Lighting, Light Fixtures, Ceiling and Exhaust Fans - ceiling fan brace old work

I ran electrical line and was preparing to add a havey duty ceiling fan brace when I realized the brace's spikes do not hit my ceiling joists. I have a 24" gap between joists in a first floor room. (no attic access)

Do I need to rip open my ceiling to add 2X4 frame work to make the brace I have work, or can I buy another brace somewhere that will allow the spikes to hit my joists? The bottom of the joist is only about 1 1/2" and the spikes on the brace I have just barely hit the top of it, which winds up pushing the brace too high.

:mad:

You can use one of these. They have a model that expands 24"
http://www.passandseymour.com/literature/pdf/49163_PnS.pdf

And, as you see, the "feet" space the brace properly off the sheetrock ceiling. Just sit the feet flat and expand the bar. Once in place you hold the supplied box to the bar via ubolts (usually), and it will be at the proper height for your install.