Roofing discussion!!!

[RoyKing]

The purpose of the tar paper is to protect the finish from the stone as the metal moves every day with the sun cycle. The new finishes don't care about condensation. The biggest problem is how you screw them down. In my opinion you only screw the overlapping seam, that allows the panels to expand and contract with out pulling on the screws. You also fasten every flat at the peak and gutter and the gable edges to keep wind from getting under it. Which way for the paper, I like the old way gutter to peak, so leaks arounds screws make it to the gutter.

 

[Gem99ultra]

Nah... It's called doing it right. Cheap is always cheap, and can never be made right. I'll call Eddie as my first witness...

As will I. Eddie's summary backs mine belief which is "Buy it cheap, buy again." Yeah, I'm on my 3rd metal roof 'repair' in less than 10 years. I can assure you, it would have cost a lot less to do it right the first time than to do wit wrong 3 times.

At each successive repair, I can spot quite a few things that the former roof repairman did totally wrong, or just cut corners - at my future expense. For example, the last repair the roofer simply laid the metal right down on the felt - no furring strips whatsoever. Laid the metal right down on the single layer 15# felt covered plywood with no way for air passage.

I suppose that by the time I'm dead from old age, I'll be an expert at metal roof repair. And broke.

 

[Fuddy1952]

I have two roofing questions!
First my metal garage, white strongpanel metal roof had some spots tree limbs rubbed...not all that bad, no rust. It's about 30 years old, so I decided to have "the best painting contractor " I could find prime and paint it. He used really quality Sherwin Williams products after prep (pressure washing, etc). It was expensive. BIG mistake! It looked good for a while but like a magnet now for mold, dirt, etc. It's been two years. A few $thousand more I could have had all new roof installed.
Second my house. The old section has no insulation. New half addition well insulated. I worked next to a roofing company so had them tear off, install architecture shingles 30 years ago. I'd go with metal this time. Can they insulate over shingles (probably insulation then 1x4s, metal screwed to that?).
Thanks.
Reason I mentioned painting garage metal, imo it was a waste of money.

 

[kthompson]

For what it is worth on the condensation of metal roof I have work shop with roof on three sides. Most of the shed is open over dirt floor. Plenty of air space for the moisture to evaporate info and that roof with right weather condition is almost like rain as the sun heats it up in normally cooler weather.

Not metal roofing but Lowes does or at least did sell a asphalt or such panel that was design for new roofing and for covering old roofing. That company had very simple instructions for covering a shingle or metal roof...run a board across the old roofing to screw or nail too and to get level surface.

Not a roofer by any means but have help install some on such as my shop and can not understand whey you must remove a shingle roof to install a metal roof. In my area see lot or metal being the second roof and not aware ever seen the shingles removed nor heard any issue from not doing so. No doubt some have the shingles removed but I can not remember seeing it done.

This I know, any roofing material can and will leak if not installed properly.

 

[davedj1]

I have two roofing questions!
First my metal garage, white strongpanel metal roof had some spots tree limbs rubbed...not all that bad, no rust. It's about 30 years old, so I decided to have "the best painting contractor " I could find prime and paint it. He used really quality Sherwin Williams products after prep (pressure washing, etc). It was expensive. BIG mistake! It looked good for a while but like a magnet now for mold, dirt, etc. It's been two years. A few $thousand more I could have had all new roof installed.
Second my house. The old section has no insulation. New half addition well insulated. I worked next to a roofing company so had them tear off, install architecture shingles 30 years ago. I'd go with metal this time. Can they insulate over shingles (probably insulation then 1x4s, metal screwed to that?).
Thanks.
Reason I mentioned painting garage metal, imo it was a waste of money.

Yes they have a product with insulation and OSB (Zip Wall system) You could alternatively put down the blue foam board of your choice of thickness and then plywood over it using the proper length fasteners. Or if you want to go a step further you could remove your roof sheathing and hire a spray foam contractor to come in and fill the bays on top of your drywall or whatever you have for ceiling. This it the route I would go if I had no or really poor insulation in my home. It won't be a cheap fix but it will be a great fix.

 

[Fuddy1952]

Yes they have a product with insulation and OSB (Zip Wall system) You could alternatively put down the blue foam board of your choice of thickness and then plywood over it using the proper length fasteners. Or if you want to go a step further you could remove your roof sheathing and hire a spray foam contractor to come in and fill the bays on top of your drywall or whatever you have for ceiling. This it the route I would go if I had no or really poor insulation in my home. It won't be a cheap fix but it will be a great fix.

Thanks. I'll have to use blue foam board. It's a 1 1/2 story cinder block, upstairs ceiling to roof is not much area, no real attic space.

 

[desertdog71]

What causes condensation is the question. When you're talking about a metal roof you have to consider condensation to a degree. Open metal building without sheeting will condensate and drip, and that is because warmer and moist air is touching a cold surface. If you eliminate or block the warmer moister air from from touching the cold metal roof you will eliminate the problem. So you can insulate, elevate, ventilate or plan from draining and drying. There's several techniques that will work. If you insulate with rigid foam you can then lay down tar paper and no gap under the roof. You can spray closed cell foam on the underside and get the same result.

Now if you're not going to insulate the roof sheating but are going to insulate the ceiling then you need a vented ceiling space above the insulation.

You should probably use an ice and water shield instead of tar paper in any of these examples.

As for topping shingles with metal, I don't see a problem with it, but depending on how well insulated the roof is, I would think you would want some 1in strips allowing the metal to breathe.

I think the correct answer is to tear the shingles off, lay down some foam board, ice and water shield, and then the metal roof. This will help at least reduce any condensation, and then stop any drips from penetrating through to the roof sheeting. Yes it costs more than slapping metal over the top of shingles.

Some things I think you can be cheap about but the roof over my head isn't one of them. If it goes between you and the ground you spend the money or in this case if it's between you and the weather spend some money. It's not uncommon for me to wear a $4 t-shirt, $15 pair of wranglers, and then $150 shoes. Why? because $150 shoes are worth it, don't get tore up in a few months, and are comfortable as ****. Shoes, jackets, mattresses, tires, flooring, roofing.......you get the idea. Some things you just need to spend the money and buy good quality.

This is all 100% my opinion and talking out my backside since I'm not a roofer. I've done quite a bit of research on the subject though in preparation to build my own place. Standing seam, over sheating, with ice and water shield, vented ridge, blown in ceiling insulation with heeled trusses is the route I am taking. It's cost effective and will last for a long time. Cost effective, not cheap.

 

[mikester]

Hello all, I just wanted to get some other opinions and objective discussion about a situation i came across this weekend. I observed a roofing contractor who installs a lot of tin roofs. He was doing something i thought was maybe worth discussing. I observed him working on an existing roof that was shingled and he was putting new tin over it. Now here is the questionable part. Instead of rolling the tar paper/felt the length of the house, starting at the bottom, and overlapping to the eve. He was starting at the end of the house and rolling from one side to the other overhang to overhang, or gutter to gutter per say, overlapping as he went about 8 inches. Now i do know this contractor somewhat, and confused about his new tar paper technique, i approached him. I had to ask him why he was doing that? and his response was it did not matter which way he ran the tar paper over existing shingles???? and after some friendly discussion i decided the best thing i could do was move on and not try to change his mind anymore! So what do you guys think will his way work. i personally think it would open up more opportunity for leaks????

Tar paper over shingles? Tin over all of that? The home owner (or soon to be new home owner) has bigger problems than which way the tar paper is oriented.

I'd say get the business name and number off his truck and tell your friends and family to avoid that guy like the plague. The only problem is in 6 months time he will have a new business name and number.

 

[ovrszd]

Some things I think you can be cheap about but the roof over my head isn't one of them. If it goes between you and the ground you spend the money or in this case if it's between you and the weather spend some money.

A very easy to understand way of saying, good foundation, good roof, equals good building.

 

[redman135]

One thing that nobody mentioned was if the house caught fire and the fire got into the roof, it is slow going to rip BOTH roofes off to put the fire out.
Also in New Zealand we generally lay roofing paper eave to gable.

 

[lman]

Around here they put furring strips over the old roofing and screw the steel onto the furring strips. The steel does not touch the old roofing or felt.

 

[PILOON]

Metal roofing sweats under the right conditions. (humidity and temperature)
I have a shed that sweats so badly come spring that you'd think it was raining.

Air circulation is needed to evaporate that sweating.

I once re roofed a building that the contractor had placed tin directly on plywood/
That ply was black 1/2 rotted and the metal was darn close to rusted thru, and it was a mere 4-5 years old!

The ideal is spaced out furring strips over the trusses with plenty of air circulation.

 

[Sberry]

One of the reasons to use steel is so you dont have to tear off.

 

[Sberry]

Fire is a problem.

 

[DieselBound]

Hmm, the topic for discussion is certainly interesting. It seems that each master has his own methods of work, so it is probably pointless to convince them. Therefore, customers should immediately look closely at the master they have chosen. Of course, a person does not always understand construction. Then it is better to contact larger companies, where it will be possible to achieve justice in case of mistakes. For example, for several years, I have been referring to https://www.maxima-aluminum.com.

Personally, I would not use such a technique for the roof either. I have slightly different quality standards, heh.

And big companies have big attorneys.

If you want a good roof/roofer check to see who does it for higher-end builders.

How a roof ought to be properly finished is highly dependent on environment and whether it's over a conditioned space or not. Others have commented, properly, on this. Roofs are vented or non-vented. Basically, if the roof type/structure isn't vented then the outer roofing material needs to be isolated from it: venting via furring strips or such is a common way. You want to have a thermal break [as much as you can] between conditioned spaces and the outside air: a unconditioned roof structure is usually one that is vented; this IS the thermal break, in which case no additional breaks are required (function of furring strips would then only be to facilitate connections of outer roofing material to underlying decking).

Regarding the subject of this thread, I would be concerned about placing steel directly over asphalt shingles because the steel would conduct a lot of heat, perhaps enough to expedite the breakdown of underlying shingles. Seems that the use of tar/roofing paper/felt could help. I'd, however, want to put steel down on a clean deck. Keep in mind that there's a limit to how much you can stack up on top of existing materials. In general, I think that it's two layers: and depends on type and construction of roof- some roofs may not allow for multiple layers [read "always need a complete tear-off"]. Placing steel over two existing layers of shingles might not be allowed. Should be obvious, but it makes the point that not in all cases could one (if one would want to) run steel on top of existing shingles.

 

[5030]

Standing seam coated steel roofing is basically forever.

 

[jthibodeau89]

We went with standing seam steel for our hill top home. Got tired of losing shingles to the wind. The old roof had been patched multiple times by the previous owner. Got a quote for $50k for 70sq of roofing and jumped on it. I will note that this quote include a full tearoff, gutters for both house and barns, and replacing 9 fixed skylights on a 30+ year old building. It helped that we had a large hail storm and had an insurance coverage for $25k of the cost. Signed the contract with contractor who then subbed it out. Had trouble right off the bat with the sub. Whenever i saw something i questioned, like no wayershieds around skylights or eaves (it was written in contract), i was told 'I don't do it that way '.....mind you i am an engineer by profession and did a lot of research before deciding on a 26ga standing seam roof product.

The last straw was when he was short on flashing for skylights, and reused the old step flashing. Called the contractor for the umpteenth time with the list of concerns once the decking was on but not trimmed. Contractor came out and agreed with my concerns and fired the sub that day. Got his regular crew to come out for a 3-5 day repair. Turned into 3 weeks. The entire roof was torn off and replaced. Found areas already soaked and saturated under a 2 month old roof. It was an area i had a concern with, but was dismissed. Love the roof now. Should last our lifetime.

Note, the locking standing seam we used must be placed on a solid deck, not purlins or fur strips.
87k

 

[EddieWalker]

One of the common things people tell me when they have a contractor that they are not happy with, is they continue with him, hoping it will get better. Always trust you gut and be ready to fire him and find somebody else. The sooner you trust your instincts, the better off you will be.

 

[Steppenwolfe]

We went with standing seam steel for our hill top home. Got tired of losing shingles to the wind. The old roof had been patched multiple times by the previous owner. Got a quote for $50k for 70sq of roofing and jumped on it. I will note that this quote include a full tearoff, gutters for both house and barns, and replacing 9 fixed skylights on a 30+ year old building. It helped that we had a large hail storm and had an insurance coverage for $25k of the cost. Signed the contract with contractor who then subbed it out. Had trouble right off the bat with the sub. Whenever i saw something i questioned, like no wayershieds around skylights or eaves (it was written in contract), i was told 'I don't do it that way '.....mind you i am an engineer by profession and did a lot of research before deciding on a 26ga standing seam roof product.

The last straw was when he was short on flashing for skylights, and reused the old step flashing. Called the contractor for the umpteenth time with the list of concerns once the decking was on but not trimmed. Contractor came out and agreed with my concerns and fired the sub that day. Got his regular crew to come out for a 3-5 day repair. Turned into 3 weeks. The entire roof was torn off and replaced. Found areas already soaked and saturated under a 2 month old roof. It was an area i had a concern with, but was dismissed. Love the roof now. Should last our lifetime.

Note, the locking standing seam we used must be placed on a solid deck, not purlins or fur strips.
87k

As a GC, I never allow a sub contractor to re sub their job out. Never.

 

[jthibodeau89]

We weren't aware the this was a sub. Thought it was one of the contractor's regular crews.

It didn't help that our project manager wouldn't go up on the roof to see our complaints. Got the principle out that sold us on the jpb, and things started rolling. In the end we are thankful our job was completed. Business owner was indicted and many jobs were abandoned. Our roof and 12kw solar system install were completed about 4mo before they went under. We got lucky.