STUCCO NEWS.NET

First a question:

What do you think of the idea of leaving tyvek in place but covering it with tar paper? This assumes you know what the structure underneath is like ( gaps between plywood/ osb etc.)..

Second: I absolutely love your approach to your craft/art. I ran a painting company for years in California with the same ethic... Always trying to do it the right way. I remember a few stucco walls we put up with tar paper, 'stucco netting' ( a very heavy chicken wire) put on with cardboard washered nails, Z flashing and three coats over four or five days. Thirty years later and multiple coats of paint, those wall are still in perfect shape (even in earthquake country)...

I am reading over your entire site... I am anticipating buying a synthetic stuccoed house and replacing it with the real stuff. I have plastered quite a bit over the years (including a Frescoe!) though I know I can't approach your level of expertise, I hope to be able to do this myself.... Economic realities require that I do most of the work and that I buy one of these synthetic stucco homes....

Thanks for all you do.

I had to stop ripping off the tyvek years ago. We just put a layer of tar paper on top. Here, we use 15 lb. felt paper. In California, grade D building paper is used. People get mad when we tear off the tyvek. These days, usually, the tyvek is wrapped behind the windows and doors and sealed with tape. I like the idea of having two vapor barriers. You brought up a good point. One must assume the plywood (or OSB) is well done and is spaced 1/8" apart, which it rarely is. Also, when we tore off the tyvek we would discover electrical outlets that were covered, or sheathing that was inadequately nailed, and other things that should have been corrected. Now we can't inspect the sheathing. These days, zip wall is used more and more. The painted OSB supposedly doesn't need an addition vapor barrier on top. We put a layer of tarpaper over the zip wall anyway. I know for a fact water will penetrate painted stucco, so why won't it penetrate painted OSB ? I like zip wall a lot. I think it reduces cracking a lot.

I want to bring up something I have wanted to bring up for years. This may offend some people, but I have earned the right to express my opinion. That is the idea of a bond breaker, or a good reason for two vapor barriers. I like the idea of two vapor barriers anyway. Certainly, two is better than one.

Here is a link to The Perfect storm over stucco:

https://buildingscience.com/documents/insights/bsi-029-stucco-woes-the-perfect-storm

The date on this page is 2010, but I remember when The Perfect Storm was published originally online about 2001. The perfect Storm went viral in the stucco world, before the word viral was used. I have read a lot of the documents from Building Science Corporation and find a lot of incredibly valuable information there. There are things in The Perfect Storm I don't agree with.

I used to think it is good that cement mortar bonds to the tarpaper. It seems a better bond holds mortar on the wall better. I think the idea that drainage is obstructed because mortar bonds to the vapor barrier isn't true. Water that penetrates stucco trickles down the stucco and exits if it can. The idea that water travels horizontally through the stucco and hits the tarpaper can't be true. Water can hit the tar paper but water trickles down through the cement, and doesn't hit the vapor barrier and stop.

If you look at the picture in The Perfect Storm that says: "Note that the damage is in the field of the wall away from windows.", there is rot below the windows typical of what we find when we tear off stucco, including one coat stucco due to faulty window installation.

Thanks so much for visiting my site !