# EPDM vs. PVC vs. TPO for a flat roof.....



## Paultergeist (Oct 13, 2014)

Greetings,

I have an addition on my house which has an almost-flat roof pitch and is in need of new roofing material. This particular addition -- in my opinion -- was not built all that well, and there are some spots on this roof where rain water will pool slightly. I have considered various possible options which might allow me to re-pitch this roof slope, but none of those options seem do-able right now. I am thus pursuing the idea of using a roofing membrane which will tolerate some shallow pooling ("ponding") of water.

This far, the big three options seem to be EPDM, PVC, and TPO. There are also a few proprietary brand names ("Fibertite," etc). I am looking for any opinions and/or knowledge about such products. I am a pretty experienced DIY-er, but I have not used such roofing membranes previously.

Thanks for any help.


----------



## Windows on Wash (Aug 30, 2011)

Are you doing this roof? All of those systems will work and all of them are only as good as the installer putting them down.

You are likely to get varied opinions on the systems much like you would get varied opinions if you asked about a particular asphalt shingle.


----------



## Paultergeist (Oct 13, 2014)

WW......

Thanks for the reply. Yes, I will be attempting to do this work myself. While I have done a couple of little DIY-esc roof repairs previously, I have no experience with membrane-type roofing such as EPDM/PVC/TPO. That being the case, perhaps ease of installation should play a significant role in my selection of material?

Incidentally, I live in San Diego County. This may also be a factor; I am being told that EPDM is not very popular in my neck of the woods due to local environmental restrictions on selling the VOC-based adhesives which often accompany EPDM.....?


----------



## Windows on Wash (Aug 30, 2011)

You're going to need welding tools to do the other two systems. EPDM is by far the most DIY friendly membrane system of those three.


----------



## craig11152 (Jun 20, 2015)

what are the dimensions of the roof? I feel one big advantage of an EPDM over a Modified Bitumen is the ability to greatly reduce seams. But I don't know how big a piece on guy can handle. I have never worked with EPDM but have done a fair amount of SBS. That stuff is pretty easy for one guy in part because the rolls are only 40" wide. But it also means more seams.


----------



## Paultergeist (Oct 13, 2014)

Windows on Wash said:


> You're going to need welding tools to do the other two systems. EPDM is by far the most DIY friendly membrane system of those three.


Thanks....I guess I need to do a little more investigation as to the implications of EPDM under the allowed materials / adhesives / solvents in California.


----------



## Paultergeist (Oct 13, 2014)

craig11152 said:


> what are the dimensions of the roof?


The roof is about 28' length x 14.5' in width.


----------



## 1985gt (Jan 8, 2011)

Paultergeist said:


> Greetings,
> 
> I have an addition on my house which has an almost-flat roof pitch and is in need of new roofing material. This particular addition -- in my opinion -- was not built all that well, and there are some spots on this roof where rain water will pool slightly. I have considered various possible options which might allow me to re-pitch this roof slope, but none of those options seem do-able right now. I am thus pursuing the idea of using a roofing membrane which will tolerate some shallow pooling ("ponding") of water.
> 
> ...



Any of these systems would be a fine choice. Any reason you couldn't use 1/8" or 1/4" tapered insulation to give it some slope? It will add some cost but will help with drainage. 

What did you plan on installing the membrane on before?

EPDM as mentioned before is probably the most DIY friendly, but as with any low slope membrane if not installed correctly things can get bad, and bad real fast. And when they go bad they get real expensive.



Paultergeist said:


> WW......
> 
> Thanks for the reply. Yes, I will be attempting to do this work myself. While I have done a couple of little DIY-esc roof repairs previously, I have no experience with membrane-type roofing such as EPDM/PVC/TPO. That being the case, perhaps ease of installation should play a significant role in my selection of material?
> 
> Incidentally, I live in San Diego County. This may also be a factor; I am being told that EPDM is not very popular in my neck of the woods due to local environmental restrictions on selling the VOC-based adhesives which often accompany EPDM.....?


DO your self and pocket book a favor, do a whole lot of video watching and look at the manufactures details before even starting. This may be one of the things that would be best to have a professional do. I'll get in to that later. 

They make water based and solvent based Low VOC adhesives for this reason. Or you can mechanically attach any of the systems. I'm not a huge fan of mechanically attached membranes except one system with TPO/PVC. But it's not DIY friendly, at least the equipment to do them are not.



craig11152 said:


> what are the dimensions of the roof? I feel one big advantage of an EPDM over a Modified Bitumen is the ability to greatly reduce seams. But I don't know how big a piece on guy can handle. I have never worked with EPDM but have done a fair amount of SBS. That stuff is pretty easy for one guy in part because the rolls are only 40" wide. But it also means more seams.


An experienced guy can put down a lot of EPDM in a short amount of time. It's lighter then SBS by more then half. but of course no one is laying down 39.75" wide rolls of EPDM either, the costs would become way to high with all the seam tape. And EPDM is not as durable is SBS.



Paultergeist said:


> Thanks....I guess I need to do a little more investigation as to the implications of EPDM under the allowed materials / adhesives / solvents in California.


Low VOC/Water Based adhesives, down side is they are about 2X as expensive as standard Bonding adhesive.



Paultergeist said:


> The roof is about 28' length x 14.5' in width.



This size could be done in one piece, it would be fairly heavy at around 180 Lbs, depending on access I may split it down the middle. Is this addition a walk out deck by chance?

Have any pictures? 


So going in to why some times its better to have a professional do stuff like this is for a couple of reasons.


1. With single ply membranes there is little to no redundancy. By that I mean if the top layer has an issue, that's it, it will leak, where as a Mod bit it may not. Inside and outside corners can be difficult to do. If you happen to mess up the install, it will either need to be patched or completely redone, and that gets expensive.

2. The cost can get pretty expensive, say you have 50' of edge metal you need to strip in, the 6" coverstrip comes in rolls of 100'. What will you do with the extras left over, all of the materials have some kind of shelf life. Where hiring someone you may not have to eat that extra cost. When I break down a job I go down to 1/2 or 1/4 a roll on things like tapes.


There is lots of things to consider while I'm all for DIY projects, some just make sense to have someone else do.

Post a few pictures or drawing of what you are dealing with, some roofs are easier then others.


----------



## Paultergeist (Oct 13, 2014)

Greetings, please allow me to start out by just saying "thank you" to everyone for their helpful replies.

1985gt, thank you especially for the detailed rely; I'll attempt to answer your questions as best as I can....




1985gt said:


> Any reason you couldn't use 1/8" or 1/4" tapered insulation to give it some slope? It will add some cost but will help with drainage.


I _might_ be able to do that. The issue as I see it is that that this flat roof -- part of an enclosed patio addition -- is already tucked just under the (piched) roof eave of the main part of the house, so I cannot really go any higher at that particular point, but I might yet be able to create some slope away from the eave. I will have to further analyze this possibility with string level, etc.




1985gt said:


> What did you plan on installing the membrane on before?


This addition -- essentially an enclosed patio (sometimes called a "California Room" in these parts) was on the house when my wife and I bought it. This room has cost me so much loss of sleep that I nearly want to tear it down, but the wife really wants to keep it in place (and considering that the main part of the house is just a hair under 1000 sq.ft., this patio room provides quite of bit of interior-esc space).

I had no plan before. I really did not plan on getting so deep into roofing issues, but fate has had other plans for me. The roof leaked soon after purchase. The first guy I hired to repair the roof put shingles on it. It looked nice, and at the time I did not understand much about roof pitch, etc. Needless to say, that roof leaked within a year. (I got good at applying various tarps to the roof while I tried to get that original roofer to come back to no avail). The next roofer I hired used granular cap-sheet roofing with a "hot-mop" installation. That roof lasted about five years; the ponding of water really seems to shorten the lifespan of the granular cap-sheet roofing material. That roof had a 10-year leak warranty, but there are some "warranty pro-rating" factors involved and the second roofer is really not interested in coming back -- it just seems like I am going to have to try to sort this out myself.



1985gt said:


> DO your self and pocket book a favor, do a whole lot of video watching and look at the manufactures details before even starting.



Good advice. Will do.



1985gt said:


> Is this addition a walk out deck by chance?



No. My understanding is that this addition began as a concrete patio slab, which was then enclosed. The shed-type roof is simply 2 x 6's extending from the house (I assume [hope]) there is some sort of ledger board well-secured to the house) extending to the outer addition wall (Roughly 14' outward). I can clearly see the extended ends of the 2 x 6s at the overhang, so I am pretty confident of that lumber dimension.
I do not think the original construction took into account the crown of the 2 x 6 lumber, nor do I think that 2 x 6 was actually thick enough for rafters of this span......hence slight ponding of water in a few spots.



1985gt said:


> Have any pictures?



No, but I can take some this weekend when I am home during daylight hours and post back.



1985gt said:


> So going in to why some times its better to have a professional do stuff like this is for a couple of reasons........



All valid points, and I am not opposed to the option of hiring a professional, but there are some other considerations of pursuing that route:

I live in San Diego County. There are a lot of very wealthy people out here. Unfortunately, I am not one of them. I live in one of the few lower-income parts of the region. That being the case, I cannot seem to attract the better professionals, as there seems to be plenty of work for them at the higher-dollar addresses (or at least such is my assumption)....

I partly make that assumption from my years of experience in talking to and trying to hire professionals at various times in our ownership of this house. One of my biggest frustrations is the "no show," by which the contractor simply does not show up for the scheduled appointment to see/discuss the issue at hand, usually after I have taken time off of work.

I would further predict that the roofers I am able to hire are probably going to suggest something fast and straightforward (for them) to apply, as did the last 2 roofers, along with all the usual assurances that their work is "guaranteed," their roofs never leak, etc. Once things actually kick-off, there usually is not time for me to address minor issues which I may notice during the process, nor do I speak much Spanish, so I really cannot communicate with the workers.

All together, I do not want to dismiss your suggestion of hiring a talented professional, but I question whether my small job is going to be lucrative enough to attract someone who will really give this some thought to arrive at a longer-term solution. That last "hot-mop" cap-sheet install cost 2K, and I now feel like it was a long-term patch.....I would like to try to find a better way to go with a longer lifespan for round 3 of this saga.....so......?



1985gt said:


> Post a few pictures or drawing of what you are dealing with, some roofs are easier then others.



Will do.....please give me through the weekend.

Again, I very much appreciate all the useful insights and guidance being freely shared here on this forum.

Thank you very much.

Paul


----------



## 1985gt (Jan 8, 2011)

I think I have a picture in my head on what your dealing with. I've got somewhat of an idea that would work for you it would require a pretty decent amount of work. I see the 2x6's being a issue, I personally wouldn't want to add much more weight on top of that as it is. That's part of the problem IMO as to why it is sagging. 

I'll wait to see some pictures so I don't confuse the issue as what I'm thinking maybe a ton of over kill, although the 2x6's concern me. In my area there would be a lot of issues but we have snow to deal with. 

I'm sorry to hear about your experiences with other "contractors" there seems to be a lot of that type around.

I've always thought of it this way, good work is rarely cheap, cheap work is rarely good.


----------



## craig11152 (Jun 20, 2015)

> The next roofer I hired used granular cap-sheet roofing with a "hot-mop" installation. That roof lasted about five years; the ponding of water really seems to shorten the lifespan of the granular cap-sheet roofing material.


What is the material? If its a half lap or 90lb asphalt roll its trash. If its SBS and the seams failed it _might_, _maybe, possibly _be salvageable for 50 bucks, a 6 pack of beer and 3-4 hours.


----------



## Paultergeist (Oct 13, 2014)

craig11152 said:


> What is the material? If its a half lap or 90lb asphalt roll its trash. If its SBS and the seams failed it _might_, _maybe, possibly _be salvageable for 50 bucks, a 6 pack of beer and 3-4 hours.


Thank you for the reply; regrettably, I lack the technical knowledge to answer your question. Perhaps some photos (which I'll plan to obtain this weekend) may help clarifiy the issue.


----------



## 1985gt (Jan 8, 2011)

craig11152 said:


> What is the material? If its a half lap or 90lb asphalt roll its trash. If its SBS and the seams failed it _might_, _maybe, possibly _be salvageable for 50 bucks, a 6 pack of beer and 3-4 hours.


I've never seen a 90lb moped down before, I think for a while it was used as flashing but IIRC it was all cold applied. This would have been well before my time. I figure if you try and mop down 90# it would burn up on impact.

It could have been just a real cheap cap sheet, and only a single layer, for all we know they mopped it over the shingles. 

I've never heard of a warranty like the OP described. Sounds like a contractor based warranty instead of a manufactures warranty. FWIW very few manufactures will put a warranty on residential low slope applications.


----------



## craig11152 (Jun 20, 2015)

1985gt said:


> I've never seen a 90lb moped down before, I think for a while it was used as flashing but IIRC it was all cold applied. This would have been well before my time. I figure if you try and mop down 90# it would burn up on impact.
> 
> It could have been just a real cheap cap sheet, and only a single layer, for all we know they mopped it over the shingles.
> 
> I've never heard of a warranty like the OP described. Sounds like a contractor based warranty instead of a manufactures warranty. FWIW very few manufactures will put a warranty on residential low slope applications.


I agree its just when he put "hot mop" in quotes I wasn't sure how to interpret that. I mean there is no mistaking a kettle cooking tootsie rolls in your driveway. :laughing:
which gets back to my point, if its an SBS and just the seams failed if he goes over those seams with tar, 4" mesh, more tar, 6" mesh and more tar plus granules he could buy another 6-10 years. If the field has failed no go. And if they went over the shingles no go either.


----------



## Paultergeist (Oct 13, 2014)

*Some photos....*

As luck would have it, I was able to get home while there was still adequate sunlight......here are some photos of the "California Room" (?) structure overall:


----------



## Paultergeist (Oct 13, 2014)

Here are the 2 x 6 rafters, looking up from under the over-hang:


----------



## Paultergeist (Oct 13, 2014)

Here is the top coat of the roofing....what I have been calling the "Cap Sheet" although I now realize that this may not be the correct term. It was originally a light gray, but I added a coat of some kind of black paint-on coating which was supposed to serve as an undercoat for an "elastomeric white rubberized coating" on top.....neither of which adhered all that well:


----------



## Paultergeist (Oct 13, 2014)

Here is the transition from the main house shingles to the addition......the cap-sheet is tucked under the lowest course of shingles. There is a gentle curve to the cap sheet as it *flows* towards a more-or-less horizontal layout. One thing which has always concerned me is that there must be a little hollow pocket underneath that curve in the cap-sheet, as it does not tightly hug the contour of the interface at that location.


----------



## Paultergeist (Oct 13, 2014)

Here is the outer-most edge of the long-side of the room addition. There is a metal strip (flashing?) going all the way around the 3 exposed sides of the roof. This flashing has a slightly-raised curved edge to it -- this edge might be as high as 1/2" in some spots. My assumption is that this raised edge might have been intended to protect the edge of the cap-sheet (?), but it seems to exacerbate the ponding of water on the roof. Although the roof get puddles in a couple of places, by far the worst ponding occurs right along the long edge. Yu can see some of the discoloration (darker areas) where dirt has gotten stuck in the water (leaving the dark spot when the water evaporates). I tried to get a close-up of that edge on one of the pictures.....


----------



## Paultergeist (Oct 13, 2014)

Well, let me just say "thank you" once again to everyone for their help. I hope that I may one day be able to do the same for others. 

To address a couple of other questions raised:

This top layer of roof was rolled on over roofing felt; the roofers had the smelly "tar-cooker" thingy going -- bringing 5-gallon buckets of tar up to the roof and spreading it quite literally with a floor mop -- which they referred to as a "hot mop."

There IS also a layer of ordinary (composite?) granular nail-on shingles UNDERNEATH the top roofing material. I do not know if there is also roofing felt underneath THOSE shingles. My plan -- limited though it may be -- is to remove as much of the old roofing material as possible in a effort to reduce weight on this roof.

My apologies if I am using the incorrect terminology. I am still learning, but I will welcome being corrected by those more knowledgable than myself.

Thanks,

Paul


----------



## 1985gt (Jan 8, 2011)

Well that is a heck of a lot better looking then I expected. 

If you are not having leaks, I would leave it for now. 

The only reason it is pooling is because they used a gravel stop on the edge, they should have used a drip edge. The gravel stop is used for Ballasted EPDM, or BUR/asphalt and gravel roof. 

While going over the shingles is a very wrong thing to do I would leave it for now.

When the times comes I would tear the whole thing down to the plywood, and start from there. With the look of it I wouldn't even add tapered insulation. It has plenty of slope for a membrane roof, heck you could even put a self adhered modified on that with out much problems. That maybe a route to go. I don't see much if any defection in the joist.


----------



## Paultergeist (Oct 13, 2014)

1985gt,

Thanks very much for taking the time to look at the photos.

Maybe this thing has been made a bit worse in my mind than it is in reality. For now, I DO have one defined leak -- this leak is located within one of the small "pools" along the outside edge. The water is somehow percolating through the roofing, and rotting the plywood sheeting underneath. In addition to that leak, the fascia board along the front has a rotted-out area in one corner where the water is running down along the corner seam. I was thinking that maybe there was some better sort of flashing which would help address this issue.

At any rate, it is encouraging to me that you feel the roof may have some life left in it. That gives me more time to develop a longer-term repair strategy.

Thanks again for looking at the pictures.


----------



## 1985gt (Jan 8, 2011)

From what I can tell in the pictures. The edge metal was not striped in properly. Normally you would run the modified to the roof edge, then the metal would be installed, then a 9" or so wide piece of Modified would be applied to that. 

I would start looking at the areas directly around the leak, see if you can pull up that edge of the modified. If you can, get some Mastic and pack that area full and put the cap sheet back down in to it. Then add a layer of mastic, then membrane, then mastic again. 

If the edge is tight, start looking at the other laps, it could very well be traveling since there is a couple of layers. 

I think you can "limp" this roof along for a little while, give you time to get a good plan together to replace it, whether that would be you replacing it or calling someone in. Either way someone around here can help with ideas or help read in to the estimates other roofers provide. I comply understand how it's easy to get lost in the information that we send out, that's why I often sit down and explain what we will be doing.


----------



## craig11152 (Jun 20, 2015)

good stuff from 1985gt. One nice thing about that roof is repair attempts are pretty user friendly. Just don't wear cloths you like and make sure you have hand cleaner. Once you open a can of mastic the stuff just starts attacking you. :laughing:

if you get tar on your clothes either throw them away or set them aside for future mucking. If you throw them in the washer you'll just get it on more stuff.


----------



## 1985gt (Jan 8, 2011)

craig11152 said:


> good stuff from 1985gt. One nice thing about that roof is repair attempts are pretty user friendly. Just don't wear cloths you like and make sure you have hand cleaner. Once you open a can of mastic the stuff just starts attacking you. :laughing:
> 
> if you get tar on your clothes either throw them away or set them aside for future mucking. If you throw them in the washer you'll just get it on more stuff.



This is probably the most important advise yet!

I'd wear latex or rubber gloves. Of course I don't actually do that at work but it's a really good idea to. Very few things get mastic off your hands. Gas works the best but that can be problematic. The Gojo types of hand cleaners work well, for stubborn areas use baby oil. 

I can't begin to tell you how many $1,000's of dollars new clothes I had to buy my wife. I swear Mastic and asphalt multiply in the dryer.


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> ...Very few things get *mastic* off your hands....I swear *Mastic* and asphalt multiply in the dryer.


I appreciate insights -- thanks again to all.

One thing I have now learned is that "mastic" with respect to ceramic tile and "mastic" with respect to roofing are NOT the same animal.


----------



## 1985gt (Jan 8, 2011)

Nope not at all.


----------



## Paultergeist (Oct 13, 2014)

The Firestone website had some really interesting PDF documents -- these contained diagrams of various ways of dealing with the edges of EPDM membranes. Strangely, I did not seem to see an example of the membrane simply brought *to* the edge of a structure such as mine (such that water might simply run off), but rather most examples seemed to create raised edges or dams -- such that the water might be more contained on the flat roof surface and (I would suspect) dealt with via a drain system?


----------



## 1985gt (Jan 8, 2011)

https://www.versico.com/view.aspx?mode=media&contentID=922 

Pretty much the same for all EPDM.


----------



## Paultergeist (Oct 13, 2014)

Thank you.....that was helpful, and consistent with much of what I have been finding on-line.

I guess the thing that has me scratching my head is this:

Intuitively -- which is not to say that my intuition is necessarily correct -- I feel like I want the water to run on a downward slope and leave the roof (as if to drop into a gutter system). The photo you linked, conversely, shows a piece of flashing (i.e. "drip edge fascia") placed on top of the membrane at the edge of the roof, and then a 6" wide strip of coverstrip material is applied over to seal the interface. This means that the depth of any water which collects on that part of the roof would have to get deep enough to flow over the combined height of the flashing thickness and coverstrip material. While I realize that this does not amount to much in the way of depth (maybe 1/4"?), it seems a bit odd to me to put something in place whch might have a slight "dam-ing" effect....?

Sorry if I am being dense; I just want to really understand more of this before I try to execute a plan. The existing roof is failing in the same location where water tends to pool, so I am trying to reduce or avoid that pooling effect.

Thanks very much for the continued help and patience.


----------



## 1985gt (Jan 8, 2011)

Yes it will create a slight damming effect, the more slope the roof has the less this effect will be, dropping the water in to a gutter is always a good idea. 

The amount of water left on the roof will be very small and will evaporate is less then 24 hours. 

If we were to do a roof like yours we would add a 1/2" layer of coverboard over the roof deck, this protects the membrane from any nails backing up through the plywood, at the gutter edge we would put a 6" wide piece of tapered edge strip, this will help keep the water moving, and lessen the amount that stops on the cover strip.


----------



## craig11152 (Jun 20, 2015)

1985gt said:


> https://www.versico.com/view.aspx?mode=media&contentID=922
> 
> Pretty much the same for all EPDM.


correct me if I'm wrong but part of the reasoning for that finish detail is wind I think. Lots of time those systems are on fairly large (and tall) commercial buildings and if an edge of rubber got caught by a serious wind it could pull up massive amounts of roof.


----------



## 1985gt (Jan 8, 2011)

craig11152 said:


> correct me if I'm wrong but part of the reasoning for that finish detail is wind I think. Lots of time those systems are on fairly large (and tall) commercial buildings and if an edge of rubber got caught by a serious wind it could pull up massive amounts of roof.


I think you use to be able to put the edge metal on then seam tape it and stick the EPDM to that, mostly I believe it is for redundancy, the field sheet in theory would protect the nailers if there was a leak at the drip edge.

There isn't a whole lot of commercial building that are tall in this area that have a gravel stop. Most are parapet walls and drains or scuppers. The tallest I can recall I've seen is about 4 stories. No one wants to hang a gutter and down spout higher then that. :laughing:


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> ...If we were to do a roof like yours we would add a 1/2" layer of coverboard over the roof deck, this protects the membrane from any nails backing up through the plywood.....


Okay, I think I'm following the logic. I had never heard the term "coverboard" previously, so that is new information for me to integrate as well. I have seen these big 4' x 8' sheets of white rigid foam (looks quite similar to styrofoam) -- I now suspect that these are a type of coverboard?



1985gt said:


> ....at the gutter edge we would put a 6" wide piece of *tapered* edge strip, this will help keep the water moving, and lessen the amount that stops on the cover strip.


Sorry if I'm being slightly dense......so by "tapered" edge strip, the lateral sides of the strip taper down to a very thin thickness of material, such that there is a little less of a dam-ing effect?

Thanks again for all the assistance.....I'm learning....


----------



## 1985gt (Jan 8, 2011)

Coverboard is a general term, there is a few different materials that can be used as a coverboard. It is often 1/2" thick.

They are used to protect the membrane like in cases like yours where there is no need for a thick layer of insulation, but unless it's new construction you generally do not want to adhere the membranes down to the existing decking (plywood). 

They are also used in lay overs, where you are going to install a new roof system directly over the top of an old system.

They can also be used over the top of other insulations to provide protection for the insulation below, can give addition hail and wind speed ratings, and also can provide puncture protection. They also will help reduce costs when it's time to reroof, depending on how it's done you will not necessarily need to remove all of the underlaying insulation, just the coverboard. 

The common types of coverboard are, 

Wood fiberboard, it's the least expensive, also does not hold up to any moisture entering the system. I feel they are ok on residential applications mostly because if there is a leak in the roof, generally it get's taken care of fairly quickly. Used for hot asphalt jobs mostly anymore. It's light, and easy to work with.

Polyiso HD, More expensive, has a heck of a lot more compressive strength. Quickly becoming the standard for coverboards, unless it is asphalt. Easy to work with but heavy. 

Gyp/cement boards, right around the same price as the HD Iso, offers more compressive strength, will give additional puncture resistance and wind speed ratings. It's heavy and the worst to work with. I have around 1/2 a truck load sitting in the warehouse, I wont use it until it is specified on a job, I could sell it for around 2/3 of what it costs today but I don't wish that on the guys, so if I have a job that needs a coverboard I use ISO or on the low end wood fiberboard 

There is other types that can be used as coverboard, 1/2" plywood and OSB can and are used as coverboard, we did one on a tall building that needed 120 MPH wind speed and a 2" hail warranty, OSB was used. There is also perlite, out of all of the roofing materials this one ranks very high on the do not want to deal with list. If you have ever been 4 wheeling in the desert with out any eye protection, that is roughly the same feeling you will get with working with perlite. The only thing that out ranks it for me is old crumbly coal tar pitch. 


Tapered edge strips are a transition strip that goes from what ever height to real close to 0.


----------



## Paultergeist (Oct 13, 2014)

Thanks again to all for the helpful replies.


I had a day off from work yesterday, and I was able to do a "field trip" to (2) supply warehouse/yards which sold roofing materials to the local trades. It was helpful to be able to see and touch some of the *stuff* I have been reading/learning about.


One note: It was suggested that on top of the Poly Iso foam (I'll probably use tapered Poly Iso in an effort to encourage more slopage) I might want to use 1/4" "Glass-Mat" as a protective board for the foam. (?)

But back to my very first question:


Neither of the roofing materials yards stocked or carried EPDM; both of them stocked PVC and TPO. This evolved into a discussion which did not resolve itself towards answering my questions. In a nutshell:

I am (thus far) leaning towards using EPDM because it appears to be very DIY-friendly. It is installed using chemical solvent/tape at the seams.

The roofing material yards keep pushing PVC or TPO "because it is what we carry and we know it works." (They stated that they had little/no experience with EPDM). The pro yards also felt that the hot-air welding required for PVC or TPO installation was not within the abilities of a typical DIY-er, and thus recommended that I hire a professional. 


*Does anyone know why EPDM would be so very rarely used in my neck of the woods?*


----------



## 1985gt (Jan 8, 2011)

No idea why they wouldn't have EPDM. I've heard that EPDM does not stand up well to some extremely hot climates, but Sand Diego is fairly moderate correct? The only thing I can think of is if codes require a white roof system. If that's the case they do make a white EPDM.

I think 1/4" dens deck is a unneeded item for your case. If you had a lot of hail or have a risk of damage from tree branches ect then maybe. 

Tapered Iso is a good idea if you feel you need more slope. To me I think the slope you have is good enough.


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> No idea why they wouldn't have EPDM. I've heard that EPDM does not stand up well to some extremely hot climates, but Sand Diego is fairly moderate correct? The only thing I can think of is if codes require a white roof system. If that's the case they do make a white EPDM.


I would consider San Diego moderate. My understanding is that EPDM can also be painted with elastomeric paint (commonly available in white). I DO know that EPDM is very popularly used in Koi ponds, and part of the EPDM around the edges is often exposed to sunlight weather -- stuff seems to hold up great.


1985gt said:


> I think 1/4" dens deck is a unneeded item for your case. If you had a lot of hail or have a risk of damage from tree branches ect then maybe.


I do appreciate your thoughts. I confess that I do not want to go ridiculously over-kill, but I am willing to reasonably err on the side of caution. My thought is that other roofers in the future are likely to be walking on the addition roof while accessing the main house (for re-shingling, etc), and that maybe it would be wise to make the Poly Iso foam a bit more protected, but I freely confess that I am not sure.


1985gt said:


> Tapered Iso is a good idea if you feel you need more slope. To me I think the slope you have is good enough.


Well, I would like to eliminate that ponding towards the outside edges if I can. There is one area in particular -- right now -- where I can clearly see the water getting through to the underside of the plywood deck. I just do not want to have to replace the rafters.....

Thanks again.......still learning........


----------



## 1985gt (Jan 8, 2011)

Paultergeist said:


> I would consider San Diego moderate. My understanding is that EPDM can also be painted with elastomeric paint (commonly available in white). I DO know that EPDM is very popularly used in Koi ponds, and part of the EPDM around the edges is often exposed to sunlight weather -- stuff seems to hold up great.


Yes it can, with any elastomeric it needs to have a good slope, they do not hold up well at all if they are in a ponding area. Yes EPDM is used in pond liners, I've seen most kits are 45 mil. They do hold up well. 



Paultergeist said:


> I do appreciate your thoughts. I confess that I do not want to go ridiculously over-kill, but I am willing to reasonably err on the side of caution. My thought is that other roofers in the future are likely to be walking on the addition roof while accessing the main house (for re-shingling, etc), and that maybe it would be wise to make the Poly Iso foam a bit more protected, but I freely confess that I am not sure.


The standard PSI ISO will hold up to moderate foot traffic. The main concern with them re shingling is putting a nail through the roof. I'd simply just inform them that plywood would need to be carefully laid over the area when that work is performed and any damages to the EPDM will be their responsibility. Wait, if you want to do the EPDM your self why not the shingles too?



Paultergeist said:


> Well, I would like to eliminate that ponding towards the outside edges if I can. There is one area in particular -- right now -- where I can clearly see the water getting through to the underside of the plywood deck. I just do not want to have to replace the rafters.....


From my experience a roof has to be in really really poor shape to need any structural work done, I'm talking years and years of neglect. I had a job a number of years ago, once we started tearing off we realized how big of a can of worms this is going to be. It was around 50 squares and we ended up replacing 3/4 of the plywood. The roof had anywhere from 4-7,8 layers of modified bitumen, all done in hot asphalt or torch down. In areas the plywood was so bad the only thing holding us up was the roofing material it's self. It was a miserable job and quite expensive for the owner. We only had to replace one rafter. Of course that was fairly easy to do since there was little to no plywood in the area and 50% of the drywall ceiling had fallen. 



Paultergeist said:


> Thanks again.......still learning........


You are welcome.


----------



## 1985gt (Jan 8, 2011)

Oh I will also add, here our weather can be -10-20 to 105 with outrageously high humidity. EPDM is the standard membrane. 

I'd ask around your area though there maybe a reason why the supply houses do not stock EPDM. If it has to be white, I would go to the local box store and buy their coating. I'm guessing once it is inspected, if it needs to be, they wont be coming back out again to make sure your roof is still white/reflective.


----------



## craig11152 (Jun 20, 2015)

1985gt said:


> Oh I will also add, here our weather can be -10-20 to 105 with outrageously high humidity. EPDM is the standard membrane.
> 
> I'd ask around your area though there maybe a reason why the supply houses do not stock EPDM. If it has to be white, I would go to the local box store and buy their coating. I'm guessing once it is inspected, if it needs to be, they wont be coming back out again to make sure your roof is still white/reflective.


Same here in SE Michigan. We get temperature extremes and EPDM seems to be a favorite with commercial roofers. I think the California issues might be with VOC in adhesives. I'm guessing the regulations make it too big a headache for a lot of folks.....just a guess.


----------



## 1985gt (Jan 8, 2011)

craig11152 said:


> Same here in SE Michigan. We get temperature extremes and EPDM seems to be a favorite with commercial roofers. I think the California issues might be with VOC in adhesives. I'm guessing the regulations make it too big a headache for a lot of folks.....just a guess.


The VOC's would be an issue with any fully adhered Single ply. They do make water based and low voc solvent based glues/adhesives for these areas. Not only making it a headache but the costs of the low voc products are double or more of the standard products.


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> ....I'd simply just inform [the roofers] that plywood would need to be carefully laid over the area when that work is performed and any damages to the EPDM will be their responsibility. Wait, if you want to do the EPDM your self why not the shingles too?


LOL! Well, one major project at a time!


My thought, however, is that the main part of the house is a pretty standard roofing job that will not require the sort of engineering and hunting for more exotic materials that the addition seems to require. I may just out-source the main roof (simple shingles) to a professional when the time comes, or -- if I feel like I can tackle it with some hired labor -- maybe I _will_ try it myself. I have some time, I think (probably have a couple more years of life on that roof).....


----------



## Paultergeist (Oct 13, 2014)

craig11152 said:


> .....I think the California issues might be with VOC in adhesives.......


I believe this is indeed a big part of the issue as to *why* PVC and TPO are more popular than EPDM out here in California. A number of the standard (VOC-laden) EPDM adhesives specifically state on their product websites that they are not for use/sale in specific parts of California (pretty much includes most of the heavily-populated counties). Seems to be related to smog and/or air-quality regulations.

There ARE low/no VOC-based EPDM adhesives, but they do appear to be more expensive. I am fine with the added cost, as I am not using vast quantities. I do, however, want to make sure that the California-compliant products still work well, or I may have to consider other options.

On to more research.......


----------



## 1985gt (Jan 8, 2011)

On my price sheet there is actually two low VOC solvent based adhesives. One is specifically stated for California. I don't know the difference other then they cost more then the standard low voc and double what normal bonding adhesives are. 

Check out the water based ones, they are pretty easy to use, more so then solvent based ones, but check to see if they can be used in California. 

Even so there is 3 types of TPO and 2 types of PVC adhesives, regular and low voc. It could also be that mechanically attached systems are the normal there IDK.


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> ....Even so there is 3 types of TPO and 2 types of PVC adhesives, regular and low voc. It could also be that mechanically attached systems are the normal there IDK.


Interesting. The supply places I visited (2) both pushed towards PVC or TPO (as I mentioned earlier), but they left me with the impression that using a "hot-air welder" (a tool which they do not rent nor is cheap to buy) was *the* way to seam/join PVC or TPO. I did not know that there *even was* TPO and PVC adhesives for this type of application.

Lots of good information.....still learning........


----------



## 1985gt (Jan 8, 2011)

Well the adhesives I speak of are the glues that hold the membrane to the insulation. Interestingly enough some manufactures offer seam tape for TPO, IMO that kind of defeats the purpose of installing a TPO.


----------



## Paultergeist (Oct 13, 2014)

For clarity, my vision (impression) is that I'll be working with 5' rools of the roof membrane material. I am most concerned with the water-tight joining of panel-to-panel (of the EPDM material to itself).......I had not even thought about how to adhere it to the Poly Iso foam......


----------



## 1985gt (Jan 8, 2011)

No reason to do it in 5' wide pieces. I'd buy a 20'x30' and do it all in one piece. If I had to I'd maybe split it down the middle.

Not having seams would save you a lot of money. The seam tape is 100' rolls.

One option would be to find a commercial roofer and see if you can buy the items from them. That way you wouldn't be buying full rolls and buckets of stuff that will just be wasted.


----------



## Paultergeist (Oct 13, 2014)

1985gt said:


> No reason to do it in 5' wide pieces. I'd buy a 20'x30' and do it all in one piece....


I did not that I could do _that_, either.....see, I'm still learning.

If I recall correctly, the Firestone rep I spoke with over the telephone mentioned 5' rolls in conjunction with shipping charges (Fed-Ex vs. Freight?).....but if I can get one continuous sheet, that would be perfect.

Thanks again.


----------



## craig11152 (Jun 20, 2015)

1985gt said:


> No reason to do it in 5' wide pieces. I'd buy a 20'x30' and do it all in one piece.


Having no experience with the stuff how big a piece can one guy get up a ladder? I assume at that size you do some folding and rolling like you would a tarp?


----------



## 1985gt (Jan 8, 2011)

Paultergeist said:


> I did not that I could do _that_, either.....see, I'm still learning.
> 
> If I recall correctly, the Firestone rep I spoke with over the telephone mentioned 5' rolls in conjunction with shipping charges (Fed-Ex vs. Freight?).....but if I can get one continuous sheet, that would be perfect.
> 
> Thanks again.


Once you get a game plan I would start calling around to the commercial roofing outfits. I sell EPDM off our self all the time. There is even a place on Ebay that will, for a lack of a better term sell you a roof on a pallet. 



craig11152 said:


> Having no experience with the stuff how big a piece can one guy get up a ladder? I assume at that size you do some folding and rolling like you would a tarp?


60 mil EPDM weighs roughly .4 of a lb per square foot. So a 20x30 would be 240 lbs. I'd fold it up so that I could get part of it on the roof then go back down the ladder and carry the other part up. It's not uncommon for our guys (with buddy bars) to carry a 20x50 just two guys. There was a couple of us who could do 12x100's with just two people. That was 10+ years ago when I was in shape from running a crew. It's a damn shame what sitting in a office does to you. 

If you split it in half it would be more manageable. It doesn't feel like 120 lbs when it's on your shoulder. By all means know your limits and get help if need be.


----------

