Recovering BUR with Sarnafil & insulation requirements


#1

Hi all,

I have a flat roof project (BUR needs replacement) that consists of about 60,000 sqft of retail space and 15,000 sqft of non-climate controlled ministorage. Location is about 50 miles inland from Gulf Coast, so high heat/humidity, hurricane prone area.

Was planning on using Sarnafil to recover, but their tech dept is saying we must put their insulation (polyiso) down over the old asphalt BUR to get a 20 year warranty. This adds significantly to the cost.

The retail space BUR already has insulation (lightweight insulating concrete over metal deck)

We have used Sarnafil before on property in Utah & they did not have the insulation requirement (due to different climate perhaps)

Questions:

(i) It seems wasteful to use insulation on non-climate controlled ministorage. We don’t need it to stay cool (and have no insulation right now), just need to keep water out. Is there another system that could be recommended for this application.

I have briefly looked into spray on polyurethane foam, and EPDM, but so far my due diligence does not lead me to have much confidence in the longevity of these systems.

(ii) On the retail space, the extra insulation has some value in reducing the tenants’ electric bills, but still may be overkill for the application given that we already have lightweight insulating concrete under old BUR.
Comments? Suggestions?

(iii) Are there any pitfalls to recover an existing roof that I should be aware of. The contractor will be scanning the roof for trapped moisture,and Sarnafil has OK’ed it with 20 year warrantee.

Thanks

John


#2

my first thought is are you an approved sarnafil installer? i am and they would never allow thier product to be directly installed over any bur roof in any area of the usa. pvc and asphalt(or ctp) will degrade the plastisizers after just a couple of yrs. ill bet your utah job had yellow flashings after a couple of days.you will spend $ on a high end pvc but not a decent substrate in which to adhere it to. thats like buying a rolls royce and puting joe blow tires on it. if you are thinking of a good spray system go to soythane.com the guy who owns this is the best in the world when it comes to spray systems his name is tom hay. good luck


#3

I am a real estate owner/investor, not a roofer. About the Utah job, I went back and looked at the paperwork & it turns out I mispoke. The roofer installed a 1/4 inch “slip sheet” (whatever that is?) over the old roof. The cost came in at about $3.15/sqft. Of course the contractor who did the work was Sarnafil approved and they issued their warranty.

Bids on this other project are coming in quite a bit higher, and that’s the issue.


#4

Materal Prices have risen over 35% this year alone and I am sure that labor costs have risen since the last project was undertaken, plus the geographic wages are probably higher in the second area.

I will also second a vote of complete confidence in Tom Hay and his

www.Soythane.com

and other SPF products. He has been doing that stuff exclusively for well over 30 years and is known as one of the best in that field of expertice, plus has written Government Protocols for specifications in many areas.

Ed


#5

My concern with the foam is I have been told (from more than one source) that the acrylic coating that goes over it is not very durable and is easily damaged by birds, etc. If that were to happen, the foam is exposed to the sun and quickly degrades in the hot climate, and the whole system may fail after 4-5 years.

Is this a valid concern?


#6

From everything I have studied, you are both right and wrong.

If the roof is done by a properly trained crew who chooses to use a high quality coating, the surface can be almost impenetrable.

On the other hand, contractors who choose to use less quality surface coat applications, or thin down the mil thickness of the appropriate coating, would definitely leave the surface vulnerable.

Rather than discussing this with myself or RoofBoss, who are knowledgeable, bit in a limited way, regarding this product, I surely suggest that you would be better educated and more appropriately served by contacting Mr. Hay.

If necessary, I will contact him via e-mail and request he jump in on this topic, but I may not hear from him in a short time, since his website and business phone numbers would get to him quicker.

Ed


#7

I have a bid for SPF with acrylic. Surprisingly, its only 17% less than the Sarnafil (even including their polyiso insulation that I am not yet convinced is required).

TPO is only 10% less than Sarnifil.

Now if one of these products was, say, 50% less, I could see giving it a try. But with the relatively small difference in costs, it seems like it makes more sense to go with the proven product.

What are the pros and cons of using fleece backed Sarnafil?

What about the pros & cons of using a slip sheet in lieu of insulation?


#8

I got a big hearty chuckle out of that one…
Don’t hold your breath, everything is getting more expensive.


#9

Now if one of these products was, say, 50% less, I could see giving it a try. But with the relatively small difference in costs, it seems like it makes more sense to go with the proven product.

Why would you think these other systems are not proven?
SPF and EPDM have been around along time and are proven reliable systems if installed properly and in the right conditions. TPO may not be as much of an old timer but a 30 yr warranty can be given on them.
Any good warranted roof system will require some sort of insulation as a separation from the old roof.


#10

“SPF and EPDM have been around along time and are proven reliable systems if installed properly and in the right conditions”

Maybe so, but seeing as I am not a roofer, I could look at a roof and have no idea of whether it was properly installed or not. I have to rely on other people to tell me that - so in choosing a system I have to rely on the data I do have.

I have not heard of any Sarnafil roofs completely failing after 4 -5 years, but I am hearing this a lot with TPO, EPDM and especially SPF - even searching the archives of this site I can see this!

Maybe its because Sarnafil is a better product, or because Sarnafil are more discriminating about how and by whom their product is installed.


#11

If you buy a warranted roof system from a major manufacture then it will be by an approved contractor and will get inspected by the manufactures rep when its complete. Then you will get a good roof that will last just as long as the sarnafil. Im sure that sarnafil is a good roof but its not alone. An epdm roof that only lasted 4-5 years was improperly installed by an unapproved contractor with no manufactures warranty im sure.
Any one can buy epdm and put it on just like shingles or concrete. If a roofer put in your concrete drive im sure it would crack but that doesn’t mean concretes junk.
If you hire a good contractor thats approved by the manufacture and purchase a warranty you will get a good roof that will last beyond the warranty weather you go pvc,epdm or tpo.


#12

As for the commercial space, you will be very pleased with SPF:

  1. High Wind Uplift Ratings…some of the only roofs left after katrina were SPF

  2. Seamless and Insulated

  3. Totally Adhered

  4. You can add ceramic granules to the acrylic coating and this will add amazing impact stregnth.

Look for an installer with a lot of experience and hire an independent inspector if you have quality concerns.

Kindly,

Brian Hunt
www.roofcrafterswest.com


#13

[quote=“john960bell”]“SPF and EPDM have been around along time and are proven reliable systems if installed properly and in the right conditions”

Maybe so, but seeing as I am not a roofer, I could look at a roof and have no idea of whether it was properly installed or not. I have to rely on other people to tell me that - so in choosing a system I have to rely on the data I do have.

I have not heard of any Sarnafil roofs completely failing after 4 -5 years, but I am hearing this a lot with TPO, EPDM and especially SPF - even searching the archives of this site I can see this!
**
Maybe its because Sarnafil is a better product, or because Sarnafil are more discriminating about how and by whom their product is installed.**[/quote]

That would be the reason.


#14

It turns out the reason the insulation is required by Sarnafil is it provides structural strength to meet wind resistance requirements. This is why you need the thick polyiso insulation in the Gulf region, whereas in a place like Utah a slip sheet would be acceptable.


#15

If its a smooth why not a 2 ply mod bit 160 and a 180 white cap?Also a slip is highly recommended on any recover with pvc or tpo there are guys here fully adhering over a smooth bur with no iso period not my cup of tea.


#16

[quote=“www.roofcrafterswest.com”]As for the commercial space, you will be very pleased with SPF:

  1. High Wind Uplift Ratings…some of the only roofs left after katrina were SPF

  2. Seamless and Insulated

  3. Totally Adhered

  4. You can add ceramic granules to the acrylic coating and this will add amazing impact stregnth.

Look for an installer with a lot of experience and hire an independent inspector if you have quality concerns.

Kindly,

Brian Hunt
www.roofcrafterswest.com[/quote]

I am sorry but your very first point threw up a HUGE red flag.

I am the Mississippi Technical Sales Representative for Sarnafil. We have hundreds of roofs on the Gulf Coast as we are known for our “Engineered” System and its High Uplift Capabiliites. We lost 1 roof. The reason it was lost is it was in the process of being roofed.

I have 19 buildings at Stennis Space Center (a little to the east of the eye of Katrina (Waveland was the eye) and we had zero failures. Our roof on the Beau Rivage had a few penitrations from flying debri but it is 35 stories tall. (repairs are as easy as heatwelding a piece of PVC membrane over the penetration.) I believe it was the only roof to survive that is on the south side of I-90.

So far we have had no problems with Gustav. If we have any I will post them.


#17

…and it looks like we have another test coming.


#18

Not quite roofboss. I know what you are saying, and generally you are correct; however, Sarnafil has/had a membrane called G410 that was a fleece-backed 90 mil PVC that was mopped directly to BUR. I’ve specified this product in the past on several Anheuser-Busch roofs, but it has been awhile and I don’t know if you can still special order it or not.


#19

john960bell:

Sounds like you may need a consultant. I’m here in Houston if you need help!


#20

I am almost certain that Anheiser Busch is the only coporation that we sell that memrane too. It has a backing that is resistant to asphalt products. Its actually called G459. (we have G membranes and S membranes G=fiberglass S=scrim)

You can actually hot mop it to the roof. We basically now only use is as a flashing for walls that our membrane would come in direct contact with that had asphalt residue on it. Asphalt will tear up PVC.