Why didnt Don Barzini send a hit squad to Don Corleones house?

The Corleone compound is a fortress. A gated off street with many houses filled with heavily armed body guards with the Don's house far from the main road.

Plus, like you said, if there was an all out military style assault, wives and children would probably be killed and that is infamabile (totally dishonorable) to Sicilians.

Although, in GFII, a hit is attempted in Michael's house, but that was by non-Italian mobsters.

"Smokey, this is not 'Nam, this is bowling. There are rules. "
-Walter Sobchak

That's not the way these people operate.

"There is no future in England's dreaming": The Sex Pistols

I don't know if women and children are the deterrent - a military-style assault would be needed and I don't think 1940s button men were up to it. In Scarface the attackers end up killing everyone but they take significant losses too, especially after they say hello to Montana's "little friend", and I always wondered whether they were not some kind of military special services and not simply hoods.
It would also be one hell of a gun battle, perhaps with explosions, and it is just conceivable that the police might take notice.

"Chicken soup - with a *beep* straw."

Are you serious? No offense man but Barzini would've been a total moron had he tried this. In the world of the Mafia there are few rules, perhaps the most important/sacred one is the rule " Families don't get touched. "

Had Barzini decided to try and attack Vito at his home, where Vito's wife, daughter-in-law, grandchildren and daughter were hanging out, the other Bosses would turn on Barzini and would kill him, everyone involved in the attack, and most of his "Family" ( his criminal organisation, not his actual family ). Why? Because they would want to make an example out of Barzini in order to make sure no future Boss and/or made man would ever try something like that again. Other Bosses have families, they would want to make sure no one would ever try to attack their families like they did to Vito ( in your scenario ).

Plus, if Barzini attacks Vito at his home ( or Sonny while Vito was in the hospital ) and the plan fails and Sonny, Michael and Tom survive... they would have an excuse to go in an all out war with Barzini and Tattaglia, and the other Bosses would most likely support the Corleone family. At the very least, the other Bosses would turn their backs on Barzini and Tattaglia so the Corleone Family wouldn't have to worry about the other families coming after them/supporting Barzini and Tattaglia.

Just to add to that, if that many soldiers were involved for that kind of attack, word would almost certainly get back to the don and the element of surprise would be lost.

Thanks for the answers and they make sense too, but in regards to Button Men not being up to the task, Sonny was ambushed and killed by six guys with Tommy Guns at a tollbooth easily, and earlier Sonny says they have a hundred button men out on the street 24 hours a day, basically covering all of the activities and businesses, would be easy to send 30 or more guys with Tommy Guns to the Corleone Mall and overwhelm the gate guards and guys outside and then storm in and finish things.

Tommy Guns would be perfect for attacking a compound and with that firepower it would be easy, just make sure that there are a lot of them and plenty of ammo and everything is easy, handguns, rifles and shotguns vs tommy guns, i think that hit squad would win easily, just ask Sonny, and double or triple the number of guys that took him out, even the police would be killed if they showed up.