- Today on Q&A Mondays we are talking about when
and when not to use sealant on a metal roof installation.
(metal music)
What's up guys welcome to the Metal Roofing Channel
welcome to Q&A Mondays
check out all the questions we are talking
about today in the description.
Today we are discussing when and when not
to use sealant in a metal roofing installation.
I got Tim Murphy, Jeff Hock here
back on the episode today.
Thanks for being here guys.
- Thanks for having us.
- So let's start with, different types of sealant.
Tell me about what types of sealant you guys see
and what are typically used in a metal roofing installation.
- Probably the two main types of sealants you're gonna see
is gun caulking sealant, where it comes in a tube
and the second one that's most common
is going to be a tape sealant.
So your gun sealant is going
to be a polyurethane tripolymer silicone.
All of them have their places
you just wanna make sure that they are
used and made for metal roofing.
- Okay - So that's number one.
Your tape sealants, they're gonna be
for metal to metal connections, things like that.
Your gun caulking can be curable or non-curing sealants
depending on the application that you're using
but those are probably the three main specific types
of sealants that you're gonna see in a metal roof system.
- When do you use each type of sealant?
I know you just talked
about metal to metal connections with butyl.
Can we talk a little bit about
you know our metal roofing assemblies, our details
and kinda what that looks like?
- Okay so with tape sealant, again
metal to metal connections.
Any time you have a Z-closure
any time you have an offset cleat
and those work by compression.
So you have your base metal then you're
say a Z-closure, you have a piece of butyl tape
in between it
that gets fastened off every four inches on center.
And that creates a compression seal
between the two pieces of metal.
We suggest going four inches on center
because when you put a fastener through butyl tape
it compresses it out two inches on each side.
- Okay - So that way you
if you say four inches on center
you have a complete seal along the whole area
that you're fastening off.
When it comes to gun caulking
you'll see that we use it in between the panel seams.
Stop any anti-siphoning down by the eave.
We use it on any of our laps, where you lap the metal
from 10 foot pieces, you have your ridge caps
sidewalls, headwalls.
Again any where that you have a metal to metal connection
that's not gonna be fastened off
say with a fastener where you would use a tape sealant.
- And penetrations, pipe boots.
- Penetrations I like to use butyl tape
underneath the pipe boot
because we're gonna be fastening that down
to the metal panel.
At the top of the pipe boot you can use the gun caulking
you know and then you're gonna put a pipe band around that
to keep it from sagging.
You know those are the main points
of where you're gonna use it.
All of our details call out where sealant should be applied
how it should be applied.
The specific types of sealant, the specific types of tape
the sizes, everything's pretty well detailed
in the installation details.
- So does caulking come in different colors Tim?
- Yeah at Sheffield we sell any color that we have on our
color card has a corresponding caulking to go with it.
- The tapes don't come in any color, it's gray.
So you're not gonna get options there
but again, the tape should be underneath the piece of metal
so you shouldn't see it.
The same thing with the sealant.
It's either in between the panel seams, it's in a lap
it is behind a Z-closure that is tight against
the vertical legs of the panel.
You know we offer the color options
because some of our customers prefer that
but that also comes in clear.
Clear is a pretty popular color.
'Cause you can stock it and not have to worry
about matching to your next job.
But again, most of the time you're not gonna see the sealant
because it is a secondary defense
and it shouldn't be oozing out of places.
- There are times though that you do use it
in architectural reasons.
If there are voids in certain connections
against different substrates
or different materials, right, I don't know.
- Like a counter flashing on a sidewall
like a surface mount counter flashing
or something like that.
We do run a bead of sealant across the top.
We have tape as the secondary defense on that.
But the color caulking would match the trim
so it doesn't stick out. - Yeah.
- Say if you're using a standard gray color caulk
or something like that on a painted roof system.
- So that leads us into our next question.
When should you not use sealant?
- You shouldn't use sealant
when you could be using metal in it's place.
You know if you have a large gap
say between your Z-closure
and the vertical leg of your panels.
You don't just wanna fill it full of caulk
You wanna put a Z-closure in that fits properly.
Talking about voids, you know you have a gap;
You wanna put down a piece of flashing that fits properly
proper lap, not just fill it with caulk and call it a day.
It might work fine for a while
but eventually that's going to fail.
A lot of the sealants break down with UV exposure.
So you know any time you have exposed sealant
it's eventually going to fail
and your roof system's going to have issues.
We've seen some just piled on goops of sealant.
You know when we're out there checking roofs
and things like that.
And we have them correct it 'cause
if you have to use half a tube of sealant on something
that's obviously not the answer.
- Yeah. - You wanna take
and you wanna make the flashing that fits properly
you seal it properly
and not count on gun caulk on a 50-60 year plus roof system.
- It goes back to really why, why you're using caulking.
You're not using it to seal the entire building off, right?
The metal is what does that. - Right.
- So let's talk about testing.
And when you talk engineering
and you're actually testing assemblies
when is sealant used on those test assemblies?
- So there's two main ones that we come acrost.
ASTM E2140 is submersion testing.
Just for mechanical profiles
snaplocks won't pass it because
you know the nature of the design of the panel.
But sealant can be inserted into the core of the female leg.
And when the panel is seamed together
it creates a watertight seal in between it.
They actually take and submerge the panel
under six inches of water for six hours
and it acts as a hydrostatic water holding test.
You're gonna see that on low-slope applications
anything below a 2:12 is usually
when we require a sealant on the seams.
We test it with gun caulk.
So we're able to offer our customers
who don't have a hot melt system.
A hot melt actually takes
and inserts a bead of sealant
a hot melt butyl sealant
as the panel's being formed.
Not everybody has that piece of equipment
so we did it with gun caulk as an option.
You know the one thing with the sealant
do use the gun caulk if you're not using a non-curing butyl
'cause if your caulking's gonna set up
you wanna make sure get that seamed
before that sealant sets up.
Otherwise you're never gonna get it to 180 degree seam
but that would be probably the most often time we see it
as far as testing's concerned.
The other one is the TAS 100 wind-driven rain test.
They have a simulation of 8.8 inches of rainfall an hour.
And they actually have a prop engine
that takes and drives this rain into a roof assembly
with a valley, high side ridge,
different flashing components.
So obviously those are gonna have to be installed
with sealant and things like that.
So you know it can create that leak free status.
The only other time that you really see sealant
and it's not always required is
in the ASTM 1646 water penetration test.
Which is a sprinkler test.
Some snaplocks can't pass without 'em
due to the design.
But 90 percent of the time you can get out,
get away without having a sealant on those seams.
So those are the three main ones as far as testing
that we see sealant required in.
The type of sealant
and the application of the sealant is dictated.
- You know we're getting close to
we're in winter now in Ohio.
For sealants that have to cure
is there a minimum temperature
that you can install those to cure properly?
- There is and it depends on the product that you're using.
And it will be on the packaging.
As far as what temperatures you can install it.
As far as high temperature, low temperature
and it will also give you a curing time.
- Okay - So based on the temperature
it might cure faster or slower
depending on the product you're using.
- So let's say if you've got a metal roofing installation
where would you get the sealants, caulkings
that you need for your install?
- Here at Sheffield we're a one-stop shop
so when it comes to sealants we have it all
for your engineered systems
and for your non-engineered systems.
Like I said before it has all the colors
35 different colors.
We have all the different types of tape sealants.
If you guys need butyl hot melt, we also sell that.
And it's available through Sheffield.
- Cool and like Jeff said all the details have
listed out where the sealant needs to be applied
where the butyl tape needs to be applied.
It's very easy to see in the details, do a great job there.
Well thanks guys, really appreciate it.
Comment down below if you have any more questions.
We love answering them every Monday
here on Metal Roofing Channel.
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I'm Thad Barnette and as always I'll catch you next time.
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