Redo small deck roof to Support Walk-on and Panels

[tk3000]

Some time ago, in a hurry, I laid down some 100watts solar panels on a small flat corrugated metal roof. There is a total of 4 100watts solar panels connected in parallel. The roof belongs to a small deck attached to the house and it lacks any sheathing. Below is an old pic depicting the situation:

I plan on installing a much larger array in this small roof and having them facing south at an angle by means of rails and a mounting system. Problem is that I need a roof with sheathing and a roofing cover that I can walk on (the corrugated steel gets all deformed and dented if one tries to walk on it). Any ideas on how redo this small roof? Plywood as sheathing?

thks

 

[Snoonyb]

Some time ago, in a hurry, I laid down some 100watts solar panels on a small flat corrugated metal roof. There is a total of 4 100watts solar panels connected in parallel. The roof belongs to a small deck attached to the house and it lacks any sheathing. Below is an old pic depicting the situation:

I plan on installing a much larger array in this small roof and having them facing south at an angle by means of rails and a mounting system. Problem is that I need a roof with sheathing and a roofing cover that I can walk on (the corrugated steel gets all deformed and dented if one tries to walk on it). Any ideas on how redo this small roof? Plywood as sheathing?

thks

What are the structural components of the roof?

 

[nealtw]

I don't like the transition from the other roof.

 

[tk3000]

What are the structural components of the roof?

I am not really sure about the structure of this small attached deck roof, but it seems that it only has rafters, some support blocks linking some of the raters. The pic below shows a view from inside:

Some spots in the metal roof panels have had some damage in the past: dented and deformed which then caused some leaks. But I was wondering about using some osb as sheathing, but then the question of increasing the height of the roof and thus eliminating whatever small slope it may have crops up? And what type of roof material: something quick and easy as metal or pvc roof panels without the issues of denting and deforming?

thks

 

[tk3000]

I don't like the transition from the other roof.

Hmmm.. Are you talking about the transition from the epdm membrane (allseason room) besides the small deck's roof (that is was done in 2010 by the roof company who redid the roof of the whole house, etc)?

 

[Snoonyb]

I am not really sure about the structure of this small attached deck roof, but it seems that it only has rafters, some support blocks linking some of the raters. The pic below shows a view from inside:

Some spots in the metal roof panels have had some damage in the past: dented and deformed which then caused some leaks. But I was wondering about using some osb as sheathing, but then the question of increasing the height of the roof and thus eliminating whatever small slope it may have crops up? And what type of roof material: something quick and easy as metal or pvc roof panels without the issues of denting and deforming?

thks

Structural members or components are what it's made up of, in this case 2X4 rafters @ 24"oc, no header and 4X4 posts.

What you do not have, in any stretch of the imagination, is a walkable roof.

We can tell you how to create a walkable roof that would withstand the additional loading of a solar array, however your local building dept. will probably have a hand out which we can assist you in applying to your dwelling.

 

[bud16415]

I have to be completely honest here and I don’t like anything about the small shed roof you have now. I’m actually quite surprised it makes it thru a northern winter. It is way under structured and unsafe to be on or for that matter under. We see a lot like that for temporary sheds for storing firewood and such. I could go into all the problems I see but I really don’t think it can be made safe. If it were mine I would carefully take it apart and you could reuse the materials including the roofing but with a totally different method of building.

 

[nealtw]

Hmmm.. Are you talking about the transition from the epdm membrane (allseason room) besides the small deck's roof (that is was done in 2010 by the roof company who redid the roof of the whole house, etc)?

Ah, Ah, AH, Lets leave the transition for some one like OLdog to comment on.
There are about 5 ways you could structure something like this, some for utility and some for looks and what you have is non of those.

Sorry but that is a tear down.
I'll bet that the 4x4 is just siding on the deck.

 

[oldognewtrick]

There's nothing about the structure that's suitable for any kind of roofing. To low of a slope. Lower roof over the shingle roof. No suitable decking or ability to apply a waterproof underlayment.

Frame rafters that tie into the shingle roof to give a minimum pitch of at least 4/12, and have battens running across the rafter to give lateral support of the metal panels, would be a good place to start. The transition at the shingle roof should have a pitch change flashing with "Z" bar and butyl tape to make it watertight. investing in new metal would be a great investment. What you have will not be serviceable.

 

[nealtw]

This guy looks at two approaches to attaching to the house, neither are to the fascia and there is a beam on top of the support posts.
[ame]https://www.youtube.com/watch?v=CbXw518CRHU[/ame]

 

[nealtw]

We can't talk about this with out questioning the roof on the addition too. I would like to see a photo in the attic of both the underside of this section and the underside facing the addition.

 

[tk3000]

This guy looks at two approaches to attaching to the house, neither are to the fascia and there is a beam on top of the support posts.
https://www.youtube.com/watch?v=CbXw518CRHU

This would be too much work for me right now, I really dont want to touch the shinges at the main structure. Besides my needs are much more modest: good structure and support+ water proofing+drainage. But a good reference!

 

[tk3000]

Thanks for all the insights! So, this was a very sloppy job and ultimately I am screwed with this small roof deck..

I have worked on a flat epdm roof before, replacing sheathing and damaged rafters using sister rafters, etc. But I totally dislike the epdm: it seems that the woodpeckers and other creatures can easily damage it.

Below is pic showing the deck sideways along with its 3 4x4 posts. Do the posts seem adquate to support the roof with short span?

Snoonyb: yep, I realize it is by no means walkable... 99% of the people don't buy permits for this type of work,so I am not the one who will. But I will always observer the code and best practices. Besides, based on the comments herein, it seems that this roof deck does not meet any code...

bud1641, oldog: thanks for being straightforward. Would you say that replacing the roof deck, adding osb sheathing, and the replacing the roof panels would suffice; or does it entail replacing the 4x4 posts for this small span roof?

nealtw: I will get a pic from the attic soon

 

[oldognewtrick]

If your plan is to add solid decking, then install roof panels, Put a layer of Ice and Water Shield over the wood decking before you install the panels. This isn't the perfect scenario, but better than direct to deck with no moisture barrier.

 

[nealtw]

This would be too much work for me right now, I really dont want to touch the shinges at the main structure. Besides my needs are much more modest: good structure and support+ water proofing+drainage. But a good reference!

So we want the strongest structure you can get on a very tight budget.

Things to be concerned with.
Posts: subject to frost if not mounted on a footing deeper than frost level.
Cheapest insurance perimeter drain even if not deep enough will keep water away from deck and eave trough when done.

Average snow load; you can look that up for your area, may not be the same as what you got last year.
Height, I think Oldog suggested it should be about 3 or 4 inches lower than the main roof.

 

[Snoonyb]

Snoonyb: yep, I realize it is by no means walkable... 99% of the people don't buy permits for this type of work,so I am not the one who will. But I will always observer the code and best practices. Besides, based on the comments herein, it seems that this roof deck does not meet any code...

I understand about the reluctance to obtain permits.

The other part of the recommendation, is to avail yourself of the opportunity to broaden your knowledge base.

The handout is free.

If you intend to "temporarily" beef up this roof, because the 2X6 the rafters are attached to, that is nailed to the 4X4's, and otherwise unsupported, should have a 2X4 nailed to the outside of the 4X4, underneath the 2X6.

Correctly attaching this to the dwelling has nothing to do with any part of the attic.

 

[slownsteady]

Hey TK, aren't you happy you asked?

 

[slownsteady]

Just throwing this out there for thoughts: what about something freestanding?

 

[nealtw]

OK the cheap fix.
At the top end they have hangers, good, With hanger you can see there are a certain number of nails holding the rafters to the fascia.
The problem is if the deck does move up and down with the frost or loading the 2 nails from the fascia to the house rafters will give up at some point. So we will want to remove the soffet install
The half hanger on each side of the rafters to the back of the fascia.
Replace the soffet.
On the other end, Well first.
Confirm that the posts are supported to something below, not just sitting on deck board, right over a floor joist would be a plus., Check the lower portions for rot by stabbing it with a screw driver.
Explain the construction there or take pictures.
More after you get this info.
This hanger is a Simpson L30.
You would like to have the roof reach out and match the add on roof?
Stand near the center post on the yard side and take a picture of the side of the roof of the add on building. Just want to see what the over hang looks like on that part of the roof.

 

[bud16415]

What you have is closest to pole barn construction. You can google that and see many examples of how the tin roofing is supported without sheathing. They have rafters or trusses in a pole barn and then on top of them they run purlins. The purlins are nothing more than 2x4 or 2x6 laid flat and attached to the rafters to support the tin. It is the cheapest way to do it and lets air circulate all around the framing and tin. The way yours is the tin slopes away from the rafters at the top and is supported by nothing the lower area is only supported where there is a rafter. So steping between rafters you are about to go right thru it.

Your posts are most likely ok and if they haven’t heaved yet they are most likely deep enough. The lower deck is fine. I would remove the tin and the rafters and the hangers and get all that out of there. You could always shorten the 4x4 poles to give more pitch and put a new support for the rafters to land on lower down. The way it is attached to the house we have no idea what it is attached to based on the rest of the construction, I’m guessing just the fascia board and we have no idea if its structural or not and as mentioned it is too high and joining the roof like that is asking for trouble in an area where you get snow and freezing and melting cycles. You will get an ice dam and water will melt off the main house run down and pool and then enter back into the house, or at least rot your overhang. I would want the tin roof under the overhang of the main roof or even not touching the house at all and that would require a few more poles. Once you are not attached to the house though you don’t have the stability from the house and need to have your poles diagonal braced a few places to prevent racking.

Last fall I built a fast and dirty roof over my hot tub for winter with a tin roof I did it free standing and left it 6 inches from touching the house and gutter. When it’s raining you get a little rain at the gap but it’s not that bad and I know it is not hurting the house at all.