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Discussion Forum

Sealoflex vs EPDM vs Hydrostop

Accelar | Posted in General Discussion on August 14, 2009 06:03am

As some will know, building a 10×32 porch with a deck surface over top. Upper deck will not get a ton of use.

Underlay will be (brand new) 3/4 T&G ply over 2×8 PT, blocked and 16″oc, with a max 9′ span and <1′ cantilever supported by double 2×12 PT headers on 10″ square columns (each hold 10,000 lbs) and a pt 4×4 down the center of each column. The roof deck will be anchored to the house via 5/8″ rods tied through a brick veneer back to a joist inside, 16″ OC (thanks to suggestions from last week – my thanks to Matt, Huck et al for catching some design flaws).

Slope 1/4″

Location: southern Ontario (i.e. we get snow, but rarely accumulations of over a foot at any one time, never more than 3 feet).

The porch roof also covers the tops of some bay windows, so a failed roofing surface not an option.

I have researched prior posts and considered EPDM and other integrated systems but haven’t found a single thread that does a straight comparison – although lots of stuff on EPDM.

On the surface (no pun intended) I like the Sealoflex for a couple of reasons:

– I can see the roof at all times and thus get to a problem without having to lift a deck.
– I don’t have to build a deck – just a roof !
– Materials Cost is higher psf for the roof vs EPDM – but no cost for a deck.
– Labor seems about the same EPDM vs Sealoflex
– No deck = no load = much less #psf to worry about
– From the sealoflex tech support guys it appears that building a railing system and flashing the sealoflex to both the brick wall, as well as to the drip edge / flashing easier to do, and less likely to fail than EPDM.
– I can renew the surface – or change the color even – on the Sealoflex in 10 years with another couple of coats, if need be, without lifting anything

I would appreciate anyone who has used any combination of the above commenting on the relative merits of one versus the other and poking holes in my assumptions.

Also, any known failures and their cause would be much appreciated.

As always, thanks to everyone for their amazing support on this site.

Gavin

Gavin Pitchford

“Sail fast – live slow” (build even slower)

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Replies

  1. rez | Aug 15, 2009 01:21pm | #1

    Greetings Accelar,

    This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.

    Perhaps it will catch someone's attention that can help you with advice.

    Cheers

    94969.19  In the beginning there was Breaktime...

    94969.1  Photo Gallery Table of Contents

     

    1. Accelar | Aug 17, 2009 08:37am | #2

      Thanks !To add to the information: the cost of materials for the roof from Sealoflex would be 850 + freight of 280, for a total of 1130.00Without doing all the math, I figure EPDM would run about half that, and the added cost of a deck on top in Toronto about $600 for PT plus the trex / eon / whatever which I have yet to cost.Net, I'm figuring the sealoflex solution is likely less expensive.Hoping someone has a comment or two...Gavin
      Gavin Pitchford

      "Sail fast - live slow" (build even slower)

      1. bd | Aug 17, 2009 02:17pm | #3

        Forrest, Didn't you use Sealoflex on your house? If so, can you provide some advice to this person?

  2. User avater
    McDesign | Aug 17, 2009 05:16pm | #4

    I have used Seal-O-Flex perhaps a dozen times for various flat roof and under-walking deck applications - no failures.  I think a thread entitled Cool Classical Portico has my attempt at a how-to.

    Forrest

    1. rez | Aug 17, 2009 05:55pm | #5

      What? No link?

       

      well, my, my, my, my. 

      1. Accelar | Aug 17, 2009 06:43pm | #6

        Yeah, but because no specific link, I just went through the whole - okay - *almost* the whole- entire 300 plus posts and I'm really glad I did. WOW!!http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=73188.41The sealoflex details were great (posts ~42-45 I think) -so thanks for that - but ultimately it was the details of the trim on the overhangs which really sparkled for me. I can't use all of the amazing ideas on my porch roof, because the architecture in Toronto in 1890 not that fancy and so it would be out of place, but my gosh - what beautiful work, Forrest, and the whole thread seemed like enough value and information on such different topics as to be worth publishing as its own book.The endorsement of the product (including his own home) by someone who does such exceptional work, while working mostly alone, is sufficient for me to be persuaded.Forrest (or anyone else) if you can think of any advice - the most likely screw up I'd have working with Sealoflex, I'd appreciate a warning - no rush - it's going to take a week to ship and get here apparently. I was going to post a picture when I finished, but after seeing Forrest's efforts, uhhh.... maybe not...Gavin Pitchford

        "Man must wait long time with mouth open before roast duck fly in..." (Chinese proverb)

        1. rez | Aug 17, 2009 06:54pm | #7

          Well, the ol' sow picked up an acorn.

           Good on ya. 

          1. Accelar | Aug 17, 2009 07:07pm | #8

            I'm sorry - not sure what that expression means (and if I'm an old sow, a nut ?, a squirrel ? a baby oak ? - but if I'm the oak, at least please let me be a Live Oak..)Gavin Pitchford"Sail fast - live slow" (build even slower)

            Edited 8/17/2009 12:08 pm ET by Accelar

          2. rez | Aug 17, 2009 07:09pm | #9

            Just an old expression.

            Carry on.

             

            Best to you. 

        2. User avater
          McDesign | Aug 18, 2009 12:24am | #10

          Hey - thanks for all that.  Since I'm in lighting R&D now, it's fun to look back at when I actually made stuff, day-to-day. 

          I'd just say to not let the pink stuff dry out before you get the reinforcing fabric rolled in, with more pink stuff on top - one wet layer for all of it, remember.  Work small sections if it's a hot day.  Some people err and merely press the fabric into the pink stuff, let it dry, and then come back with a second coat of pink - don't do this!

          Also, two top coats of the white stuff.  You can tint these with normal paint colorants, if you don't take the main lid off before you get it to the paint store - they won't shake anything that has had the pail lid seal broken.

           

          Forrest

          1. Accelar | Aug 18, 2009 01:03am | #11

            Thanks Forrest - sound like some good tips.In the pix, you seem to have done a section roughly 2'x5' - is that a good rule of thumb at a time ?When I've rolled fiberglass mat with epoxy, I've found that if I stop the epoxy anywhere on the mat, and don't saturate all of it at one time to the very edge, I end up with a kind of a wavy bump where the epoxy stopped the first time (so I don't do that anymore ;-). Maybe epoxy sets up a little faster, but is that a possibility here ?I got the idea from the manufacturer's tech rep - and I think I have this the right way 'round - that one needs to do the flashing by rolling under, press the flashing down, and then go over it a second time with pink, but I think I understood him correctly in that the main part of the roof, after priming, one can lay out the fabric and then simply pour the pink on top and roll / spread it out and it will go through the fabric and encapsulate it. In the phone call, I may have missed if I needed to roll a base coat of pink down first. It seems thats the way you do it (?)Thoughts ?Lighting R&D ? Thanks again !Gavin
            Gavin Pitchford

            "Sail fast - live slow" (build even slower)

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