Elestomaeric Question

mikenewman@fron

Hi Guys I am a paint contractor and have been asked to bid an elastomeric coating on a membrane roof. The roof is membrane with parapit walls and gravel. The HO wants the gravel removed and coated with elastomeric. Has anbody done this . Any advice appreciated. Mike in Moab UT

mdshunk

Run Forest, run!

mikenewman@fron

Thanks mdshunk, I had the same gut feeling care to expand on that? Mike

mdshunk

I can't expand on it, because I don't know squat about it. I do, however, trust my gut. Shoveling off the UV protection (the rocks) from a worn out roof and slathering some crap all over it doesn't sound like a very sound repair to me, is all. I see you being on the hook for a leaking roof for eternity.

AaronB.

elastomeric is good for one thing....color. Gravel roofs are not a candidate, unless you remove it (the roof ballast) which nearly guarantees blowoff without additional securement.

What type of roofing system is it? Is there any current leakage? Is there any standing water? What type of primers are you thinking of using? What is the goal for the coating?

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mikenewman@fron

Thanks Arron I am going to let this one go to a real roofing contractor. My thing is strickly coating. Mike

tekwrytr

Elastomeric coatings are great if you apply them properly. On a gravel roof, that usually means power washing, etergent and all, to get the surface clean enough to accept the primer/sealer coat.

Only difficulty is that if you are unaccustomed to rough surfaces, you might try to shoot it with the gun perpendicular. The trick is to cross hatch, with the gun held at a slight angle to get full coverage on the embedded gravel. In short, you need to be a little lop-sided, spraying a bit to the side, rathr than straight down, or back and forth with the gun perpendicular.

Ideal would be to lace it; shoot one pass from slightly to the left, then a second pass from slightly to the right, especially with the primer/sealer coat. If you put your money, time, and effort into the preparation work, by the time you get to shoot the elastomeric, the job is a snap.

Many roofers dislike elastomerics because they tend to skip the fine points of prep work, which makes the finished product less than perfect. Sometimes a LOT less than perfect. The problem is in the application, not the product.
tekwrytr

Grumpy

When properly installed as a system, elastomeric is a good system. Great for resurfacing smooth surfaced membranes. I would not use it over gravel, however some manufacturers have specs allowing it but you are using like 15 gallons per square (off the top of my head and probably not accurate), and you are using the urethanes, and it will end up costing nearly as much as a tear off. Unless the gravel is just ballast and can be easily removed/vacuumed.

P.S. I only offer warranties on fully reinforced systems with polyester matt, otherwise it's just a coating IMO.

P.P.S. We pour our elastomerics, we don't spray anything. It definetly takes longer but we are not insured for over spray. Also I find it alot easier to make sure proper quantities are being applied.

tekwrytr

One of the big advantages of polyester mat is that it is "just a coating" for re-roofing purposes, not a "re-roof."

Cost is an issue, but not insurmountable. Even over gravel, elastomeric, with or without polyester reinforcement, costs less than a tear-off, while adding negligible weight. If loose rock is removed, weight is reduced.

I have never seen, or heard of, anyone pouring elastomerics. Most applicators use airless, so overspray is almost a non-issue. A good spray rig and a skilled applicator can do wonders.
tekwrytr

Grumpy

www.Adurel.com their specs specifically say "pour" while most others I have raid say "spray". They are the ones who trained us, and though I have looked into lower priced elastomeric companies, I keep selling the Adurel.

On a modified bitumen system, fully reinforced with polyester mat saturated in bonding resin, you are looking at about 5 gallons per square. Lucas's specs are nearly half that. I looked into one comapny Asec (I think it was called) but the salesman was a real jerk off, when I started asking questions about spray vs pour and finished mills he got really offended and started insulting me telling me "I thought you knew what you were talking about, but it's obvious you don't. I don't think I have time to talk with you." Basically saying do it my way or F-off. And though I wasn't saying his way was wrong I was asking him to tell me why his way was right. I have found in life that people are very willing to make statements but get very offended when you dig deeper and ask them to back up those statements.

Yes an airless sprayer would be good, but there will still be some over spray involved. A good gust of wind at the wrong moment and I am washing a parking lot full of cars. Plus I'm not looking forward to all the maintenance involved with those sprayers. The upfront cost is negligible and would have been paid for after the first few jobs. I'm just a firm beleiver that faster and easier is not always better. I can more easily control quality by pouring.

tekwrytr

Pouring implies self-leveling, which in turn implies dead-level, plus some kind of spreading--squeegee, broom, or other. At the price of elastomeric, pouring seems counter-productive because of quality issues (uneven coverage, inconsistent thickness, etc.), and the potential for run-off (watching 20 gallons of material oozing down the wall or out the downspout, while the applicator runs-off to the next state).

Inexperience is not a permanent condition. How do you get even product distribution? Or am I missing a key issue because of the word "pouring"? Do you use squeegees or rollers or brooms to spread it AFTER pouring, or is the pouring part the actual application? When you say "pouring" an image comes to mind of pouring hot from a pour can. That just doesn't seem feasible.
tekwrytr

Grumpy

Pouring is literally that... Pouring the liquid from the bucket. It is the first step in the application process and will need to be spread and smoothed.

You'r not pouring sooo much at once that anything is going to run away, and yes... pour push roll. It's a 3 man job. One man pours and mixes, pours out about 2.5 gallons at a time in a straight line. Next man follows behind with an 18" 1/8" notched (typically sometimes 3/16") squeegee spreading the material about 3-4' runs. The squeegee man controls the overall thickness by pushing more and removing where necessary. Then the 3rd man rolls with an 18" 3/4 napp to smooth for perfect finishing coverage.

keep in mind I am just describing the top coat. The polyester matt fully saturated in base resin is a different process all together, but similiar. Pour abotu a quart to set the roll. The 2nd man starts kicking out the roll while the bucket man keeps his broom wet with quart splashes. When it's all said and done the polyster should be fully saturated.

You will not see any material running off the roof, we've done this on 1/8" slopes (typical chicago two flats). Only time we have had any run off is when using acrylics and it rains the same day. Stupid us!

I feel pouring is the ONLY way to control quality. For example a typical coverage of top coat on a fully reinforced system is about 1 gallon per square. So if you are pouring out 2.5 gallons in a smooth steady bead you know that your bead should be about 80' long if your spreader is spreading at 3'. (80'x3'=240'). If he's a taller guy spreading at 4' then you want to pour about a 60' bead.

The same principal is true with the base resin. While more eyeball work is required to ensure the polyester is fully saturated you can still use the same simple math formula to deduct how many feet you should be getting per 5 gallon bucket. A smooth modified roof would be based at 2.2 gallons per square. If you are pouring 2.5 gallons buckets then you should be getting just over a square per half bucket. Using a 40' polyester roll (36" with 4" overlap) a half bucket should be about 45'. You will have to go thicker and thinner in some areas based on the existing surface conditions. A granulated modified roof would require 3.25 gallons per square or 30' per half bucket.

If you are spraying how do you really know how many gallons you are spraying out per square? Eyeball?

BTW I don't do any metal restorations, and would agree that a spray gun would be the only vialble option, thus the reason I don't do any metal roof restorations (we aren't insured to spray).

P.S. you may be asking why I broke everything down to the half bucket, or 2.5 gallons, and the reason is because carrying, and pouring 2.5 gallons is much easier to work with than 5 gallons.

tekwrytr

Grumpy, I really appreciate the detailed explanation. Your technique is very similar to a method I used years ago to set polyester mat in asphalt (very popular at the time).

The notched squeegee, for those unfamiliar with it, is a great quality control device. If you get the right size notch, you have corn rows of material of a specific size--the bottom of the notched squeegee removes the excess material. The effect is evenly distributed material at a specific volume. The roller step then breaks down the corn rows and spreads the material evenly.

Can the same thing be done with spray? Absolutely. A competent spray applicator can adjust a half-gallon per square up or down with minimal effort, and finer increments when the situation calls for it.

I appreciate your clearing up the misconceptions regarding the term "pouring." I think a lot of roofers are using the same techniques, but generally calling it "hand-applied" rather than "spray-applied." Same idea, different terminology.
tekwrytr