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What is the best way to seal a hole through stucco?
February 3, 2011 4:47 PM   Subscribe

What is the preferred way to waterproof/seal a hole through stucco for the purposes of mounting lighting and the like?

I need to mount some things (for example, lights) on our stucco-clad house. I know that the waterproofing is done by the housewrap underneath (tar paper in this case), so I'm worried about the water collecting on the upper surface of the light, wicking down through the stucco, and then riding that convenient cable through the moisture envelope. 

Is simply "caulking the heck out of it" the right way to do it?  If so, should I be using like an elastomeric sealant?  I'm used to considering caulking as a band-aid that should be remedied by proper flashing. Or, is there just no "right" way to penetrate the wall and something like ugly surface mount conduit is safest?
posted by RikiTikiTavi to Home & Garden (3 answers total)
 
IANA carpenter, but when setting up our wireless mesh network in our neighbourhood, we sealed all of our cable/lag bolt entries with clear, 25-year silicone. Haven't had any problems. YMMV.
posted by liquado at 5:01 PM on February 3, 2011 [1 favorite]


I am an electrician. First thing I would say is drill the hole tight. Don't make the hole any larger than it needs to be. Second, mount your light tight. It should be as tight as possible to the wall. Finally, a healthy amount of all weather silicon caulking. The you will be fine.
posted by Flood at 5:58 PM on February 3, 2011 [1 favorite]


Another thought on this for you - You know that where-ever the wire comes out the side of your house, you should have something there to meet it.

I mean, ideally, you will drill the hole through the wall exactly where you want the light. So then, the light will cover the hole you just made. Then you caulk to edge of the light tight to the house.

If you have to drill the hole in a different spot, then run the wire to the light location, then you need to have that wire in conduit (pipe). Never have exposed high voltage wire running along-side your house! In this case, you will cover the hole with an EMT LB fitting, and then caulk the LB to the house. And then from the LB, run the conduit and wire to the location you want.

Low voltage wire (cable, phone, 11v landscape light wire) can be run along the wall of the home without any conduit. In that case, then you want the wire to be super tight. So tight that the connector on the tip of the wire can not pass through the wall. Cut the connector off, and re-attach it when you pass the wire through the wall. And caulk the whole really well.

How do you attach a CATV or phone connector? That is a little more complicated. Is that what you need?
posted by Flood at 5:04 AM on February 4, 2011


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