Who to Hire to Replace a Sill Plate?

A rotting or failing sill plate may cause an alarm bell to go off inside your brain. The undeniable signs of structural rot on the sill plate include misaligned siding, sagging windows, and cracked brick or stucco. When determining who to hire to replace a sill plate, hiring a structural engineer is a must, as this professional has the expertise to calculate loads for a safe and exacting repair job. You’ll most likely, also, need to hire a foundation repair company to do the actual work.

Benefits of Hiring a Structural Engineer for Replacing a Sill Plate

Because the sill plate is the piece of wood that supports the weight of your home and connects it to the foundation, it is very important to maintain your home’s integrity. The best place to start for this type of repair is with a local structural engineer. 

A structural engineer has the education, licenses, and experience needed to accurately determine the ability of a sill plate–or other foundational structures of a home or building–to support weight. Every home or building has force from vertical and horizontal loads. Vertical loads are the weight of items in the structure’s construction pushing downward. Horizontal loads can occur with standing up to wind or earthquakes.

The sill plate distributes these loads evenly across the foundation, maintaining the integrity of the home or building, and preventing sagging.

A structural engineer will use mathematical calculations to determine the proper size of the sill plate. When replacing a sill plate, these calculations are vital. There is no room for error.

It’s important to understand that the engineer will not actually replace the sill plate but, rather,  provide the calculations to the company doing the work–usually a foundation repair company.

Can I DIY Replacing a Sill Plate?

With the high cost to replace a main house support beam, you may want to consider a DIY job, rather than trying to figure out who to hire to replace a sill plate. However, we don’t recommend attempting this job on your own–especially if you’re not quite sure of the difference between a joist and beam in your home’s structure.  

The calculations provided by the structural engineer are imperative to do this job safely. Making an inaccurate calculation could lead to a pier and beam foundation repair in the future, or could cause your entire home to lose structural integrity, leading to far pricier repairs.

To DIY this project, you will also need special equipment to support the weight of the home during the repair process. You probably don’t own or have access to the hydraulic jacks and girder beams needed to lift and support the home.

Your homeowners insurance may cover the cost of foundation repairs–eliminating the need to DIY the job if you’re trying to save money. However, most insurance policies include exclusions for this type of work. It’s worth talking with your insurance company before making any repairs or paying your bill, but you are probably going to be on the hook for hiring and paying a pro to replace your sill plate.

Can I Hire a Foundation Repair Company for Replacing a Sill Plate?

Once you have the structural engineer’s calculations, hiring a local foundation repair company to replace your sill plate is your next step. 

Most foundation repair companies can do everything for you. The company may do the initial inspection, hire a structural engineer, and then replace the sill plate. Some of these companies may have a structural engineer on staff.

You may prefer having the foundation repair company handle the job from start to finish. Because a structural engineer doesn’t do the actual work, this pro often works as a consultant for a foundation repair company, so you’ll see this arrangement often.

Additionally, if the rotted sill plate is causing other foundation problems for your home, the foundation repair company can make these repairs at the same time. For example, a bowing basement wall repair can cost up-to $10,000 if done on its own through a foundation repair professional. However, this cost may be significantly less if it’s done as part of another project–like replacing a sill plate.

How Does a Pro Replace a Sill Plate?

A professional who is replacing a sill plate will follow specific steps to ensure this job is done safely, and with the least amount of risk to your home’s structural integrity. 

• A structural engineer or a foundation repair company will inspect your home’s foundation to ensure the sill plate needs repair.

• The structural engineer will calculate the loads that the sill plate must support, which will determine the size of the new sill plate. If your old sill plate failed because it was the wrong size, for example, this calculation is vital.

• The foundation repair company uses hydraulic jacks and other supports to lift the home a few inches off the foundation, gaining access to the sill plate.

• The pros remove the old, damaged sill plate, and replace it with new materials that fit the structural engineer’s calculations.

• The foundation repair company lowers the hydraulic jacks until the home is resting on the sill plate again. If everything works properly, the pros will then attach the sill plate to the foundation.