What's new
What's new
By:
Advanced search…

OT- Metal roof screws...life of rubber grommets ?

Milacron

Milacron

Administrator
Staff member
Joined
Dec 15, 2000
Location
SC, USA
A few leaks in metal building where I own some flex spaces....metal roofing specialist found the expected loose or missing screws but they also recommend replacing all screws, supposedly 10 to 12 years typical life of the screw seals.... (our building is about 11 years old)

1. true, false...maybe ?

2. $7,500 to replace 6,500 screws seem reasonable ?
 
Not terribly surprising if the screw seal has a cheap design where the force flow is directly through the rubber. With a better design including a compression limiter, it seems a little on the conservative side for a properly compounded EPDM.

What's the actual age of the roof?
 
EPDM rubber, which some sealing screws use, is supposed to be pretty good under UV exposure: Rubber Membrane Roof Life Expectancy: A Complete Guide | Cox Roofing
but if cheaper screws use a lesser grade that's more affected by UV, ozone, or other environmental attacks then perhaps replacement is needed. And sure, most of the rubber is shielded by the metal washer, but there's still open areas for ingress of whatever.

On replacing, it would depend a lot on how corroded the old screws are. If they come out easy, then it shouldn't take more than a minute/screw for replacement. If heads start popping off, then multiples.

Did they do any sample replacements? Are they using the same size screw, or upsizing to make sure good threads are cut? And what's the condition of the roofing? If panels are buckling then more/new screws may be needed to reset the sheets.

For reference, my building has screwed metal sheeting at ~1/10 pitch or so, and some of the trim has come loose from repeated ice dams and the like. So I do have a few places that leak, but it's ~24 years old. If I stay at this location I may move to a membrane roof as in my link.
 
There is a "decal" about 2" round sold just for this reason, IIRC $.33 each.

I assume the labor is the problem though with the seals.
New screws would be faster to apply (even including removal of the bad one).

Have you inquired of a spray on elastomer overcoat ?
 
Are the screws screwed into metal frame or wood frame? I do a lot of work for a construction company that builds metal buildings and one project I was recently at that was 1 1/2 yrs old had a large number of wall screws backed out, some as much as an inch or more. probably 1/2 the screws on this wall were loose to some extent. No idea why.
The rubber should be enclosed under a domed washer so it will be protected from UV and last a long time, way longer than 9 years.
I would climb up on the roof and look to see if they are loose, which is most likely. Unless they use larger screws that will grip the metal tight most likely the screws will cut new threads weakening the metal, and the grip power.
$7500 for a couple guys for a couple days sounds high to me.
 
10 years for screws, obviously from the guy selling you screws.

While the number for replacement is not onerous on a per screw basis, I for one would want a 20 year warranty on the screws.

IF you are not willing to jump on the roof yourself however the question may be moot.

I think a certain amount of weeping may have to be tolerated from an exposed fastener roofing system, but real leaks sounds like the ones that were not installed properly to begin with.

IT probably costs a grand to get a guy on a [tall slippery] roof so I guess it gets kind of pointless to start telling him to only replace the bad ones

I also wonder if it is a all metal building if you are hosed if the original screws come loose and a new screw won't grab, compared to a wood framed metal building [like a Morton round here] where you could theoretically use longer screws
 
My metal roof is about 15 years old. I have had no problem with the grommets/washers deteriorating.
I don't like the way the installers drove the screws home though. They pre-drill the roof panels for all the screws.
My roof is about a 3/12 pitch so it's easy to walk on. The screws near the installer's feet are installed nearly perpendicular
to the roof. But as he leans forward to drive the up-hill screws, he tilts the screw gun towards himself. If he isn't careful the screws are driven at a angle with the upper side of the washer barely touching the metal.
Some screws have backed out a little but I think that may be because of snow and ice sliding off the roof.
D, no worry about that for you.
 
The problem with metal roofing screwed to wood is as the screws back out a little the water can seep under the head into the wood, thus rotting the wood. If you dont stay on top of it after a while the screws are not holding on to anything.
 
Milland said:
I'm interested in this, but laying an insulating foam cap first, then coating. Any experience with that process? I've heard some horror stories about roofing foam getting waterlogged and becoming a real mess.
Click to expand...

Nope, plain rubber like material, no foam.
YouTube

first part of the video shows the process that I had a local vendor do to
a rusty leaky roof for my client.
 
And this is why when I built my last shop I used a hidden fastener system on the metal roof. It could be worse for you. On my property, have an old barn with a metal roof with ring shank rubber washered nail. They are either loose or leaking. All have a dab of tar over them. Thank god that pile of crap building is coming down this summer.
 
Flail said:
And this is why when I built my last shop I used a hidden fastener system on the metal roof. It could be worse for you. On my property, have an old barn with a metal roof with ring shank rubber washered nail. They are either loose or leaking. All have a dab of tar over them. Thank god that pile of crap building is coming down this summer.
Click to expand...

What color is the bad roof ?
 
digger doug said:
Nope, plain rubber like material, no foam.
YouTube

first part of the video shows the process that I had a local vendor do to
a rusty leaky roof for my client.
Click to expand...

If I go membrane, I need to add insulation too, which is why I mentioned it. But I have to do some serious research first, like I mentioned I want to avoid water or other crap that could degrade the foam. Applying insulation to the inside of my building is a real headache, hence the cap idea.
 
Flail said:
What color is the bad roof?

Galvanized.
Click to expand...

I see allot of new metal roofs going up, and some are black.

I have a white/silver one, and I can hear it go "tink-tink-tink" when a cloud
covers the sun.
So movement of the tin is sometimes what causes the fasteners to loosen/pop out.
 
Rob F is correct on the need to use an oversize screw when replacing screws in a metal roof. I wouldn't sign on to replacing all the screws unless I had a third party recommend this - one that isn't financially interested in what the answer is. I've been on the professional side of roofing a LONG time, and this is the first time I have heard anything like this - sounds fishy as hell.
Milland, for meany metal roof panel profiles you can get strips of rigid insulation made to fit the "pans" of the roof. Then you can mechanically attach a good membrane down to the still sound but leaking metal roof panels, or into the deck if there is one. And get a 20 year warranty.
I try to stay away from "roof in a bucket" solutions. Look at the warranties that are offered with those.
Any metal roof is going to move with temp changes, doesn't matter what color it is.
 
My shop metal roof is about 25 years old but tall trees on the side shade it for parts of the day and, I assume, reduce the sun damage to the screws washers. However about four or five years ago I've noticed a few small leaks around some dozen random screws. The leaks were small and rather than replacing the screws I've decided to experiment with sealing the leaks. I used Thompsons Water Seal in a 3 gallon garden sprayer and on a hot summer day, after pressure washing the roof I've sprayed a small circle of the liquid around each screw (standing on a ladder and with a long wand in the garden sprayer. My 12/6 gable roof is only about 15 feet on each side so I could reach without climbing on the roof).
The leaks are gone and did not reappear since the treatment. Thompsons Water Seal is a paraffin wax solution and penetrates deep around the screws. Paraffin is an excellent sealer (old timers might remember it being used to seal jelly and jam jars) and even if I have to repeat the process every five or six years it will not be a problem.
 
I also have a 25 year old galvanized metal roof on metal purlins, and no leaks yet... except in one small area, which happens to be down pitch from the exhaust stack of a natural gas fired unit heater. The only screws affected were at the roof edge where the lower middle of the contoured panels were screwed to the eave, and I assume water could puddle around these screws. The odd thing was, the roof sheet had holes rusted through under the heads The quick fix was to replace the screws with larger, placing washers bedded in caulk under the heads to capture the metal. Can't say why the weird corrosion problem, but suspect something in the products of combustion from the heater is mixing with the rain water to make a mild acid.

Dennis
 
You must log in or register to reply here.

Similar threads

B
OT? shop roof
2
Replies
36
Views
4K
bryan_machine
B
R
Wear on splines of output shaft of a gearbox
Replies
8
Views
6K
Peter Colman
P
Fal Grunt
Brother - 6 Month Report
3 4 5
Replies
99
Views
26K
DouglasJRizzo
DouglasJRizzo
P
Life with a fiber laser
Replies
0
Views
6K
PracticalMan
P
P
A Production Line Takes Shape
Replies
0
Views
5K
PracticalMan
P








 

ABOUT PRACTICAL MACHINIST

With more than 10.6 million unique visitors over the last year, Practical Machinist is the most visited site for metalworking professionals. Practical Machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. Register for the world’s largest manufacturing technology forum for free today to stay in the know.

Learn more about us.

STAY CONNECTED

Facebook Instagram YouTube LinkedIn Pinterest Twitter Tiktok

Register Become a forum member. Register today.

Sign Up Sign up for our e-newsletter.

© 2024 Copyright Practicalmachinist.com. All Rights reserved.

Back
Top