Buddy of mine wants a hand to build a couple of brick peers(piers?) to support a five bar wooden gate,they(the peers) are going to be around 6ft tall so pretty substantial,he is of the opinion that a "tower" 2 bricks by 2 bricks will suffice with nothing in the middle except a 9" square hole!I think we should be fillling that hole with something or the gate will just crack the joints when its opened and the full weight comes to bear...so who's right? any advice would be much apreciated...than you