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do you need to use a primer on BUR following removal of gravel and water blasting Post New Topic | Post Reply

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tom bachus
Posted: May 02, 2006 05:25 AM
do you need to use a primer on BUR following removal of gravel and water blasting
Gerry Wagoner
Posted: May 03, 2006 11:18 PM
Water blasting? Nope. If it was power broomed, primer might help.

Aaron Scurlock
Posted: Jul 10, 2006 04:25 PM
Well how about smooth BUR then? I have al;ways heardd it is best to prime ANY substrate.
Posted: Jul 10, 2006 06:16 PM
try not to use water as a cleaner on the roof. a power washer can be used in filthy areas.(such as nasty pigeon droppings in one area)but don't do the whole roof! when you do that stubborn area, give the water at least 2-3 warm sunny days to evaporate out from under any openings/tears/small holes that you can't detect and so forth. dont seal up the washed area with roofing mastic!you will trap the water! you could be looking at a giant bubble that appears from the water turned to water vapor under the foam. (or a bunch of little bubbles) the 100 mph backpack blower and stiff broom are Way better than water!
take a core cut on the dry part of the roof 1.5" x 1.5" x 1-2" deep. if its soggy & wet:bad news for foam. if its dry:great for foam! fill the hole with roofing caulk & trowell it smooth.
Aaron Scurlock
Posted: Jul 11, 2006 08:25 AM
What do you think of the one way relief vents? Thyre designed to allow for evaporation and release of vapor pressure, in theory, not causing a blister.

Of course, I realize that you dont wnat water in contact with the mix as youre spraying it to avoid spiking and disbondment.
Posted: Jul 11, 2006 09:30 PM
i stay away from vents. if there is that much moisture, i would rather cut out the section that is wet. better to start out dry than wet and trying to dry it out. its more expense.30 yard dumpters, crane to put roofing cutter on the roof and more manpower. bid to foam & coat the roof. add a extra charge per square foot fee for removal of wet roofing material. two layers of wet material can mean replacing the wood of steel roof deck. have a rubber roof like that right now.roof vents are not the way to go on this wet roof.
NO VENTS FOR ME! seasoned roof foamers:what is your opinion on vents?
Aaron Scurlock
Posted: Jul 21, 2006 10:17 AM
I have found that with my 16 years of commercial roofing experience that even when we broom and blow the roof to remove gravel, youre still left with a layer of dust/dirt that will eventually come loose and cause dis-bondement.

The guy that consults me on the foam roofing applications said to pressure wash and blow it dry dry dry.
Gerry Wagoner
Posted: Jul 26, 2006 06:19 PM
RK Hydrovac does our roof prep (most of it). They water blast the roof and vacuum the water, dirt and gravel in one swoop. Then we let it dry for a day. Then foam it. I wouldn't bother priming smooth bur. Foam seems to adhere very well to it.

As to one-way vents, they can help dry out isolated areas, but we find that trapped water vapor seldom moves much laterally. It might go as much as 15'. DuroLast uses a vent every 1,000 ft² on all of their roofs.

GraveledFoam does pretty well at allowing wet roofs to dry out. Just make sure that you eliminate the ponding that helped cause the saturation (with more foam or additional drains).

all the best,

Aaron Scurlock
Posted: Aug 18, 2006 11:09 PM
OK, thanks.
Melvin Chandler
Posted: Aug 19, 2006 08:09 PM
I thought that RK just did a wet vac. Didn't realize that they actually pressure wash. I'd wed vac and then pressure wash but if we're talking smooth, just a power wash should do.

I wonder if Durosales require the vents every 10 squares because their installers think it's okay to go over anything that is wet?
Gerry Wagoner
Posted: Aug 20, 2006 11:07 AM
Perhaps, but they have some success at drying out roofs. The stated reason is to eliminate a moisture film under the membrane (which is a vapor barrier).


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