# Pergola roof top



## cibula11 (Jan 6, 2007)

What do you mean by 'flat'? They need to be installed on their edges a spaced out every 16" or so. If you lay them flat and span 12' they will quickly begin to bow or sag.


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## Slashp (Apr 28, 2014)

There will be 9 2x6x12 joists laid vertically to support the boards roughly drawn here:










Regards,
John


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## cibula11 (Jan 6, 2007)

Okay that makes sense now. You still may want to consider beefing up the 2x6s. Not sure where you are located, but any snow will create quite a bit of weight causing the whole thing to sag, which may happen anyway over time. 

Why not pitch the roof structure and bit or use slats (2x2s) that run perpendicular to the 2x6s...you'd still get quite a bit of coverage, but wouldn't have to worry as much about sagging.


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## Slashp (Apr 28, 2014)

cibula11 said:


> Okay that makes sense now. You still may want to consider beefing up the 2x6s. Not sure where you are located, but any snow will create quite a bit of weight causing the whole thing to sag, which may happen anyway over time.
> 
> Why not pitch the roof structure and bit or use slats (2x2s) that run perpendicular to the 2x6s...you'd still get quite a bit of coverage, but wouldn't have to worry as much about sagging.


Hi,

I live in California so snow will never be an issue. The problem is that it can get very hot and I have no shade in backyard. This is why I want to cover the entire roof. I am not to worried about the sagging of the 2x12x12 as they are spaced out around 24in appart and nobody will walk on them. Are you saying that I should replace my 2x6s by 2x8s for the joists?

John


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## AndyWRS (Feb 1, 2012)

I would build it and then call local roofing companies and get some quotes. It is really small, cant cost that much to have a roofer come in and do it right.
​


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## Slashp (Apr 28, 2014)

AndyWRS said:


> I would build it and then call local roofing companies and get some quotes. It is really small, cant cost that much to have a roofer come in and do it right.
> ​


I got a quick quote from an IB roof contractor, they wanted to charge 2000$ for such a small work. (twice the amount of the materials for the entire pergola...)

Putting a roof shouldn't be too hard on a small, flat, square area. Just need to decide what to put to weatherproof it.


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## AndyWRS (Feb 1, 2012)

3-ply mod bit - ideally torch applied. Still need a roofer unless you have a torch.

I think that's the best option, good roof and not that much $.


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## Robpo (Mar 30, 2014)

http://www.ducan.com/deck-coating/default.php I used something like this on a deck many years ago. I bought it at Meeks lumber yard in Tahoe. I would think you could find it or something like it.


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## 1985gt (Jan 8, 2011)

Slashp said:


> I got a quick quote from an IB roof contractor, they wanted to charge 2000$ for such a small work. (twice the amount of the materials for the entire pergola...)
> 
> Putting a roof shouldn't be too hard on a small, flat, square area. Just need to decide what to put to weatherproof it.



Your right us roofers shouldn't charge so much, after all the hot air welders, extremely high priced insurance, trucks, fuel, training, peoples wages, ect. 

To be fair 1,333.00 per square is a decent price, especially if they put down a coverboard, installed metal edges and tied in to another roof. 

For the self adhered membrane you have to have some slope, plus you are also looking at around $300 for the nail base sheet and cap sheets alone.


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## Slashp (Apr 28, 2014)

1985gt said:


> Your right us roofers shouldn't charge so much, after all the hot air welders, extremely high priced insurance, trucks, fuel, training, peoples wages, ect.
> 
> To be fair 1,333.00 per square is a decent price, especially if they put down a coverboard, installed metal edges and tied in to another roof.
> 
> For the self adhered membrane you have to have some slope, plus you are also looking at around $300 for the nail base sheet and cap sheets alone.


I understand that for such a small work, the fixed costs like truck, fuel are still there and proportionally bigger. But since I do most things myself in my house (otherwise I would not be able to afford them) this is definitely the kind of job I could do myself.
I watched the IB videos and it doesn't seem complicated to do on a small square surface like mine with no openings (especially knowing that it is a patio cover, not a roof on the house - a leak would be easy to fix later and would have no consequence). The issue is that the tool cannot be rented. It is a shame because IB membranes looked great and for my surface using an online estimator, it was around $200 of materials...

There are things for which I use the help of contractors because I don't want to mess things up (Furnace / AC installation, main roof renovation...) But what I can do myself, I do.

John


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## 1985gt (Jan 8, 2011)

Slashp said:


> I understand that for such a small work, the fixed costs like truck, fuel are still there and proportionally bigger. But since I do most things myself in my house (otherwise I would not be able to afford them) this is definitely the kind of job I could do myself.
> I watched the IB videos and it doesn't seem complicated to do on a small square surface like mine with no openings (especially knowing that it is a patio cover, not a roof on the house - a leak would be easy to fix later and would have no consequence). The issue is that the tool cannot be rented. It is a shame because IB membranes looked great and for my surface using an online estimator, it was around $200 of materials...
> 
> There are things for which I use the help of contractors because I don't want to mess things up (Furnace / AC installation, main roof renovation...) But what I can do myself, I do.
> ...


So go find your local commercial roofer and ask for a 12'x12' chunk of TPO, or white EPDM. You won't have any hanging over the edges but you could still have them form a drip edge for the area. The thing is while you can glue directly to wood any nail pops go through the membrane. We always put a coverboard. I hope you were planning on gluing it down, you can't just flop it up there and hope it stays, it has to be attached some how. I would call your nearest commercial roofer and ask amount material sales. We do it all the time. I'll give you a roof in a box if that's what you want. Probably make more money doing it then actually installing a roof of that size.


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## Slashp (Apr 28, 2014)

1985gt said:


> So go find your local commercial roofer and ask for a 12'x12' chunk of TPO, or white EPDM. You won't have any hanging over the edges but you could still have them form a drip edge for the area. The thing is while you can glue directly to wood any nail pops go through the membrane. We always put a coverboard. I hope you were planning on gluing it down, you can't just flop it up there and hope it stays, it has to be attached some how. I would call your nearest commercial roofer and ask amount material sales. We do it all the time. I'll give you a roof in a box if that's what you want. Probably make more money doing it then actually installing a roof of that size.


I was planning to put flashing around the edges of the 12x12 surface and glue the membrane directly on top of the boards (the screws holding the 2x12x12 boards will be recessed to avoid damaging the membrane).

Are you saying that I can directly order a white 12ftx12ft EPDM with a drip edge? Do you have a rough idea of the price?

Another idea that I had is to not use 2x12x12 boards + membrane to make the roof but rather to use insulated white corrugated metal sheets. But I could not find a local (San Francisco bay area) distributor yet and I have no idea on how to connected the sheets together in a waterproof way.

Thank you for your help,
Regards,
John


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## cibula11 (Jan 6, 2007)

Slashp said:


> I got a quick quote from an IB roof contractor, they wanted to charge 2000$ for such a small work. (twice the amount of the materials for the entire pergola...)
> 
> Putting a roof shouldn't be too hard on a small, flat, square area. Just need to decide what to put to weatherproof it.


Yes, I wonder that with the weight of 2x12s laid flat the 2x6's could start to sag. If you're considering roofing the structure, you don't need something as beefy as a 2x12. Just another thought.


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## 1985gt (Jan 8, 2011)

Slashp said:


> I was planning to put flashing around the edges of the 12x12 surface and glue the membrane directly on top of the boards (the screws holding the 2x12x12 boards will be recessed to avoid damaging the membrane).
> 
> Are you saying that I can directly order a white 12ftx12ft EPDM with a drip edge? Do you have a rough idea of the price?
> 
> ...


I guess I never asked why 2x12s? Why not plywood?

Membrane comes on rolls. EPDM comes up to 20' wide and 100 + feet long. TPO that is white the widest roll is 12' (at least from our manufactures). You need some kind of covering over the wood to protect the membrane from getting punctures. Hence the coverboard 1/2" insulation. Then glue the membrane on top of it. Screw down the edge, and then strip the edge in. 

Sounding like you may need to do some more research on this before tackling it. To do all this for $200 is just not going to happen. A 100' roll of coverstrip cost US around $200. When I sell it by the foot it's more then $2 a foot. You need 1/2 roll for 48'. So theres more then $100. Plus primer, and cleaner, a gallon of each (more then enough) will be more then $50. You need coverboard so that will be around another $100+, The glue depending on material our cost around $85 for 5 gals. You will need around 1/4-1/2 a bucket, you may get lucky and someone has a half open bucket they will sell so $50.00 for that. Then you need the screws and 3" plates to attach the cover board, I'd probably throw those in since you only need 75 of them. Ops forgot you still need the sheet it's self, another $100. Then you need the metal around $150 for the labor to bend it we use 24 ga prefinshed. 

As you can see you are around the $600 mark for materials. That's just off the top of my head, using what little EPDM numbers I have in my head. PVC will be more expensive but it's not an option for you since you don't have the welder. So you ahve EPDM or TPO or the SA modified. Like I said with S/A modified you are at at least $300 for just the rolls, not including anything else. metal and everything else you need will be close to the same amount.

Do some serious research before you do anything. All of the manufactures I'm aware of have details on the web to look at.


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## Robpo (Mar 30, 2014)

Home Depot sells corrugated in 12 foot lengths. Corrugated is easy to overlap if 12' isn't long enough. I know they have galvanized which would reflect heat. Don't know if they have white. Did you look at the paint on deck stuff.


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## Slashp (Apr 28, 2014)

1985gt said:


> I guess I never asked why 2x12s? Why not plywood?
> 
> Membrane comes on rolls. EPDM comes up to 20' wide and 100 + feet long. TPO that is white the widest roll is 12' (at least from our manufactures). You need some kind of covering over the wood to protect the membrane from getting punctures. Hence the coverboard 1/2" insulation. Then glue the membrane on top of it. Screw down the edge, and then strip the edge in.
> 
> ...


Hi,

Thank you for all those details 
I want 2x12 for 2 reasons over plywood:
- Aestetics
- Thicker material so will give more insulation again heat
Ideally I wanted to see the redwood roof from below (plywood won't look as good as redwood boards for a pergola roof).

There are a lot more steps involved than what I thought, do I really need the cover board since I won't walk on the pergola roof and since the 2x12 will have a smooth finish and recessed screws).

If I were not to use 2x12 for the roof. Do you know a company in the bay area that distributes white corrugated insulated metal panels?
Thank you again,
Regards,
John


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## Slashp (Apr 28, 2014)

Robpo said:


> http://www.ducan.com/deck-coating/default.php I used something like this on a deck many years ago. I bought it at Meeks lumber yard in Tahoe. I would think you could find it or something like it.


That is an interesting solution


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## Slashp (Apr 28, 2014)

Robpo said:


> Home Depot sells corrugated in 12 foot lengths. Corrugated is easy to overlap if 12' isn't long enough. I know they have galvanized which would reflect heat. Don't know if they have white. Did you look at the paint on deck stuff.


I saw that, but they unfortunately don't exist in white or insulated


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## cibula11 (Jan 6, 2007)

Slashp said:


> Hi,
> 
> Thank you for all those details
> I want 2x12 for 2 reasons over plywood:
> ...


You can do it how you drew it up... I think others are chiming in on what problems might arise. If all you are going for is some shade an and outdoor structure you're on the right track. I assume when you say insulation you mean to keep the heat out?? I think any material blocking the sun will do that , not sure if spending extra on insulted material will give you any added comfort or benefit. 

You could even use 1x6 or 1x8 redwood if available instead of the 2x12. Just make sure you leave a gap ( like deck boards) so water can go somewhere and not sit on the roof.


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## 1985gt (Jan 8, 2011)

Slashp said:


> Hi,
> 
> Thank you for all those details
> I want 2x12 for 2 reasons over plywood:
> ...


I can see the aesthetics, wood will transfer the heat though. 

Unless you already have the material, you could do your 2x6's plywood on top, then waterproofing. On the under side 2x6 shiplap or something for the visual of it. You could also box in the open area (fascia) with the shiplap. Trim off the roof with a drip edge and stain the underside and fascia. The air space would have some kind of insulating properties. The main thing is reflecting the heat from the roof. Menards or HD should be able to order white corrugated panels, but then you would have exposed fasteners. Could ruin all your hard work. Plus if it doesn't have any slope that could be a problem. 

You don't technically need a coverboard over the wood you can glue directly to it. But there are risks, nail/screw pops being one. Woodfiber coverboard is cheap insurance against it.

I don't know if anyone distributes them around there, I'm sure you could order some but shipping would probably cost more then the panels them self.


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## Robpo (Mar 30, 2014)

1985gt said:


> I can see the aesthetics, wood will transfer the heat though.
> 
> Unless you already have the material, you could do your 2x6's plywood on top, then waterproofing. On the under side 2x6 shiplap or something for the visual of it. You could also box in the open area (fascia) with the shiplap. Trim off the roof with a drip edge and stain the underside and fascia. The air space would have some kind of insulating properties. The main thing is reflecting the heat from the roof. Menards or HD should be able to order white corrugated panels, but then you would have exposed fasteners. Could ruin all your hard work. Plus if it doesn't have any slope that could be a problem.
> 
> ...


I like the idea of an air space. I don't know if insulation would help or hurt. Just a suggestion.
I look at your sketch again, really nice, you must be an artist. :thumbsup:


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## cibula11 (Jan 6, 2007)

Are you desiring a pergola type structure or a park shelter? Seems like if you want some shade it can be pretty simple. If you're looking for more than that then obviously you'd need some roofing material.


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## Slashp (Apr 28, 2014)

cibula11 said:


> Are you desiring a pergola type structure or a park shelter? Seems like if you want some shade it can be pretty simple. If you're looking for more than that then obviously you'd need some roofing material.


Hi,

I want to block both the sun and the water.
John


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## Slashp (Apr 28, 2014)

1985gt said:


> I can see the aesthetics, wood will transfer the heat though.
> 
> Unless you already have the material, you could do your 2x6's plywood on top, then waterproofing. On the under side 2x6 shiplap or something for the visual of it. You could also box in the open area (fascia) with the shiplap. Trim off the roof with a drip edge and stain the underside and fascia. The air space would have some kind of insulating properties. The main thing is reflecting the heat from the roof. Menards or HD should be able to order white corrugated panels, but then you would have exposed fasteners. Could ruin all your hard work. Plus if it doesn't have any slope that could be a problem.
> 
> ...


I didn't buy the materials yet but what you propose sounds interesting:

Plywood on top of the 2x6s, Shiplap on the bottom, Drip edge and fascia on the side. It would be way more effective than 2x12x12 for heat insulation thanks to the pocket of air (for about the same weight), would still look nice (and would also allow me to put recessed lighting between the two.

Regards,
John


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## 1985gt (Jan 8, 2011)

Slashp said:


> I didn't buy the materials yet but what you propose sounds interesting:
> 
> Plywood on top of the 2x6s, Shiplap on the bottom, Drip edge and fascia on the side. It would be way more effective than 2x12x12 for heat insulation thanks to the pocket of air (for about the same weight), would still look nice (and would also allow me to put recessed lighting between the two.
> 
> ...



Yeah the roof structure would be lighter even with shiplap and would look better IMO. 


I've thought about doing something similar over our deck. Right now we have a metal gazebo that the canvas gave up on. I've been kicking around the ideas about different things but then I realize it just makes more projects for me as if I don't have enough.


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## JustinK (Oct 4, 2009)

I wouldn't get too carried away with waterproofing the roof. The slightest wind will soak everything under it anyway. Something like a roof coating would be fine like suggested before. Wait for the wood to dry out then caulk the seams then put on some type of roof coating. Make the roof with a slight pitch even if it is just an inch. Pitch the beams.


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## Slashp (Apr 28, 2014)

JustinK said:


> I wouldn't get too carried away with waterproofing the roof. The slightest wind will soak everything under it anyway. Something like a roof coating would be fine like suggested before. Wait for the wood to dry out then caulk the seams then put on some type of roof coating. Make the roof with a slight pitch even if it is just an inch. Pitch the beams.


When you say pitch the beams do you mean like this:
*1*









or like this:

*2*









- 1 seems to be the easiest to achieve. but will only be structurally sound for very small slopes
- 2 seems the way to go for more slope but there is a lot more maths and cutting for the rafters (birdsmouth cuts)

If I go for a pitched roof, which technique should I use (1 is way easier to achieve, but what is the max angle that I can have in that case?)

As a side question, if I do a pitched roof covered with plywood on top, what is the minimum slope to install composite shingles (would solve my waterproofing problem)?

Thank you,
John


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## PatChap (Nov 17, 2012)

Slashp said:


> When you say pitch the beams do you mean like this:
> *1*
> 
> 
> ...


2.5/12 if you cover it with peel and stick underlayment(ice and water shield) first, but any pitch above and beyond that is better. 4/12 or more is ideal.


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## JustinK (Oct 4, 2009)

With plywood it doesnt matter which way you pitch it. Using the 2x12 layed flat I suggest the way your have shown so the seams would carry the water away and not get trapped. I install sunrooms and depending on the system/manufacture all that stops the roof from leaking is a good quality chaulk. Although there isnt as much expansion and contraction with glass it should still last for many years.


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## 1985gt (Jan 8, 2011)

JustinK said:


> I install sunrooms and depending on the system/manufacture all that stops the roof from leaking is a good quality chaulk. Although there isnt as much expansion and contraction with glass it should still last for many years.



Just because someone does it that way doesn't make it right. caulking will not hold up as long when it's exposed to the elements as it does sandwiched between materials. 

If I was building a structure like this I wouldn't be relying on any caulking or coating to make it waterproof.

You could do it to 1-2:12" and put the self adhered on it also. It works better with more slope, shingles will work with the slopes listed but then you would be running in to most of them except the higher end ones will absorb the heat.


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## JustinK (Oct 4, 2009)

1985gt said:


> If I was building a structure like this I wouldn't be relying on any caulking or coating to make it waterproof.


my whole point is that it is not a waterproof structure. I would never do that if it had walls but there is no point in spending $2000 on a roof membrane when wind will blow rain under roof anyway.


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## 1985gt (Jan 8, 2011)

JustinK said:


> my whole point is that it is not a waterproof structure. I would never do that if it had walls but there is no point in spending $2000 on a roof membrane when wind will blow rain under roof anyway.


The wind won't be able to blow it anywhere will it will cause any damage.


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## ddsrph (Nov 23, 2013)

I am going to be building a similar structure soon. I may leave it uncovered but if I do cover I will use roofing metal. Is there any problems with redwood being in contact with metal? On pressure treated which is what I will be using it can't contact the metal directly due to corrosion. You can find roofing metal companies that can custom cut the panels to exactly what length you need, choose from many colors and for a twelve foot width need only four sheets. In my area the heavier 26 gauge for a 12 by 12 would be less than $150.


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## 1985gt (Jan 8, 2011)

ddsrph said:


> I am going to be building a similar structure soon. I may leave it uncovered but if I do cover I will use roofing metal. Is there any problems with redwood being in contact with metal? On pressure treated which is what I will be using it can't contact the metal directly due to corrosion. You can find roofing metal companies that can custom cut the panels to exactly what length you need, choose from many colors and for a twelve foot width need only four sheets. In my area the heavier 26 gauge for a 12 by 12 would be less than $150.


You need a separation/water poofing layer between the wood and metal.

You might be able to get the panels for that but you still need felt, edge trim, foam closures and fasteners.


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## ddsrph (Nov 23, 2013)

1985gt said:


> You need a separation/water poofing layer between the wood and metal.
> 
> You might be able to get the panels for that but you still need felt, edge trim, foam closures and fasteners.


That's true but still overall not much money involved. If I go with covering I would probably put down some untreated one by 3 or 1 by 4's on two foot centers at right angle to metal to attach to. I would oil stain the entire unit and what little leaked thru the flat roof would be minuscule to a uncovered roof and quickly dry especially if no felt was used. I may also put a small slope back towards house roof at a level above gutters and then it shouldn't leak at all.


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## bobinphx (Nov 25, 2011)

I would like to suggest fiberglass mat and resin. There are a couple of videos on how to do this. About 6 or so years ago, I did my flat roof garage 25 by 25 with crickets, scuppers and vent stacks and its holding up great!!!! High heat, sunlight, dirt etc.. no problems so far. I was not easy, its messy and there is a short learning curve, but all told, it was 1/2 the price of a torchdown and the lifespan looks like it will be comparable to torchdown.


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## 1985gt (Jan 8, 2011)

Wait till things start to move and the cracks start showing up...


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## bobinphx (Nov 25, 2011)

6 years on a 30 year old building and no cracks.. no chalking, no bubbles, no maintenance and best of all no leaks. Yes, prep was hard and working with resin was sticky and messy, but in my book, the results were worth it. just my opinion and I am only suggesting this as an option.


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## Slashp (Apr 28, 2014)

Hi all,

After all the discussions and your insights I plan to do a 12x12 flat roof with the following details:

I plan to go with 2x6 joists spaced 24in in the center with 4ft x 8ft x 3/4in plywood on top looking roughly like that:










I may (or may not) put some shiplap below the structure.

I will cover the plywood with a glued white EPDM membrane (any suggestion?) and I will put a drip edge around the roof (something like that: http://www.homedepot.com/p/Construction-Metals-Inc-2-in-x-2-in-x-10-ft-White-Roof-Edge-Flashing-RE22WH/202093202?N=5yc1vZaqp7)

Do I really need to slope the roof or can I leave it completely horizontal? (I don't plan to put a gutter)
I have a personal preference for no tilt for two reasons:
- Aestetics
- Slightly Simpler to build
Any cons of leaving the roof horizontal (there is no snow where I live) since it should be completely waterproof because of the EPDM membrane?

Thank you,
Regards,
John


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## Robpo (Mar 30, 2014)

Slashp said:


> Hi all,
> 
> After all the discussions and your insights I plan to do a 12x12 flat roof with the following details:
> 
> ...


 Ok but you have to do the plywood like this.







That is typically how it is done.


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## AndyWRS (Feb 1, 2012)

I didn't read through all the posts, but why not use T1-11 for the deck, that will look better than seeing just plain of plywood from underneath the structure.

I don't see any real down side to a flat deck, its not idea, but we get little rain here.


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## bobinphx (Nov 25, 2011)

T1-11 may not be rated for use as a roof. I know many years ago when I built a patio cover, the city said no to t1-11, unless I went over it with plywood on the top. Just my experience a long time ago in an arizona city!!! btw. I did use t1-11 with plywood glued and screwed to the top of it. It sure looks nice and I have gotten lots of compliments on it. and its still up 17 years later!!!


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## AndyWRS (Feb 1, 2012)

I would do the same thing, the T1-11 just looks great. As you mentioned I would also skin over it with plywood. I will be building a patio cover next month at my friends home, we are doing the T1-11 first for a more finished look from the underside. We are skinning it in ply also because I need to nail my base sheet...we will be doing a 3-ply mod bit roof.


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## Slashp (Apr 28, 2014)

Robpo said:


> Ok but you have to do the plywood like this.
> View attachment 84698
> 
> That is typically how it is done.


Hi Robpo, in my drawing, since the roof is 12x12, I need 4.5 4ftx8ft plywood boards.

in your drawing you seem to have very small plywood boards. Are you suggesting that the boards need to run parallel to the joists and not orthogonal?
John


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## Slashp (Apr 28, 2014)

AndyWRS said:


> I would do the same thing, the T1-11 just looks great. As you mentioned I would also skin over it with plywood. I will be building a patio cover next month at my friends home, we are doing the T1-11 first for a more finished look from the underside. We are skinning it in ply also because I need to nail my base sheet...we will be doing a 3-ply mod bit roof.


T1-11 is a good idea but I would not put it directly below the plywood but rather below the joists so that I have an air pocket of 6in between the 2 boards to isolate even better for the heat.
That will also allow me to put recessed lighting in the cavity.

John


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## bobinphx (Nov 25, 2011)

t1-11 below the rafters works great too!! we did that on my brothers patio and trimmed it with 2x6 to picture frame it. Looks really nice. my patio, I wanted a more rustic look, so we stained all the wood. The t1-11 really looks nice above the rafters and stained. we did install a couple of lights and fans. we framed in the electrical boxes and spray painted the conduit brown.


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## 1985gt (Jan 8, 2011)

White EPDM flat would be fine, I can't remember exactly on white EPDM but the manufactures we use the 12' rolls are actually 12'6" so this would leave you enough to wrap the EPDM down the fascia boards. I would use a different drip edge, if you are getting the material from a commercial roofer they should be able to bend you the drip. 3" X 3" would be best. You will also need to strip it in. 


The way you laid out your plywood would be the correct way to install it. Make sure to screw it and caulk any gaps bigger then 1/4"


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## Slashp (Apr 28, 2014)

1985gt said:


> White EPDM flat would be fine, I can't remember exactly on white EPDM but the manufactures we use the 12' rolls are actually 12'6" so this would leave you enough to wrap the EPDM down the fascia boards. I would use a different drip edge, if you are getting the material from a commercial roofer they should be able to bend you the drip. 3" X 3" would be best. You will also need to strip it in.
> 
> 
> The way you laid out your plywood would be the correct way to install it. Make sure to screw it and caulk any gaps bigger then 1/4"


Hi,

Thank you for all those details 

1 - Should I nail the drip edge to the plywood and glue the EPDM on top wrapping it around the edges
or
2 - Glue the EPDM first (still wrapping it around the fascia), then nail the drip edge on top, and put a strip of EPDM on top of the joint between the drip edge and the previously laid EPDM

I guess the answer is 2 but I just want to make sure.

The hard part will be to find a white EPDM distributor that sells small rolls of EPDM... (the one I contacted for Firestone white EPDM only sells 10ftx100ft rolls while I just need 12ftx12ft...)

John


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## 1985gt (Jan 8, 2011)

Slashp said:


> Hi,
> 
> Thank you for all those details
> 
> ...



EPDM down to plywood, nail down edge metal and strip it in with cover strip. 

This detail here http://www.versico.com/view.aspx?mode=media&contentID=892


I just looked it up since I don't deal with white EPDM much, 10' rolls is what you get either in 50' or 100' long. I'd look in to TPO, you can get 12' wide they are actually 12'3". Detail on the edge can be the same, it will be white and more commercial roofers will stock it. I'd call around, again it's not uncommon for a commercial roofer to sell you the whole kit. A 12x12 membrane, the edge metal, the cover strip primer and glue, they will have partials laying around the shop they would be happy to sell, at least they should. Then you won't end up with a whole lot extra.


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## Slashp (Apr 28, 2014)

1985gt said:


> EPDM down to plywood, nail down edge metal and strip it in with cover strip.
> 
> This detail here http://www.versico.com/view.aspx?mode=media&contentID=892
> 
> ...


I was thinking of using only one layer of decking boards instead of shiplap + plywood on top of the 24in spaced joists:
http://www.lowes.com/ProductDisplay...gId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1

It has the following advantages:
- Would look nice from below
- Would be simpler to install than 1 layer of shiplap + 1 layer of plywood
- Would be lighter for the structure than shiplap + plywood

Do you see any inconvenients? Do you think I can directly glue EPDM / TPO on top?

Thank you,
John


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## 1985gt (Jan 8, 2011)

Slashp said:


> I was thinking of using only one layer of decking boards instead of shiplap + plywood on top of the 24in spaced joists:
> http://www.lowes.com/ProductDisplay...gId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1
> 
> It has the following advantages:
> ...



I thought I posted an answer to this yesterday, sorry must not have hit send. 


Anyway, I do not see anything wrong with doing it that way. I would screw the boards down, and make sure any splits,cuts,knots anything that is a sharp edge or could be come a sharp edge is sanded and caulk any large gaps.

Other then that I think you have a very nice plan.


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## Slashp (Apr 28, 2014)

1985gt said:


> I thought I posted an answer to this yesterday, sorry must not have hit send.
> 
> 
> Anyway, I do not see anything wrong with doing it that way. I would screw the boards down, and make sure any splits,cuts,knots anything that is a sharp edge or could be come a sharp edge is sanded and caulk any large gaps.
> ...


Thank you for your help


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## Slashp (Apr 28, 2014)

Here are a few 3D models of what I plan to build:





































John


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## Slashp (Apr 28, 2014)

Work in progress from yesterday:










I will add extra bracing to make the structure stronger


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## 1985gt (Jan 8, 2011)

Looks good!


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## Slashp (Apr 28, 2014)

Hi,

How do you think I should fasten the rafters? Would toe nailing them be enough or should I use somthing like this:
http://www.lowes.com/pd_21993-166-RT7A-TZ_0__?productId=3375046&Ntt=rafter+tie&pl=1&currentURL=%3FNtt%3Drafter%2Btie&facetInfo=

or this: 
http://www.lowes.com/pd_21457-166-RT7A_0__?productId=3375034&Ntt=rafter+tie&pl=1&currentURL=%3FNtt%3Drafter%2Btie&facetInfo=

Thank you,
John


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## Robpo (Mar 30, 2014)

Slashp said:


> Hi,
> 
> How do you think I should fasten the rafters? Would toe nailing them be enough or should I use somthing like this:
> http://www.lowes.com/pd_21993-166-R...ie&pl=1&currentURL=?Ntt=rafter+tie&facetInfo=
> ...


 They will work. I think they make rights and lefts depending on which side you want to put them. or


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## Slashp (Apr 28, 2014)

Robpo said:


> They will work. I think they make rights and lefts depending on which side you want to put them. or


I used that, that works great thank you


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## Slashp (Apr 28, 2014)

I decided to finally go with two layers on top of the rafters to cover the roof (as suggested earlier in this thread): one layer of T1-11 (with the grooves visible from below) and one layer of 19/32 or 23/32 plywood on top to make it stronger (it's a shame T1-11 doesn't exist directly in 3/4 in thick...).

My problem is that with a even spacing of the 5 rafters between the two beams, the seams between 4x8 plywood boards won't end on a rafter... Is there a solution other than adding extra rafters (I won't align the seams of the two plywood layers, will that be enough?)

Another question: Should I put roofing paper between the two layers (I have some leftovers from my Hardwood floor installation) ?

Thank you,
John


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## 1985gt (Jan 8, 2011)

You will want to have them end on a rafter, one way to do it would be basically split the sheets so they all end on the middle rafter. So you would need 6 sheets for the T1-11.

Or another option is and I don't know if it's available 12' sheets. 

No need for the paper between.


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## Slashp (Apr 28, 2014)

Work in progress:


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## Slashp (Apr 28, 2014)

More progress:




























I installed the T1-11 + the second layer of plywood. 
For the waterproofing, I went to visit 3 roofing material companies in the bay area and the smallest quantity I can order of EPDM or TPO is 500 sq ft (100x5ft rolls).
I will go for the Gaco liquid membrane (100% silicon): http://www.gacoretail.com/gacoroof.html. 

Does anyone have experience with this product?
Thank you,
John


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## Slashp (Apr 28, 2014)

To be more precise, I called Gaco and they told me that plywood was not an appropriate substrate... They were unclear whether it would work or not. They said that it would not be guaranteed if installed over plywood.

Did anyone use such a product on plywood?
Regards,
John


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## Robpo (Mar 30, 2014)

Slashp said:


> To be more precise, I called Gaco and they told me that plywood was not an appropriate substrate... They were unclear whether it would work or not. They said that it would not be guaranteed if installed over plywood.
> 
> Did anyone use such a product on plywood?
> Regards,
> John


I used something similar to there Gaco deck kit, was a long time ago. http://www.gacoretail.com/gacodeck.html?phpMyAdmin=8a1f99acb5bc36e9d848b2c3356446b0


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## Slashp (Apr 28, 2014)

My problem with Gaco deck (reading the instructions) are:

"The	deck	should	be	sloped	in	order	to	freely	drain,	preferably	to	a	drain	or	gutter	(see	Figure	4).	One-quarter	inch	slope	per	
foot is recommended. Slope is a function of structural design, and the GacoDeck Kit cannot be used to provide such a slope 
where it does not already exist. A deck that lacks adequate slope may experience leaks at low thresholds, standing puddles, 
or surface stains from ponded water and debris. Avoid soiling the fascia by incorporating a gutter or drain into your design. 
Insert drain flush with plywood. Install a positive drip so that drainage is outside the fascia."

I have maybe a inch over 12 feet of slope but that's it.


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## Slashp (Apr 28, 2014)

Hi all,

If I decide to installed corrugated white metal panels, do you know how I can prevent the rain water to come between the panels and the plywood at the roof border (Since the panels are not flat)?

Do I need to silicon caulk? Are there some plastic pieces that I can insert at the extremity of the panels to seal the holes?

Thank you for your help,
Regards,
John


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## 1985gt (Jan 8, 2011)

A commercial roofing contractor would have sold you the material in the size you need. For closures for the corrugated panels where ever you bought them from should have the foam ones.


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## mako1 (Jan 7, 2014)

There is a butly tape that goes on the seams between panels that seal them.At the edges you should have flashing or rake that goes over the panels and extends down over the fascia.There will be foam closures for the open ends that god under the flashing and between the ribs.Metal panels should still have at least a 3/8" slope.


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## Slashp (Apr 28, 2014)

Hi all,

Here is the finished product with the metal roof. Thank you all for your help 



















I also added 2 2x8s for horizontal bracing to make the structure sturdier.
John


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## listo (Nov 19, 2008)

Looks good, but the shade is over on the grass. Should have told the sun to shine at a different angle

Saskatchewan, near Saskatoon


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