Underlayment for Metal Roof

[ustmd]

After the last set of storms, we are going to replace our roof.

Currently we have asphalt shingles, but are strongly considering going to a standing seam metal roof (my wife figuring that I still have a few organs to sell on the black market to pay for it :laughing. I have had the parade of roofers this week discussing both shingles and metal roofing.

One of the top contenders for the metal roof mentioned that as their SOP for all metal roofs they use the synthetic material (similar to the ice dam/flashing material) as the underlayment for the entire roof (vs using felt paper).

Given that I am in Central Texas, ice dams are not an issue. Is this really a value add or just a sales point on their part?

Aside from the standard stuff for roofing (I am having everyone quote a complete tear off), are there any critical questions I should be asking the potential roofers?

For those of you outside of Texas, any yahoo with a coil nailer can call himself a roofer. It is a "buyer beware" situation.

 

[jfh28]

metal roofs are hotter then composite shingles so the underlayment must be formulated to withstand that extra heat.....standard roofing felt will not.......so make sure they are using underlayment approved for use under metal roofs........personally I love the ice and water shield as an underlayment......it's not just for ice build up but also for water protection....it's almost like having a backup roof under your primary roof....but again it must be a type that is approved for use under metal roofs.....the other thing to look for is to make sure you get the manufacturers specs on the metal roofing they are proposing tio use........there are several different formulations of coatings used for the colors.....some are better then others so you will need to do a little research on that and find out what your roofer is proposing to use......also pay attention to the fastening system they propose.....don't know how often you get hurricanes at your locality but high wind attachment may be a concern......again there are different systems that different manufacturers use........also pay attention to the gutters as torrential rains just fly off metal roofs especially at valleys......I have found that the gutters are best bumped up a size in width top prevent over run and dams used on the gutters at valleys........its also best to have the gutters supplied by the metal roof manufacturer so the colors match........as for the seaming ask if it's a single fold or double fold........double is better and will be more water tight......as will be a system that includes a mastic at the seams.........but this is also going to raise the price so you will have to decide on the trade offs........metal roofs will be a little noisier then composite shingles but if you have insulation in your ceiling it shouldn't be noticeable and personally I like the sound of rain on a metal roof .......metal roofs are my favorites because if they are installed correctly there is very little that can go wrong with them over time.......oh....and don't forget to let your wife pick the color......haha........Jack

 

[gsganzer]

I'm getting ready for a new roof and I'm considering metal as well. I'm interested to see what responses you get.

There was a house one street over from mine that had a standing seam metal roof. It was pummeled during a recent hail storm and had to be replaced. I was surprised at how bad it had been dinged and dented, considering I have a roof on my workshop that is R-panels and it didn't have any damage from the same storm.

 

[PILOON]

Having installed a few metal roofs I can point out that you can order a heavier gauge than generally offered.
If you experience occasional hail storms you might wish to consider that option.
While a tad costlier the extra can well be worth it as it kinks and wrinkles much less making for a more perfect finished look.

 

[ustmd]

Having installed a few metal roofs I can point out that you can order a heavier gauge than generally offered.
If you experience occasional hail storms you might wish to consider that option.
While a tad costlier the extra can well be worth it as it kinks and wrinkles much less making for a more perfect finished look.

So far, everyone is offering 24 gauge and I am going for the simple Galvalume. Standing seam, striated (to help with oil canning) with 17 inch centers.

 

[bigtiller]

Have a look at what is called "stone coated metal roofing". It's new in this area. It is a steel roof that looks like shingles and has a very long warranty.

 

[forgeblast]

Big tiller lots of issues with them. I was going to go with it, until I saw the issues that were reported in Canada. The granular pieces will not adhere for that long. The original company "sold" itself to another company that company will not honor the warranty claims against the other company.

I googled duraloc allmet stone coated roof problems.

Duraloc now called Allmet stone coated roofing serious problems - RedFlagDeals.com Forums

Painting Defective Stone Coated Metal Roof - Roofing/Siding - DIY Home Improvement | DIYChatroom

Consumer Reviews of Dura-Loc shingles

There were too many issues that we went with a 30 year shingle.

 

[bigtiller]

I didn't know that.... looks like I was lucky it was out of my price range last year and stayed with the traditional shingle with an architectural design.

 

[Cord]

You will want a "high temp" underlayment. There are some synthetic felts out there but we typically use a ice & water product. For a residence, I'd encourage you to consider a concealed fastener roof. Each screw is a leak opportunity which is why I wouldn't use a exposed fastener panel on a house. With the newer formed metal panels the cost of the concealed fastener roofs have really dropped in cost. Even then, some roofers look at the metals as a rich man's roof and will triple the cost of a shingle roof.

Galvalume is very bright and shiny so make sure you are OK with the look.

 

[Deere Dude]

My current house had Forrest Green metal put on the roof 8 years ago. I noticed darker colors fade more in hard sun. That might be okay but if you put on an addition the colors will be way off. My original roof vs. the new addition last year was noticeable but not terrible. To correct that I would have to replace all the old tin, so I took a closer look at it matched perfectly:laughing:

Around here, they went right over the shingles with the tin and worked out fine. For the addition I built it like a pole shed roof but used a thin insulation under the tin for condensation. I put in a foot or so insulation in the attic so noise isn't a problem.