*
What’s the real story about stucco exterior? Will it eventually fail if applied over wood sheathing with plastic/tarpaper/tyvek wrap? Can it applied over cement board sheathing… in order not to rot? Is there any other type of sheathing (less costly) over which it can be successfully applied? (Wouldn’t applying synthetic stone to wood sheathing with wrap eventually fail as well?)
Please help.
Replies
*
Sorry to disappoint you, but there is no "real story" about stucco other than it is a plaster that sticks to walls. A good wall system that has been logically planned, competently built and well maintained will last a very long time. There are more choices for stucco and synthetic stucco-like walls out there today than you can shake a stick at (and even more opinions about what is best.) Your choice depends on the look you want at the price you can afford.
The sheathing in a stucco-clad building is more about the framing strength, specifically shear, than the exterior shell of the house.
However, If you really want something that won't eventually fail , I'd suggest the early Greek method of limestone blocks.
*This interests me also; I do not have all the answers. I want traditional stucco, vs synthetics. Traditional AFAIK requires lath to be fastened down at specific intervals, so seems to me that precludes cement board since it does not take nails or staples. (Could cement board make lath not necessary?) I am tending toward going with plywood sheathing nailed and glued, maybe even 3/4", but the key will be in the wrap. The best solution I have considered thus far would be two layers of tar paper, with some kind of textured building paper (??) in between to act as a moisture control plane.Then around the window trim, I am considering a dummy wood strip that would be removed after the stucco is fully set (weeks), to be replaced with a foam rope topped with a poly caulk bead. How to handle where it meets the trim at the roofline and whether/hom to trim out the bottom edge -still thinking on that.Garry Morrison
*I thought that cement board exterior sheathing might preclude the lathe, and be far more reistant to any moisture that might eventually contact it than wrapped wood.
*Most of Southern California post WWII tract housing is stucco. It was done with no sheathing just standard 2x4 framing, then baling wire about a foot or so apart.Then one layer of 15# felt, then chicken wire held on with nails with spacers so the wire is about 1/4" off the paper. Then 3 coat stucco. Tends to get some hairline cracks as things settle over the years. Joe H
*b WBA At Your ServiceThose of you that are considering using a really expensive sheathing product like cement board for a stucco substrate due to plywood rot concerns should be concerned about water infiltration with this type of system. You can't stucco directly on top of the cement board without a water barrier such as 30# felt. You can't nail the wire lathe properly because the cement board won't hold the nails. I don't know what the concern is here. I have removed 75 year old stucco that was covering 15# felt (that was equivalent to today's 30#) that was in excellent condition. The felt was protected by the stucco. Cement plaster if undisturbed and unstressed will not crack. Unfortunately houses shrink and move and cause fine cracks which allow water to enter. 30# felt does a wonderful job of preventing infiltration. You must give the water a way to get out of the wall at it's base through a well designed weep system. eamgjw- why don't you consider using some of the existing plaster accessories for your job instead of removable wood strips. 1/2" Square edge metal casing would provide excellent grounds for your plasterer to work to around your windows and could be installed with a caulkable gap. It sure would save a lot of work on your part and it gives you a perfectly straight surface around your windows. You need to find a quality masonry supplier for products like this.
*Yeah Joe, I lived in S. California. Thats one reason I moved couldnt see paying 300,000 for a 50,000 house.
*I would like to use a stcco exterior on a residential addition/remodel. The existing home is stud framed, with fiberglass vapor barrier insulation, Celotex sheathing and sheet and lap siding. Can anyone give some advice on the best sheathing system to use on the remodel to prepare the home for stucco?
*I recently visited a stucco building that was built in 1892 and moved in 1927. It seems to have lasted pretty well.-- J.S.
*This is one of the studies I unearthed while trying to remedy stucco problems. Maybe it will be helpful.http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/99117.htm
*My very first carpentry job was building what I know now to be a rain screen wall. Two layers of #15 felt, then strips of lath on 16-in. centers topped by expanded metal lath (I lost a lot of blood handling that stuff. In fact, the day I quit, I counted over 20 cuts on my hands). Finally, three coats of portland cement stucco. Very labor intensive, but I think the inside of that house could rot to dust and the shell would still stand.Andy
*
What's the real story about stucco exterior? Will it eventually fail if applied over wood sheathing with plastic/tarpaper/tyvek wrap? Can it applied over cement board sheathing... in order not to rot? Is there any other type of sheathing (less costly) over which it can be successfully applied? (Wouldn't applying synthetic stone to wood sheathing with wrap eventually fail as well?)
Please help.