"Best" white elastomeric roof coating

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Old 06-05-13, 08:45 AM
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"Best" white elastomeric roof coating

I have a flat roof that has been refereed to as a "built up" roof. It has the tar/asphalt and sheet layers and is angled to the canales.

I recently installed vents in the parapet to help cool down the roof (the builder did not install any in the roof and it would get very hot on the sunny side of the house) but I wanted to make it more efficient

A neighbor of mine put this coating on 2 years ago (his house was built by the same company as mine) and added the vents and he says he has almost cut his summer electric bill in half and doesnt need the AC until late May. I have been using mine since March

Anyways, which is the "best" one. I had looked around and was leaning toward this one
687 Enviro White Premium White Roof Coating | Henry.com

Also I was going to use a roller to put it on, is this the best way? One of the hardware store guys told me to use a thick nap, but didnt really say how much, I was thinking 3/4 is that enough? Should I go bigger?

This is how my roof looks




Thanks I appreciate all the input/advice on this board, its a life saver
 
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Old 06-05-13, 09:56 AM
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I'm not real familiar with the different brands of elastomeric roof coatings.
A 3/4" nap would be the shortest you'd want to use, I'd use a 1" maybe bigger. The main thing is to apply a good thick fluid coat of the elsatomeric. It isn't quite the same as painting a wall, you need to do more than just color the roof.

What brand did your neighbor use? how is it holding up?
 
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Old 06-05-13, 01:38 PM
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Im not sure about my neighbor, I know they didnt buy theirs at home depot or lowes, a few of his coworkers pitched in and bought a pallet and did all their roofs, so Im assuming it was a builders/contractor supply store. Ill try to find out.

Ill look for the 1" that what my "gut" was telling me, should have just listened, haha
 
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Old 06-05-13, 08:07 PM
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The best elastomeric roof coating is the one that is installed properly. I usually use Kool Seal with a 10 year warranty. It is not designed to be used on a roof that has any standing water. You need to clean the roof first TSP then apply two coats at about 80sf /gal/coat. I use a 1" brush on a handle. First coat , North /South. Second coat East/ West. You may need three good weather days to do the job. Your roof may even require a primer. Check out the Kool seal web site for info.
There is also Hydro Stop for roofs with standing water. Primer, base coat/ fabric, top coat. Hydro stop is a bit expensive.
 
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Old 06-06-13, 10:12 AM
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thanks dan0661,

I was planning on sweeping up the dust/leftover roof granules, then spraying down the roof with a pressure washer (as a local roofer suggested but scares me) or the stream nozzle and my garden hose

My roof is "flat" but it has an incline that is pointed to the canales you can see the drainage of the water by the patterns of the collected dust.

what is TSP?

Thanks
 
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Old 06-06-13, 10:57 AM
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TSP is a very strong detergent powder mixed with warm water for heavy cleaning. Normally in the paint area of stores. There is also a TSP substitute....not sure if it's as good.
 
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Old 06-06-13, 11:30 AM
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ah I see, thanks again. Cool avi by the way, loved metal slug way back when there were still arcades
 
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Old 06-06-13, 03:23 PM
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TSP = tri sodium phosphate
 
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Old 06-06-13, 03:51 PM
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question about the TSP, it is very very dry here, from my google searching it seems like the TSP is to remove mold and algae from the roofing tiles

would this be the only reason to use that?

Thanks
 
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Old 06-06-13, 03:59 PM
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Here in the southeast, I mostly use a bleach/water solution for cleaning mildew off of siding, decks, etc for repainting. If the current finish is glossy or has other grime that needs removal - I add TSP to the mix. I've never heard of TSP being exclusively used for mold and algae removal. As Vic stated, it's a heavy duty detergent which makes it a good cleaning agent. It does require rinsing as any leftover TSP residue can affect the coatings ability to bond well with the substrate.
 
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Old 06-06-13, 04:21 PM
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Ah I see,

so would there be any harm in just rinsing/scrubbing/rinsing the roof prior to coating it?

Thanks
 
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Old 06-07-13, 05:42 AM
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It is always a good idea to clean prior to applying any coating! ..... just be sure to give it time to dry out.
 
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Old 06-08-13, 06:30 AM
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Trisodium Phosphate TSP

A non-sudsing powdered Trisodium Phosphate compound that is formulated for heavy duty cleaning. Preferred by painting and cleaning professionals for removing heavy deposits of greasy grime, smoke, soot stains and chalked paint from walls, woodwork and floors. Removes mildew and mildew stains when mixed with bleach. Also recommended for washing away paint remover sludge.
 
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Old 06-08-13, 06:48 AM
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A nice thing about the white elastomeric is that it will keep the roof cooler. If you really want more efficiency, you can lay rigid insulation over the existing roof and use a system like the Hydro Stop to cover and finish it. The added insulation would give you about R 4-8 per inch of thickness and add about 20-75 cents per sq ft per in.
There are also companies that will spray foam the roof and then coat it.
 
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Old 06-11-13, 09:35 AM
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adding insulation and then covering it seems way over my head in terms of my DIY'er skill set
 
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Old 06-21-13, 02:40 PM
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Hi guys, one more question about this. Today I finished up the vents over my kitchen/dining room roof, and I swept/washed the roof.

really had alot of crud.

Anyways, I noticed there are 3-4 areas on the roof that accumulate a little water, do I need to do anything to these areas prior to installing the elastomeric coating?

The instructions on the coating I bought doesnt really mention anything like that, it mainly addresses leaky roofs.

Thanks again
 
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Old 06-21-13, 04:52 PM
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I'd try to address - I'm not sure what's the best way to build it up

The elastomeric should seal it ok but anywhere you have standing water it is asking more of the coating and sooner or later that will likely be the first place to fail
 
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Old 06-22-13, 08:05 AM
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The website for the coating I bought has this stuff to put on ponding areas to build it up, not sure how well it works and that none of the local home improvement stores have it.

I'm starting to wonder if maybe I was putting more water than the roof drainage could handke thus causing those little ponds.
 
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Old 06-22-13, 09:42 AM
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How deep was the water? how long did it stay puddled up?
 
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Old 06-24-13, 09:50 AM
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it was just a fraction of an inch, not much more after the water drained. it stayed puddled up for maybe 30 minutes to an hour, then it evaporated.
 
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Old 06-24-13, 11:40 AM
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I don't know that I'd be concerned about puddles that small.
 
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Old 06-24-13, 07:40 PM
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What effect does ponding water have on cool roof coatings?
Waterbased coatings do not perform well on roofs that pond water (i.e., areas of a roof that have slow-draining puddles on them). Dirt can accumulate in depressions and inhibit the reflectance of the coating. If a waterbased coating is under water for a prolonged period of time, the water may work its way under the coating causing it to peel, or erode the coating and create gaps in the film where water can intrude. Positive drainage is needed to flush away surface dirt and retain the reflective properties of the coating. Keep drains clean and re-grade the roof if needed so that ponding does not occur.
This is from Gardner-Gibson's web sight.
Most Elastomeric coating are not waterproof. Which one did you buy?
 
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Old 06-25-13, 04:22 AM
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Dan, while I'm not real familiar with elastomeric roof coatings, I've used a lot of elastomeric masonry paint which is mainly used to waterproof the walls. Are elastomeric roof coatings that different??
 
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Old 06-25-13, 06:43 AM
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The answer is a big "Yes". If you shop around you can find 5 gal from $75- $300. Not that price will guaranty the product to be any better than another.
It seems that the elastomeric roof coatings are used quite often to provide a "cool roof" , and are water resistant or have improved waterproofing capabilities. If you need "waterproof" it needs to say so on the product and if it says no standing water, there should be no standing water.
 
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Old 06-26-13, 02:33 PM
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dan0661
What effect does ponding water have on cool roof coatings?
Waterbased coatings do not perform well on roofs that pond water (i.e., areas of a roof that have slow-draining puddles on them). Dirt can accumulate in depressions and inhibit the reflectance of the coating. If a waterbased coating is under water for a prolonged period of time, the water may work its way under the coating causing it to peel, or erode the coating and create gaps in the film where water can intrude. Positive drainage is needed to flush away surface dirt and retain the reflective properties of the coating. Keep drains clean and re-grade the roof if needed so that ponding does not occur.
This is from Gardner-Gibson's web sight.
Most Elastomeric coating are not waterproof. Which one did you buy?
This is the one I bought
687 Enviro White Premium White Roof Coating | Henry.com

I read the technical brochure a few times and I couldnt really find anything talking about ponding water in the surface prep, but it does say this in the "Precautions" section

"NOTE: Ponding Water Resistant up to 48 hours. For older, low-sloped roofs where depressions pond water for extended
periods, Henry #176 Pond Patch® is recommended to provide positive slope in these areas and eliminate ponding."
 
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Old 06-27-13, 12:40 PM
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Seems that you are now at the whims of Mother Nature. If you are main coating for the "cool" effect then you should be all right for some years to come. If you are coating to stop leaks then maybe not. With the puddles and a couple of wet and cloudy days or melting snow you may not be leak protected.
 
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Old 06-27-13, 02:53 PM
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I did the coating solely for the cooling, my roof is/was leakfree when I started this project.

I had one leak, but it was on a skylight on the garage roof, but I fixed that.

usually it doesnt stay wet here for too long, during the monsoon season (July to Oct) we get light to medium rainfall (in the range of 1-2 inches per month)

during jan/feb we will get snowfall but its nothing crazy, usually its just cold, or it gets too cold and no snow

Thanks
 
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