Home » Articles & Projects » Garage Floor Coatings » Should I fill My Expansion Joints Before Coating?

Should I fill My Expansion Joints Before Coating?

We sell a lot of garage floor coatings. Some questions get asked again and again, and one of those questions is, “Should I fill My Expansion Joints?” Spoiler alert. It is not something I would do in my own garage — but there are Pros and Cons.

Filling Your Joints is Not Required

First, let’s start with something that should be relatively obvious after the paragraph above. Filling your joints is an aesthetic thing and, in some cases, a practical thing. It is not in any way, shape or form a requirement.

There are some who will argue that if you do not fill your saw cuts or expansion joints, your floor is more likely to have chips in those areas. While there may be some cases that this is true, generally speaking, if you coat the side of the joint as you are doing the floor, and your prep is good, it is not required.

It Is Difficult and Time Consuming

If you ever have a vendor tell you otherwise, I would question everything they tell you. SL polyurethanes are not hard enough. Pouring sand in and adding a coating sounds great, but there is more effort involved.

In most cases, you are mixing (in perfect ratio) two parts that will cure in 5-10 minutes, overfilling the joint to slice it off later and hoping that even though you have never done this before, it will be perfectly flat and not look like that drywall patch you did last year 🙂

It Does Make Cleaning Up Easy

The huge advantage of filling your saw cuts or expansion joints is it makes cleanup easy. The two examples that are commonly used if working on cars and spilling fluids or working with wood and cleaning up sawdust. If those are major concerns for you, filling your expansion joints might be a good idea.

It Looks Amazing?

I added a question mark here because this is a matter of opinion. I actually think lines on a large floor create a nice architectural break and look nice. Others want that completely flat and seamless look. It is 100% possible to do that, and we have customers do it all the time. As previously stated, it’s harder than you think and takes considerable time and effort. Likely, it’s the portion of the job that more customers mess up than any other portion.

Parting Thoughts

I have no illusions that I am going to talk you into one decision or another. If you are on the fence, lean towards no unless you do a lot of automotive or woodworking — or something of similar nature.