- Putting down underlayment.
is one of the first things you do
on a new roof installation.
So today we're gonna discuss
how to choose the right underlayment for your project
and the best methods for installation.
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What is up guys, welcome to the metal roofing channel.
I am Thad Barnett.
If you follow the channel,
you know that we are in the middle of a standing seam metal
roof installation series
working on Adam Mozella's house.
So we're gonna take this opportunity
to talk about how to dry-in a metal roof.
If you wanna stay up to date on that project,
make sure you subscribe here.
So to help me out,
I have Dave Stubs
from the Sheffield Metal's technical department.
He's got years of installation experience
and he really knows what he's talking about.
So Dave, great to see you.
I appreciate you.
- Thanks for having me.
Glad to be on the Metal Roofing channel again.
- Absolutely.
So first I think it's good to talk
about different types of underlayments,
what exists out there and then how you should choose
the right one for your application.
I know when I started in the business,
it was all about felt paper, 30 pound on the roof,
15 pound on the wall, or some orchestration of that.
And its flexibility was limiting
to what we were trying to accomplish.
And thank goodness, we'd come up with some other stuff.
There's some great synthetic products out there.
There's some great, self adhered products out there.
And those include grazed shark skin.
There's some stuff out there from TAMKO,
so there's just an array of different products
and it depends on the solution that you're going for.
We've come a long way.
I still think there's some better means
to get where we wanna be as far as duration
and flexibility.
And one of the biggest things
is the UVs, how long things can be out in the weather,
out in the sun.
- When you're choosing a product
for your project,
what are some things you should be looking for
in terms of quality?
Specifically you're looking at,
a lot of code enforcement stuff is gonna dictate
what you can use or what you can't use.
More importantly, what you can't use.
In different regions of the country
they like to use different things
and then some of the assembly,
part of the problem
is there's some different assembly theories
or installations out there
as far as where the insulation is,
where you thermal break is
or where the temperature changes
from within and where it projects onto the assembly.
So there's a lot of different criteria when you're going in.
I prefer to use a fully adhered membrane
or a fully adhered dry-in material on the roof.
I think it equips you for a better product,
a greater duration of time that you're gonna stay dry.
It's a little more labor intensive,
but what you get in the end is a lot better product,
a lot more consistent,
a lot less worries before you start
to install your metal panels, less worry after you're done.
You know, what you got.
- So does your geographical location,
as you mentioned, codes already,
but does geographical location factor in
when you're talking about fully adhered synthetic
versus mechanically attached synthetic,
talk to me about that choice.
- All over the country is different criteria.
Let's just take California,
you've got coastline,
you've got snow country
and you've got everything in between.
And so when you're dealing with coastal measures
and high humidity and things like that,
there is the possibility that you want some breathability.
So in which case you'd wanna do a synthetic underlayment
and maybe not appeal and stick
to let the building breathe
or let the assembly breathe,
depending on that criteria in there.
And then of course in snow country,
I always suggest using a fully self adhered underlayment
just for the sheer fact that it's snow.
It's gonna hold some snow.
It's gonna hold some moisture.
And then you've got different thermal movements.
You've got different thermal criteria.
You've got vapor drive.
So that's really important to take into account
when you're using a fully adhered UDL.
It's your best protection.
- Look at Adam's house.
What we've been working on,
this is a before shot of his shingle roof.
You can see he's got a couple pipe penetrations.
There's a chimney there and a couple of valleys.
So can you talk to me about the practical steps
that you need to take in order to dry-in a roof?
We are using Sharkskin Ultra SA
which is a peel and stick fully adhered underlayment.
So talk to me about the practical steps
you would take to dry this roof in.
- First of all, when you're tearing something off,
it's really super important that you clean the surface
in which you're gonna put the new underlayment
for a lot of different reasons.
First, you don't want any punctures
through your new underlayment from the underneath.
So you wanna be without any nails,
remove nails, staples, clean off the entire thing.
That's not something that you need to skimp on.
That's something that has to be done.
It has to be done properly.
You'll see it in every installation guide
to every manufacturer of any underlayment.
And it's super important.
And then from there,
make sure you measure the roof and make sure
that you have enough underlayment.
I see so many times where, oh,
we got everything done except for,
and it's usually the ridge because you need to start
at the bottom.
You need to start at your eave line
and you wanna go across in a horizontal fashion.
And so it starts at the eave
and you work your way up the roof line.
You actually start from the eave at a rake
and work into the valley, go all the way through the Valley.
I say six feet, just because more
is better than less,
but it's really important
that you have enough underlayment
and that extra role could serve you later on
in case something were to happen.
It's never a bad idea to have a little bit
of extra underlayment in case the metal is sharp.
If you're putting a metal roof on the metal is sharp
and the probability of you severing
or slicing the underlayment
is pretty high when you're dealing with sharp stuff,
especially metal.
So always a good idea to have the ability
to patch if necessary,
but start at the eave do a horizontal
and go up the roof line
from your gabble or rake into the valley.
- Yeah, talk to me about the watersheding principle,
you're saying to start at the bottom
and that's due to watershed, is that correct?
Are you talk to me about that?
- Yeah, absolutely.
That's all about watershed.
You've got to keep in mind how the water is gonna go,
and it's generally gonna go downhill.
You've got some capillary action,
but it's generally start at the bottom work your way up.
And that's kind of that lap factor
going up the roof as we go.
So something of that, I actually take it a little bit
and for granted that it just comes secondary nature to me,
but yes, starting at the bottom,
going to the top is the best way to go.
And then when you get to the ridge
or the peak of the roof,
the underlayment goes up and over
and then you lap both sides.
So you actually have two layers at the Ridge.
And you know,
something to keep in mind is try to keep those
as tight as possible
so that you can actually see the top of the ridge.
It's super important to be able
to identify the top of the ridge.
If it gets a little wonky or you get too much buildup there,
it's hard to define that line,
but you'll need to find that line at some point
to do your peak flashing or even a high eave flashing.
So it's always something to keep in mind
to keep your dry and tight.
- So tell me more about the Valley.
Can you get a little more specific
on how you'd finished out that Valley?
You said, bring it over six feet,
the shark skin or the whatever underlayment
you're using over six feet on the Valley.
Talk to me more about that.
- There's a lot of different ways to do a Valley.
I've always been a belt and suspenders guy,
so I would actually lay a bit of a sacrificial layer
in the Valley first and then run my underlayment
into the Valley.
And it goes through the Valley up the other side.
And then the other side goes through the Valley
and up the other side,
and you actually have three layers
of protection going through the Valley because a valley,
is a high area for a high volume of water
and the potential to leak
because whether if you've got a 412 roof
or pitch of a roof 412 and a 412 pitch
of the roof going into a Valley,
it's still the easiest area to walk in.
And it's the easiest area for just traffic.
And so you really wanna protect the valley
as much as possible for both traffic
and with your underlayment for sure.
- So how about penetrations?
I see we have a chimney here.
We have a couple round penetrations,
couple of pipe penetrations.
What do you do when it comes to those areas?
- Once again, you always start at the bottom and you run,
we'll just start with the chimney.
So you run up the face of the chimney.
You run the underlayment up the wall, and then at the sides,
you wrap the sides around the sides and you have to cut it
at a 45 and you tie those around.
I think Sharkskin does a really good job
with their instructions.
They have individual details for all these details.
They do a really good job of showing
how to turn those corners.
And so when, on either side of that chimney,
you turn the corners and then the underlayment
on each side goes up the wall
and goes over those two tabs that you've turned
and that allows the water to get around
and on the backside as the laps go,
everything goes over the top or the lower.
So you've got to, once again,
you've got that water condition of watershed
where the top goes over the lower,
over the top, over the top.
- Yep.
And how about for a round penetration like these pipes here?
- Round penetration is as a little bit tough to describe.
So you've got the round penetration
and generally with your underlayment,
you'll put an ax and put the pipe through.
For me really,
I've always preferred a self adhered underlayment.
In which case you can do an X, put it over the pipe,
and then you can actually cut a ribbon,
maybe depending on the size of the pipe.
And you can wrap it on the underside against the pipe
and down and around and wrap it around the pipe
at the lower end and do the same with the top
for a watershed,
and then always roller it in with a 10 pound roller
or a hand roller to roll that thing
and to make it watertight.
You can use some sealant around there.
I prefer not to use too much sealant
just because it can be a problem later on
when you try to put the boot over the top
of the pipe penetration.
So minimizing some sealant in certain areas,
a lot of the sealants that you use,
you can't go over the back over the top of,
without removing them like silicone,
not the best thing to try to go over.
So sealant really isn't the remedy
for all these different situations,
but a temporary seal is fine.
- So let's look at a couple of other conditions here.
What about when you're coming up to a wall
like in this particular area right here,
what happens with underlayment there?
- So often we get to projects and we're called in
maybe last minute or something.
And it's so important for us to get our underlayment
behind the wall, underlayment or envelope.
We're all trying to build an envelope
to where whatever's on the wall, Tyvek,
whatever sort of wall wrap they're using
or building wrap they're using.
We need to get our underlayment back behind there
to develop and encompass the entire envelope
of the building so that whatever,
if something were to penetrate the wall,
it drains out the wall and above and not behind
our underlayment to let the water escape.
So often we get to these jobs
whether it's a re roof condition or they just didn't,
their sequencing was wrong.
It's kind of a battle
with metal roofing because you don't want other traits
on the roof before or after it's done.
When the product's done.
And it looks really nice.
They can really torture the metal.
They can really scratch it up.
They can do a lot of damage to the roof
when they're trying to put on the siding, whatever it is.
And so predictably,
we try to do a possibly a pre flash
that we can get back to where we put some flashing in
that we can attach to
for the formal final finished product.
It's a pre flash,
and then they can do their wall system
and then we can execute the roof.
And the sequencing works out.
Sequencing and construction
is the most underrated portion of all of it.
And once again,
it even comes down to the basics
of underlayment or your dry-in to the building.
- One thing that we didn't mention
before on Adams houses
is after the entire roof is dried in
and the perimeter flashing goes on,
Sheffield requires another roll of underlayment
to go over the fasteners on that perimeter flashing.
Can you talk about that?
- It's one of our belt and suspenders systems.
No, underlayments great.
And most of them have nail penetration sealability.
Most of them have that,
but it's just another layer of security
if you strip that in, strip your fasteners in,
it limits the water, it limits the condition,
it limits a lot of different things
that can be prohibitive to the metal staying attached.
We don't wanna see,
a bunch of water infiltrating the perimeters.
That's always a bad thing,
but if we can protect it with just a simple use
of self adhered underlayment, it's a better scenario
than not doing it.
- And I know that we could go through all day
about condition after condition.
Cause every roof is different.
You know what I mean?
But I'd like to take a look at one more real quick.
And when you have this kind of roof where it comes up
to a point, you have four hips coming up to a point,
how would you deal with something like that
when it comes to drying in a room?
- You've got a lot of layers
because every hip you're gonna be on one plane.
You're gonna rap to the other side.
And same way with the other side.
So you've got a lot of different back and forth those hips.
So you got a lot of, you know,
you're gonna use probably twice as much underlayment
as you thought you were gonna use.
And then when you get to the top,
I always try to do
one last one last thing on the top,
one last layer on the top,
kind of the crown of the top and try to cover it up.
Look the top, isn't gonna see that much water.
There's not gonna be a lot of water.
That's just gonna sit on top of there,
but inevitably somebody is gonna want
a weather vane up there,
a nice looking weather vane or something like that.
So it's always a good idea to one layer is good.
Two layers is better.
Three layers might be the best.
So I'm just never afraid to use more dry-in
than what's necessary
because it's your last effort
or your last ditch product to keep the water
out of the building and that's our end goal is to keep
the water out of the building.
- What else haven't we talked about
that you think would be important
to mention about this topic?
I think picking out the product
that best suits the installation.
For instance, there's a lot of different products out there
that you think a self adhered, underlayment,
it's apples to apples or it's apples to oranges.
And it's not, there's some products out there
that might only have a five year warranty,
and we're trying to do the best we can
with the products that we have.
Weather tight warranties range, as far as Sheffield,
Weather tight warranties range from five years to 35.
We don't want to specify
or select a product
that is a five year warrantable underlayment
on a 20 year roof.
That just doesn't equate to a good process
or a good selection of product.
So specifically that is so important
to align the warranty with the product.
We really have kind of tied ourselves
to some shark skin, which is fine.
It's not the end all.
If somebody wants to put a different product on there,
we take it in, see what we can find on that product.
We've found some that were less than desirable
to say the least,
but there's still some great products out there.
I'm missing out on some of the trade shows,
looking at new products.
It's always exciting for me
as much of a roofing dork as I am.
I still like looking at new products.
I like to see what's been developing.
A lot of the traction stuff
that's been going on with underlayments,
nothing specific as far as products,
but just the traction that they've developed
when I first started the Cadillac it was Grace Ultra,
into the bike or product and it's very slick,
a great product, just really slick.
Sharkskin's got great traction on it.
There's a bunch of other products
that have wonderful traction on them.
And they've got some great warranties on them,
but we've come a long way.
I don't know where else we can go with good product
durability, great traction,
but inevitably there'll be something new out there
that's better, last longer,
whatever, which kind of excites me
just cause I'm in the business for sure.
- Dave, thanks so much.
I think we got a lot of good information today
when it comes to drying in your roof
and really what it takes
to maintain that weatherability
throughout the whole process.
So if you have any questions, please comment down below.
We'd love to answer them.
Subscribe here to the Metal Roofing Channel.
As always I'm Fab Barnett.
Catch you next time.
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