Masonry Drainage Materials

Why should you use cavity drainage materials in your masonry wall? It is somewhat expensive. Not as much as copper or stainless steel flashing, but more than PVC or EPDM. When a job is over budget, one of the things some contractors look at to reduce the cost is that expensive stuff, like copper flashing or cavity drainage materials. The flashing will be in use, when put in properly, for quite a while, as long as it is a good quality flashing like a copper or stainless steel. The cavity drainage material will be in use while the building is going up and as far as I know, that is when it is most important. It protects the weep openings, could be tubes, vents, etc., from getting clogged by mortar droppings and not allowing water to escape. When people ask me how much cavity drainage materials are and I tell them, many tell me it is expensive. I try to make it clear to them that I understand they will not go home at the end of the job and say, "I am sure glad I used that product." However, they will certainly know if they should have used it. It is extremely costly to replace flashing, weeps and brick after the job is completed. There are many products to chose from and I will list some below.

MortarNet - http://www.mortarnet.com/index.htm

Cavclear - http://www.cavclear.com/

Mortar Break - http://www.advancedflashing.com/commercial-mortar-break.cfm

Mortar Mitt - http://www.h-b.com/index.php?main_page=index&cPath=28

I found some very good articles about the masonry cavity wall. The first one is from the Brick Industry Association. It is Tech Bulletin on Brick Masonry Cavity Wall Selection Of Materials. On page 6 there is a description of cavity drainage materials. It mentions none by name, but if you want to know even more about masonry construction, it provides good basic information.

http://www.advancedflashing.com/clientsuppliedcontent-forms/BIATechNoteTextPDFs/Tech%20Note%2021a.pdf

The next link is from the Portland Cement Association. It is a quick excerpt on why you should keep the cavity clean. It is a nice short read.

http://www.cement.org/masonry/cc_fn_cavities_clean.asp

The last link is from Masonry Contractors of America. It is written by Sarah B. Atkins. The letters to the editor comments say the article was written for the Dec 04 issue but the date of the posting for the internet is March 05. The article and the letters to the editor suggest that the masonry contractors agree that there is an issue with mortar buildup and bridging and that the weeps need to be kept clean, but as to how it is best done, is still a discussion. Read the article and the letters to the editor and see what you think.

http://www.masoncontractors.org/newsandevents/masonryheadlines/headline.php?id=20050331084700