Grout is often used to fill hollow metal door frames in masonry walls. The grout helps to stabilize the frame and increase its durability and strength. It also makes it more difficult for people to break into or out of the building. Some frames are grouted to deaden sound transfer or to minimize the impact of heavy vibration in nearby equipment. The grout is typically installed in the frame as the surrounding masonry blocks are being laid. It can also be installed later after masonry work is complete, though this process is more difficult and time consuming.
Adding Grout During Block Installation
Install mortar guards at all hinge pockets and lock strikes. This will prevent the grout from interfering with hardware operation.
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Add silencers to any pre-drilled holes in the frame. Silencers are small rubber discs that prevent the frame from banging against the door when it is closed. These devices are have a cone-shaped head that is inserted through the hole in the frame. If silencers are not installed, the grout may leak through these holes.
Install spreader bars or 2-by-4 inch boards at three or more points along the height of the frame. These bars are designed to help the frame hold its shape as the grout is added. If you plan to add grout to the header, be sure to install vertical supports as well.
Mix mortar and water, according to the instructions on the package. Add an anti-freezing agent if the frame is being used in an exterior opening. As the masonry is installed around the frame, pour or trowel a small amount of grout into the frame. Work on one course at a time to keep pace with the block work.
Wait until the block work has reached the level of the frame's header, then pour grout into the top of the frame to fill this space. Check the project specifications before completing this step, as not all headers are grouted.
Grouting After Walls are Complete
Add mortar guards and silencers as you install the door to minimize the risk of leaks or hardware interference.
Mix your grout, according to the instructions on the package. Because the grout will be pumped into the frame, it must have a fairly liquid consistency.
Use a bi-metal hole saw to cut a one- to two-inch hole at the top of each jamb. The hole should be just a few inches below the header on each side.
Install spreader bars at three or more points along the frame to prevent twisting or distortion during the grouting process. Add vertical supports if you plan to fill the header.
Fill the hopper of your grout pump with grout, then insert the tubes into the holes in the frame. Allow the frame to fill with grout until just before it reaches the level of the holes; turn off the pump and remove the hoses.
Use auto body filler (such as Bondo) to patch the holes in the frame. Sand the patched area once it has dried. Add paint to blend this area with the rest of the frame.
Repeat the process to fill the header. Place the hole near the top of the header in the center of the frame. Check with the project owner before completing this step, as headers are often left ungrouted.