Do I Need A Foundation Pad For My Mobile Home?

Solid Pad for My Mobile Home

What Is a Mobile Home Foundation pad?

Mobile homes and manufactured homes need a foundation pad. The foundation pad is an area of fill dirt sometimes made of sand and clay. This pad is built where your new mobile home will be setup.

Mobile homes are installed by a State licensed installer.

The homes are set up on a pier and beam foundation, a double wide mobile home has four steel I beams, a single wide has two.

The dirt pad is the foundation on which the pier system is installed.

The factory will usually supply a blocking plan for the installer to reference when setting up the unit. Engineers will have designed the foundation to support the weigh of the mobile home on a block pier foundation.

The pier and beam system transfers the weight of the home down to the foundation pad. The load-bearing capacity of the foundation pad is used to calculate pier spacing and footer sizes. Generally, the higher the load-bearing capacity of the pad, the stronger the foundation of the home will be.

Regular soil and garden dirt are not sufficiently clean or compacted enough for use as a solid foundation. More often than not soil will contain trash and organic material.

foundation with rebar

Why Do I Need A Mobile Home Foundation Base Pad?

The ground under a mobile home needs to be graded in order to prevent water and moister from collecting under your home. The size of the pad should extend at least six feet beyond the perimeter of the mobile home.

NOTE: Mobile homes must be built on a pad foundation in the state of Florida.

The quality of the foundation of any home is extremely important, it is the base for all other construction. The better the foundation pad, the more support and stability will be transferred to the home. Your foundation pad needs to be built so that it can survive a long time especially even in harsh environments.

How Thick Should A Dirt Pad Be?

The pad needs to be thick enough to support the load of the home when compressed and compacted in place, usually a minimum of 8 inches.
The pad should be thick enough to produce a slightly domed profile which will be a minimum of 4 inches around the edge and 8 to 12 inches towards the center. The pad should be smoothed out with a box blade to remove any large holes which could collect water or moisture.

The foundation pad underneath your mobile home should extend at least four feet beyond the perimeter of your pier foundations.

The sloping foundation pad installation will ensure that any surface water runs away from the house and not towards it.

How Wide Should My Pad Be?

The foundation pad needs to extend a minimum of 4 feet beyond the edge of the home. Ten feet extra all the way around the home would be ideal, as this extension of the pad allows the grade to reduce gradually down to the adjacent ground.

Spread the fill dirt as wide as necessary to give a smooth transition slope to the regular ground level.

Do not bring the pad out straight and level with a sudden drop off down to ground level. Doing this will look strange and cause pad erosion.

It will also look better if the foundation pad is graded naturally into the rest of the landscaping plan for the property. If you are intending to sell the real estate in the future then curb side appeal matters.

Load Bearing Capacity?

The load-bearing capacity of the soil will depend on the existing ground conditions and the firmness of the fill dirt brought in by the contractor.
Load-bearing capacity is usually measured in pounds per square foot and will be tested by the contractor or local engineer at the time of obtaining the building permit.
The contractor will use a penetrometer to test the soil in six different locations. These readings will then rounded down to the nearest 500 pounds to give the load capacity in square feet.
This reading will be used to determine the base pad size and number of piers needed to support the home on that particular pad.

Do I Need a Foundation Pad For My Mobile Home

Does The Foundation Pad Need To Be Compacted?

Compacted fill makes sense and if you have the chance to do this then go ahead. Compacting the fill dirt shakes the particles into a tighter formation which will make the pad stronger. Compactions of 90% to 95% can be requested by engineers if they are involved in your building contract.

Ask your mobile home contractor, “Do I Need a Foundation Pad For My Mobile Home?” to see what he recommends. Some contractors use compacting others do not. However, in Florida, it is not code and is generally not required.

The foundation pad sizes will be adjusted to meet the load-bearing capacity of the fill.

What Type of Fill Dirt Do I Need?

The quality of the foundation material used will have a direct bearing on  the stability of the mobile home long term. The load bearing capacity of various materials varies greatly with sand (less than1000 lbs/sq. ft.) at one end of the scale and  a concrete pad (3000 lbs/ sq. in.) at the other.

Sand would give you an estimated 1000 lbs per square foot load-bearing capacity which is ok but would call for larger base pads to increase the footprint (Avoid if at all possible.)

The best suggestion would be a sand and clay mix at a ratio of 80:20.  This mixture will usually give a load-bearing capacity of between 1500/ 2500 lbs per square foot, more if left to harden.

Try to avoid shale or rocks as these are difficult to work with and tend to move over time. If you decide to use millings then it would be best practice to install a layer of base material beneath the aggregate layer.

Other Important Foundation Pad Considerations.

Here are some other questions that mobile home owners have asked about their foundation pad:

Do you need footers for a mobile home?

Concrete footers that are poured in place and reinforced with steel (rebar), are usually not required for a regular home installation. However, there are certain locations that do require reinforced footer and beams to be poured, in particular the Florida Keys and other shoreline areas (exposure “D”) which are prone to high winds (wind Zone 3) or flooding.

Do I need a permit?

The building of your foundation pad will be part of your mobile home set up permit. The setup permit will be issued  for the entire project. Some local authorities do have lot grading requirements that need to be taken into consideration. If this is the case you will probably need to have a boundary survey completed.

How do I find out the pad requirements for my area?

Make a call to your local building department, you can usually find out what is needed by talking to a permit technician or asking questions in the zoning department.

Usually the materials used in the building of the foundation pads in your area are available locally. Sometimes all construction sites will be utilizing the same common materials to build foundations for their projects.

site plan

Who will arrange the building of the foundation pad?

You can arrange the building of the pad yourself as a home owner but please make sure that you consult with your contractor first. Some contractors like to build their own pads and they are often familiar with the local regulations and skilled tractor drivers who do this every day.

Do I need a site plan or a survey?

You should always have a plan for most major events in life.

Draw a site plan out with the location of the home, the utilities, the driveway the parking spaces included. With a sketch or plan it is easier to explain your goals to contractors and the permit department.

Later your plan can be drawn to scale for the building department or given to your surveyor to be included on the boundary survey.

Most installations on private land will require a survey.


I am sure that you have all heard of the old saying about building your castle on sand and the consequences of that action!

Make sure that a foundation pad is included in your mobile home construction project. You will have to pay for the extra work but this investment will be worth the money in the long run.

This dirt pad is one of the most important aspects of your foundation and if you get this part right and your home will stay solid and level for a long time.

Call 863 808 2200 for reputable contractor references. Or use our contact page.

Also Check: Mobile Home Shed Plans For Your Backyard.