Roofing question

[Wooden Skye]

I have a small section of deck that I would like to cover (probably 8'x8' haven't taken precise measurements yet) and am thinking of doing the following.  My reasons for this are two fold.  The first reason is to provide my dogs with some cover when they are outside.  The second reason is that when it rains or snow melts, it leaks very badly into my shop, essentially reducing the size of usable space.  Now I know that I should have repaired properly, but this will probably require tearing down a section of the house, but as we save to do an addition, a temporary fix or at least some improvement is my goal.

So now for my plan:

I am going to install PT 2x4 against the house, with a bottom plate and top plate.  I will cut the 2x4's at an angle to help create a slope.  Against the edge of the deck, there is a privacy fence and I am planning to do the same.  Right now I think the height will be about 6 feet tall.  I am then planning on sheathing the roof and laying tar paper and shingles and flashing.  So now for my questions.

Would I be better using metal or PVC roof panels instead of shingles?
If I want to ensure that water rubs from the house to the deck edge, what amount of slope do I need?
Since it isn't structural, would 1/2" sheathing be alright, or should I use 3/4"?
Would adding a gutter and downspout be needed?

Now I realize that rain and snow doesn't always fall the same direction, would enclosing the front about 6 of the 8 feet be a good idea or unnecessary.  Nobody will see this, would tyvek be enough of a water repellent on the front or should I just paint the exterior sheathing?

Any advice would be appreciated, if I am completely out of my mind thinking this would work, please tell me.

Thanks
Bryan

 

[tjbnwi]

Please take some pictures and post them. It will make it much easier to understand your situation.

Is it allowed in your area to place the structure on the fence? Most areas have set back requirements.

This is structural, it is holding something up, including (per your post) a snow load.

Consider corrugated fiberglass roof panels. No sheathing or shingles needed.

1/4" per foot of slope is the minimum for most run off.

Shingles require a 4/12 pitch.

Tom

 

[Wooden Skye]

Tom

Thank you.  I will take a few pictures tomorrow.  I won't be attaching to the fence just butting up against the fence.  The setback wouldn't be an issue, because of the driveway and the deck doesn't extend past a portion of the house.  Thanks for correcting me on the structural issue.  I will check into the corrugated fiberglass panels. 

Bryan

 

[tjbnwi]

Look at ploycarbonite also. Lowes in your area may have them.

http://www.eplastics.com/Corrugated-Fiberglass-Panels

Tom

 

[wow]

I suspect that 2x4's on edge will not meet your structural requirements. 2x6 (on edge) probably will. Depends on your snow load, and how they are supported.

If you have a Menards near you they will help you design it and print out a materials list for you - all for free. HD & Lowes may do the same thing, but I've never checked.

I'm sure none of us is going to come check, but I also suspect you'll have to pull a permit and have it inspected for safety reasons unless you're fairly rural. You can make an anonymous call to your municipality's building department to find out before you start. If you're concerned about them identifying you via Caller ID, either call from work or a public place and don't give 'em your name or address to start.

 

[Stone Message]

I am not a roofing engineer but I have built a few roofs.

If the structure is to be open then you have a lot more options as far as the design and materials go.

For an 8x8 structure 2x4 timbers will be perfectly okay. The barn that I built 6 years ago is made of 2x4s with a heavy agricultural standard corrugated roof. It is about 9x5 metres and about 4.5 metres high.

With high falls of snow the pitch should be raised to 35-45 degrees and some extra rafters and purlins would be useful.

I built a shed 27 years ago and it has withstood 2 hurricanes and a few moderate falls of snow. The roofing material was Onduline (available world wide) and as it was so good I used the same stuff when I re-roofed it a few months ago.

For the amusement of the professional roofers out there I will link the video that I made of the shed re-roofing process.



Peter

 

[tjbnwi]

I am not a roofing engineer but I have built a few roofs.

For an 8x8 structure 2x4 timbers will be perfectly okay.

Peter

The maximum span for a low pitch SPF nominal 2x4 (effective 6/1/2013) rafter 16" on center is 6' 7" in his snow zone.

Tom

 

[wow]

I am not a roofing engineer but I have built a few roofs.

For an 8x8 structure 2x4 timbers will be perfectly okay.

Peter

The maximum span for a low pitch SPF nominal 2x4 (effective 6/1/2013) rafter 16" on center is 6' 7" in his snow zone.

Tom

I didn't look up his snow-load info, but your numbers sound right, Tom. No way would I go (or allow) an 8' span on a 2x4. And if he wanted to do 24" o.c. spacing (which I assumed since it's kinda the standard truss and rafter spacing) I suspect the load would only allow about a 5 foot span.

 

[tjbnwi]

I am not a roofing engineer but I have built a few roofs.

For an 8x8 structure 2x4 timbers will be perfectly okay.

Peter

The maximum span for a low pitch SPF nominal 2x4 (effective 6/1/2013) rafter 16" on center is 6' 7" in his snow zone.

Tom

I didn't look up his snow-load info, but your numbers sound right, Tom. No way would I go (or allow) an 8' span on a 2x4. And if he wanted to do 24" o.c. spacing (which I assumed since it's kinda the standard truss and rafter spacing) I suspect the load would only allow about a 5 foot span.

SPF nominal 2x4 is 5'9" span @ 24" o.c. effective 6/1/2013. Trusses are most often 24" on center, stick built in my are is 16" o.c. for sawn lumber 19.2" o.c. for engineered lumber.

Tom

 

[Wooden Skye]

Here are some photos of the area I would like to cover.  The stuff in the photo will be cleared out.

 

[tjbnwi]

Need photos of the entire area showing, home, deck, fence in one shot please.

The fence appears to be 5' or less from top to finished floor.

Tom

 

[Stone Message]

The maximum span for a low pitch SPF nominal 2x4 (effective 6/1/2013) rafter 16" on center is 6' 7" in his snow zone.

Tom

I understand that you get a lot more snow than we would expect here - many thanks for the technical update.

Just for interest I have attached a couple of pictures of the barn showing the truss arrangement to cover the 4.5m span using 4x2 timber - this was subject to a local authority inspection (similar to US Code system I assume). Most of my joints were mortice and tenons - I would use the DF700 next time.

Peter

 

[tjbnwi]

Truss and rafters are two different animals of the same breed. I've seen 2x4 trusses on a 60' span. You can't compare the two.

As Wooden Skye describes his project, it is a single pitch roof. If he were to truss it he would have to do a W web ladder truss, it would not be the practical solution in this case.

Tom

 

[Wooden Skye]

Not trying to be difficult.  That picture would be hard to do.  This level of the house is at street level in the front, but is more like the second level in the back (which is where we are talking about), taking a picture with everything you mentioned you won't see anything, because I would be on the ground shooting up to the second floor.  In the 3rd picture, the other side of the fence is the driveway, which is about 9 feet below the bottom of the fence.  

I measured this morning and it is 8x7.  In the town I live in you can build temporary structures less than 12x10 without permits.  I have a friend that is a contractor and may just have him come look at it, or just do something like a 2" raised platform as a cover.

 

[tjbnwi]

The area you are trying to keep dry is below this deck?

Tom

 

[Wooden Skye]

Yes, the area in the picture is the front corner of the garage which is unusable for cars, but I use as my workshop.  I would like to try and keep dry, so I can store some wood without it getting soaked when it rains or snow melts.  I have a lumber rack on the wall with a tarp over it, but no sheet good storage.  I would also like to be able to put a couple machines that get little use in that area as well.

 

[tjbnwi]

I would suggest redirecting the water under the framing rather than building a roof over the deck.

Use shower pan liner to collect and redirect the water that comes through the deck. You need to create a pitch as you install the liner, collect the water in a gutter then off to the yard. Here is a link for some pictures of how I accomplish this;
https://picasaweb.google.com/tbadernwi/ScreenedPorch

In your case I would go to the bottom of the joists using 1x to secure the liner. Maybe some tarps you can roll up around the sides to block some of the sideways rain?

Shade for the dogs, look into a retractable awning. You would not have to cover the entire surface with the awning, just and area for their comfort.

Tom

 

[Wooden Skye]

Tom

Thanks, the shower pan liner is an interesting idea and definitely investigate further and see where I can get the materials.

Bryan

 

[tjbnwi]

Tom

Thanks, the shower pan liner is an interesting idea and definitely investigate further and see where I can get the materials.

Bryan

Home Depot here has it in bulk. You purchase it by the lineal foot.

You have to cut it on a tapper. Work off the center line for the first piece, use a roofers hook blade (shown in the photo) to make the cut, run on the solid edge of a guide rail.

It works extremely well. Make sure you have a pitch away from the house and plan how you're going to collect the water and divert it. The one in the photos has a trough gutter hidden in the beam wrap with the down spout hidden in the post wrap. 

Photos of the bottom of the deck would help.

Tom

 

[Wooden Skye]

Tom

I stopped by Lowes and they had it by the foot and precut 5'x6' packages.  We are supposed to get rain tomorrow and Saturday so I am going to try and accurately determine where the leaks are.  Maybe a real simple solution will present itself.  What you showed I would have to do it in the garage ceiling, but it wouldn't take away any of the limited headroom.  I also looked at a product called deck drain, but doubt that is a viable option, since it would be harder to get the water out of the garage.