roof over deck

[FSHKPR]

planning on putting a roof over half of our deck. then plan on screening that part in later on. the finished size of the roof will 12 feet out from the house, and then run 23 feet down the house. my question is, are 2x8s strong enough to span 12 feet? i planned on nailing 2 2x 8s together to make a beam front and back, then tonailing these to the tops of the 4x4 posts. then using joist hangers to run the joists(rafters). there will be about a 8 inch pitch from back to front. i was then going to cover with 5/8 treated plywood and cover with rubber. i already planed on running a support down the middle in the winter to help handle the snow. any thoughts on this? am i on the right track? . oh also this is for the trailer up north, that is not on a foundation. so i want to keep it unattached from the trailer. both deck and trailer are freefloating. thanks

 

[ae708]

Re: roof over deck

I think if you run the joists 16" OC then 2x8's should do the job just fine for 12'. Just make sure that you have enough pitch to shed the snow up there. Piled up snow gets mighty heavy. I think that if you add a support beam,as you say, during snow season that you'll be safe.

 

[beniam]

Re: roof over deck

A 2 by 8 at 16 inches on center will give you a load of 60 pounds per square foot. 2by8 at 24 in spacing will be 40 lbs per sq foot. Aslope of 8 inch over 12 foot will let snow accumulate. <br />How about a V roof,slope 4 inch for each foot?<br />You might want to go to the library and look for a handy guide on framing. <br />Good luck. Batavier

 

[notinbig]

Re: roof over deck

Why not buy an awning? We have one and it is the greatest thing since sliced bread, and the sell screen kits for em.

 

[Barlow]

Re: roof over deck

FSHKPR .. If you send me an e-mail with the exact spec's and measurements I'll run the calculations for you and give you a real design criteria..<br /><br />-BUT-<br /><br />If you plan to disregard it and want "beer-bottle" engineering don't bother and I won't waste my time either..<br /><br />just being upfront and honest about it... <br /><br />I'm willing to help out .. but only if taken seriously.. Yes,its a simple "shed" roof but your spans, loads and fastenings are in for a little work-up.<br /><br />BTW/FYI - the above posts are totally inadaquate and incorrect.. ..

 

[deputydawg]

Re: roof over deck

It has been a while since I realy figured this out but from the basic charts on wood loads you will be OK. If I remember right the charts show 1x8's on 16" (for floor joists) will hold up to 30 to 40 pounds per square foot for up to 13' 1" span. <br />Go to your library and see if they have a book on residential framing. In these books they will have lumber charts showing the load capacity for each type of wood (ie: pine etc.) <br />Covered with the plywood and rubber roofing you won't have that much of a dead load per square foot. The snow and wind will be the problem. It will depend on how much snow will collect. One center header would decrease your span to 6' but will take away head room. Check the price of 2x10's in your area and remove the doubt. Here they are not much more per board foot that 2x8's right now. If you use 2x10 rafters you could probably back off to 1/2" plywood or OSB at about the same cost.

 

[notinbig]

Re: roof over deck

Hey Barlow, whats wrong with buying an awning. I got a sunsetter and it's great, then I roll'er up in winter!

 

[Barlow]

Re: roof over deck

Originally posted by nothinbig:<br /> Hey Barlow, whats wrong with buying an awning. I got a sunsetter and it's great, then I roll'er up in winter!

pardon nothinbig .. wasn't refering to the awning .. should've edited and clarified a bit..

 

[Link]

Re: roof over deck

I would take Barlows advice and help if your planning on enclosing it.<br /><br />Barlow did you pick up on the fact that he is going to use 2 2X8s on each Joist?<br />I missed that the first time I read it.<br /><br />nothinbig <br />Those are so cool. We are going to put one of those up out at my MILs cabin. Its only used a couple times a month but weather isnt always on our side to sit out on the deck and watch the Puget Sound. Warm enough but that wet sun-shine we get here suxs!

 

[Barlow]

Re: roof over deck

Originally posted by Link:<br /> ...<br />Barlow did you pick up on the fact that he is going to use 2 2X8s on each Joist?<br />I missed that the first time I read it.<br /><br />...

well thnx for the vote Link ,, hmmmm..<br /><br />

Originally posted by FSHKPR:<br /> I planned on nailing 2 2x 8s together to make a beam front and back.... , then tonailing these to the tops of the 4x4 posts. then using joist hangers to run the joists(rafters)...

Ya might've second guessed yourself Link (?) the way I read it is that the double 2x8 ("2 2x 8s" as typed in FSHKPR's post) will be the beam in which the hangers are applied to..

 

[deputydawg]

Re: roof over deck

Hmmmm, I read this almost wrong too. How far apart are the 4x4 posts going to be? Consider treating them for termites and weather rot. <br />With that slope you will probably get by but it might not last too long. Go with Barlow and get his design specs. By running the figures doing it right you will probably come out the same price if not a little cheaper, and it will last longer. <br />Except for the double 2x8's top and bottom it looks like it should hold up without trouble, but I don't know how much snow you see in a typical winter. <br />Also remember if your in a very wet area the 2x8's stuck together will make an excelenmt place for moisture to gather and rot to start. You need some air circulation to allow them to dry. At least in my neck of the woods this is a problem.

 

[Link]

Re: roof over deck

Originally posted by Barlow:<br />

Originally posted by Link:<br /> ...<br />Barlow did you pick up on the fact that he is going to use 2 2X8s on each Joist?<br />I missed that the first time I read it.<br /><br />...

well thnx for the vote Link ,, hmmmm..<br /><br />

Originally posted by FSHKPR:<br /> I planned on nailing 2 2x 8s together to make a beam front and back.... , then tonailing these to the tops of the 4x4 posts. then using joist hangers to run the joists(rafters)...

Ya might've second guessed yourself Link (?) the way I read it is that the double 2x8 ("2 2x 8s" as typed in FSHKPR's post) will be the beam in which the hangers are applied to..

KO your correct... <br />Only knowing enough to be dangerous in this area I always get advice from people who know what they are doing.