# Can i screw metal roofing directly to joists?



## jlhaslip (Dec 31, 2009)

You will need support underneath that runs perpendicular to the ribs on the panels, so, yes, you will need to install 1 by's across the joists to screw the panels to unless the joists are perpendicular to the ribs (unlikely).


----------



## Bud9051 (Nov 11, 2015)

Sheathing over the rafters is a structural component and when not used, just a metal roof, cross bracing may be necessary as the metal does not provide enough. Being just a 12' patio cover may require less, but you don't want that metal blowing away. A 70 mph wind can rip things apart very easily and in some locations the winds are much stronger.

As for the 1x? on top it provides a much better attachment as ribs and valleys don't always land on a rafter.

Bud


----------



## BigKielbasa (Feb 27, 2017)

Bud9051 said:


> Sheathing over the rafters is a structural component and when not used, just a metal roof, cross bracing may be necessary as the metal does not provide enough. Being just a 12' patio cover may require less, but you don't want that metal blowing away. A 70 mph wind can rip things apart very easily and in some locations the winds are much stronger.
> 
> As for the 1x? on top it provides a much better attachment as ribs and valleys don't always land on a rafter.
> 
> Bud


Just one more question Bud. I want to start putting up the 2x6 joists today. I need to figure out how much room to leave? Like i guess total thickness would be 3/4" + another 1/4" for the metal panel? 
So do i leave about 1 1/4" between top of joist to the underside of the endwall flashing?
Sorry for noober questions, first time doing this!


----------



## jlhaslip (Dec 31, 2009)

BigKielbasa said:


> Just one more question Bud. I want to start putting up the 2x6 joists today. I need to figure out how much room to leave? Like i guess total thickness would be 3/4" + another 1/4" for the metal panel?
> So do i leave about 1 1/4" between top of joist to the underside of the endwall flashing?
> Sorry for noober questions, first time doing this!


Is this roof attached to an existing roof?

If so:

1. consider the height of the ribs above the strapping. Likely around 3/4 inch or thereabouts.
2. allow foe a piece of flashing to run under the existing roof material and over top of the new roof so wind doesn't blow water into the gap. Allow for 4 to 5 inches of overlap.


----------



## BigKielbasa (Feb 27, 2017)

jlhaslip said:


> Is this roof attached to an existing roof?
> 
> If so:
> 
> ...


No, its not attached to an existing roof. I am assuming the endwall flashing goes on top of the ledger board? and gets screwed to my vinyl siding? So i was thinking about leaving about 1.5" from bottom of endwall flashing to the 2x6 joist?


----------



## Bud9051 (Nov 11, 2015)

Remember I'm giving advice with my eyes closed as I'm not there to see your project.
I'll list some thoughts.
1. Posts need to be anchored according to local code requirements. Tornado alley have tougher regulations than where I live. Also, use hurricane brackets on the rafters to the header running post to post as well as header to post.
2. I would add some diagonal bracing across the bottom of the rafters to take the racking forces off of the panels.
3. You should flash the top edge to wherever it is attaching (as jlhaslip just mentioned) to prevent snow and rain from blowing past. Hard to advise how to do that without some pictures.
4. Also as jlhaslip mentioned those ribs are more than 1/4 inch.
5. Screw length will depend upon where you install the screws, on the flat or through the rib. The screws have a rubber washer and leakage isn't super critical for a patio so through the flat can be easier.
6. If you have soffit ventilation you need to be sure it is not blocked by the roof or snow accumulation.
7. Your patio roof to house attachment needs to meet code as well. Local requirements vary so unsure what you need.

Bud


----------



## jlhaslip (Dec 31, 2009)

You will need to flash above the roof as well in order to stop rain from getting to the ledger ans dripping onto the patio.

*edit*

See Bud's reply above.
Agreed with screwing to the flats. The screw pattern will be determined by the manufacturer. Most of the time, unless otherwise directed, screw beside every rib, not on both sides of the rib to allow the sheet to move with heat/cold. The ribs allow for the movement and if they are screwed down on both sides, the movement doesn't happen properly.
Video shows one manufacturer's method here:


----------



## BigKielbasa (Feb 27, 2017)

jlhaslip said:


> You will need to flash above the roof as well in order to stop rain from getting to the ledger ans dripping onto the patio.
> 
> *edit*
> 
> ...


Doesnt look like the sealant tape does much? what is it for? Is there another piece that gets layed before the tape?
here is some pics of my project


----------



## jlhaslip (Dec 31, 2009)

It is used to hold the foam bug screen in place. I have ever seen it actually installed.


----------



## Bud9051 (Nov 11, 2015)

If this is a permitted project and you are going to have an inspection then now would be a good time to talk to them. I don't believe just lag bolting through the siding will meet their approval. If no permit, well I don't know, that approach can come back in the future at 10x the cost. If a permit is required and you do not get it and the related inspections then any storm damage or damage to other property where that roof lands may not be covered by your insurance.

Always difficult for us to provide advice after a project has started and especially if it is not permitted when required.

Bud


----------



## BigKielbasa (Feb 27, 2017)

Bud9051 said:


> If this is a permitted project and you are going to have an inspection then now would be a good time to talk to them. I don't believe just lag bolting through the siding will meet their approval. If no permit, well I don't know, that approach can come back in the future at 10x the cost. If a permit is required and you do not get it and the related inspections then any storm damage or damage to other property where that roof lands may not be covered by your insurance.
> 
> Always difficult for us to provide advice after a project has started and especially if it is not permitted when required.
> 
> Bud


What are you talking about Bud?? How else do you attach a 2x10 to the side of a house with siding?


----------



## drtbk4ever (Dec 29, 2008)

I can't tell from the pictures, but what are you using as a beam on the lower end of that roof? 


Sent from my iPad using Tapatalk


----------



## kwikfishron (Mar 11, 2010)

BigKielbasa said:


> How else do you attach a 2x10 to the side of a house with siding?


The ledger needs to be attached to the sheathing, not the siding. The way you have it is a leak from day one and after a few years the wall behind it could very likely be a rotted mess. The roof to wall flashing detail is one of the most important steps with a project like yours and should not be skipped.


----------



## Bud9051 (Nov 11, 2015)

As Kwik said, it has to be flashed in properly. As for the lag bolts they may be allowed if they hit a stud, but to avoid hitting wires the depth would be limited to 1.5" which may not be enough. Attaching to the sheathing only would not be sufficient unless backed up in an approved manner.

With that ledger board extending over the rake board it gets complicated. One thought would be to install a proper ledger short of the rake and then another ledger board over that one, spaced as necessary, to become the extension.

Looking at the pictures again, that ledger over the sliders and single door could have a header behind it which might provide sufficient depth for lag bolts. But your code might require bolts with washers and nuts. I'm more familiar with deck ledgers so unsure what you actually need.


----------



## BigKielbasa (Feb 27, 2017)

Bud9051 said:


> As Kwik said, it has to be flashed in properly. As for the lag bolts they may be allowed if they hit a stud, but to avoid hitting wires the depth would be limited to 1.5" which may not be enough. Attaching to the sheathing only would not be sufficient unless backed up in an approved manner.
> 
> With that ledger board extending over the rake board it gets complicated. One thought would be to install a proper ledger short of the rake and then another ledger board over that one, spaced as necessary, to become the extension.
> 
> Looking at the pictures again, that ledger over the sliders and single door could have a header behind it which might provide sufficient depth for lag bolts. But your code might require bolts with washers and nuts. I'm more familiar with deck ledgers so unsure what you actually need.


thanks Bud! One more question. Should i use pressure treated 1x to screw onto joists? or can i use regular pine? or spruce?


----------



## Bud9051 (Nov 11, 2015)

Your question opens up another box of questions.
Depending upon the chemicals used to treat your PT lumber the fasteners you can use (and have used) can vary. So start with what type of screws are acceptable with the rafters you have. There may be a tag on one end or the store should have that information. Don't just go with the "oh these fasteners will be fine" you need the ones the mfg requires.

Now, as for using PT strapping on top vs regular strapping I'm not sure if there is a code issue or not, but by avoiding the PT you eliminate some of the chemical and fastener issues. Although the regular fasteners have a rubber seal they can leak over time, especially without the added diagonal bracing below. But it would be minimal and take some time to deteriorate the wood.

others here may have better advice on this so let's see what they say.

But do determine what should be used for your PT wood.

Bud


----------



## BigKielbasa (Feb 27, 2017)

You can use pressure treated, but you have to put down a barrier between, it cannot touch the panel. I bought white primed 1x4 instead


----------



## ktmrider (Apr 3, 2017)

I think instead of asking questions about the metal roof I would back up and attach your ledger board up right, you need to pull a couple of courses of siding off so you can flash it right,than cut siding around ledger board, and it's hard to tell but it looks like the roof is too high and is going to hit existing soffit, you have a mess I would do a little more research before going on


----------

