Has anyone successfully placed an exterior balcony over a conditioned space below without water problems? If so, what construction technique (s), product (s) were used? Concrete slab over barrier over concrete slab? Concrete slab with barrier with paver? Coating on top of concrete slab?
I am looking for any and all suggestions available.
Thank you
I’ve used all three. The system depends on the look that the architect wants (and, as always, budget).
The key, in my opinion, is to treat it more as a roof rather than a balcony (i.e. proper flashing, slope, drainage system, etc.).
I have had success with Noble Seal’s Deck Seal product as a primary waterproofing membrane with thinset tile over the top.
I’ve also done all three and absolutely agree with Ron – treat it as though its a roof. Absolutely make sure the drains are where they should be, and do something so that they drain continually and can’t get clogged up.
if you anticipate plants (big plants with leaves that fall all over the place) up there, then make sure there is a way to deal with them – planting wells, or something like that.
when I’ve seen failures of these installations, its always the dumb stuff— slabs sloping away from the drains, water barrier improperly installed, discontinuities in the finish…
American Hydrotech has what they call the “Ultimate Assembly” which includes waterproofing, protection board, rigid insulation, pavers, etc as a single warranted assembly. We like to use it so that one manufacturer warrants everything to reduce the amount of finger pointing in case of a leak.
Here’s their info: http://www.hydrotechusa.com/ultimate-assembly.htm
Siplast has a similar assembly called Teranap Plaza Deck. We’ve never actually used it though so I can’t vouch for it from first hand experience.
We have variations of all three on the boards right now. The cost can vary here easily by a factor of three so you need to select based on which is the right fit for your project’s budget and purpose.
In our firm we would insist that your primary moisture barrier be sloped to drain.
I wasn’t going to name names, but the Hydrotech system with pavers is a favorite of ours too.
My office generally tries very hard to avoid this kind of condition, but when it occurs we use Grace or Cetco products (such as swelltight) with protection boards, drain mats, etc… The key is to make sure the structural roof as well as the topping slabs/pavers BOTH slope, and if possible, to slow outward positively, AND provide deck drains for secondary drainage.
That Hydrotech solution looks interesting.
Is the question solely about topside protection or (also) dewpoint/condensation at underside?
It wasn’t a balcony, but a helicopter landing pad over occupied spaces, and I used Xypex in the top concrete mix; split slab with drainage between, plaza deck style, and internal drains. And then a finish of a UV and jet fuel resistant fluid applied coating - with the colors we needed per the FAA. We called it the belt, suspenders and rope approach.
Ron Geren:
If the balony-over-occupied-space is really considered a “roof”, does the code provision for 1/4" per foot of slope apply?
Thanks.
I have seen the Teranap product used successfully on a couple projects, including Monona Terrace (a resurection of a FLW design) The system had insulation and a paver system on top. No mater what product is used, detail areas (pentrations, flashings, etc.) are the most important.
David,
Balony-over-occupied-space? Not certain about “balonies” but “Balconies” over conditioned occupied spaces are “DECKS”
Decks over conditioned space are considered roofs, sloped to drain at 2%. Insulation may be above or below the deck floor structure.
Concrete balconies are cantilivered, not over conditioned space, and are also sloped to drain at 2%. Similar to a concrete eyebrow for sun shading.
Source: My training while at Morrison Hershfield.
Wayne
David:
I have to agree with Wayne. Although the IBC doesn’t define what a “roof” is (just a “roof assembly”), the ordinarilly accepted meaning would apply as stated in Section 201.4.
If the surface cannot be classified as an exterior wall per Section 1402.1, then I would consider it a roof, and, depending on the roof covering material, the appropriate slope would apply. In the case of decks, it would be a minimum of “one-fourth unit vertical in 12 units horizontal (2-percent slope).”
Apologies for the typo; thanks for the correction and feedback.