that are hurricane prone. The closer your home is located to either the Gulf or Atlantic coast, the more likely your location will be in this zone. The home must be able to resist wind speeds up to 110 mph in wind zone III. For residences located along certain coastal regions, it becomes imperative for homes to be constructed to withstand these wind speeds due to the heightened occurrence of hurricane-force winds in these specific areas.

In regards to soil classes, each of the classes test to their corresponding soil conditions. Measured in pounds per inch (in. lbs.), these five classes can be broken down into 1, 2, 3, 4A, and 4B with soil class 1 including solid hard rock at inapplicable in. lbs. and 4B featuring loose sands, firm clays, slits, and alluvial fill at 175 to 275 in. lbs. Through the process of testing the soil around your home where the anchors are to be installed, the soil conditions and their subsequent class are revealed.

It is only by taking these two factors into consideration that you are able to determine the proper anchor for your home in order to ensure utmost stability and safety.

Testing the Soil Around Your Home

In order to discover the soil class and determine the soil conditions around your home, it is imperative to use a Soil Test Probe (59200) to maximize the ground anchor’s holding strength. Used to distinguish the soil conditions below the surface near the anchor’s helix, this essential step ensures the selection of an approved anchor model that perfectly complements the specific soil characteristics of the site. Several states require these soil readings be taken during the set-up process.

The five soil classes are differentiated based on their test values. Extracting a soil sample with a Soil Test Probe is a straightforward, three-step process, requiring only one person to perform. After having collected the soil readings, the soil class and conditions are discerned based on the reflection of the colors on the wrench to the soil classification chart.

Only once the soil class has been established can the proper ground anchor be selected.

Ground Anchor Selection and Installation

With the intent to offer durable and adaptable solutions for securing objects during windy conditions, Tie Down’s ground anchors are designed to ensure strong stability. Each anchor undergoes rigorous testing to meet HUD regulation 3280 standards, ensuring they can withstand a working load of up to 3,150 lbs. and an ultimate load of 4,725 lbs. within their designated soil class. Ground anchors in Tie Down’s collection bear clear and informative markings on their head, displaying their name, class, model number, and conformity with RADCO listings.

Following the use of the Soil Test Probe and prior to the installation of any ground anchor in its respective soil class, determine the location of any underground electrical cables, phone lines, water lines, sewer pipes, or gas lines in order to prevent injury.

Ground anchors offer multiple installation processes, though the recommended method involves Tie Down’s Electric Drive Machine (59620). Intended to make anchor installation hassle-free, the EDM operates quietly while maintaining its high performance with its ½ HP motor running a speed of 20 RPM. Its versatile adapter head fits all double-head anchors while its inside socket accommodates the Soil Test Probe. To implement its simple six step process is to ensure proper installation of ground anchors.

The general understanding for ground anchors states for looser soils, such as those classified as 4b, longer anchor models are recommended whereas shorter models are more suited for harder soils, such as those classified as 1. Before the selection and installation of a ground anchor, it is imperative to check with local and state regulations as a specific anchor may be required for each individual class. Should the regulations not require a specific anchor, the following recommended anchors may be used in their respective class.

Fitting for Class 1’s sound hard rock soil conditions, Tie Down’s Cross Drive Rock Anchor is engineered with precision with the intent to be installed within 1 in. from the bottom of the anchor base, ensuring maximum stability. The swivel tensioning head allows for exact alignment during installation, providing a reliable and robust anchoring system. Available in 30 in. (59100) and 48 in. (59111), its black-painted finish adds durability and protection against the elements, ensuring long-lasting reliability.

Anchors within the 551 to 175 in. lbs., such as those falling in classes 2, 3, 4a, and 4b, are recommended to be accompanied by a stabilizer plate in order to prevent lateral movement of manufactured homes subjected to high wind loads and to comply with HUD requirements. Stabilizers, such as Tie Down’s 12 in. Wide Stabilizer Plate (59292), XL Stabilizer Plate (59286), and Quik-Set Stabilizer Plate (59291), serve as crucial additions to enhance the stability and reliability of the home’s anchoring system, effectively preventing the anchor from slicing through the soil laterally and ensuring a secure hold in the direction of the frame tie.

Should the Soil Test Probe indicate a 551+ in. lbs. measurement or read blue for Class 2, Iron Root Double Head Double Helix ground anchors (59090, 59095, 59097) are most fitting. Often accompanied by a 12 in. or Quik-Set Stabilizer Plate when subjected to lateral loads, these anchors feature a distinctive double head to allow the passage of two bolts which connect seamlessly to the frame, serving as an uplift protection and sidewall connection. Specifically designed for wind zones II and III, their innovative design encourages a wide range of strapping and attachment possibilities.

Class 3 readings measure 351 to 550 in. lbs., and thus, Tie Down's Deep Set Anchors (59091, 59664) are most fitting. Intended to combine stabilization and anchoring in one design, these anchors resist lateral movement through the soil. By eliminating the need for a separate stabilizer plate, they streamline the installation process and save you valuable time.

When it comes to class 4a, or readings amounting 276 to 350 in. lbs., more versatile options are available. Whether opting for Iron Root Double Head Earth Anchors (59080, 59085), Iron Root Double Head Double Helix Earth Anchors (59128, 59086, 59250), or Deep Set Anchors (59092, 59665), these anchors ensure stability and reliability. When subjected to lateral loads, stabilizer plates such as the 12 in. or Quik-Set should be implemented for all anchors aside from the Deep Set. A 17-½ in. (59286) or ABS (59293) Stabilizer Plate should be used when the home resides in Florida.

For soil class 4b, or soils rated 175 in. lbs. to 275 in. lbs., an Iron Root Double Head Earth Anchor (59099) is ideal. Suggested to be accompanied by a 17-½ in. or ABS Stabilizer Plate when subjected to lateral loads, these anchors feature a double-headed configuration to facilitate the use of two bolts. This anchor ensures robust attachment for both sidewall and I-beam connections and acts as ideal frame attachments for wind zones II and III.

It is only through the implementation of the anchor most fitting for the tested soil class and wind zone that a home will remain properly secured throughout its lifetime.

Concrete Anchors Selection and Installation

Should ground anchors not be applicable, i.e. when the home must be anchored to a concrete slab, Tie Down offers the choice between wet and dry concrete anchors.

Wet concrete anchors, such as Tie Down’s J Rod Concrete Anchor, available with (59109) or without a swivel head (59120), are strategically placed during the concrete’s pouring phase. This results in a strong bond with the concrete as it solidifies, ensuring a durable and dependable anchor point. The J Rod Anchor features a unique J hook that conveniently attaches under rebar, ensuring exceptional stability and reliability. Boasting a substantial load capacity of up to 4,725 lbs. per anchor, this anchor assures steadfast support for a range of applications.

On the other hand, dry concrete anchors are employed in situations where a pre-existing concrete slab requires anchoring. Tie Down’s Double Head Anchor (59125) or Single Head Anchor (59029) are most fitting for existing concrete slabs. These anchors are introduced by drilling expansion bolts into the existing slab, establishing a permanent and robust anchoring solution. The Single Head Anchor requires only the use of a single slotted bolt while the Double Head requires the use of two slotted bolts. The decision between the two is determined based on the strength of the concrete slab.


In the instance where the home must be anchored into asphalt instead of concrete or ground, Tie Down’s Asphalt Anchor (59367) is a reliable and sturdy anchoring solution designed specifically for asphalt surfaces. With an impressive working load of 1,889 lbs., this anchor provides the strength and reliability needed to keep structures firmly anchored to the ground. While not intended for vertical anchorage, this anchor is ideal for horizontal applications at a maximum angle of 50 degrees.

What To Do Next

The HUD code states that when a home is not designed to resist the wind loads for high wind areas like those in zones II and III, the home only requires lateral frame ties. For the homes located within the zones more hurricane prone, a vertical tie installation at each lateral tie location is required in order to reinforce the strength of the ties against the increase in wind speeds.

When anchoring down a home, steel strapping, such as Tie Down’s G60 (59150) or G120 (59218) galvanized straps, must be used to attach the home’s I-beam to the anchor. The straps must exceed 3150 lbs. working load and 4725 lbs. ultimate load. In doing so, the straps are compliant with the HUD code.

It is crucial to eliminate the tail on the strap when strapping down a home to the anchor. The strap end must be flush with the bolt in order to ensure utmost security and to prevent the risk of it unraveling due to high wind forces. The excess strap can be used as a strap protector. Without this strap protector, there is a risk of the I-beam cutting the strap. It is best to risk bending the I-beam, rather than a strap being cut, as an I-beam can be fixed, whereas a house is not as easily replaceable.

Disclaimer

Keep in mind most projects require a license in order to install the anchors to tie down your manufactured home. Make sure to double check with local requirements before installing the proper anchor.