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Waterproofing Help!!!

typea
13 years ago

Hello all. I am looking for some advice regarding our balcony deck. We are in the process having an addition built onto the back of our house that will be topped with 1 1/4" travertine pavers. It is partially covered but the entire balcony area is about 1300sqft with an outdoor room underneath.

In the process of contracting this a sub came out and installed a Westcoat ALX system that is used for under tile situations. This is installed over a structure that is pretty stout that includes 11 7/8" 560 TJIs 16" on center and 3/4" toungue and groove plywood for a deflection of better than L/480. Max span is 17'. Needless to say the deck is really stiff.

After the install was done and I looked at the spec sheet for the ALX system and it indicates a maximum of 12" plywood span and 1" thick plywood to be within their warranty. The sub is currently working with the manufacturer to come up with a solution since leaks in this balcony were my primary concern for the overall project and the Westcoat warranty indicated that they stood behind their product.

Am I pretty much screwed or is there something that will make this alright? Any help is appreciated.

Also, does anyone have recommendations for thinset that will add additional waterproofing properties to the surface. I've heard that some thinset will re-emulsify if it has water on it for > 24hours. Sometimes it rains here for weeks.

Comments (4)

  • deckexpert
    13 years ago

    You have a few issues to get help on-was it known by the contractor who did the work that you had this situation? Was the subfloor/joists accessible for them to inspect prior to specifying a product?

    Was there a product specified on your plans? Did you deviate from the plans with respect to the product and tile?

    Search the web on westcoat alxut -there has to be many pages full of info on decks/waterproofing/tile decks etc.

    If the contractor knew about your conditions-plywood thickness/joist size/spacing, and he specified ALXUT, he at least in California, has an obligation to know what his products can and cannot do and be warranted for...

    Westcoat will stand behind the product so long as the structure is built within code and the requirements for there warranty...but don't get to sucked in on the warranty bit, it's only for defectively manufactured materials installed by a QCA. You'll probably spend a bunch of money bringing things up to westcoats requirements to find you don't have much in the way of protection anyway...it's basically all on the installer's back...

    I will be interested in hearing from you in following up on this job in about 3-5 years to see how the system has held up under lots of rain...

    I'm a contractor and half the work I do is fix tile decks done poorly. Just today I looked at a huge home on the ocean that has 2000+ sq feet of tile over a waterproofing...metal lath, cement, urethane on top...all gone to hell in about 3 years. Can't say it's Westcoats or whose it is, but I can say it's not working over 16' oc joists with 3/4' plywood...but some dumbass installer thought it would. 80k probably to fix it all...

    good luck,

    Bill Leys
    The Deck Expert

  • typea
    Original Author
    13 years ago

    The ALX system is not specified on the plans. The plans deviated from their original in that we chose not to put a 3" concrete layer on top of Bituthene which was specified on the plan. The plan also called for 12" oc 2x10s which would have given an L/360 deflection. This would have likely failed since the movement under dead load would have been over an inch. So we went with another engineer and he beefed up the structure to L/700.

    We also lightened the dead load by changing to 1 1/4" travertine pavers (not tile). These come in @ ~13lbs sqft as opposed to 17lbs sqft for the concrete. As a result of this change we found a qualified installer for a product that is used under tile. The installer came out, inspected the structure, and reviewed the deck prior to bidding the project. All joists and plywood were visible, accessible, and reviewed with the GC.

    Strangely, I (the homeowner) found the installation requirements after he had put the membrane down and he was shocked with the requirements. All other Westcoat products specify 5/8" ply and 16 oc. The ALXUT specifies 1" ply with 12" max span. It's odd that it does not specify on center. Apparently if I were to install the walking surface first -- which is just another layer of the same stuff -- I would be within specs for the product.

    BTW, with the 560s this leaves 12 1/2" span on 3/4" T&G ply.

    Have you had any experience with Westcoat products? Is there possibly another product that should or could be put on top of this prior to thinsetting the pavers down? I don't want an $80k bill in 3 years. What about a Hydroban layer on top of the ALX? I'm just stabbing in the dark here because I am extremely nervous.

    On another note I'm holding payment until I get a viable solution.

  • deckexpert
    13 years ago

    well if you were installing the job as a traffic coating as oppposed to tile waterproofing you would be in spec. Tile is a whole different animal. Hopefully you have enough in the framing/substrate that ='s L460 or greater...depends on the size of the tile too.

    Don't know where you are, (state) in California, as a contractor, I am required to know what requirements there are to put down a product, ie joist size/spacing...

    Westcoat just makes anyone who shows up at their "training classes" a qualified applicator so they can sell materials...

    put westcoat on the hot seat, get them involved...tell them your in touch with me and see how fast they jump. find out if the contractor is a QCA more info at www.westcoat.com

    I'm familiar with Westcoat, look me up at deckexpert.com and search for westcoat...you'll find plenty!

    You have a structural concern 1st, and then you have a product selection concern 2nd. and 3rd, a question of whether the waterproofer was competent to select the system applied...it is not an approved Tile Council of America method for tiling/waterproofing, nor does Westcoat ALX UT carry an ICC report in Division 9 tile waterproofing/underlayment.



  • PRO
    MICHAEL MCVEY
    last year

    Interested to see how this was resolved. I use Westcoat, but never in a tile assembly over living space.