We have done several brick home clean and seal and I found that Siloxane is the best brick sealer out there. Our local [FONT=arial, sans-serif]Siloxane distributor gives it a 30 year guarantee. Spraying it on is the best way to go. You can try rolling it on but you'll loose a lot of sealer. Be careful spraying and make sure its not windy and you have everything covered.[/FONT]
We use both Siloxane and Seal-Krete. We always apply with either an airless sprayer, or a 12 volt on demand pump. The Siloxane will leave a natural finish on the brick and the Seal-Krete leaves more of a satin finish. We've applied the Seal-Krete to 3 hotels and they all still shine like the day we sprayed them. The little bit of sheen seems to really repel the mold and mildew.