Gaco Western 100% Silicone Roofing

[NM_Shooter]

(Edited to fix coverage rate.  Note to self : don't eat turkey leftovers and do math)

Greetings!  It's been awhile.  Hope you all have been well.

(Apologies in advance.  This is going to be a long one).

I've had a heck of a maintenance issue at my house, and thought I would share as the solution looks very promising. 

A few years ago, I had a urethane foam roof put on my flat roof for my house.  Never again will I buy a house with a flat roof, as it has been nothing but heartbreak.  But I digress.

Urethane foam is a closed cell foam that is pretty nice stuff all in all.  A big downside is that it is terribly sensitive to UV.  So they foam the roof and then put a coat of something on to keep the sun off.  In my case, that top coat was acrylic. 

That's worked pretty well.  However, the acrylic needs to be recoated every 7 years, or so I was told.  When I went back to find my roofing company, they were out of business, and I could find no one who wanted to come out and re-coat my roof.  So I took a look at it, the acrylic seemed to be holding up well, and I made the mistake of letting it ride. 

Here's the problem with that.... there were lots and lots of tiny cracks and pinholes in the acrylic developing.  It doesn't sound so bad at first, but think about a stationary pinhole as the sun tracks across the sky.  As the hole gets deeper, the sun starts to erode out a cone shaped opening under the hole.  Pretty soon acrylic starts to flake off, and water starts to ingress. 

I noticed that I had some blisters in my foam roof, and I knew I was in trouble.  I could step on them and hear a squish. 

I found Gaco Western 100% silicone coating, and figured that it would make a good top coat.  Heck, I think they call it a 40 or 50 year roof when applied correctly. 

I bought some 2.5lb spray foam from "Foam It Green".  I then went up with an angle grinder, a wire brush to fit it, and I went after the bubbles.  I was relieved to see that the majority of the bubbles were a surface bubble.  The water did not penetrate to the roof.  I had one spot that had, and I had to cut out the deck, re-deck, and then foamed the surface.  It took some practice to get the foaming right, as I tended to over foam.  For the cut out blisters, I ended up with a new solid foam blister that I had to take off with a hand saw and then sand down flat.  It was not too bad.

I bought a 5 gallon pail of Gaco Western to experiment with.  $285 locally.  I covered all the new foam with a coat, and was a little worried that it wasn't going on very well.  The mistake I was making was that I was trying to PAINT with it, instead of COATING with it.  You get 250sq feet of coverage out of a 5 gallon pail (250 square at two coats, or 500 square feet of your first coat, followed by a second coat, either way, an end product of 250 square per 5 gallons).

I went back up today and put a coat on some of the spots that looked like they were considering being problematic, just to get them covered up.  I was much more aggressive in coating, and it went on very easily and very well.  I realized that I was being too skimpy with the first try. 

I need to buy the rest of the coating to do the entire roof, and the parapets.  I need another 18 pails     

But the first batch that I put on the roof looks great.  It is somewhat flexible, has excellent adhesion. 

FYI, I called a local roofing company that popped up that specializes in roof repair using a two part silicone that they mix on site.  They came out, looked at my roof, told me it was sound and did not need further repair, and that they could coat it..... for only $18,000.  No thanks.  I'll spend the ~$5000 on materials and do it myself.

Anyway..... I'll post an update after this is done to provide a final opinion, and will try to remember to do a follow up later. 

[rick91351]

Hey our OLD Friend....  So good to hear from you. 

Sorry to read about you roof problems. I have never heard much good about flat roofs other than it takes a special type of clumsy to tumble off one!  Wink!!  Please keep us informed!!!

[MountainDon]

Lots of flat roofs here in the land of little rain. Actually most are not really flat, just very low pitch. But I've been on some old ones that are virtually flat except for the dips...

[hpinson]

Hi Frank. You are back.       I'm sorry -- I confused your name with John - we all met with Don at Quarters about two years ago.

Curious if the foam is open or closed cell? My understanding was that the older foam roof systems used open cell and this caused a lot of problems with water retention. I also understand the new foam systems use closed cell foam and this is not such a problem.

Any issues with outgassing during curing? Could you live in your home while that was happening?

We have a flat roof too, and in need of more than simple repair.  I'll post this mainly because it might be of interest - it is a different system that you are using.

We had an estimate this past spring for the PVC roofing system  (about 2000 sq. feet).  The PVC system is impressive - uses the same material that are used in the really durable whitewater rafts.  Seams are welded, just like the rafts. It really holds up well to the sun (in my experience with Zodiac boats that use a similar material).  Many of the new big flat roof building are using it. They claim 30 years.  Warranty is 10 years on workmanship, with material failure warranty unspecified.  It is installed over the old roof, with an overlay of closed cell foam board, taped, and then PVC goes on top and is welded, with welded boots for all cutouts. Parapets are also covered with the PVC, but the colors are very limited and probably won't match whatever stucco or paint that might be on the building.  Cost is high, but in theory, the roof should last 2/3 longer than and tar and gravel roof, even in a high UV environment like the Southwestern US.

One company in New Mexico does this type of roof.

The estimate was 18K and they skimped on or omitted a lot of details that can run the price way up - like replacement of rotten plywood sheathing, almost a certainty on a flat roof, and dealing with our very complex roof heating ductwork.  Felt the estimate was fairly dishonest in that regard, especially as I have been burned before by gross underestimates by roofing contractors.  Other things that turned me off were no insurance against water damage during installation (am I being unreasonable? A friend in Albuquerque got hit with this just last year big-time) and a healthy distrust of roofing warranty's as so many of these roof contracts seem to go out of business and there is a sole provider in this state. Also, the person who did the estimate was very cagey about the training level of the workers. My understanding, is that PVC installation is a fairly complex skill, and your typical pick-up day laborer will not have that. I got the feeling that the company was having difficulty retaining skilled staff and maybe sending out untrained people to do the work. Just a hunch and no direct experience.  Anyway I can easily see this job blooming to well over 20K before it would be over. Maybe that is the cost of a roof now days? 

We might have done it if we felt the estimate was a bit more honest.

So the PVC roof is not going to happen.  Not quite sure what we will do. Probably just a tar and gravel roof again.  It works well enough if done right, is much less expensive. But you do have to put a lot of work into maintenance.





   

[Onkeludo2]

You sure it is not EPDM...PVC is so rare for residential.

[hpinson]

PVC for sure. EPDM is an alternative. Of the two, PVC seems to be getting the better rep for long-term durability in hot and sunny (or so I read, and there are arguments on both sides - with EPDM being a good deal less expensive I understand).  We are in a state with a lot of flat roofs, and the PVC is the roof of choice on the big new flat roof houses it seems.  The contractor who is also a manufacturer rep, says he cannot keep up with the work requests.  They even gave us little fabric samples. The PVC is much like Hypalon.

[NM_Shooter]

Ola! 

We are overdue for a NM CountryPlans revival lunch. 

It is definitely a closed cell foam, and high density.  Many of the spray foams for inside are a 1# density, this is a 2.5# closed cell foam. 

There is absolutely no way that the foam it green company is a do it yourself for an entire roof.  The nozzles are just too inconsistent in spray coverage for a surface that needs to drain.  It worked pretty good for patching, but only because I worked it flat after it cured. 

What type of roof do you currently have?  Did you say tar and gravel _again_?  Gaco has a good website with videos showing it going down over membrane roofs, and other types.  Tar and gravel obviously a no-go.  They have an excellent tech support line, it might be possible to silicone directly on tar.  I don't know....

I previously had a torch down bitumous (sp?) roof which was not done well.  The seams opened up and it leaked like a sieve.  I had that pulled up and foam put down.  Good thing about the foam is that there are no seams and it goes on in a day.  They also spray up the parapets and it seals well.  Once I get the silicone on, I should be good for my life.  (YMMV ).

Hey... once I get my silicone delivered, c'mon over and bring boots.  I normally charge people to entertain themselves on my roof, but for you... free!  I'll even provide the rollers.

[NM_Shooter]

You know what though?  You ought to find out what a foam roof would cost to have put on.  You might even see if they would work with you and let you do the silicone coat.  They might not want to do that as the silicone is the easy-money part of the job.

[rick91351]

Lots of flat roofs here in the land of little rain. Actually most are not really flat, just very low pitch. But I've been on some old ones that are virtually flat except for the dips...

Our house we sold before moving up here it was like a 3/12.  Lots of those were done here in the sixties.  That was one reason I wanted to get out even though we loved it.  But you went to insulate more and it was impossible up next to the eves and all.  It was a beast to heat unless you forced a lot of wood through the insert.  When it can time to reroof every one we talked to they would stand there and give us the flat roof thing.  They do not last as long and this and that.  The huge car port was flatter yet.  It was like like stupid flat for an area that can pile up 12 inches of snow and get a lot of rain on top of it. 

[MountainDon]

Ola! 

We are overdue for a NM CountryPlans revival lunch. 

I'm game! I'm free most Monday thru Friday for a lunch in/near Rio Rancho. I can't leave here until 12:05 as a rule... except Mondays when we don't work and are in town I could be available at virtually anytime.

[hpinson]

How about Monday, 12/8 at 1 at Fat Squirrel Pub and Grill on Southern in Rio Rancho?  Or Thursday 12/11 at 1?

>> What type of roof do you currently have?

Tar and gravel now, with a very complex rooftop heating ductwork system.  I'm actually surprised it has held up since 2004 as well as it has. A few leaks here and there, which I have been able to keep ahead of... but it is reaching the end of its life and I'm having to do more and more. I'm pretty sure the roof will have to be stripped down to the plywood and some panels replaced - so maybe the foam is an option.  I'll look into that, though if you got a quote of 18K that is close to the cost of the PVC.

Rick, something like half or maybe even more of the houses in Albuquerque are flat roofed.  Most new ones are - very few pitched roof houses are being built.  The newer flat roofs have a tiny pitch. These houses are in the Adobe style though are mostly stick built.  Not much snow here as a rule, but when it comes, it causes lots of problems.

[MountainDon]

How about Monday, 12/8 at 1 at Fat Squirrel Pub and Grill on Southern in Rio Rancho?  Or Thursday 12/11 at 1?

At present our weekend plans include a trip to the cabin Friday PM or Sat AM with a return Monday AM. We should be back by 11 - 11:30 AM, so Monday lunch should work for me.  Thursday would be okay too; either one at 1 PM sounds good. 

[MountainDon]

Harlow and I think Thursady would be a good day to aim for... Frank?

[hpinson]

Thursday works for me. Frank?