Metal Roofing

Started by firefox, May 19, 2011, 09:23:46 PM

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firefox

I was admiring Don's roof when he mentioned the ladder attachment.
I have some questions as follows:

1- What are the tradeoffs between the various type of metal roofing?
  ie, things like aluminum vs steel vs galvalume, etc.

2-Which types can be color coated with long lasting coatings,
   not necessarilly designer pretty stuff, just rugged.

3-Is it possible to get custom size panels with out breaking the bank.
   For example 8' x 9' or 8' x 12' with the ribs along the longer axis.

4-Any leads on who is a good company to work with in northern
   California or northern Nevada?

Thanks for any leads,
Bruce
Bruce & Robbie
MVPA 23824

Alan Gage

Our local building supplier strongly recommended, and convinced me to go with, standing seam rather than the barn style roofing most people use. Very few exposed fasteners being the main consideration. They think leaky screw gaskets are going to start being a problem once all the new metal roofs get some years on them.

It's about the twice the cost of barn steel roofing. It can be installed directly over the sheathing though so no purlins to mess with.

This is the stuff I'll be getting:

http://www.whirlwindsteel.com/pub/Weather-Guard

Not really what you were asking about but I thought I'd throw it out there for your consideration.

Alan


firefox

Thanks Alan. I appreciate any and all input!
Bruce
Bruce & Robbie
MVPA 23824

MountainDon

We bought the panels for the cabin and before that for our home from MetalMart. They are TX based I believe and have stores here and there. They deal with contractors or the public. The ribbed panels they have come in a variety of patterns and colors. The panels come in std widths (36" I think) and are all custom cut to length at the factory. They were cut to the exact requested measurement. Yes they use neoprene gasketed screws. My understanding is that if they are tightened properly and not overtightened they are quite troublefree.  :-\  Time will tell.   Ours are both installed over sheathing as the metal is not structurally rated as it must be if purlins over the rafters (no sheathing) is done.  Ours are galvalume and came with a 40 year (? I think?) no perferation due to rust warranty.
Just because something has been done and has not failed, doesn't mean it is good design.

firefox

Thanks Don!
  I really like the way yours look.
Bruce
Bruce & Robbie
MVPA 23824


glenn kangiser

Number to a small time sheet metal operator in Turlock, Ca.  -  Rolls various sheeting - color and Galv.  Good Prices  AFAIK

Direct Metal Roofiing
Don Hensly
Hensly Manufacturing

1430 Ellerd Rd.,

Turlock, Ca.  95380

209-632-2118
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

firefox

Bruce & Robbie
MVPA 23824

glenn kangiser

Hope it's of use to you, Bruce.  I have bought from him before.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

davidj

When I was looking it turned out there were basically two bigger companies in N California that manufacture most of the metal roofing material.  One is Metal Sales, who I think are Sacramento-based.  The other is ASC.    They both do numerous styles and colors.  I used Metal Sales low-end standing seam on the main house ("Image II"?).  I had someone install it, it seems fine, although it's flat ("striated?" - no minor ridges like most standing seam) and does ripple slightly with temp changes. Lots of folks seem to stock both companies (my roofer and the local lumber yard will do either).  They don't seem that different and it probably comes down to subtle differences of color or design.

My neighbor has shopped around a bit for this, and kept on ending up with the same companies too.  He tried to buy closer to the source to save money but now he just gets it from the local hardware store as it's no different in price and much more convenient.  Whatever you do, expect to have to special order it and it taking a couple of weeks.

Home Depot in Reno (and maybe the foothills, but not on the coast) do carry some non-standing-seam green metal roofing in stock.  However, finding a store with all of the lengths of material and trim you need often requires multiple trips.  I did a shed like this but I just special-order now as its less hassle - you just need to plan 2-3 weeks out.

As far as material, I think all of the decent stuff is steel of varying thicknesses with some kind of galvanized coating and then some kind of powdercoat-like colored layer(s) (if it's not technically galvalume, it's probably very similar).  It comes in standard widths (which vary depending on the design) and custom lengths. Don't forget color-coordinated screws of the right length (even with standing seam, some trim screws are exposed).  Working out trim is often best done with a

If you install it yourself, note that the ridge pieces (and other trim where possible) screw into just the metal ridges of the main sheets, not all the way through to the sheathing.  I believe the correct way of attaching boots for e.g. vents is also to just screw it to the metal, not the sheathing (so everything can move with thermal changes), although it's often not done that way.

One other tip is to work out the first sheet correctly - work out where the real axis of your roof is and go with that (like you would when tiling a big floor).  Don't just line the short edge up with the edge of the sheathing as that piece might be slightly off.


davidj

For smaller areas, exposed fastener is probably more common.  Stuff like Metal Sales R-Panel or Classic Rib or ASC's Strata Rib.

Try and order the exact length to save cutting for the panels (I think the right thing to do is just measure the length of the roof - you can leave maybe a 1" gap at the top for venting and overhang by 1" at the bottom).

firefox

Thanks David,
This is all wonderful info!
Bruce
Bruce & Robbie
MVPA 23824

hpinson


Native_NM

Quote from: Alan Gage on May 19, 2011, 09:40:26 PM
Our local building supplier strongly recommended, and convinced me to go with, standing seam rather than the barn style roofing most people use. Very few exposed fasteners being the main consideration. They think leaky screw gaskets are going to start being a problem once all the new metal roofs get some years on them.

It's about the twice the cost of barn steel roofing. It can be installed directly over the sheathing though so no purlins to mess with.

This is the stuff I'll be getting:

http://www.whirlwindsteel.com/pub/Weather-Guard

Not really what you were asking about but I thought I'd throw it out there for your consideration.

Alan

Does the one side just lock over the other without fasteners?  I see they are wind-rated and uplift rated.  I did a large addition on our old house by myself.  Drilling all those self-tapping screws was a real PITA.  This system seems far easier to install - pan head screws into the decking on one side.
New Mexico.  Better than regular Mexico.

Alan Gage

Quote from: Native_NM on May 21, 2011, 10:27:35 AM
Does the one side just lock over the other without fasteners?  I see they are wind-rated and uplift rated.  I did a large addition on our old house by myself.  Drilling all those self-tapping screws was a real PITA.  This system seems far easier to install - pan head screws into the decking on one side.

Yes. There are still a few exposed fasteners at the eve and peak I believe. I also liked the fact that it seems easier to install without help (and directly to the sheathing).

I talked to a roofing salesmen the other day (sells both barn steel and standing seam) about his preferences and he also recommends the standing seam. He hasn't seen any big leakage problems but around here metal roofs have only been common on houses in the last 5 or 6 years. One example he had was as couple that built a house 10 years ago and decided to go with a metal roof with exposed fasteners. They've seen no leakage from inside the house but last fall they had to go up in the attic and they noticed water marks in the sheathing around each screw penetration.

Most of the concern seems be on larger houses with longer panels that expand and contract more with temperature fluctuations. Apparently this can wear on the screw washers and cause them to leak.

I guess only time will tell if it's really something to actually be concerned with.

Alan


Native_NM

I remember when I did my old roof they recommended putting a dab of silicone on each screw, which I think I started doing and quit.  The screws were self tapping with a neoprene gasket.  I like the idea of going into the deck.  I bet a bead of silicone down each overlap would keep them dry in any weather.
New Mexico.  Better than regular Mexico.

Don_P

Silicone, depending on type, can eat the metal. The sharp smelling stuff can rust the roof. Butyl is the normal sealant. You can predrill the entire stack on the ground with an 1/8" bit, pull the end sheets off and drill them by themselves, remember the edges will be different.

Water stains inside on the sheathing are probably due to condensation when warm moist air hits the cold tip of the penetrating screw. I've seen fasteners in attics with frost on them. They do make oversize washered screws, when the original ones fail you can back out the original and run in the oversize.

The color will fade, probably before they would like to admit to. Hey it's harsh up there  :D

Standing seam clicks down over the tabs on the previous pan. The bottoms get wrapped over a drip edge. To get high wind rating the drip edge needs to slide over a starter strip that is screwed to the fascia. The drip edge needs to be bent for the roof pitch. I prefer to use drip edge, properly secured, up the rakes as well and then bend a ripped pan over that drip edge rather than using their clunky commercial looking rake metal. This leaves it looking more like a high dollar site formed standing seam job. I just talked through about $500 of tools. A battery impact is the way to go with screws on either type of roof. Ther will be no exposed screws on this type of standing seam job, there will be some exposed rivets, they come color matched. There are 2 metal fabricating shops that make the barn tin and standing seam locally, I can order from Fabral as well. The local shops shine, they can make custom trims quickly per order. I pay a set up fee and a footage price but pretty much if I can draw it they can fab it. We did 2 bays and a bow on one last year. When I order from Fabral I get a few extra flat sheets and take them over to the HVAC shop and have them make my custom trims. He is limited to 12' sticks where the metal shops have run me full length stock for rakes, etc.

By and large metal roofs are an example of shrewd marketing.

MushCreek

I've looked into metal roofing quite a bit. Since I'll be about 60 by the time my place is done, I'd like the first roof job to be the last! I know from personal experience that shingles aren't going to make it, at least not in the sunny south. Here in FL, a 15 y/o roof is an old roof. Metal should be able to outlast me, if properly installed and maintained. There are many examples of very old metal roofs still on the job.

Where I am conflicted is the installation, and the structure under it. I was always led to believe that the best method is to double strap the roof. This consists of vertical furring strips, fastened through the sheathing to the rafters/trusses. Then horizontal purlins are attached, and the tin is attached to them. The theory is that the vertical channels created allow condensation to drain, and create air flow behind the tin to help dry things out. This way, moisture can't sit trapped in place, and do what moisture does. Another plus is that the horizontal purlins make a dandy ladder while working on the roof. Being the type that wears a belt AND suspenders, I am going to use Zip sheathing, carefully taped, AND tar paper or Tyvek. What I've always felt about roofs is that it's not a matter of if moisture gets behind the roofing, but when. This all sounds good, but then I read that tin installed over purlins will be much more susceptible to hail damage, and more prone to peel off in high winds! Currently, I'm looking into metal shingles to see what the pluses and minuses of those might be. Slate, anyone???
Jay

I'm not poor- I'm financially underpowered.

Don_P

If you allow air under the metal, it had better be alot. This pretty much guarantees condensation on a daily basis. If the metal is sealed to the deck, over tarpaper any minor vapor ends up in the tarpaper and it does not sweat on a daily basis. I do like the old terne metal roofs. I replaced a solid zinc roof with standing seam about 10 years ago. The zinc roof was recycled off the courthouse when they built the new one in 1908. I wish we could get roofing like that.

firefox

I am just curious, what if you glued a thin sheet of foam to the underside
of the metal roofing? Would that keep it from sweating.
Say maybe just a 1/2 inch rigid foam.
Bruce
Bruce & Robbie
MVPA 23824

glenn kangiser

Best is to spray it with Icynene - ask Okie BoB.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.


firefox

Thanks Glenn,
  I agree in general, but I am doing something
a bit out of the ordinary.
  Need to know basis....
Email me if you need to know ::)
Bruce
Bruce & Robbie
MVPA 23824