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Discussion Forum

DRYLOK Masonry Waterproofer

Mike_Mills | Posted in General Discussion on January 26, 2010 03:08am

I used a self-leveling underlayment (SLU) to create a level sill/threshold. The doors went in beautifully well because of this flat, hard surface. The thing is, the SLU is fairly permeable to water and the outer edge of the sill is currently exposed to the weather. It does not leak liquid water, the SLU absorbs moisture and gets damp. The edge of the SLU is about 1″ high and 70″ wide – as wide as the door. I need to seal this edge. I was thinking of using DRYLOK to paint the exposed surfaces of the SLU. What do you think, is this going to work? Other options exist. I could just “paint” it with liquid epoxy. That stuff is strongly adherant and water proof. I could paint it with silicone caulk. Whatever I do, I was thinking I would use some concrete or mortar to form a small bullnose edge/curb which covers the SLU edge and keeps the liquid water away from the Drylok. What do you recommend?

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  1. Snort | Jan 26, 2010 03:53pm | #1

    Drylok is not a water-proofer, it's a damp-proofer. With the water issue, I'm assuming this is an exterior door... think about a sill pan as another option. It will redirect any water where it belongs.

    1. Mike_Mills | Jan 26, 2010 06:58pm | #4

      Yes, it is an exterior patio door.

      The SLU was applied to the top of a concrete slab. There is no option for a sill pan, as the edge of the slab is about 12" from the exterior of the SLU.

      From my earlier post, "Whatever I do, I was thinking I would use some concrete or mortar to form a small bullnose edge/curb which covers the SLU edge and keeps the liquid water away from the Drylok."

      I was thinking of using the concrete curb to keep the liquid water away from the SLU. The curb would be capped by the aluminum door sill and protrude out and away from the door.

      In the sketch below (click on the thumbnail to better see it), the red line would be the DRYLOK. The concrete curb would be the blue. The SLU is the green and the door is the tan object on top of the SLU. The grey concrete slab extends out to the left at least 12".

  2. User avater
    rjw | Jan 26, 2010 04:44pm | #2

    Plus, drylok needs a rough surface to adhere to ...

    1. Mike_Mills | Jan 26, 2010 06:57pm | #3

      The SLU is fairly rough. It is entirely matte in appearance and it is quite porous/permeable. I could roughen the surface further, using a stiff bristled wire brush, if that helped.

      1. Snort | Jan 26, 2010 07:24pm | #5

        I could get a sill pan in there, but it sounds like you've already got the drylock, and want to use it. LOL

        1. Mike_Mills | Jan 26, 2010 07:46pm | #6

          Can you describe what you are suggesting? Perhaps I do not understand what you mean by "sill pan".

          For reference, the concrete slab runs off to the left about a foot more than shown in my sketch and it is approximately at soil level (about 1/4 - 1/2" above soil).

          P.S. - I do not yet have the DRYLOK but it is the product I am asking about.

          1. Snort | Jan 26, 2010 08:42pm | #8

            Something like this:

            http://www.suresill.com/temp/newweb/suresill_products_slopedsillpan.html

            You want any water directed away from the sill.

            Cut what needs to come off of the pan overhang. Put a bead of PL Polyurethane caulk along the front edge of your poured sill, and a healthy squiggle on top of the levelastic to keep the pan stuck down. Make sure door tape or house wrap overlap the the pan ends

            If that door is exposed, and that close to the slab, there's going to be some splash back, maybe a lot. I'd also find a door bottom with a drip cap

            Thinset's not waterproof, either.

          2. Mike_Mills | Jan 26, 2010 11:48pm | #9

            Yep, that's what I thought
            Yep, that's what I thought you meant. I've never seen one that is large enough. It would need to be 12" to 18" wide for the lip to hang over the edge.

            I don't expect anything to be totally waterproof. I was thinking of using the concrete/thinset to keep most of the water off the SLU. Then the Drylok would hold off what gets past that. What gets through should be a minimal threat to the longevity of the SLU which is a cementateous product, itself.

            Will the concrete/thinset adhere well enough to the SLU? How about to surface of the old concrete slab?

          3. Snort | Jan 27, 2010 10:28am | #11

            Your drawing has the SLC formed into a raised sill. Trim the ovehanging lip of the pan to match... no need for it to be 12" wide!

          4. DanH | Jan 27, 2010 02:24pm | #13

            Doesn't do any good in terms
            Doesn't do any good in terms of keeping the water out, though. It just becomes another joint through which water can leak.

          5. Snort | Jan 27, 2010 03:54pm | #18

            I give, diyers use thinset,

            I give, diyers use thinset, it's gotta be the ticket. LOLARME!

          6. DanH | Jan 27, 2010 04:49pm | #19

            It works.

          7. DanH | Jan 27, 2010 09:45am | #10

            That won't work in a lot of
            That won't work in a lot of situations. In our case there is a single monolithic slab forming both the foyer for our split entry and the stoop outside. The OP's situation is similar, though not as extreme.

            And I know thinset's not waterproof, but it's damn close.

          8. Snort | Jan 27, 2010 10:37am | #12

            Actually, with some

            Actually, with some modification, and/or the right pan, it will.

            Stand inside a door way when someone is outside pressure washing around it... you'll find a way to do get a pan in, too...

          9. DanH | Jan 27, 2010 02:25pm | #14

            I don't make a practice of
            I don't make a practice of pressure washing my door.

          10. User avater
            rjw | Jan 27, 2010 02:55pm | #17

            >>I don't make a practice of
            >>I don't make a practice of pressure washing my door.

            Heck, I've seen people pressure washing their roof shingles!

  3. DanH | Jan 26, 2010 08:28pm | #7

    My favorite for this duty is still good old thinset. It adheres well, doesn't absorb/transmit water very much, and is easily formed into shape. I've used it several times to create a "fillet" on a slab where I wanted to prevent water flow back into a structure. Used it under my front door, among other places.

    If you used thinset, I don't know why you'd want/need the Drylok.

  4. Mike_Mills | Jan 27, 2010 02:29pm | #15

    DanH, you've made a good
    DanH, you've made a good point. I know this because now that you've made it, it is OBVIOUS.

    I am going to use thinset to form that little curb. There will be no Drylok between the curb and the SLU.

    So, thinset it is. Drylok is out.

    If, in the future, I get any dampness in the SLU, I can use Drylok on the outside of the thinset. Drylok comes in grey, so it weill match the concrete and the gry door jamb.

    If the moisture comes from a crack/gap between the thinset or the jamb, I can use caulk or concrete sealer or epoxy to seal the gap.

    1. DanH | Jan 27, 2010 02:35pm | #16

      Yeah, the one negative of thinset, in this application, is its color. Even after a decade of exposure it still remains darker than normal concrete. But just about any concrete coating product will stick to it pretty well, so the color can be "adjusted".

      1. Mike_Mills | Jan 29, 2010 03:54am | #20

        I am far more worried about efficacy than color. If it doesn't work, it doesn't matter what color it is, how cheap it was,...

        It will be a few more days until I can do this. I have to wait until the coming weekend, as I have a regular job during the week.

        Then, unless we get more rain this winter, it could be another year before we find out if it worked. :-)

        I managed to put up a rain gutter last weekend. It rained the very next day. The gutter really helped the SLU situation. The gutter diverted all the rain water and the SLU stayed totally dry. It was not a "storm" with wind-driven rain but it was a full day of rain. I was very happy about that working well.

        Here, by the coast, we get really heavy condensation almost every night. The gutter has been catching all the run-off from that, too, diverting it away from the SLU.

        I have had dry SLU for over a week. Still, thin set goes in this weekend.

        1. brucet9 | Jan 29, 2010 04:48am | #21

          Thinset comes in dark gray and white. If color is a concern, blend the two thinsets to the right shade of gray.

  5. Mike_Mills | Feb 01, 2010 03:31pm | #22

    I did the cement work last weekend. It went great and looks good.

    I used a product called "Cement-All". It is a quick-curing cement which is supposed to bond to other cement very well. I broom-swept the area, then scratched the old concrete and the underlayment using a stiff, steel-bristled paint scraper. I swept away the dust and moistened the area (per the instructions).

    Having the proper sized trowel to lay in the material and smooth the edge was a BIG help.

    We are getting rain this week, so we will see if it fixes the dampness issue. It will have had 2 1/2 days to cure before the rain arrives.

    If this does not fix it, I may reconsider the Drylok.

  6. Mike_Mills | Feb 06, 2010 02:05am | #23

    It's been raining all day
    It's been raining all day long, today. Everything is still dry, so the thin set worked without the need to resort to Drylok. I am a happy camper.

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