Wall construction material and sequence
I am at zone 3B – little rain/wind only in the winter months with no snow. I plan to use the following wall assembly for stucco wall from inside out:
Dry wall
Cellulose insulation / 2*4 wall
Building Paper layer 1
Building paper layer 2
Typar
Stucco
A few questions:
1. My contractor is trying to tell me that I don’t need 2 layers of paper. What would you tell a contractor who is not familiar with green building to make him comfortable with this extra layer of building paper?
2. What type of building paper should I tell him to use? He said that there are many types.
3. Anything he needs to do between the 2 layers of building paper
4. He is familiar with Tyvek but not Typar. Is the installation method the same?
5. He is putting windows in before the house wraps. Is this correct sequence? I am not a builder but I think the wrap should go in and tuck into the windows, so I figure I check with you experts to make sure. If I am right, whats the best way to explain to him why the wrap should be installed first?
My contractor is very nice and competent. I like to explain to him in a way that he can understand rather than just doing what I want him to do. He builds a lot of house in my neighborhood and he will apply the knowledge to future houses he builds if he understands the rationale.
Thank you for your help.
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Replies
Rian,
Stucco should never be installed against plastic housewrap products like Tyvek or Typar. If you want to use plastic housewrap, you need to install one or two layers of asphalt felt or building paper on top of the housewrap so that no stucco ever comes in contact with the housewrap.
Are you planning to include any wall sheathing? You didn't mention any.
Stucco tends to hold water and dry slowly, and many stucco-clad homes have experience wall rot problems. I strongly urge anyone interested in installing stucco to include an air gap between the stucco and the wall sheathing.
For more information, see To Install Stucco Right, Include an Air Gap.
Thanks for the pointer and I have corrected the sequence below. I did forget to mention sheathing.
Dry wall
Cellulose insulation / 2*4 wall
Plywood
Typar
Building Paper layer 1
Building paper layer 2
Stucco
I am skipping rain gap because it does not rain much in my area and I am already putting 2 layers of building paper which my contractor thought was way over kill.
Do you have any advice on other questions? He is putting on windows this week before house wrap and build paper. Is this OK?
Do you have an article comparing asphalt felt and grade D building paper? For the 2 layers, should I stick to the same type or 1 layer paper+1 layer felt?
Thanks.
Rian,
You wrote, "I am already putting 2 layers of building paper which my contractor thought was way overkill."
Two layers of building paper under stucco is not "way overkill" -- it's the minimum number of layers required by code. I would get another contractor; your current contractor doesn't appear to know much about the stucco trade.
And windows never go in before the wraps and felt. Become a member here pronto and read... and watch some videos.
Here's one:
http://www.finehomebuilding.com/item/13076/building-skills-how-to-cut-housewrap-for-window-rough-openings
Thank you AJ.
A couple questions:
(1) Whats the problem of putting in windows first? I need to explain to the contractor. I have already committed to this contractor and really enjoy working with him.
(2) Should windows go in before or after the building paper? Option (A) or (B) below:
Dry wall
Cellulose insulation / 2*4 wall
Plywood
Typar
(A) Put in window
Building Paper layer 1
Building paper layer 2
(B) Put in window
Stucco
Rian,
Here's a link to a series of eight videos that explain how to flash a window:
https://www.greenbuildingadvisor.com/window-sills-wont-rot-sloped-sill-or-backdam