Replace traditional shingled roof with metal roof? Experiences?

[MacLawn]

After losing two shingle roofs and water leaks, I was fed up with shingles and went with metal 15 years ago. Love it! I've researched a heap about this, and learned the only reason for furring strips is IF ye sheathing is OSB. If plywood, ye don't need furring strips - the reason is only that the screws don't hold as good in OSB. Furring strips give ye more screw strength.

In 1964 - yep - way back then my Dad and I built a 20x20 barn using 5 V galvanized tin and lead head nails. That old barn is still keeping things dry, and looks like it'll last another 50 years, roof and all. Yep, I like me some metal roof.

 

[therealmjfox]

Metal--I only wanted hidden fastener since I was told in about 10 years I would have to replace the screws with the washer when they started to fail.

Yup, I belong to a club that has a clubhouse with a metal roof that is now about 10 years old. The grommets on the screws that hold the metal down are all deteriorated from the sun and the roof is leaking. It's looking like a pretty big job to replace all the screw/grommet combinations.

 

[tcreeley]

If the metal roof is right on top of the sheathing, when the sun warms and the day cools, there is a greater chance of the steel sweating and condensation. Laying the metal roof over a 2x4 structure 16 or 24 oc allows air flow (vent the roof) and decreases the condensation. It also helps cut the build up of ice dams in the winter. Our house was done with built up 2x4's and our barn was built without roof sheathing. Both have done well.

 

[johnrex62]

I had my asphalt shingle roof replaced with a standing seam hidden fastener roof in 2009. I did not want to have to have the screws replaced every 10 years or so. I wanted a put it on and forget it roof.

They stripped off the shingles and repapered the plywood decking and applied the metal directly to the surface, no purlin strips. It went on quickly and painlessly. The cost was almost double the cost of a 15yr shingle roof.

I am quite happy with it. It has reduced my summer cooling bill by about 10% (already had radiant heat shield on the plywood decking which gave me over 40% reduction) and it has survived a couple hail storms, many heavy rain storms and several wind storms without a whimper or dimple. I can barely tell the difference from the asphalt roof as far as noise goes. I remember by grandmother's standing seam roof and how loud it was in a rain storm, but I am sure it was applied to purlins on bare rafters.

 

[nikdfish]

Modern fasteners use a contured metal cap above gasket material, are applied on the flats for a good seal and can be had colored to match the metal. The ones used in the work we had done were included in the 40 year warranty. Fastener durability was one of the elements we investigated when deciding on the metal option for our job. They would have been willing to lay metal on one layer of shingles, but we wanted a tear off to ensure all needed repairs were done to the decking. They laid down new membrane after the plywood repairs were done and then installed the metal directly over that. A ridge vent was part of the job as well. It was accomplished by using a rigid foam filter standoff the full length of the peak that elevated the ridge cap over the ridge line cuts.


Nick

 

[mbohuntr]

We went steel 2 yrs ago. We weren't told about the screw/grommet issue. We can get 4' snowfalls overnight, and I'm getting too old to climb up there anymore. The only downside is that the shed snow lands on the decks and in front of the garage doors. Heavy as concrete. LOVE IT!!!

 

[toppop52]

We did our shop with metal over a 15 year old shingle roof in 2000, used galvanized barn tin and it looks and functions like the day they finished, wish we'd done our house that way when we built 2 years ago, only with colored.

 

[randy41]

i put a blue metal roof on my house when I built it 15 years ago. haven't had any issues with the screws holding it down. this is laid on 1x's over eps which is over t&g pine. i put a 5v metal roof on my workshop 25 years a go with nails into 2x4's and its still holding well....rusty but still intact.

 

[jeff9366]

Beware that you will have weaker cell phone reception under a metal roof. You may also also need an outside antenna for local TV stations.

I had my old shingle roof stripped off down to roof deck, then new membrane installed, then 1/1/2" foam panels, then metal roof. Foam provides excellent additional insulation and nearly eliminated roof noise in the rain. Air conditioning energy consumption reduced 30% in summer, here in north Florida.

I specified all stainless steel fasteners.

There is considerable difference between metal roofing, from vender to vender. There is an equal variation in installation quality from roofer to roofer. Do not necessarily go with the lowest bidder.

 

[EddieWalker]

I've never done it, but have seen a few jobs that where both great and really bad. You have two types of metal roof types to consider. The standard R panel, which comes in three foot wide panels and is cut to any length you want. It's used on barns a lot because it is attached to purlins. No decking is used or any sort of water proof paper. Just the wood and then the metal and you are done. It's light, fast and easy to install.

When installing it on a house with an existing roof, I've seen where they just nail purlins right on top of the existing shingles. This is a mistake and will lead to issued down the road. The purlins need to be solid and anchored to the rafters. The shingles make this impossible to do and you end up with loos purlins, which means the metal moves and the gaskets on the screws leak fairly quickly.

The other type of metal is a standing seam. This is installed over tar paper on top of decking. this is very similar to how you install shingles and a good choice for a house. It's more money then a R panel, and it comes in one foot widths. You don't see the screws and it is probably more attractive then an R panel, but it is also more labor intensive.

One isn't better then the other, it's more of personal choice of what you like. You do get what you pay for in metal thickness and quality of the paint. Do not buy from the box store, and be sure you buy from a big name, well known supplier. Once it's up, you don't want to find out you have something that is fading or peeling.

Like everything, prep work is what it's all about. Either way you go, you absolutely have to strip the roof down to the decking. Anybody who tells you differently is somebody you want to walk away from. Do not save a buck by skipping this step.

Eddie