Thread: Should Drylock water resistant be applied before stucco

Is it recommended to apply drylock water proofing around the windows prior to applying stucco ? I see some houses with the drylock but I am not sure if its needed if stucco will be applied

thanks in advance

Matt

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NO. Remember the window is an opening in the wall, the drylock ends at the window and can lead the moisture to the opening. It makes more sense and is typcial that the window opening, before the window is installed, the opening be wrapped with a barrier (such as ice-water shield, or house wrap) then barrier over wrap the block. This is called "butterfly".
In other words, wrap the interior of the opening bring out over the opening and layer on top of the block. Then a diagonal piece is placed over the miter corners of the wrap.
Scott Brown
EDI Ceritifed Third Party EIFS inspector
Certifed Water Intrusion Analyst
Moisture Warranty Certified Inspector

Thanks Scott for your reply. What about windows on Cinder Block. The bonus room is wood frame so its wrapped but the one in question is on concrete block


Thanks
Matt

I don't know what you mean by bonus room, but let's talk about the wall. Scott is experienced, so I would like his feedback.

Yes, you can apply stucco (I assume you are referring to a sand mix) directly to the blocks. But before we do let me ask you this;

Would you leave the blocks bare? Do you think the bare blocks would absorb and leak (moisture) to the interior? I think so (I know so). Well in that case don't you think applying a sand mix stucco directly to the blocks will give you the same result? What I am getting at is that in my opinion, I believe a Liquid Applied Moisture Barrier (first) would be the best bet.

Additionally, In order to avoid cracking I would suggest wire mesh (after the LAMB). I would also recommend holding the stucco back from the window frame in order to allow for a sealable joint. A filet joint is also good.

I agree that the rough opening should be sealed. I prefer a self stick flashing. And if you really want to do it right, a pan flashing would be in order.

Another way to finish the way is by applying some type of liquid barrier on top of the stucco. More or less like a polymer based base & finish.

So it really all depends upon the finished and long term results you are looking for.

Scott, how do you feel about this?

The original poster is from Jacksonville, FL where CMU construction is common. I would think that it would be advantageous to waterproof the CMU with a product similar to Drylok which is a brand name. It would be no different then how commercial CMU buildings are waterproofed.

I agree with Steven that the CMU will allow water to seep through if it is not waterproofed. I have seen it many times....

I have a feeling that the FL building codes might address this but I don't know for sure. We might want to here from a FL inspector on this.

Well I spoke to the builder today. He said he actually prefers not to use Drylock as the water he explained that would be absorbed by the concrete block but then just drain downwards.

He did say just this month new building code passed that every window should be water proofed with DryLock prior to stucco but a different type of window was used. The code just passed a month ago so it would not be applicable to my house. One other aspect is that I paid to have the concrete block filled with foam so I don/t know if this allows the water to drain download and not into the house

thank you all for your input
Matt