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Rubber Roofing vs Gaco Silicone

I was wondering if anyone has knowledge or experience regarding the comparison of Rubber Roofing vs two-step (primer followed by silicone) silicone roofing type product like Gaco. I need to replace an old hot-tar & gravel flat roof and wonder if the rubber roof is really worth twice the cost of silicone.

Re: Rubber Roofing vs Gaco Silicone

Rubber roofing installed correctly is a 30-35 year roof system with routine maintenance. It's a good retrofit option over any existing roof system (assuming all existing wet roofing/insulation/deteriorated decking is removed/replaced) However none of the tier 1 or 2 manufactures offer a labor warranty on residential buildings.
Rubber being black in color will generate quite a bit of heat to the building unless you have at least 20 R-value insulation. However rubber does receive paint well and as long as it is not an oil based paint it will not harm the membrane. So if you wanted to paint it white it would help reduce/eliminate the heat island affect. Keep in mind if the roof ever needs repaired the paint will have to be removed for proper adhesion.

Gaco is an excellent coating. One of the highest solid silicone products on the market. Simple to install and they do offer 10 year labor and material warranties, with options to extend in 5 yr increments. Local Gaco representatives have say on project warranty qualifications. If they think the roof surface could be used as a patio they are not likely to approve a labor warranty. Gaco would typically be applied over an existing roof system.
Keep in mind Gaco is a "coating" not a roof system. It will not be structurally strong enough to hold the old existing roof together. If there is a split in the existing asphalt roof felts or failed seam in modified membrane the Gaco will fail at that point and it will not be covered by manufactures warranty.

If were my home. I would use rubber membrane. Yes it is worth every penny.

Re: Rubber Roofing vs Gaco Silicone

Curious on the assembly of the Gaco quote?
You mentioned the existing roof is a gravel surface asphalt. I would assume they intend to sc**** off the existing ballast to expose the felts for direct application of the new Gaco product.??
Depending on the square footage of roofing, building height and geographic location (coastal region) being in a high wind zone. Removing the gravel could compromise the attachment of the built up roof if the assembly intended for the gravel to have a duel purpose. Most gravel surface built-up roof systems utilize the gravel for both weight to hold the roof in place and UV protection of the felts.
If the roof is rather small like less than 200 SF than I would not worry about it. But if it is the roof on the entire home or garage. When that gravel is removed the roof attachment will be compromised and the Gaco product will not provide any sort of overburden or ballast to replace it & the Gaco warranty will not cover roof blow off of the underlying existing system.

Re: Rubber Roofing vs Gaco Silicone

The rubber roofing is a known quantity- it's been in use for a long time and performs as it should when installed correctly. The Gaco doesn't have this length of track record so there could still be things discovered about it possibly making it a poor choice. In cases like this I always prefer the devil I know to the one I don't because I've seen to many "new and improved" things end up as "new and removed" because they didn't work like they were supposed to.

My opinion is subject to change on seeing an adequate track record- till then I'm a skeptic.


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