Titanium is a brand name of an underlayment that comes to mind and is what was used on our build. It is self adhering and its elastisity allows it to expand and contract w/ temperature changes. It is meant as an underlayment that can actually stand alone when drying in a house when the roofing cant be applied right away. It is guaranteed to be able to sit through a winter, doesn't wrinkle like felt, and remains an excellent underlayment when finally covered w/ the roofing.

It's my understanding that w/ standing seam roofs, an ice shield is not neceesary for the overhangs,vallies,along roof to wall connects,etc, but imo, it cant hurt either. You definetely want to go overkill w/ a roof as its as important as flashings in keeping your house dry, that's why imo, a quality underlayment is key for the roof as well as the walls.

If your contractor has the"it's only a shed" attitude, i would give him an attitude adjustment by stating he needs to remove the now wrinkled felt and get a quality underlayment the wont wrinkle and will hold up before roofing it. A shed stores valuables as a rule and needs to be dry.

As far as applying over ice and snow(if i read you correctly), What is this guy thinking?

I should have stated that w/ self adhering underlayments such as titanium, even though self adhering, should be nailed off w/ cap nails.

Another thought: Find yourself a quality minded contractor. Imo, this one has definetely already failed your test!

covered with ice and snow [membrane] Now that would be a good way to go! The 15 lb will be useless under a metal roof. Most recently, I used 30 lb under 30-year asphalt shingles. But the lifespan of a metal roof--up to 75 years for copper--justifies a much better material. So you won't have to re-roof till the 2080s. :-)

30 # is great, been around forever, and still used in a lot of my projects. 15# is ok as an underlayment under sidings, but 30# should be a minimum for roofs and both these felts should only be used if they can be covered up immediately w/o too much exposure time to the elements, especially concerning "wet".

"This contractor put 15# tar paper over OSB decking that was covered with ice and snow".

Did he put the 15# over ice and snow shield(membrane) or literally over snow and ice?

If the latter, again, What was this guy thinking?

sierraeast: I need something like the Titanium for a workshop building. Is it good under asphalt 3-tab shingles? I might want to delay a few weeks before putting the shingles on.

Oh, and is it readily available, in smallish quantities? Bldg. is about 400 sq.ft. with a 4:12 roof pitch.

thanks, in advance.

Hi pheonix, It is generally available from roofing suppliers and you can also usually purchase it from roofing contractors. I've never seen it in the big box stores although i never asked at the pro desk if it could be ordered. The rolls are 200/sq.ft rolls, so unfortunately you would need three, as your roof sq footage will be more than the sq. footage of the building w/ the pitch as well as if you have overhangs.

30# saturated felt is fine so long as it doesn't get wet for a time. A little raining on wont hurt it, but several days rain will. It causes the felt to wrinkle which would be a problem to shingle over.

On our build, i framed our house and asked the roofer to felt it for the winter as it was getting too cold to shingle. He used an untried underlayment that was wrinkle free when setting and was geared to go 6 months or so w/o covering. It turned out the products weakness was u.v rays and failed at the plywood seams, leading to a wet subfloor when we returned in the spring. He then around that time started using titanium on his projects w/o u.v failure and w/o wrinkling which is what he replaced our underlayment with. I was real impressed with this product and can only wish it had been used in the first place. So as the story goes, not all of the newer underlayments hold up to their claims. I also wished i just would have had 30# felt put up and then replace it with new 30# or titanium when it came time to shingle. Oh well. part of the learning curve. If you are in cold,wet,snow country, i would make the effort to locate some titanium. If it looks like you will be high and dry for the time you want to leave the underlayment exoposed, 30# felt is fine. As far as costs, you might consider just felting regardless of the weather and replace that felt when the time comes w/ new 30# felt as you dont have a large roofing project there, and replacing the felt would be a lot less than the titanium underlayment as it's considerably more than 30# felt. I believe 30# felt is 300 sq.ft rolls, so you would need two rolls.I could be off on the sq. footage in a roll on both underlayment types so be sure to inquire during your search. It's also a good idea to use cap nails to fasten the underlayments on both underlayment types, not relying simply on staples.

sierraeast: thanks a lot for all the details. I've got another small outbuilding I could use the Titanium on, too. I'll look into it a little more. You might be right about just using the heavier felt and replacing it. Climate here is unpredictable, but a good bit of winter rain.

Thank, again. I'll print your post to work off of.

Here's a link to titanium's website

Here is a link that might be useful: titanium

Here's a link that might interest colorado80116

Here is a link that might be useful: standing seam