[chemman]

Anyone have an opinion on this metal roof? The guy giving me the quote had a ton of pictures with addresses of work he had done in my area for the past 20 years. Everything was sounding really good until he said that it was OK to install over my existing asphalt shingle roof. He was quoting $15k for 27 squares, which didn't sound bad at all.

 

[AndyWRS]

We have used it a few times, i like the look of it but even with the foam it dents with foot traffic, the more foot traffic the more dents. Everything we have done has been with a tear off, i do see the website says you can go over though.

I would rather tear off than go over. If i were you i would ask him for addresses of jobs he did as a go over and as a tear off, go look at them and see if you see a difference in the way the roof looks. Talk to his customers and see if they have any regrets with the go over.

 

[joecaption]

Unless you remove the old shinlges how would you know if there's any sheathing damage under the shingles? Really going to suck if the new ones fail because of that one simple to take care of issue.

 

[jagans]

Underlayment

I would tear it off and put ice dams material over the whole deck and double in the valleys, then put on the metal shingles. What do the manufacturers installation instructions say?

 

[jagans]

Sorry

OOps I forgot to mention, you need high temperature ice dams material under metal. I really dont like the fact that it dents, as someone else here said, and I thoroughly agree to tear off and inspect the deck for damage, and proper anchorage first.

 

[joecaption]

By ice dam material I guess you really mean Storm and ice shield?

 

[ParagonEx]

By ice dam material I guess you really mean Storm and ice shield?

Is storm and ice shield different from ice & water shield?

 

[Windows on Wash]

We do a decent bit of metal and going over top of existing asphalt is never a good idea in my opinion. In most cases, it invalidates much of the benefit of the metal roof.

+1 to the other feedback. Strip down to the deck completely and re-build from there as stated above.

What's the pitch on the roof?

 

[jagans]

Ice Dams Material

The first manufacturer, as far as I know was WR Grace with their Ice and Water shield.

This mateial is basically a peel and stick Styrene-Butadiene-Styrene rubberized asphalt material that was developed in response to Ice Damming.

There are now many manufacturers of the material, but as far as I know they are all based on SBS, and they all have a release backing of some type, usually craft paper.

They work by sealing around the shank of roofing nails as they are driven into the deck.

There is a particular type that is appropriate to metal roofing due to the elevated temperatures that are reached under that type of system, and if not used, the result can be dripping of sticky asphalt material down your fascia as the material melts.

 

[chemman]

Thanks all for the feedback. I couldn't agree more, and I don't care if the manufacture says to put the stuff on using peanut butter, I don't think roofing over my shingles is a good idea at all. It makes no sense to cover something with a lifespan of 15 years with something that could last over 50 years and costs so much to install. It was shocking hearing someone with decades of experience and had been doing just metal roofs for 20 some years (he looked like it too!) just say he'd go right over my existing roof. I honestly think my mouth was hanging open in awe.:laughing: My biggest concern with the new roof is that I'm about 99% sure that the original OSB decking from 1978 is still present on the roof, and a previous roofer covered the upper roof OSB with plywood at some point. (Two story home with single story attached garage, all 12/4 slope) I didn't think you needed ice and water shield under metal. I thought that they just laid down a nice heavy felt.

Andy I never thought about it denting until you mentioned it. Considering I'm going to get my siding replaced after the roof is done they might make a real mess. I was also considering standing seam which I'm now thinking might be a better choice, but I've been told by several people that they think standing seam is ugly and they'd never by a house with it. If I were go with this guy I'd make sure we were on the same page about tear off and I'd get some addresses from the area and knock on some doors.

 

[AndyWRS]

You could tear off, repalce any wood that needs replacing and dry in the deck, leave the roofing off in the areas that need siding until it is completed...then roof it. This works well but it also depends on the layout of the home and when the siding is expected to go on.

As for the denting, it is the truth. Do not let them them tell you otherwise. It can be minimized by adding the foam insert for every roof panel, but you still HAVE to be careful. No one with anything besides a soft soled tennis shoe should walk on it... and even then minimize the foot traffic, better yet dont let anyone up on the roof.

I have pics of the last repair i did on the CM, 40 + sqs all dented to hell. Multiple roof mounted AC units and too much foot traffic in general destroyed it. I will check my work PC for the pic in the morning.

 

[jagans]

Denting

I would personally not install a roof system that dented from foot traffic. That means that hail will dent the heck out of it doesn't it? You would be wise to really check the warranty of these systems, most of them guarantee no leaks through the metal panels. That does not include the seams. Make sure you can get a SYSTEM warranty, not a product warranty. Thats about as good as a Kodak Film Warranty. They supply you with a new roll of film, the coast of the trip back to Africa to film the lion is on you.

Just so you know, asphalt shingles are without question the best buy there is in a steep roofing material, hands down. And they don't dent.

 

[AndyWRS]

That particular roof is Aluminum, even with the foam insert it is still not the strongest material. It can be walked on easily, the problem is trades lie about knowing how to and they smash it up. I flashed around a new roof mounted AC on the last one i did, the AC guy, (260lbs btw) is up there wearing heavy boots smahing all my new panels i just put in. Its not comp, you need to take some care and use common sense. If you smash the first panel you stand on then you should probably get off the roof. You will get not get a different result on the next panel you stand on.

The cost of this particular roof is high, the OP could very well get a SS for around the same $ and it would be far more walkable. The CM is great looking and its a good system, but i wouldnt put it on my home...id put that $ into SS or even a stone coated shake direct to deck application.

 

[chemman]

Andy, if you can find that picture I'd greatly appreciate it. I'm starting to think that I don't want this stuff. It looks really nice but it sounds too fragile. I can just imagine some big bubba strutin' across my nice new shingles smashing them in as he goes. It'll be hell getting someone to pay for their replacement, that's for sure. I think I'll look for a few more metal roofers in the area and get at least another quote for a standing seam and see how it compares. Jagans, I'll make sure to pay closer attention to the warranties, as you make a good point.

 

[mgp roofing]

I agree that denting from foot traffic is likely to be a problem. Here in New Zealand, is where the stone coated steel tile system was invented back in the 1950's, and is still popular. We routinely tear off the old ones and replace with asphalt shingles, on some roofs we have to really search to find any tiles that are not dented. If you're close to the sea, corrosion is a problem too. Go to the roofing talk forum and search for "decra to shingle reroof", you'll see what I mean.

 

[Windows on Wash]

I agree that denting from foot traffic is likely to be a problem. Here in New Zealand, is where the stone coated steel tile system was invented back in the 1950's, and is still popular. We routinely tear off the old ones and replace with asphalt shingles, on some roofs we have to really search to find any tiles that are not dented. If you're close to the sea, corrosion is a problem too. Go to the roofing talk forum and search for "decra to shingle reroof", you'll see what I mean.

I have seen that thread before and appreciate the pictures.

I don't like any of the systems that are down on a set of horizontal battens without any sort of drainage provisions that allow the water to pass through. Seems like a recipe for disaster because any metal system will allow water to get into them in a bunch of situations.

It would be like putting up vinyl siding and it not being able to dry out.

The pictures in that thread certainly demonstrate a coating failure but I didn't see obvious samples of rust. Do you have any of those?

 

[AndyWRS]

I found the CM with all the dents, i hope this pic loads. They installed this over the existing wood shingle. They also installed the AC unit into the roof system, it was a complete nightmare. THis did not have foam which made it dent pretty easy. The entire roof looked like this section. The New AC was installed on an elevated platform.

I do have some pics of a new CM we did after a City tree landed on a garage. The problem was the old CM color was to faded so the customer paid for the main house while the city paid for the garage.

Looks fantastic new, just gotta keep people off them. We used the foam on any we do.

 

[mgp roofing]

I have seen that thread before and appreciate the pictures.

I don't like any of the systems that are down on a set of horizontal battens without any sort of drainage provisions that allow the water to pass through. Seems like a recipe for disaster because any metal system will allow water to get into them in a bunch of situations.

It would be like putting up vinyl siding and it not being able to dry out.

The pictures in that thread certainly demonstrate a coating failure but I didn't see obvious samples of rust. Do you have any of those?

Here goes, sea salt corrosion and also some from runoff from copper hot water cylinder vent pipes.