Grout is a matter of security, more than you may realize. Many property managers wonder if they should add grout to their steel door’s frame. You might think that it will improve the stability of the door but, depending on the circumstances, it may actually undermine the security of your door. It is a common misconception that fire-rated doors need grout. In fact, the grout may impede them and negate their fire rating.

Here is what you should consider if you’re thinking of grouting your steel door.

When Should You Add Grout to a Steel Door Frame?

The only time that you should add grout to a steel door frame is when the manufacturer indicates that you should. This includes fire-rated doors.

Most manufacturers will not have you add grout to their door for a few reasons. First, the design of the door should be solid enough that the grout will not add any strength to the frame or its anchor. The frame will already pass the relevant tests that it has been rated for, including impact, fire and cycle tests.

Grout can actually weaken a door. The grout has moisture that escapes it as it dries. That moisture has to go somewhere. It can go into the drywall, which weakens the frame. The frame of a grouted door may not repel force the same way that it should and that it is rated for.Grouting may also create thermal bridging, allowing heat into or out of the building, undermining your heating and cooling efforts.

Also, the moisture from the grout can go into the door, which can cause serious rusting problems. Rust may destroy the hardware and certainly advertises that the door is weaker than it should be. You may find your door is a target when rusted, and you may find that it is much more easily defeated than it should be.

What About Sound?

One of the only real improvements that grout can make on a metal door is to dampen sound. However, the disadvantages of weakening the door and typically not worth this effect on the door. There are other soundproofing options that you can invest in.

How to Apply Grout to Steel Doors

Yes, we just explained that you shouldn’t add grout to almost all steel doors. But, some will call for it, specifically acoustical frames. When they do, you should follow the manufacturer’s guidelines and these general principles:

  • Use mortar grout because it will harden entirely, curing by chemical action.
  • Mix the grout to a 4-inch maximum slump (you can find detail on this in ASTM C476-20 – Standard Specification for Grout for Masonry)
  • Apply the grout for the door at the same time the masonry for the frame is laid and only by hand troweling. Do not use a pump.
  • Brace the frame before you apply the grout.
  • Do not add grout to the exposed side of the frame.
  • Do not add grout in standard drywall openings.

When in doubt, reach out to your local door professionals to discuss if grout is needed for your steel door.