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Apr 29

Hollow Metal 4″ Frame Head

One of the topics that I’m covering in my hollow metal 101 class is when to use a hollow metal 4″ Frame Head.

We run into this application most when dealing with masonry block walls.  The use of the 4” head is all about the lintel.  A lintel is a horizontal architectural member supporting the weight above an opening, such as a window or a door.

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The lintel ensures that the weight of the blocks above the opening do not rest on the frame header.  This would eventually lead to the frame head sagging and cause the door to rub and possibly not close as the building settles.

Let’s take a moment and focus on the wall assembly itself.  A typical masonry block in the US measures 16x8x8, and is undersized approximately 3/8” to allow for mortar joints. Thus a completed layer, or course, of block measures 8” in height.

The door shown is a 3’0 x 6’8” with an overall opening requirement of 40” x 82” to allow for the 2” face of the hollow metal frame.  You can see how the lintel had to be notched to accommodate the height of the frame.

Per industry standard, which according to this picture does not mean always, an exterior hollow metal door in a masonry wall measures 7’0” in height, using a standard 2” frame face would require an opening size of 40” by 86”.

Following the example above, considering the height of the courses of block, we would need a 6” notch in the door lintel.  This would leave only a 2” strip spanning the opening to carry the load.  The structural integrity of the lintel would be critically compromised.

A full lintel could be laid across the 11th row of blocks at 88”, leaving a 2” gap.  Below, are examples of how this 2″ gap is usually dealt with.  Not necessarily an aesthetically pleasing solution.

IMG_1967 IMG_2214

This is the point where the 4″ head comes in to play.  By providing a 4″ head on a 7’0 door the 2″ gap is taken care of with a nice finished look.

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When I planned on creating this lesson, I had in mind to take the pictures I needed during my travels throughout my territory.  I had no idea how difficult it would be to find pictures showing the correct use of a 4″ Head.  I visited the backs of many strip centers and warehouses all in my quest for education!

Note: when dealing with existing masonry openings, you can use the 4” head to get creative.  There might have been a non-standard door height in the opening previously, but by using a 4”head you might be able to use stock material.  Just play with the measurements.

If you have additional input on when to use a 4″head, please comment below.

 

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