Waterproofing membrane questions

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Old 04-22-15, 08:12 AM
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Waterproofing membrane questions

All, I am planning a project for a slate tile covered outdoor table. I plan on laying the slate on cement board using thin set mortar but since it is an outdoor table I wanted to waterproof it on all sides first. I want to make sure that I use something that mortar and tiles will stick too. I came up with Redgard which sells locally but the smallest I can find is a 1 gallon container at $50.00. I dont even need half that amount. Does anyone have any alternatives that are cheaper with less volume? I need to cover about 30 square feet twice.
 
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Old 04-22-15, 03:15 PM
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Look into a product such as Wedi board. http://us.wedi.de/ They are waterproof and would take the place of your cement backerboard so there is a cost offset. Don't use a silicone sealant to cover your fastener holes as it will interfere with the bond on the thinset. A product similar to nobleseal 150 http://noblecompany.com/products/noblesealant-150 is designed for waterproofing seams in shower installations. Welcome to our world, all the good stuff is expensive.
 
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Old 04-22-15, 03:22 PM
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No way would I be using slate to cover a table.
It's brittle and far to poris.
 
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Old 04-23-15, 05:33 AM
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Thanks, I am open to opinions. This is my first job of this type. My wife wanted a 6 person firepit deck table and the one she liked was $2000.00 Looking at it I felt like I could build it for a fraction of the cost. The plan is a 54" diameter top with cement board fastened to plywood to get some thickness and rigidity then waterproofed. I really want a stone look so planned on using slate tiles but if I can find ceramic tiles I like I would be ok with that. It will have an 18" hole in the center where I will put a stainless steel pan and a propane burner.

I originally wanted to cast a 1.5" concrete table top but by my calculations that would be roughly 300 lbs. While my base can support 300 lbs I was worried about it 1. being top heavy and 2. the base diameter is 24" so that would leave an over hang of 15" and I was worried that would eventually have problems. So I went with a lighter tile covered surface. Also I can get 20% off at my local big box store so I want to use things I can get there.
 
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Old 04-23-15, 06:31 AM
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Ahh, fire changes the mix a little....

Prices on fire tables run full circle, I know as I recently bought one. A diligent search will turn up more cost effective tables. I think I paid about 1/4 of what your were looking at. Amazon.com : Camp Chef FP40 Monterey Propane Fire Pit : Outdoor Fireplaces : Patio, Lawn & Garden Wow, the price dropped from what I spent. Anyway, we love it. The table we have came with glass beads instead of lava rocks. The glass gets how in the flame, but are cool enough to handle out toward the sides.

Plywood outside may not be the best Idea. And as much as you think you will waterproof it against the elements, it will still get wet. May want to skip that step and go pressure treated instead. Are you running this off portable propane, or is it going to be hard wired to a permanent gas line? Need to hide the tank if figuring into your design.
 
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Old 04-23-15, 07:08 AM
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Thanks, I should have been a little more specific. I planned on using OSB but dont mind using pressure treated if everyone thinks that would hold up better. The base is a 55 gallon drum that I will be cutting down shorter and putting a door on the side. I will put a propane tank inside with the control knowbs on the side next to the door. I will probably weld a plate on the inside to help isolate the top fire bowl from the propane tank. I got my inspiration from this and also plan on using fire glass. http://st.houzz.com/simgs/a3d1dcb50f.../fire-pits.jpg
 
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Old 04-23-15, 12:53 PM
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I have a small outdoor end table that is similar to what you have in your link. I just checked and it is a completely poured resin base. It probably has some mesh embedded in it, but can't tell. However, point being, it is completely rot proof. The linked picture probably is make the same way.

Finish out your profile so we know what part of the country you are from.

Stone is not "waterproof", grout is not "waterproof" so moisture on a flat surface will gravitate through to the layers below. OSB is definitely out. Pressure treated tends to warp and cup if not nailed to another surface. Cement boards are not structural on there own.

There are some nice porcelain tiles out there that mimic slate.
 
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Old 04-23-15, 02:49 PM
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This is just spitballing here, and may be completely unrealistic to actually implement, but is there a way to set tile onto an expanded metal substrate? Maybe stucco the metal (as if it were a very high-density lath mesh), then put the tile over the stucco with thinset. Alternately, if the appearance underneath isn't an issue maybe just construction adhesive to put the tile directly onto the metal? You may want to use some kind of caulking or silicone grout for this in case the metal expansion becomes an issue, and I've got no idea if the stucco would be workable with the overhang and might make the table impractically heavy.

Also, ditto cizzi's comment about the porcelain options for mimicking slate, it's impressive what they've got out there, and for a table it's got the benefit of being uniform in thickness as opposed to natural stone pieces.
 
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Old 04-24-15, 06:47 AM
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czizzi, do you have any more information on casting with resin? That was actually what I originally wanted to do to mimic marble but I couldn't really find much info on the process. Everything always led me to clear resin over an existing top or concrete casting.

bmgreene, I thought also about using expanded metal. My only issue is my limited metal working abilities. I can weld, cut, and grind but bending is out of the question. I went out looking for a pre built expanded metal table but could not find one big enough.
 
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Old 04-24-15, 01:42 PM
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The only multi part epoxy resin I use on a regular basis is bondo, but I can not find anything on how thick you can cast it. For your application, and from a relatively user friendly point of view, you may have luck building up fiberglass with resin and glass mats. Both are relatively easy to find and work with. It would be making a form that would be the tricky part. I'm sure you can watch some video of boat makers casting hulls, or video of people making hot tubs. You would not have to make it very pretty as you will be top coating with tile. I'd have to investigate what type of thinset would work best over that.
 
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Old 04-24-15, 01:52 PM
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redguard's great stuff as is any good material how expensive would it be using cheaper materials then repairing, rebuilding, or replacing this very fine table ? if you build it correctly, you also get other advantages: 1, you don't have to look @ a pos in a short time; & 2, you don't have to deny YOU built it

my choice - redguard all sides of 3/4" marine ply base, screw down expanded metal mesh, thinset, & slate,,, while slate's porous as previously posted, all stone's porous,,, slate was used for cemetery memorials over 200yrs ago - how long do you want this table to last ?

epoxies aren't uv-resistant &, typically, need a uv-resistant protective coat of urethane... my suggestion - build it right OR suffer the slings & arrows from your bride... saving mucho bucks will soon fade as any rational option.

czizzi, what use do you have for bondo other than repairing dents on your wife's car ?
 
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Old 04-24-15, 02:21 PM
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czizzi, what use do you have for bondo other than repairing dents on your wife's car ?
I leave the dents in her car as a warning to others to stay clear.

All Purpose Bondo (grey color) as opposed to Auto Bondo (red color) is one of those go to items from time to time. I had to hang crown moulding in 26 room at a hotel with block walls behind glued up drywall. The ceilings were poured concrete. The crown was bed molding which is the smallest profile of crown. I drilled pilot hold in the moulding, counter sunk, held it to the ceiling, used a mason bit to drill hole in the block. Inserted a wittled piece of wood into the hole I drilled in the block and fastened it with a deck screw. The bondo filled in the countersink which I then sanded to match the profile of the wood. Got so I could do a room in a hour and a half.

That is just one example. But I have repaired many a error made by previous contractors or over aggressive homeowners who hack away material and then realize they can't do things that way. Most recently, I tiled some bathroom at the same hotel. The previous counters were supported by a 45 degree piece of metal rod that was drilled completely through the baseboards. 1 1/4" hole in the baseboard drilled down at an angle. One evening on the way out the door, through some bondo in the hole. Sanded it smooth the next morning. Can't even tell that there was ever a hole in it.
 
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Old 04-24-15, 07:58 PM
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Czizzi, at one time I was married to a woman like your wife. Mine drove using the Braille system--when she heard something "clunk," she (usually) reversed direction. But, man, she was a good cook!
 
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Old 04-25-15, 10:13 AM
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i married their 1st cousin
 
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Old 04-27-15, 05:07 PM
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Seems like you should be able to do an expanded reinforcement without needing to bend much, if anything. Also, small local bends are pretty easy, it just takes some kind of form (for expanded stock, a chunk of wood would work), a smooth-faced hammer and a bit of time.

If you have the tools and skills to cast concrete, you could probably use a couple layers of expanded metal separated by some spacers (3/4-1" bits of bar/tube would suffice) either wired together or tack-welded to create a "sandwich" structure; then set that into the concrete with the upper layer of metal near the top surface of the piece (minimal thickness of concrete over the top to ensure it holds together). I'm not familiar with ferroconcrete in particular, but looking at that as a "composite" element, this arrangement would leave the metal to carry the tension side of bending stresses in the cast table top, and the concrete at the bottom will be in compression due to overhangs and weight on the table, which is what concrete is good at. Of course this may, at some point become more work than it's worth (maybe one of the hallmarks of many of my ideas that I've taken up over the years...). Cosmetics of the casting shouldn't be too important since it'll be tiled over.
 
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