Top 7 Backer Rod Alternatives and Why They Are the Best

Backer rods are round, flexible, durable, and cheap foam materials. They are used to seal gaps, holes, or crevices on walls and floors. Backer rods come in various sizes and diameters. The size you purchase is dependent on the size of the gap you intend to seal. They help reduce the amount of caulking or sealant used.

You might consider going for backer rods alternative for reasons such as; the kind of gaps you intend to seal, its depth, the location of the gap, and costs. This blog will recommend top seven backer rod alternatives and why they are good choices.

Are there Backer rod Alternatives?

Yes, there are backer rod alternatives. You can use an expand foam, seal n’ peel, grout, sealer grout, caulking cord, pool noodles, fiberglass insulation as a backer rod.

Although the use of a backer rod is not a critical part of building construction, it’s essential to use. Backer rod acts as bond breaker, allowing the sealant to adhere tightly to the wall of the joint. Also, they act like gap filler between surface and save fillers.

Types of Backer Rod

The foam cell structure of backer rods varies. The foam cell structure of backer rods determines what and where it can be used. 

Also, the type of sealant you intend to use will influence the type of backer rod you buy. Below are the three main types of backer rods and their functions. 

  1. Open-cell Backer Rod

Open cell backer rod is characterized by; unrestricted air movement and easy compression. They are flexible and a good choice for filling expansion/contraction joints on floors. An open-cell backer rod is ideal for sealing joints or gaps in dry areas.

  1. Closed-cell Backer Rod

A closed-cell backer rod is characterized by; an enclosed cell wall, easy compression, and high surface bonding. They are highly flexible. Closed-cell backer rods are good choices for sealing gaps in wet areas. They fully hold onto sealants or caulking without bubbling. 

  1. Bi-cellular Backer Rod

Bi-cellular backer rod is an intermediate between the open-cell backer rod and the closed-cell backer rod. It is characterized by its high flexibility and outwardly closed cell structure for moisture resistance. They can be used in wet areas with irregular shapes

Top 7 Backer Rod Alternatives

A good backer rod alternative must be able to seal up your desired area effectively. The alternative does not necessarily have to act as backers for sealant or caulking. Depending on the kind of gap and its location, the backer rod alternative can serve as the backing material and sealant.

Below is the list of the top 7 backer rod alternatives and their functions.

  1. Expanding Foam

Expanding foam is otherwise known as spraying form. It is used for filling deep gaps or crevices in walls and floors. They serve as a good choice for filling holes that cannot be filled with backer rods due to their depth and shape. Spraying foam is a great alternative to backer rods for filling large, deep, shapeless gaps and holes. The foam is highly durable, affordable, and easy to apply. 

  1. Seal n` Peel

Seal and peel are unique, temporary, removable, waterproof insulation stripe for windows and doors. They prevent heat from seeping out through windows and door crevices during winter. Also, they prevent cold air from seeping through doors and window crevices during winter.

They are usually canned gel-like liquids. Seal n` peel can be applied directly on door or window crevices to prevent wind draft during winter. They can also prevent insects from entering your home through the gaps in your window/doors. Seal n` peel can easily be removed during the summer seasons. 

Seal n` peel is an easy alternative to backer rods that is removable and cheap

  1. Grout 

 Grout is a waterproof sealant used mostly by tilers. They are used to fill up gaps and holes in a tiled floor or wall. 

Just like backer rods, grout is of 3 types which include; epoxy grout, furan grout, and sanded grout. The epoxy grout is ideal for wet areas such as; bathrooms and kitchens. Epoxy grout does not shrink, crack or dry off. 

Grout is the best alternative to backer rods for sealing wet-tiled areas.

  1. Sealer Trim

Sealer trims are tape-like, sticky adhesive-backed stripes used to seal small gaps on walls or floors. They can be installed directly on existing caulking or sealant. 

The sealer trim is waterproof and doesn’t dry out or crack. Sealer trim is used for wet areas such as bathrooms, toilets, and kitchens. It is highly durable, easy to fix, and cheap. The Sealer trim is an alternative to the backer rod for sealing small gaps in wet areas. 

  1. Caulking Cord

Caulking cords are soft rope-like caulking materials used mainly on doors and windows to seal crevices, deaden sounds and keep insects at bay. It is waterproof and doesn’t crack. Caulking cord can be used around fiberglass doors or windows. 

The ropes are usually ¼ – 3/8 inches wide. It can be used to seal any gap, crack, or crevice that is about the stated inches. It is a great alternative to backer rods for sealing small crevices, especially on windows. You do not need to apply sealant or caulking on the rope. 

  1. Pool Noodles

Waterlog, popularly known as pool noodles, is a flexible, waterproof, and buoyant polyethylene foam. They are often used for swimming practice. A pool noodle`s thickness is usually 7cm, with an ideal length of 160cm. They are lightweight. Waterlog can be used to seal up expansion and contraction joints on floors. This usually prevents the use of excess sealant for such joints. 

They can be used as backing rods alternative when cut into your desired length. Pool noodle thickness makes them fit into large holes and awkward joints on the wall or floor. They are the best available alternative to the backer rod in terms of similarities. 

  1. Fiberglass Insulation

Fiberglass insulation is made from plastics reinforced with recycled fine glass and sand. The insulation material is of two types in terms of shape and surface area. They can either be in bat or roll form.

 The roll type is easily manipulative and can be cut into your desired size or shape. The batting type has been pre-cut into different sizes. To use the bat type of fiberglass insulation, measure the size of the holes or gaps you want to fix it in. The measurement should be used to purchase your desired size.

Fiberglass insulation can be stuffed into large holes and gaps before applying sealant or caulking. This will help reduce the amount of sealant you use. It will also provide a smooth finished surface. It is a great alternative to backer rods when dealing with large holes or gaps


Backer rods are purposely used to reduce the amount of sealant used when filling gaps and crevices. They can be used to seal gaps with smaller diameters in comparison to the diameter of the backer rod. 

When you want to seal up larger holes and gaps, backer rods might not do a perfect job. This blog has explained the top 7 backer rod alternatives that you can use. Choose the best backer rod alternative based on the kind of hole, gap, and crevice you want to seal. 

To fill small gaps in wet areas, use sealer trim or seal n` peel. For large holes in wet areas, use expanding foams, pool noodles, and fiberglass insulators. Use grout and caulking cord to seal small crevices on doors and windows.

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