Framing Studs: Steel vs Wood

Summary

In this episode of the Build Show, the host explores the differences between wood and steel studs in construction. Wood studs are prevalent in residential builds due to their ease of use and renewability, despite imperfections like lack of straightness. Steel studs, favored in commercial construction for their fire resistance and straightness, suffer from thermal conductivity issues that reduce insulation effectiveness. The video discusses strategies to mitigate these issues, such as using exterior insulation and proper masonry anchors, and emphasizes the importance of choosing the right assembly for energy efficiency and code compliance.

Takeaways

• 🏗️ Most residential builds in America use wood studs due to their long history of use and benefits such as renewability and ease of cutting.
• 🔩 Commercial construction predominantly uses steel studs for their standard sizes, straightness, and fire resistance properties.
• 🔥 Steel studs are fireproof and won't catch fire, making them ideal for commercial applications where fire safety is critical.
• 🌡️ Steel studs are highly conductive, which can lead to thermal bridging and reduced insulation effectiveness compared to wood studs.
• 🌲 Wood studs are a renewable resource, with well-managed forests allowing for rapid renewal of materials.
• 🛠️ Wood is easier to work with for residential construction due to its lightweight and availability, despite its imperfections like not being perfectly straight.
• ❄️ Exterior insulation is crucial when using steel studs to mitigate heat transfer and condensation risks, especially in cold climates.
• 📊 The effective R-value of a wall assembly with steel studs can be significantly lower than with wood studs, even with the same insulation material.
• 🧱 The use of exterior insulation, such as Rockwool Comfort Board, can greatly enhance the thermal performance of both wood and steel stud walls.
• 🛑 Proper installation of masonry veneer anchors is essential to avoid creating points of water or air infiltration in walls, especially with steel studs.

Q & A

Why are steel studs predominantly used in commercial construction?

Steel studs are predominantly used in commercial construction because they offer standard sizes, consistent straightness, no rot or warping issues, and most importantly, they are fireproof, which is a critical factor in commercial buildings.

What are the benefits of using wood studs in residential construction?

Wood studs are beneficial in residential construction due to their ease of cutting, availability, structural strength, lower cost compared to steel studs, and their renewability as a natural resource.

How does the heat conductivity of steel studs affect insulation performance?

The high heat conductivity of steel studs can significantly reduce the insulation performance of a wall assembly. Even with high R-value insulation, the effective R-value can be less than half due to thermal bridging, where heat is conducted through the metal studs.

What is the role of exterior insulation in improving the thermal performance of steel stud walls?

Exterior insulation, such as mineral wool, plays a crucial role in improving the thermal performance of steel stud walls by acting as a 'sweater' for the building, reducing thermal bridging and increasing the overall R-value of the wall assembly.

Why might wood studs be a better choice for residential construction despite their imperfections?

Wood studs might be a better choice for residential construction because they have insulating properties, reducing the risk of condensation and thermal bridging. They also have a higher R-value per inch compared to steel studs, which are almost zero due to their conductivity.

What is the significance of the study conducted by the Canadian Mortgage and Housing Corporation on steel stud residential construction?

The study conducted by the Canadian Mortgage and Housing Corporation found that residential houses built with steel studs had issues with moisture, mildew, and corrosion due to thermal bridging, highlighting the importance of proper insulation and moisture management in such constructions.

How does the Proo AR-Guard system contribute to the performance of commercial buildings?

The Proo AR-Guard system contributes to the performance of commercial buildings by providing a continuous membrane that acts like a rubberized bedliner, offering a water and air barrier, which is crucial for the building's envelope performance.

What is the purpose of the Thermal Grip MVA masonry veneer anchor in construction?

The Thermal Grip MVA masonry veneer anchor is used to securely fasten masonry veneers to the studs, whether they are steel or wood. It ensures a tight seal against water and air infiltration, especially when used with exterior insulation.

Why is it important to avoid missing studs when installing masonry veneer anchors?

Missing studs when installing masonry veneer anchors can create holes in the gypsum sheathing, which can lead to water or air infiltration. It's crucial to accurately mark and hit the studs to maintain the building envelope's integrity.

What assembly values can be achieved by using exterior insulation on both wood and steel stud walls?

Using exterior insulation can significantly improve the R-value of both wood and steel stud walls. For a 2x6 wood-framed wall, the overall wall value can reach 22.7, while for a 2x6 steel stud wall, it can increase to 14.4, effectively doubling the R-value with just an inch and a half of exterior insulation.

Outlines

00:00

🏗️ Wood vs Steel Studs: An Overview

The video script introduces a comparison between wood and steel studs, two common materials used in construction. It highlights that wood studs are prevalent in residential construction due to their benefits, such as renewability and ease of use, despite their imperfections like not being perfectly straight. Steel studs, on the other hand, are favored in commercial construction for their standard sizes, straightness, and fire-resistant properties. The script sets the stage for a detailed exploration of the differences and applications of each material.

05:01

🔥 Fire Resistance and Conductivity

This section delves into the fireproof nature of steel studs, demonstrating their ability to withstand direct flame without catching fire, a critical feature for commercial buildings. It contrasts this with wood studs, which can ignite and burn. Additionally, the script discusses the high thermal conductivity of steel, which can lead to heat transfer through the material, potentially affecting the insulation performance. The example of a thermal camera is used to visually demonstrate the heat retention on steel versus the self-extinguishing nature of wood.

10:03

🏡 Residential Construction Challenges

The script addresses the challenges of using steel studs in residential construction, focusing on the issue of thermal bridging, which significantly reduces the R-value of insulation when used with steel studs. It references a study by the Canadian Mortgage and Housing Corporation that examined the long-term performance of steel stud construction in residential homes, revealing issues with moisture and condensation due to the cold surface of the metal. The discussion emphasizes the need for careful consideration of construction materials in relation to climate and building science.

15:06

🧱 Exterior Insulation and Masonry Anchors

The final part of the script discusses strategies to mitigate the thermal bridging issue in steel stud construction, particularly the use of exterior insulation like Rockwool's Comfort board. It explains how this insulation acts as a 'sweater' for the building, improving its energy efficiency. The script also introduces the Proo Thermal Grip MVA masonry veneer anchor, a product designed to secure masonry to studs without compromising the insulation's effectiveness. The importance of proper installation and the avoidance of gaps in the insulation are emphasized to ensure the building's energy performance and moisture management.

Keywords

💡Wood Studs

Wood studs are vertical structural elements used in building construction, typically made from lumber such as pine or spruce. They are commonly used in residential construction for framing walls. In the video, wood studs are contrasted with steel studs, highlighting their benefits such as being renewable and less expensive, but also their downsides like not always being perfectly straight and the potential for rot and warping.

💡Steel Studs

Steel studs are metal framing members used in construction, known for their strength and durability. They are standard in commercial construction due to their fire resistance and straightness. The video discusses how steel studs are almost always used in commercial jobs and are preferred for their consistent straightness and lack of issues like rot, but they are less common in residential construction due to their high thermal conductivity.

💡Thermal Bridging

Thermal bridging refers to the thermal shortcuts created by materials with high thermal conductivity, such as steel, that conduct heat more effectively than the insulation around them. In the context of the video, thermal bridging is a concern with steel studs because they can conduct cold from the exterior to the interior, potentially leading to condensation and reduced energy efficiency within the wall assembly.

💡R-Value

The R-value is a measure of thermal resistance used in the building and construction industry. It indicates the effectiveness of insulation materials in preventing heat flow. The video explains that wood studs have an R-value of about R1 per inch, contributing to the insulation value of a wall. In contrast, steel studs have almost zero R-value due to their high thermal conductivity, which is a significant factor when considering energy efficiency in construction.

💡Fireproof

In the video, 'fireproof' refers to the property of materials that are resistant to catching fire or spreading flames. Steel studs are highlighted as being fireproof, as they do not catch fire even when exposed to high temperatures, making them ideal for commercial construction where fire safety is a critical concern.

💡Condensation

Condensation in the context of the video refers to the formation of water droplets on cold surfaces when warm, moist air comes into contact with them. The video discusses how steel studs, due to their high thermal conductivity, can create cold surfaces that may lead to condensation within wall cavities, especially in cold climates, which can cause moisture and potential damage to the building envelope.

💡Exterior Insulation

Exterior insulation is insulation material applied to the outside of a building's structure to improve energy efficiency and reduce heat transfer. The video emphasizes the importance of exterior insulation, especially with steel stud construction, to mitigate thermal bridging and enhance the overall R-value of the wall assembly.

💡Rock Wool

Rock wool, as mentioned in the video, is a type of mineral wool insulation made from natural minerals like basalt. It is used for both cavity insulation and as an exterior insulation product called Comfort Board. The video discusses how rock wool can be particularly effective as exterior insulation, helping to increase the R-value of a wall assembly and reduce thermal bridging.

💡Thermal Grip MVA

Thermal Grip MVA, as highlighted in the video, is a masonry veneer anchor system used to attach masonry to the exterior of a building, especially in conjunction with exterior insulation. The video explains how this system works with both wood and steel studs, providing a secure anchor point for masonry while accommodating the thickness of exterior insulation layers.

💡Proo AR Guard

Proo AR Guard is a fluid-applied air and water barrier system mentioned in the video. It is used on the exterior of commercial and residential buildings to provide a protective membrane that seals out moisture and air infiltration. The video discusses how Proo AR Guard can be combined with exterior insulation and masonry veneer anchors to create a robust and energy-efficient building envelope.

Highlights

Wood studs are traditionally used in residential construction due to their benefits and long history in the U.S.

Steel studs are almost always used in commercial construction for their standard sizes, straightness, and fireproof properties.

One of the main reasons for steel studs' prevalence in commercial construction is their fire resistance, as demonstrated by the torch test.

Wood is easier to cut and find, with lumber yards widely available across the U.S., and is typically less expensive than steel studs.

Wood is a renewable resource, with well-managed forests providing a rapid supply of wood studs every 20 years.

Steel studs are highly conductive, which can lead to thermal bridging and reduced insulation effectiveness compared to wood studs.

A study by the Canadian Mortgage and Housing Corporation found that residential houses built with steel studs had issues with moisture and condensation.

Exterior insulation, such as Rockwool's Comfort Board, can mitigate the thermal bridging effect in steel stud construction.

The Masonry Veneer Association discusses the risks of condensation in steel stud construction and the importance of proper insulation.

Proo's Thermal Grip MVA masonry veneer anchor is a two-piece tie designed for attaching masonry to both steel and wood studs.

Rockwool's effective R-value chart shows that adding exterior insulation can significantly increase the overall R-value of a wall assembly.

For a 2x6 wood-framed wall with exterior mineral wool insulation, the overall wall R-value can reach 22.7.

For a 2x6 steel stud wall with exterior mineral wool insulation, the overall R-value can double from 7.1 to 14.4 with just an inch and a half of exterior insulation.

Builders should consider assembly choices carefully, ensuring low risk and compliance with local building codes, especially when using steel studs.

Exterior insulation is becoming increasingly required in building codes across North America for both commercial and residential construction.

Transcripts

all right guys today's build show we're

going to take a deep dive into wood

studs versus steel studs now if you've

been in the business for any length of

time you realize that most residential

job sites most builds are made from wood

we've been using wood in America for a

long time and wood has a lot of benefits

of course one downside is uh the wood's

not always perfectly straight but steel

studs if you're a commercial Builder

this is your wall system you know you

almost never see wood on Commercial jobs

you see these roll formed u-shaped ready

to accept the

drywall very different properties very

different materials let's take a bit of

a deep dive on today's build show and

the differences and why you might use

one versus the other today's build show

wood versus steel studs sponsored by

proo let's get

going

okay so let's start with steel you know

commercial jobs as I said they almost

never have Wood Construction it's almost

always steel construction and there's a

lot to like when it comes to Steel

standard sizes and other words just like

you know typical Lumber you can get what

we call pre-cuts Made For Your Standard

wall Heights they're always straight

there's no rot issues there's no bow and

warping you're never pulling on off and

siding down it to see if it's going to

be nice and straight for you but one of

the big reasons it's used in commercial

construction is this right here

fireproof right I can run this torch on

this steel stud all day long and it's

not going to catch fire at some point it

may get hot enough to melt but it's not

going to be a source of fire and that's

one huge reason you see it in commercial

construction all the time now wood on

the other hand when we uh frame houses

we do need to be a little bit particular

when we're using our wood because wood

has some downsides like it's not always

perfectly straight uh it's certainly

heavy you can get

splinters um however it is extremely

easy to cut it's also really easy to

find there's lumber yards all over the

us that you can get these uh it is

structural it's typically less expensive

than steel studs and of course one of

the big reasons I like it it is God's

material right here it is renewable

those trees grow incredibly quickly

every 20 years a well-managed forest is

cut we're able to get these rapidly

renewing wood studs and so I'm a huge

fan of wood and one big reason why you

see this in residential construction

besides of course the history is that

it's structural you can get structural

steel but most of the time when you see

steel studs in commercial buildings it's

in a nonstructural application where

it's only holding drywall on one side or

the other

but why are we not using steel studs

more in residential construction if you

were to ask me I think there's one big

reason and it kind of goes back to one

of the big benefits we talked about so

check this out line it up one two 3 four

five 5 seconds and look how hot that

steel gets of course it's going to get

hot right cuz we just heated it up

but look as I run my Fleer camera back

all the way to the back side of the stud

oh I can feel that that's hot back there

let's see if I can actually show you a

value on the back side of that it looks

like it's gone up about I don't know 15

maybe even 20° in just 5 Seconds of

putting that on there now of course you

know what's going to happen to the wood

if I do this but let's let's have some

fun anyways 5 seconds on the wood one

2 3 four

5 oh interesting it's self extinguished

I didn't even have to use my little

water bottle so that's good so you can

see where the where the fire was it's

still hot here but now you could you of

course know what's going to happen I

touched the backs side of that and

nothing it's totally fine back here this

one I can still feel that heat on the

back side of my hand it's still pretty I

can touch it it's under

100° but it's not far off it's in the

upper 90s here whereas this wood stud at

the face it's still hot but back here

where my hand is I'm fine I'm not I'm

not feeling that heat at all here's the

deal steel studs highly conductive steel

right we make wires from steel we make

frying pans from steel it's meant to

conduct heat it conducts heat really

well wood on the other hand does not

conduct heat very well we would never

make a frying pan or try and run the

electrical wiring in our house out of

wood in fact wood has a pretty common

rated R value of roughly one per inch R1

per inch so this 2x4 stud inside your

stud wall is giving about an R4 for

insulation value this steel stud if I

can touch it is still pretty hot almost

zero not quite zero but almost zero

because it's very conductive I found a

really great example of this online on

the website building enclosures online

and Daniel Overbay has this great um uh

illustration here which says look if we

used an r19 bat

insulation uh it would be rated r19 but

if we were to put that bat insulation

inside a stud cavity with 2x6 metal

studs on 16in on Center the actual

effective r value of that wall would

only be R 7.1 so way less than half

the rated value whereas that same bad

insulation r19 rated if we put in a 2x6

wood stud cavity we're going to have an

effective r value of 16 which means that

in residential construction wood is a

great choice and if we're going to use

steel studs we have to take a couple of

other precautions let's go back to the

studio and we're going to break this

down a little bit further I'll see you

back there okay y'all we did a mockup to

try and break this down a little bit

further for you so typical res

residential construction 2x4 often in

the south in fact I built my house with

2x4 construction usually some type of

wood sheathing I'm a big fan of Zip

system sheathing commercial construction

though we talked about this earlier in

the video you know most commercial

construction around North America is

this Steel studing on the exterior of

the building and it's not structural

steel usually that building is held up

by some type of platform uh construction

where you've got uh reinforced concrete

decks being held by Steel and then

you'll see often on the outside of that

the sheathing is a uh gypsum sheathing

it leads to a fire rating for a rated

assembly and then a great option for

adding both an air and a water Bearer on

top of that is this proo AR guard system

you've seen me do some videos on this on

residential but it's all over the

commercial world and really that's where

it came from I've kind of uh encouraged

residential builders to steal that

detail because this acts like a

rubberized kind of like a bedliner on

the outside of that building and you can

see as it goes on it forms a continuous

membrane so we really like that but back

to the point we were making earlier that

steel studs are highly conductive so

that even if I use my rock wol bats in

here I'm still going to have a pretty

big disadvantage for all that thermal

transfer they call that thermal bridging

at each one of these studs which is

going to negate the high r value of the

cavity such that the wall assembly's

overall rating is less than half what

the assembly rating would be if it was

just the bats now the masonry veneer

Association has a really interesting

article on this because apparently it

was pretty common uh in the 80s and 90s

to actually build residential houses

with this type of construction and in

fact there was a study done by the

Canadian mortgage Housing Association

which my Northern friends probably know

all about American builders don't know

much about them but they did a really

interesting study and I'll link to that

in the description below that the

masonry advisory council did a summary

on as they were talking about this type

of construction and they said this study

was houses that were residential houses

built with this type of construction 2x6

depth rather than 2x4 depth like my

mockup shows and they said the study was

done over a 7-year period with this type

of construction and they monitored the

inside of the wall cavities with

thermocouples relative humidity sensors

moisture sensors and pressure Taps and

then four years after they started the

study they opened up the wall to see how

it was performing and they said the

results are startling building paper on

the outside now they weren't using uh

this proo ARG guard they were using

building paper building paper and

exterior gypson board were very wet with

significant amounts of mildew minor

corrosion of the building frame and

fiber glass bat insulation that was very

wet now here's the deal here's the

reason it's not just an energy transfer

that we're worried about when we use

this we have a risk of condensation and

that's what was happening on those

Canadian houses that were built with

this type of construction was real cold

outside that cold was transferring

through and the inside metal just like

you saw my hand earlier getting hot the

inside metal here was really cold and a

cold surface can be a condensation risk

especially in a cold climate in the

winter we have breathing we have cooking

we have showering we have humidity

inside our houses and if any of that air

leaks into this wall cavity it's really

easy to find a cold condensing surface

if this was your construction type the

same can be true with Wood Construction

but because wood is an insulator and has

an R value like I said earlier of about

R1 per inch that there's a little bit

less of a reduction in that risk not

totally though but that's where this

comes in that I wanted to talk about

specifically here and this is how we

mitigate the risk of that condensation

and all that BTU transfer by thinking

about exterior insulation now if you've

saw my uh my house my videos that I've

made a lot used a lot of this product

this is called rock wool rockwool is a

mineral wool insulation and they make it

for both cavities like you see that R15

bat that's made for the interior of a

2x4 wall but they make this product

called Comfort board it's an exterior

insulation

it'd be akin to putting a sweater on in

the winter time rather than stuffing

insulation in between your ribs you get

more benefit from putting a sweater on

the outside if it's cold outside than

you do trying to stuff insulation in

between your ribs and that's what this

comfortb is going to do to our wall

assemblies on both wood framing and

especially in steel framing and these

days with codes changing almost

everywhere in North America and when you

see these steel studs on exterior uh

commercial buildings you're going to see

some type of exterior insulation uh and

you're also seeing a lot of rock wool

that's getting uh High adoption rates in

the states however there is a bit of a

trick to this because now when I fasten

this to either my metal studs or my wood

studs I need to think about that process

because I'm I'm going to have to Anchor

whatever cladding is on the outside now

you've seen me do a a lot of rain

screens where I've got some type of

baton that I'm screwing on and screwing

through into the studs but it's very

typical in commercial buildings and

certainly residential buildings to have

masonry on the outside to have brick to

have stone rock whatever masonry on the

outside and proo sells this really cool

product this is called the thermal grip

MVA masonry veneer anchor it's going to

come in two pieces to your job site this

piece right here is going to have a

washer on it already and you'll see that

this washer has some tongs some kind of

grips on it so it'll actually grip

through into that insulation and then

this is actually the masonry anchor that

is going to go on this tie after it's

been screwed in and this is going to go

in the courses of masonry so in between

your Brick Layers where you're mortaring

it on that's going to go in there and

what's cool about this is when we anchor

this into a stud whether it's a steel

stud or a wood stud this can actually

vary in its location of where it's going

to sit in that mortar joint now these

come in various sizes and they're what's

commonly called a two-piece tie where

you've got this little piece right here

this little orange uh anchor that's kind

of Arrow shaped is particularly cool

because when this anchors in and by the

way you're going to get them in all

kinds of sizes I just have four or five

of their sizes here in the table you'll

see that the shaft varies in length

depending on the exterior insulation

thickness when this shaft penetrates

into the gypsum sheathing on the outside

and especially when we've got this proo

AR guard sheathing on here you're going

to see the tip of that shaft actually

penetrate into the gypsum sheathing a

little bit before it stops and that's

pushing against that fluid applied

weather Bearer that we talked about that

kind of rubberized coating in the

outside of the building which is going

to form a nice tight water and air

gasket on the outside of this anchor and

what's cool about these is this is an

all-in-one solution the Mason just

screws these into each of the studs

drops that on and we're done one thing

you do want to note though if you miss a

stud leave it in that's really a big

problem if you start screwing in holes

and leaving those holes cuz now we've

got a place where water or air can get

into that uh cavity because we've made a

hole in the gypsum so if somehow you

didn't mark those correctly and you find

that this driller uh tip right here is

just spinning and is not didn't actually

purchase don't put another one in leave

that one in and move on and put put

another one on that's a really good tip

here guys I think we've uh covered the

most of it I do want to end with some

assembly values for you which I think

are really interesting here by the way

rockwool has an effective r value chart

on their website that you can put in a

bunch of uh assemblies and of course I

made a 2x4 mockup but let's just say

this is a 2x6 mockup use your

imagination if this is a wood-framed 2x6

wall 16in on Center studs and we added

that inch and a half of exterior mineral

wool insulation now we go from that

Comfort bat in the cavity which would be

R23 and roughly R six on the outside for

that exterior instulation to an overall

wall value of

22.7 that's huge that's really really

good number so that exterior blanket

that exterior sweater makes a big

difference for the building now check it

out the same thing but let's say it's a

2x6 metal frame steel stud building if

we use Comfort bat inside the cavity

which is R2 4 but then we put an inch

and a half of mineral wool on the

outside now the whole assembly r value

is

14.4 in effect we've doubled the R value

from before when we only had cavity

insulation you saw that I think it was

7.1 uh on that chart before now we've

gone up to 14.4 so only an inch and a

half of the exterior insulation we've

doubled the overall R value of the

assembly and that's a really big deal

guys lots more information about the

these masonry anchors in particular on

the prco website everything we talked

about today with products I'll put a

link in the description below but if

you're a builder out there thinking

about steel studs versus metal studs

think carefully about the assemblies

make sure that you're choosing an

assembly that's going to be lowrisk and

make sure you're also meeting your codes

for wherever you're building locally

because I suspect almost everywhere

you're building in North America if

you're building with steel you're going

to need some exterior instulation and

almost everywhere in the states these

days too except from maybe a few places

in climate zone 1 2 or three is

requiring exterior insallation as well

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