IF statement to return empty value on false

Greetings everyone.

I am having a little difficulty getting the below formula to return a NULL(empty) value if false. I cannot seem to understand why my formula will not work... The true part of the statement works perfectly, however, when the code is False it puts the word FALSE in the cell...

=IF('Wooden Bldg'!$B$5=TRUE,CONCATENATE(Data!$G$1," base cost =",""))

Thanks in advance.
David