How OFTEN to coat and Are All Flat Roofs not FLAT

Finished my 2nd coat of Alum on new full tearoff/rebuild.
What is the guideline when putting on a fresh coat of Alum. Every 3-4 years on the mark ? Or wait till you see aluminum loss, less bright/reflectivity ?

Second, as I coated the roof, I noticed how NOT flat my brand new Flat Roof is. It appeared pretty flat on the Densboard/tri ply base. Then it all went downhill from there. All over, there are foot depressions on the roof. I assumed/presumed that a brand new flat roof would be almost dead flat and as they worked their way back, with each roll layer, it would be ~mindful~ to not walk on the new soft layers to create depressions…

So I’ve gotta ask. Are all flat roofs not flat …

—When they put the 1st layer on, after they had left for the day, I notices areas where I could literally make out the tread pattern of boot sole. We’re talking depressions of the treads around 1/8" deep. I pointed it out to the owner that same night via text and he advised he would make sure the offending boot wearer would not be wearing said agressive tread when the final layer went down*

Flat roofs are not necessarily flat…most “flat” roofs have a pitch/slope of 1/8 to 1/2" per foot. Having a depression on the roof would get my attention because it will cause either a bird bath or ponding. Ponding will shorten the life of your roof.

Stop with the aluminum coating junk. Clean the roof down with a short stiff bristle bush. Wash the whole roof with simple Green and a good stiff brush and rinse it thoughly. Use a leaf blower dry it down and give it a good coating with Gaco liquid roof and a 3/8 nap roller. Garden rule is 5 gallons does two coats on 2.5 sq on none granulated and never worry about it again. 50 year warranty on material

During the exploratory phase of what route to go with the new roof (torch or SBS, etc), the question on Gaco was posed. I recall there was 2 or more fellow veteran roofers that advised that there was nothing wrong with going with Alum. Coat when I asked should I go Gaco or Alum.

I dont trust Gaco or any of the “one time coatings”.
To answer your question,
I would check it every year and put on another coat when you see the paint cracking.

Ditto about miracle coatings. I know very few products that will handle weather and abuse on a roof for 50 years. Heck, I don’t know too many roofers that will handle roofing for 50 years.

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donl. sorry, missed your response. I know a flat roof is pitched…and mine is. I was just expecting the final surface to be ~flat flat~ since this was a full tearoff/rebuild so the roofer was working with a clean substrate/base all the way up…

I know Youtube is not exactly the encyclopedia, but in looking at the vids, seems like ALL roofers walk XYZ as they torch so the foot depressions I’m talking about are normal …:confused:

Yeah, I’m somewhat disappointed with the depressions, especially since this guy was the highest bidder…but I guess it’s normal. Don’t see any other forum fellow roofers stating it’s not…

OK. Now that I see how the alum coating has dried on the paddle mixers, its not a thin coating of just aluminin…but a thickish film build of aluinum with asphalt/rubber components.

When I see the coating blister/crack as time goes by, does one apply new coating on a HOT day, so that possibly on a micro/macro level, the new coating permeates deeper into the exisiting coating ?

Or don’t do it on a hot day. While applying the alum. coating, even on a mild 60’ish degree sunny early morning, I’ve noticed the product does flash off pretty quick.

If you coated it 2x it should last well over 10 years.

New aluminum coating builds well onto old coating.
That is what is so great about it.
It doesnt need to be “clean”, hot or cold.
It just needs to be dry.
It bonds incredibly well.
Recoat when you see cracks in the paint for best results
Ignore how many years you think it is supposed to last.
I would go up there every year with just a paint brush and hit any cracking spots.

A paintbrush :wink:

LOL, I’m going to use up the whole 5 gal if I’m going to do touch up.
Different for a PRO I suppose, so you are using up material from one job to the next.
Last thing I would want is to have 4 gallons leftover for next years touch up job, only to come back to the can and find the solvent’s all evaporated out.

Gaco flex silicone coating is one of the best coatings out there at this time. One thick coat is all it takes and it’s raining ready in 2hrs. As for the depressions in your finished roof caused by foot traffic, install walk pads from the roof access to all utility unit that require maintenance.

Mechanicals guys came back 4 weeks after the roof was finished. The tar was nice and dried by then…

The depression is merely due to as foot traffic on the fresh laid sheets…
For the most part, after rain and some sun, while there is no standing ponding water which is a good thing, I can make out some level of water in the depressions…I’m sure it will dry out fine and fast in the warmer months - TBD during winter.

My biggest gripe is every running sheet has foot depressions. I suppose hot tar and any weight of anybody@150lbs or more / weight if feet will create a depression in the hot tar…

I’m no roofer, but if it was me, I would have worked my way back, making sure I did not step on the fresh hot sheets as there were torched down. Maybe easier said than done…

In looking at Youtube videos, looks like torched roofs are stepped in any direction pretty much anytime…so I’m concluding foot depression even on a brand new flat roof (aka, no prior layers underneath) is SIP - standard industry practice…

Pro’s, correct me if I’m wrong.
Anyone actually pay mind to not walking on the hot membrane sheets to not create depressions…

It all depends on many factors like over heating during installation also the ambient temperature will slow the cooling process. If foot depressions are being left behind during installation the installer can try pulling the rolls towards him with a hooked pole as he heats the rolls. Either way foot depressions are bad news because it cause’s membrane displacement. This results in a thinning of the membrane mils. Less mils means a shorter life for the roofing system.

The coating for a flat roof varies, depending on the roof’s substrate and whether the coating adheres. Usually, coatings don’t adhere as well to smooth and hard surfaces, in contrast to irregular or rougher surfaces. Coatings do not adhere as well to chemically inert surfaces as they do to chemically active surfaces. To improve the coating’s adhesion, use a base coat or primer beforehand, as recommended by the coating manufacturer. Coatings are available for specific types of roof membranes and substrates.
Coating the roof periodically offers additional advantages besides extending its lifespan. It lowers the temperature of the roof, which may result in utility bill savings. Various coatings include different performance factors. Make sure that all necessary roof repairs are completed before coating is applied. It is also imperative that the correct coating for the particular substrate is applied, so consult with the roofer or manufacturer to ensure that the proper product is used on your roof.

This is a roofing forum afterall. Probably represent .00001 % of what’s out there.

Thread Bump…
How many flat roofers on here use a hooked pole
& OR
How many of ya’ll just push the roll forward and it’s ~industry practice~ to have foot depressions due to how this method of install is done…

If it is leaving footprints the roll is being heated too much.

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24 Month Check in. The new flat roof got the roofers aluminum coating - which literally rained 3 hrs after he had applied it. and I followed up with 2X coat of Karnak 298 on when the surface was nice and dry. I’m getting old (yikes) so I figured let me do another coat while I can lug 5G cans to the top ;-/

Roof looked clean and where there was depressions (due to roofers walking on hot new surface), I spied 2-3 areas that showed some cracking on the film/top. Ended up doing another 2 coats with Karnak 298 as well again

I’m glad I went up to the roof. the gutter strainer was too clogged and there was standing water in the gutter. Looks to have been like that for quite some time, based on the dirt accumultation. Off to make a DIY better gutter strainer with a larger opening (chicken wire as the other one I suspect was just too dense ?

I just came back to this thread and got to re-read the comments.

SHOULD I go back up to the roof 2-3 years from now, should I continue to use the standard alum. coatings or go straight to Gaco ? And or what is the newest flavor of the month ~coating~ out there these days for a flat roof

Keep using aluminum. GACO is a waterproof coating, aluminum is for reflectivity to stop UV degradation of your roof. An asphalt roof which is coated regularly will last 25-30 years. If you install GACO and have a problem down the road you make the roof much more difficult to repair. Aluminum coatings will last 5-7 years before needing a new coat, maybe longer depending on trees, light, and rain.

thx. Is newly painted aluminum much more reflective that post cured/dried/in the elements . Just short of surface dirt ? - in which there was very minimal.

I’ve noticed like 2 years ago and the same post coating aging this year, the surface is really bright once painted.

When I went up to roof recently since going up 24 months prior, there was zero cracking of the surface and while the the surface was nice and bright, it was not as ~shiny~. I don’t know from a benchmark perspective, how often to recoat with alum. topping.

I did find 2-3 spots of cracking, but this is where there is a -depression* in the sheet due to the installers walking on the surface as they laid it…

The roof was not a inexpensive tearoff by far, and it was a mission of a project getting the mechanicals removed, and then reinstalled back, linesets purged, etc. Looking to maintain the flat roof as much as I can