Is ice and water sheild needed with a metal roof?

[NM_Shooter]

Trying to get stick framed and roof on this weekend... seems like ice and water shield is mostly needed for shingle roofs. 

What say ye?

-f-

[MaineRhino]

With a screw down metal roof I would use the ice & water shield. Every screw has the potential to cause a leak, IMO.

[MountainDon]

For a building that is going to sit there, unheated most of the time there's snow around I'd not bother.

[Redoverfarm]

Frank as they say it all "depends". Is there going to be guttering on the house?  Even with a metal roof and guttering there will be an Ice dam build up as the snow slides to the gutter and stops. Then freeze thaw it could back water up.  Although not that great amount any is too much in the ceiling near the sidewalls.  I would say at least make one run along the eves.  If you are planning a valley for a porch or room then definitely. A cheap investment for a little peace of mind.  

On the other hand if it is 10/12 pitch or greater and no plans to ever put up gutter then I would probably not.  

[MountainDon]

I believe that with a metal roof and the quantity of snow that falls up at Frank's ranch if he installed gutters this year, come spring he would find them on the ground or at best bent, twisted and hanging from the odd spike or screw.


I was thinking of using gutters to catch rain water. Then my neighbor up there showed me the twisted remains that came off his experiment during the first winter. I still want to catch rainwater but first need to figure out an easy method to remove and reinstall them, or hinge them so I can fold them up under the wide eves, or...

When/if I figure something out I'll do a show and tell here and install another cistern or two up there.

[Redoverfarm]

Don the installation of  "snow birds" would take care of the gutter damage.  But some say they too will fall victim to sliding snow on a metal roof.  The older style original snow birds were much better and lasted vs. the newer style which are no more than angled plexi-glass.  But the price of the original style birds are probably cost prohibitive on a cabin.  As an alternative I am going to find some 1 to 1-1/4" aluminum angle iron and affix it approximately 12" from the eves.  Aluminum can be painted to match the roof color.  Steel will rust.  I installed in on an outbuilding and periodically have to paint.

Yesterday a neighbor had gutters put on his house (cabin) and the contractor guarenteed it would withstand the snow.  The heavy hangers were put on at 16OC.  Maybe just a sales pitch but I have my doubts. We will see.

This is the modern version  http://www.snoblox.com/?gclid=CLHqlrH4sJwCFeFM5QodOgOPjg

These are the original http://www.worthpoint.com/worthopedia/12-antique-snow-birds-roof-snow-birds-l-k  

[MountainDon]

As an alternative I am going to find some 1 to 1-1/3" aluminum angle iron and affix it approximately 12" from the eves.  Aluminum can be painted to match the roof color.  Steel will rust.  I installed in on an outbuilding and periodically have to paint.

Got a photo of yours?

posted after your edit with the links above.....

[Redoverfarm]

Don I can take one but it will have to wait until tomorrow.  It's already dark on the east coast.

And by the way my fat fingers hit the wrong numerical symbol. It was 1-(1/4") not 1/3". 

[NM_Shooter]

Thank you for the comments....

will be a 6/12 pitch, no gutters.  No winter heat.  Don, I like the idea of swing away gutters.  Let's figure that out!

I'm collecting materials for a build this weekend.  The framed walls in my garage make quite a pile.  Lots more to go to load on.  Picked up the metal roof today. Heading back to Lowe's in 15 minutes to buy windows, sealing tape, possibly chimney components too. 

Yee ha.  Here we go.

[MountainDon]

Seems to always get dark early there, John.   


I can see how those snow birds/bloks work. Interesting. My preference is to allow the snow to slide off whenever it wants to simply to keep the load off the roof. Something about seeing 4 feet of snow up there bothers me. It would be nice to be able to collect all the melt from it though. 

[MountainDon]

I was curious so I checked on the Grace website (makers of Grace Ice & Water Shield). Below is a tidbit I found in their section of product application.

Check with the manufacturer of the metal roofing system for any special requirements when a
self-adhered underlayment, such as Grace Ice & Water Shield, Grace Select, Grace Ultra or
Grace Basik, is used under metal roofing. Do not install Grace underlayments directly under roof
coverings especially sensitive to corrosion, such as zinc, without providing proper ventilation.

I believe my metal roofing panels are galvanized under the paint job, so I wouldn't feel right about thinking the paint was going to protect the zinc.

Then in another (non-Grace) site I found a mention that when using metal roofing over the Ice & Water shield one should install roofing felt over the ice and water shield before applying the metal roofing.

And an incidental find. Here in the SW it is recommended to only use the butyl rubber types, not the SBS. The SBS can actually flow under high temperature conditions, whereas the butyl do not.

Also Note: Grace does sell a product ("Ultra") that can be used directly under metal roofing.

[Redoverfarm]

Most of the contractors here that use Ice shield do so only the portion next to the eves (or valleys)and then do use 30# felt over it and continue to the ridge.  So I guess it will sufice.

[Redoverfarm]

Don I almost forgot. Didn't get home until late and it was starting to get dark.  Been working on firewood most of the week.    I went ahead and took one which will give you the general idea. They are suppose to be white to match the roof but I put on some brown primer and never got around to painting them white again YET. Shoot it's  just a shed anyway.  BTW that is last years unused wood under the shed and to the left.  What I am cuting is for the next couple of years.

[MountainDon]

Thanks John. That's pretty much what I thought; I love pictures though. 

[bayview]

Hinged Gutter . . .