Replies

1. Expert Member
   Akos | Mar 22, 2021 07:55pm | #1

   I've had good experience with EIFS, cheap way to get exterior rigid insulation and pretty durable. There is a couple of details that the installer needs to get right but they are pretty straight forward (WRB, grooved foam, flashing at windows).

   The big issue with EIFS is that it always looks off, the worst offenders are the fake stone details. So if you want real stucco look, you need to install actual stucco. This is very easy to install wrong over insulated assemblies, so make sure all the details are worked out in advance and your installer follows them.

2. 
   onslow | Mar 22, 2021 11:52pm | #2

   Cbut,

   Real three coat stucco is much much harder than EIFS, but also much much heavier. Be sure to account for the load and fastener requirements. Staging for either will be similar, but you will be on site longer with real stucco. Real stucco will hold a lot more water than EIFS so proper gapping for drainage is very critical. Proper WRB choices must be made.

   Getting people who really know how to put on true stucco can be a chore. Misting the coats to keep them from drying too fast to avoiding cracking is seldom done properly from the jobs I have observed. EIFS is a bit more forgiving because it is one coat then the synthetic top. It can still be screwed up by indifferent workers. I agree that real stucco can produce a classier surface than EIFS. There is a product called Grailcoat that unfortunately seems to be a west coast thing. Might try looking it up in your area. The sample I have was very impressive, just not available to me.

   I have EIFS over EPS and woodpeckers to deal with, so I elected to use a different base coat that had much better impact resistance than the standard material. This avoided using the heavier grade (expensive) stronger mesh material recommended as the alternate way to increasing impact strength. So far the woodpeckers have left after breaking their noses. Not sure if the baby pigeons one sees in the park are as big a problem, but I hear the full grown ones hide on top the the buildings. ;)

   I would definitely go check out the work of whoever you contact and if possible view buildings done some years before. Then pray that the same crew is working on your building.

1. 
   viapapillon | Mar 24, 2021 08:55pm | #3

   Roger,
   Can you elaborate. I am seeming to have this problem you mention-not finding a stucco installer that has experience with the traditional 3-coat over 2" of GPS (Thermal Tight). What fasteners do you recommend?

3. 
   onslow | Mar 28, 2021 05:06pm | #4

   Monsieur Butterfly,

   Fasteners are a big problem. I am looking to mega furring strips in order to build out a deeper foam outsulation on a new build, unless I can get clearance for the StoCoat. Below are some links that hopefully provide better guidance than I can offer. Make sure the inspector is down with any decisions you make. Check out the InsoFast site and their tech page for fastener guidance.

   Provided you can get adequate back plane drainage with direct fasteners that are holding the mesh, you might get approval. The addition of furring strips certainly enhances the back plane drainage though it introduces some detailing around windows and doors that are best planned for early in the design. The length of screws for furring over 2" of foam are less onerous than deeper foam. Lots less pricey too.

   You haven't noted your climate zone and rain fall, so be sure to read the Apocalyps article. The rest of the links may help you find technically valid information that I simply can't provide. My EIFS is direct application to the foam which is glued with vertical placed notched cement adhesive, so no fasteners.

   The biggest issue I had observing 3 coat jobs in the area involved inadequate misting. I live in a semi arid environment, so misting is really important. I spent days keeping my foundation and slabs wetted adequately since no one else seemed to care. I can only guess that my efforts were rewarded. Virtually no cracks in the slabs so maybe I helped. Finding people that really understand and care is a challenge.

   https://www.buildingscience.com/documents/bareports/ba-1204-external-insulation-masonry-walls-wood-framed-walls/view

   https://www.jlconline.com/how-to/exteriors/three-coat-stucco-over-foam_o

   https://www.buildingscience.com/document-search (check the stucco box to narrow results)

   https://eifs.com/eifs_primer.html