Replies

1. 
   barnbuilder | Dec 31, 2002 12:32am | #1

   I live in the sunny okanagan where we also get cold winters. We install plenty of metal roofs on barns as well as on houses. The theory you friend has is a common miss conception of metal roofs, I believe it stems from when most of the metal roofing was aluminum. Aluminum definitely expands and contracts a lot more than the 30 ga. metal roofing used today.

   The best advice I can give you when installing a metal roof is to make sure you install a minimum of 30ga. metal and if you can afford it go to 29 ga. and make sure you are screwing the metal down with #10x1-1/4"  roofing screws that have a rubber washer and install the screws on the flat part of the metal not on the raised ribs. I recommend using #10x1-1/4" screws because they have a smaller head 1/4" nut driver size and they offer less resistance to snow therefore less chance of being pulled out.

   The other half of getting a quality metal roof that lasts is the preparation, Your screws are only as good as what they are screwed into! We always strap our trusses with 2x4 @ 2' o/c and if it's a roof that is already sheeted with plywood you can get away with 1x4 strapping at the same spacing. And last but not least you should consider installing 15# felt paper under the metal because metal does sweat and the felt paper will go a long way in controlling that sweating!!

   Don't be afraid of installing sheet metal roofing because of one mans opinions... we've installed sheets in excess of 40' using the techniques described above and we have never seen any problems with expansion and contraction

   Good luck and have a happy new year!!

1. 
   FastEddie1 | Dec 31, 2002 03:13am | #5

   Looks like you're a first-time poster.  Welcome.  Now, where the heck is okanagan?

1. 
   cheakamus | Dec 31, 2002 03:46am | #6

   It's in south-central British Columbia if spelt Okanagan. Otherwise, it's south of the border in Washington State (and spelled Okanogan). Both are relatively dry, sunny, and good fruit-growing areas (as well as wine). Lots of tourism because of the fabulous lakes, some as long as 50 miles. Skiing in winter.

2. 
   junkhound | Dec 31, 2002 03:46am | #7

   200 leagues west of okanagan (Seattle area) we've got mostly D fir vs hemlock -- the metal roofs I've seen where there can be a buildup of the acid needles eats thru metal roofs in short order, don't understand why people cut down their trees rather that study the roblem in the first place. First noticed this in the 70's, when galv. gurtteres would fail in 6 months if filled with fir needles.  

   A Mt St Helens histogram -- a friend had just put a steel roof (galvanized and painted) on his barn ain Chehalis and the ash acid ate thru it the first rain.

1. 
   FastEddie1 | Dec 31, 2002 04:14am | #8

   Do you suppose the gutter failures had anything to do with the mass of needles retaining moisture?

1. 
   junkhound | Dec 31, 2002 05:00am | #9

   No, I believe it is just the basic acidity left in the small water pools in the gutter. 

   My own house has 2nd floor wrap around deck that gives me easy access to clean gutters at least weekly. I first had galv. guters on them (30 years ago) of which the first 2 sets rusted thru in a year each. Now have (ugh) vinyl gutters (only vinyl on own house) that hold up about 10 years, usually fail due to too many needles getting into the joint during the rleatively few freeze/thaw cycles and thus leaking past the seals.

3. 
   barnbuilder | Dec 31, 2002 08:22am | #11

   Ya I'm a first time poster ... the okanagan is in Beautiful British Columbia Canada...... thanks for the welcome

2. 
   JeffBuck | Dec 31, 2002 12:56am | #2

   Plenty of tern roofs on porches around here. Flat seams.....just need repainted every now and then......with the good paint.........that ya add linseed oil too.

   Jeff

   Buck Construction   Pittsburgh,PA

    Fine Carpentery.....While U Waite                  

1. 
   DaveRicheson | Dec 31, 2002 01:21am | #3

   Brand name on the paint, Jeff.

   Has nothing to do with metal roofing, but I am interest in the paint. Stuffs great for wood too.

   Dave

1. 
   JeffBuck | Dec 31, 2002 11:06am | #12

   Dave...I have no idea on the brand name.

   I just know of a local hardware store I stop each time to get it.  Not HD or Lowes...not sure if they'd carry it or not.

   I've only bought it in red...kind of a burnt red color..as that seems to be the original color of all the roofs I've repainted around here.

   I can say the linseed oil has some chemical reaction when mixed in. On a cold day..the mix will heat ya up......and on a hot day it'll make you dizzy!

   So it must work, right! Anything that smells bad enough to hurt generally works better! I'll see what I can find....might have an old can in Dad's garage.

   Now I'm not even sure what I ask for.....I just tell the old hardware guy I'm painting a metal roof? For all I know...might just be regular old oil base.

   I'll get back to ya.

   JeffBuck Construction   Pittsburgh,PA

    Fine Carpentery.....While U Waite                  

3. 
   MikeCallahan | Dec 31, 2002 02:10am | #4

   I live in heavy snow country (Lake Tahoe). I worked on a crew that did a lot of insurance repair on roofs. 99% of the repairs were on metal roofs. Valleys build up snow and crush the ribs no matter how thick the metal. Idiot architects that spec a chimney at the eave see the chimney sheared off after the first big winter. The repair requires relocating the fireplace at the ridge or building a massive engineered snow splitter. Even the ridge metal gets crushed often. The snow slides off in slabs and can kill anyone below. Decks have to be designed with impact load in mind if they are not on the gable end. Ice layers form under the snow slab and often shear off the screw heads when they let go. Heat in the summer will inevitably cause the screws to back out. Then you have to replace the screws with thicker shanks because the hole is reamed from the expansion.

   The only design that works is a box with the entry on the gable end and all vents and chimneys at the ridge. Like someone said you must screw the metal on the flat section. Many naive amatuers still install the screws on the ribs.

   If you are in snow country I reccommend a 40 or 50 year comp roof. These days they require roofs engineered to hold the snow so there is rarely the event where you may have to shovel the roof. Most building departments require an ice membrane under metal roofs 5 feet along the run just like under a comp roof.

   Mike Callahan

   We may be slow, But we're expensive.
4. 
   Piffin | Dec 31, 2002 06:45am | #10

   I have seen expansion. It happens. But a well applied roof deals with it.

   I have over twenty years of roofing experience in all types of climates with all types of materials. I have enough confidence in metal roofing that I installed it on my house when I built it. The snow sliding off has it's good and bad points.

   I did just learn something though. I used to always use 26 gauge and I knew that 29 was available for application over plywood and not strapping but I never would have dreamed that thirty would become the norm. Getting thinner by the decade, I guess.

   .

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit.

   The second is to look things in the face and know them for what they are."

   --Marcus Aurelius