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Discussion Starter · #1 ·
Hi all,

I've got an LA-based warehouse client with an existing 30yr roof that needs to be replaced, it's about a 100K sqft and not leaking much but definitely on its last legs. I've received a number of different bids from roofing vendors but I'm not savvy enough yet about roofs to decipher what is the most appropriate.

Basically, I need to decide between a Title 24 white modified bitumen roof system or a 2-ply polyester reinforced emulsion roof system.

The APP torch down modified bitumen roof is slightly more expensive, but it's a whole new roof and the warranties I've been seeing are 7-10yr labor / 10-12yr material.

The emulsion system is basically a coating system reinforced by polyester and installed on top of the existing roof: existing roof, emulsion, polyester mat, emulsion, polyester mat, elastomeric coating. Labor warranty of 5 yrs / material warranty varies.

Both sides are pushing their products and talking down the other, thus I'm a bit confused. Emulsion opponent says that it will not last as long as modified bitumen roof and needs regular re-coating within the material warranty period to keep up the warranty. However, I'm also being told that even a modified bitumen roof requires re-coating every 6-7 years.

Any advice?
 

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Well, both are correct. Emulsion is not a new roof. It is a maintenance coating. Left alone it will generally last 2-5 yrs. With inspection, touchup of penetrations and flashings and recoating every two or three years, it could last up to ten years.

Torchdowns done properly should last 10 yrs but don't expect much more. Should be inspected at five and, if necessary, a coating applied to extend the longevity.

Neither are a long-term roof solution and for 1000 squares They really need to look at lifecycle costs. How long do they plan on keeping the bldg? 5 yrs? Then go with the emulsion if the roof is still in good general shape. If they plan on keeping the bldg 20, 30yr? Indefinitely? Then they should look at something more long-term and proven like PVC or Low-slope metal or another proper BUR. It will cost more up front but in the long run they will be saving hundreds of thousands of dollars
 

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Both systems perform well IF installed properly.

Does the 2-ply emulsion system include a chopped-glass/emulsion top coat? That is a 20yr.

The modified bitumen, (especially APP), (torch-applied), are subject to the material quality itself, as well as the technical installation craftsmanship. Of note; Depending on the "dirt", (fill), content of the APP, the mod-bit's can & have quickly failed.

Another aspect is the fact the emulsion/chopped-glass system requires significant equipment and training, whereas, any-Ole Tom, Dick or Harry can pick-up a torch and have at it.

Most importantly;
a) Qualify your prospective bidders
b) Do-diligence on the materials
 

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I have fixed many torch down roofs from improper installation.picking up the torch and putting fire to the roll isnt the just of it. it takes technique and experience. but thats just my opinion. and im sure others would agree.
 

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1000 sq's and no manufactures warranty?

What's the existing roof?

What manufacture are they using for both systems?

How flat is the roof?

Drains?


Both systems will need to be recoated every 5-7 years.

More info is needed to help you make an informed choice.

I vote put a proper roof on it, not a layover. Any crack that develops in the bottom layer will transfer over the top. But I'm willing to be there is a huge money issue involved and they can't believe how expensive a roof actually cost... If that's the case, 1,000sq of roof will have expansion joints. Do a section at a time properly. If it doesn't have expansion joints I'm surprised there isn't issues and there should be some anyway, at least roof dividers.


I have fixed many torch down roofs from improper installation.picking up the torch and putting fire to the roll isnt the just of it. it takes technique and experience. but thats just my opinion. and im sure others would agree.
Part of the reasons why our torches have been put up years go. To many idiots claiming they can torch a roof, insurance sky high, and even experienced companies partially burning down buildings causing millions in damages to the structure and contents.
 

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Discussion Starter · #7 ·
Appreciate everyone's response. I'll answer the questions that I can:

Roof size: 100,000 sqft
Existing roof: torch down
Roof flatness: nearly completely flat, sides slope a bit
Drains: throughout perimeter of roof

Proposed modified bitumen spec: 1 layer of resin asphalt saturated fiberglass base felt nailed to deck, title 24 compliant 95lb modified bitumen cap sheet using torch down, title 24 coating

Emulsion: Apoc #300 emulsion at 4 gallons per square, apoc polyester mat, 2nd layer of Apoc 300 at 4 gal per square, 2nd layer of polyester mat, layer of Apox 248 gray coating at 1.5 gallons, 2nd layer of apox white coating. 5 yr install warranty with 10yr material warranty. Emulsion vendor states that benefit of coating system is that additional warranty can be provided for an additional 10yrs by just respraying the white portion (per APOC), whereas other systems like modified bitumen would have to be torn off after material warranty expires. Lastly he's stating that this system a 100% tax write off, which seems amazing.
 

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Appreciate everyone's response. I'll answer the questions that I can:

Roof size: 100,000 sqft
Existing roof: torch down
Roof flatness: nearly completely flat, sides slope a bit
Drains: throughout perimeter of roof

Proposed modified bitumen spec: 1 layer of resin asphalt saturated fiberglass base felt nailed to deck, title 24 compliant 95lb modified bitumen cap sheet using torch down, title 24 coating

Emulsion: Apoc #300 emulsion at 4 gallons per square, apoc polyester mat, 2nd layer of Apoc 300 at 4 gal per square, 2nd layer of polyester mat, layer of Apox 248 gray coating at 1.5 gallons, 2nd layer of apox white coating. 5 yr install warranty with 10yr material warranty. Emulsion vendor states that benefit of coating system is that additional warranty can be provided for an additional 10yrs by just respraying the white portion (per APOC), whereas other systems like modified bitumen would have to be torn off after material warranty expires. Lastly he's stating that this system a 100% tax write off, which seems amazing.

So on the new torch roof they will be removing the existing roof, or nailing down a sheet through the layers of roofing to the deck.

Both of the systems that were proposed are a band aid IMO.
 
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