metal roofing, Tips/Tricks?

[ddjjeep]

Im going to be putting a metal roof on my new shop. Any tips or tricks I should know? Can I just lay the metal down on the roof purlins? I have read about putting felt under it first. Is this needed? How about overlapping panels? I have a roof that will be 16' from the eaves to the peak, and have access to some panels that are various lengths like 6', 8' and 10's. Can I use a 10 and 6 and just have them overlap? Or is this frowned upon?
thanks

 

[TOMWELDS]

I helped a friend with a tin roof in the Adirondacks. Biggest problem was the ice buildup would pull the screws and there would be these little leaks popping up on the ceiling. The felt would probably eliminate squeaking noises in the sunlight.

 

[NHCharger]

Hey ddjjeep, hello from a fellow New Hampshirite
I was going to install a metal roof on my new garage/shop when I built it . Figured I would save money. Purlins and metal versus plywood and shingles. Both the lumber yard and the metal roof supplier recommended that I use a plywood base, 30 LB. felt , then the metal roof. They both told me that with the quick change of temperature in the mornings up here (mostly spring and fall) that a large amount of condensation would form on the bottom side of the metal and it would obviously get the insulation over the shop wet or any object in the garage area. It made sense to me because I have noticed water dripping off the bottom of my cars in the garage due to the temperature change. I ended up going with shingles since that ended up being cheaper in the end, also it matched my house which kept the wife happy.

If you are going to use metal you must use the heavier 30 LB. felt. Check with the roofing supplier to see what they recommend.I installed a metal roof last year up in Wakefield. Yes you can over lap the panels, check the installation guide for how far to over lap them. I saw one guy make the mistake of screwing the panels on the flat section, not the raised rib. Check your roof for square, when I started the roof I installed the first 3 panels with only a few screws to make sure everything was lining up. If you roof is not square the panels will run off from the edge of the eaves. Another thing to be careful of is to not overtighten the screws. The screws have a rubber washer which seats against the roof to prevent water from leaking in. When you overtighten it flattens out the rubber washer. About the ice dam mentioned above, that's caused by a lack of insulation in the ceiling and/or inadaquate ventalation in the attic. Make sure you have two cordless screw guns ready. I was changing batteries every 15-20 minutes once we got rolling on the roof.

 

[ddjjeep]

Great info, thanks. Im still not sure if I will go with the metal, but I am hoping to. It may end up cheaper to just shingle it like you did. Owell, at least it would match the house.

 

[Jazz1]

Great info, thanks. Im still not sure if I will go with the metal, but I am hoping to. It may end up cheaper to just shingle it like you did. Owell, at least it would match the house.

I used shingles when I built garage 20 years ago and now I need to reroof. Time flies! I'm going metal for the ease of installation. Just screw metal right down on shingles.
I applied plywood to roof when i built so screws will bite better

 

[K'ledgeBldr]

Im going to be putting a metal roof on my new shop. Any tips or tricks I should know?

Use a hidden fastener system. The amount of overlap is dependent on the pitch of the roof- plus your overhang.

 

[NUTTSGT]

Back from the dead from a now banned spammer.

 

[terry603]

Hey ddjjeep, hello from a fellow New Hampshirite
I was going to install a metal roof on my new garage/shop when I built it . Figured I would save money. Purlins and metal versus plywood and shingles. Both the lumber yard and the metal roof supplier recommended that I use a plywood base, 30 LB. felt , then the metal roof. They both told me that with the quick change of temperature in the mornings up here (mostly spring and fall) that a large amount of condensation would form on the bottom side of the metal and it would obviously get the insulation over the shop wet or any object in the garage area. It made sense to me because I have noticed water dripping off the bottom of my cars in the garage due to the temperature change. I ended up going with shingles since that ended up being cheaper in the end, also it matched my house which kept the wife happy.

If you are going to use metal you must use the heavier 30 LB. felt. Check with the roofing supplier to see what they recommend.I installed a metal roof last year up in Wakefield. Yes you can over lap the panels, check the installation guide for how far to over lap them. I saw one guy make the mistake of screwing the panels on the flat section, not the raised rib. Check your roof for square, when I started the roof I installed the first 3 panels with only a few screws to make sure everything was lining up. If you roof is not square the panels will run off from the edge of the eaves. Another thing to be careful of is to not overtighten the screws. The screws have a rubber washer which seats against the roof to prevent water from leaking in. When you overtighten it flattens out the rubber washer. About the ice dam mentioned above, that's caused by a lack of insulation in the ceiling and/or inadaquate ventalation in the attic. Make sure you have two cordless screw guns ready. I was changing batteries every 15-20 minutes once we got rolling on the roof.

funny, when I put a metal roof on, the lumber yard that had been in business for 60 years, told me, only a couple of vendor tell you to screw on top of the rib, all the others say screw on the flats

 

[joey1320]

I used shingles when I built garage 20 years ago and now I need to reroof. Time flies! I'm going metal for the ease of installation. Just screw metal right down on shingles.
I applied plywood to roof when i built so screws will bite better

Don't go right over the shingles, install purlins over the shingles first.

 

[Dagny]

When i was young my dad built steel buildings we used the nails with lead washers and nailed them on the humps. The consensus now is next to a hump. I didn't think of it till this year but next to the hump would make shoveling the snow off much easier.

 

[hedtedjr]

I have put on a few metal roofs (builder by trade) in NH. Almost every manufacturer will tell you that an underlayment is required. We typically use a synthetic product. You can use the other panels, as long as the screw holes fall in the right location. I would second (or third) the sentiment that you should not lay metal directly over existing shingles. This is for 2 reasons, first is if the roof is leaking (which is when people usually decide to fix it) you need to identify why, covering it does not treat the problem, but masks it (bars leak stop is not a replacement for a failed head gasket); second, the metal will show the general texture of the roof (ie. you will likely get odd shadows and lines.
Keys to success, make absolutely certain that you start with your first panel square. We typically run a string line from one end of the roof to the other at out desired over hang (typically about 3 inches)and use a combination square to ensure that the edge is following our line. Also fasten on the flat, not the rib. To my knowledge that is a must for every manufacturer. Don't over tighten and I usually try to work from my panel overlap (rib that goes over the previous panel) to the other edge. I seem to get better more even alignment this way. Hope this helps.

 

[joe--h]

https://www.garagejournal.com/forum/showthread.php?t=416153

 

[joe_padavano]

The right answer is to download and read the installation manual that the manufacturer provides. Every metal roofing manufacturer has a detailed installation manual that not only answers your questions but also shows how to properly finish all the details like ridges, eaves, valleys, penetrations, etc. They also sell a wide variety of detail items like drip edges, ridge caps, foam closeouts, etc. Every metal roofing system is different. My experience is that most installers don't bother to read this material, don't use the right installation or closeouts, and ultimately have problems. Do it right and you won't have any issues.

 

[brownbagg]

pre drill the holes on the ground first