Alamo Building Materials

[cje]

I remember when I was 16 years old (many years past now) and visiting the Alamo. The material for the front of the Alamo Church and what was used for the sides and back of the church were and still are of course, completely different!
It took me a trip to the Alamo to see just what the back of the Alamo Church looked like and was made of. I was very surprised to see the real difference! I can understand where the front of the Church had to be more attractive in what it was constructed with. But the back just seems to have (excuse me) a whole lot of river rocks cemented somehow together. And just what did they use t cement those rocks with? It has sure lasted a long time now!
Just one of those things I have been thinking about. Thanks.

[Rich Curilla]

This is basically true for all the mission churches. I think the difference is the need for ornamentation. On the Alamo church, the only plan for ornamentation (stone carving, fluted columns, etc.) was the central portion of the facade. Therefore, that was carefully built of quarried limestone tufa, cut into blocks and carefully fitted together. The goal was to have a smooth surface for the stone carvers. Also, tufa, when it came out of the ground, was quite soft and carvable. Then, as it weathered for a while, it became (forgive me) hard as rock. If you notice, the side portions of the facade -- the baptistry and confessional walls -- are also built like the back of the Alamo. Here again, the exception is right around the two small windows which are squared tufa blocks like the central portion so that the frames could be carved.

The rest of the building is "rubble construction." This is just basically rocks mortared together into a wall -- your river rocks are probably not out of the question. I don't know if I have ever heard that the mortar for all this was anything more than the adobe mortar used with adobe bricks for construction, but I would guess that somehow it was made far more resistant to weather somehow -- lime, goat's milk, whatever the legends say. LOL. I know that old records refer to roofs being a thick two-foot layer of "cement" over boards over beams, but I don't think that would be anything like modern cement.