Pressure-treated lumber is a strong and reliable option for wall studs, but it does not stain or seal exceptionally well. The International Building Code requires siding and stud walls to be pressure treated, as there is a good chance that moisture can reach the wood. However, there are concerns about using treated lumber for interior applications, as there is no danger.
For outdoor projects, pressure-treated lumber can be used, but it requires hot dipped galvanized nails to fasten it in place. The treatment will rust, and wood framing is permitted in some aspects of all five construction types. Exterior walls in Types III and IV buildings are required to be fire retardant-treated.
Lightweight steel framing is becoming increasingly common due to its durability, uniform shape, and resistance to fire and moisture. If the framing will be protected from weather and not in contact with the ground or foundation, untreated wood is generally appropriate. Use pressure-treated wood for any part of the framing that will be in contact with concrete or potentially exposed to moisture.
For studs, it is important to prevent the wood from getting wet and treat it as a Band-Aid. Using treated lumber only addresses a symptom and not the entire structure.
The International Building Code requires any lumber touching concrete to be pressure treated, including wall studs. However, treating the exterior and interior concrete surfaces to make them more impervious to water penetration is not recommended due to two reasons: treated lumber shrinks as it dries and not at the same rate. If the lumber could potentially get damp or would be difficult to replace, treated timber should be used. In fact, putting plastic on the bottom of the studwall on the concrete is unnecessary.
📹 Framing Studs: Steel vs Wood
Matt puts both steel and wood studs to the test to figure out which is best for residential use and then tests out a new product from …
Do you need plastic on exterior walls?
Building codes based on climate zones require vapor barriers on a structure’s interior or exterior. In Marine 4-8 climate zones, Class I or II vapor retarders are required on the wall’s interior frame. Climate zones 1 through 3 do not require vapor retarders. ASTM E96 assigns a material’s ability to restrict moisture by assigning a class of barrier or retarder. Vapor barriers stop vapor diffusion, while vapor retarders slow it. Class I vapor retarders are 0.
1 perm or less, while Class II vapor retarders are 50 to 100 times more moisture than vapor diffusion. A superior air barrier system, like Polyguard’s, is needed to limit or prevent moisture accumulation and condensation in the building envelope.
Are 2×4 studs treated?
Lumber, including 2×4 and marine plywood, is pressure treated or not. While pressure treated wood is durable and resistant to insects, it may not be suitable for every application. When choosing window treatments, consider the desired level of light in your home. Some prefer blinds that allow light in, while others prefer treatments that block harsh sun rays. Larger slats allow more light in, while smaller slats create an ambient glow.
Some blinds are better behind curtains, so consult with window treatment professionals to determine the best option. By understanding these factors, you can streamline your shopping experience and make the right blinds for your home.
Can I use untreated timber outside if I paint it?
If your outdoor wood is untreated, it’s crucial to treat it immediately to prevent rot, fungi, and weathering. Use a wood preservative, either a wax-enriched preservative or a wax-free preserver, for an all-round coating. If the wood is dip-treated or paint-stained, it may fade after 6-12 months and provide less protection against the weather. Treat this with a wood stain, paint, or preserver. You can treat un-treated or dip-treated wood at any time.
Are studs untreated?
Wood stud walls may be constructed with fire-retardant-treated or untreated wood studs. The use of fire retardant-treated plywood in designs incorporating untreated plywood is permissible, provided that all other specified attributes are equivalent to those of the wood structural panel utilized in the design.
How long will untreated timber last outside?
Untreated timber has a shorter lifespan compared to treated timber, lasting between a few months and two years. Factors affecting its longevity include sun exposure, moisture absorption, type of timber, and exposure to insects and rodents. Sun exposure depletes natural oils in wood, leaving it dry, discolored, and disfigured. Moisture, from humidity, rain, or snow, can cause expansion and shrinkage. Certain timbers, like redwood, white oak, cedar, and cypress, can sustain themselves untreated, while others like alder, hemlock, and pine should be avoided.
Exposure to insects and rodents also impacts the longevity of timber. To prolong its lifespan, it is recommended to use untreated timber for indoor projects, out of direct sunlight, and in humid environments. Opt for timbers that can handle life without added support.
Are exterior wall studs load bearing?
A load-bearing wall is a wall that can support more than 100 pounds per linear foot of vertical load, while a non-load-bearing wall is any wall that is not a load-bearing wall. Common questions when determining if an exterior wall on a multi-story building is load-bearing include:
- What is the load capacity of the wall?n2
Do exterior walls need waterproofing?
Waterproofing exterior walls is crucial for property integrity and prevents moisture seepage, leading to structural damage. Regular inspection, thorough cleaning, application of waterproofing sealant, installation of drainage system and vapour barrier, and maintenance are essential steps. Birla White Seepguard is a high-quality waterproofing product designed to protect exterior walls from water damage. It is a two-component system with a primer and topcoat, providing a seamless barrier against water penetration.
Birla White Seepguard is highly resistant to UV rays, ensuring long-lasting protection even in areas with high sunlight exposure. Regular maintenance ensures the system remains effective for years to come.
Do you need treated wood for stud wall?
In the case of framing parts that will come into contact with concrete or be exposed to moisture, it is recommended that pressure-treated wood be used. Conversely, standard wood may be employed for studs and headers that are not in direct contact with these elements.
Should exterior walls be treated?
In the event that an exterior wall is situated in direct contact with a foundation or slab, it is imperative that all lumber in proximity to the aforementioned structures undergo preservative treatment. Furthermore, wood sheathing situated at a height of less than 8 inches above grade must also be treated with a preservative.
Do exterior studs need to be pressure treated?
Outdoor wood should be pressure-treated according to the AWPA, as its use determines the necessary treatment. For indoor or outdoor projects involving humans or pets, extra precautions are necessary. The chemicals in pressure-treated lumber are pesticides, so handling them with the same precautions as hazardous materials is crucial. Wearing gloves and face protection is recommended, as sawdust from cutting the wood can be irritant. Painting exposed wood surfaces with water-repellent finishes, paint, or stain can protect skin if leaning or kneeling on the sides.
Can untreated lumber be used outside?
Before investing in treated or untreated wood, consider project needs, indoor vs. outdoor, aesthetics, and maintenance requirements. Treated lumber is ideal for outdoor use, while untreated wood is best for indoors due to its manufacturing process that protects it against weather and pests. While treated wood can last up to 40 years with proper care, untreated wood can last forever if regularly maintained. Both types of wood have their advantages and disadvantages, so it’s essential to choose the right choice for your project.
📹 DON’T make this mistake! Learn from mine. Basement wall Framing. WINNI
I made a Rookie Mistake when framing out my basement wall. All basement walls need to have some type of vapor barrier, and i …
Matt, I have watched and enjoyed your articles for a couple of years. This was one of the most informative I have watched. 23 years ago we built our house with 12 gauge light gauge structural steel framing (including trusses) and have never regretted our decision. We live in Florida and thermal bridging was a concern. I used 1″ Polyiso as exterior insulation and 4″ open cell foam for cavity fill. When I opened walls for modifications I haven’t found any moisture nor mold. In the last 2 decades bulding science and materials have come a long way. To do it over we would incorporate some of the new concepts but still go with steel studs. Thank you for the work you do in bringing interesting, informative articles for our education and entertainment Keep up the good work.
No. Look at communities burned down by wildfires. Steel studs, metal roofs, siding and cars, gone. I rebuild after wildfires and we burn test with the ICC and Intertek. It takes MGO, fiber cement, concrete, Rockwool and intumescent coatings to build fire resistant homes. A propane torch doesn’t simulate a wildfire with wind driven flames and 1500 degrees.
Perhaps you could feature a steel-framed house in a future show. Back in 1995, I was Owner/Builder of a house with a detached garage, both 2-story, in FL. Above the monolithic slab the exterior walls, floors & site-built roof trusses were 18ga engineered to 150mph and energy efficient; with all electric appliances and heat pump, the power bill never exceeded $150. For those that are still reading the exterior was fiber-cement siding, ½” PolyIso to prevent thermal bridging, 5.5″ cee studs with 2″ flanges for easier sheathing attachment, blown cellulose insulation, and ½” gyp board interior. With a non-combustible structure, the insurance rate matched masonry and weathered 3 hurricanes with no damage. Without a food source, there was also no need for termiticide poison. Although it does require different skills and tools with self-tapping screws, I would never build another house or apartment out of 2x wood.
@16:02, this dude is promoting wood stud over steel stud by emphasizing the superior energy conservation property of wood stud framing over steel stud framing. As not all building are located in very cold or hot geography, the higher R value of a wood stud framing is not that persuasive. As most building uses 2×4 framing rather than 2×6 framing, the article’s showing the R14.4 value of steel stud framing is sufficient. Finally, it’s the total cost of ownership of a building that matters, not just R values. Steel stud framing doesn’t warp, crack, split, rot, mold, or suffer terminate infestation — all vulnerabilities of wood stud.
Matt, love your article’s & always insightful. I am building a 2 story home with structural steel studs & I beams for several balconies. One of them being 50 ft long & super heavy. The project has 2×6 studs & steel trusses in California. The area is considered a high risk fire zone. I shear walled the home with radiant barrier & plywood. After perusal your article, I wished I had used the rockwool on the exterior. Right now I’m insulating the wall cavities with R23 Rockwool & turning the 24 inch batts horizontal so they will fit tight. Its time consuming with a few more cuts. I’ve personally framed several homes with wood & it’s so much easier to work with. This may not be an orthodox way to go & certainly more time consuming, but the house feels pretty comfortable. Structural studs are also pricey compared to wood. One benefit with steel has been altering the floor plan a few times, since its easier to disassemble & rebuild with less material loss. I don’t regret the choice in building materials, but would recommend wood for most residential builds for time & expense.
Hey Matt! I’m a huge fan of your website. Something I haven’t noticed you covering that I’d love to learn more about is how to apply passive house standards to mid-rise residential buildings like the three-story walk-ups you see all over cities like Chicago. We already know that, pound for pound, these are much, much more environmentally friendly than detached single-family homes; I’m very curious to know what would be involved in building a new one to a high standard of quality and sustainability!
This brings up something I have commented on before, with no good answers. It is acceptable to have steel studs in commercial installations (think strip malls, light commercial, retail, etc.), where the exterior wall is essentially a curtain wall of steel studs, with the remainder like noted in this article (gypsum exterior for example). If one tries to do the same thing in Residential then there are a multitude of objections, also related to things noted in this article. My questions is why is there a such a difference in practice and acceptable structures between commercial and residential? They contradict each other. Just curious to hear thoughts from others.
The beauty of metal studs in commercial interior walls is they are easy to take down when a new tenant moves in and needs a new floor plan. I think that’s called “build out”. They’re non load bearing, can be removed or added and easy to run data/electric to. There’s really no reason to use metal studs in residential in the USA.
The main reason steel isn’t used IMHO is that builders do not want to train their crews to build with steel. And especially here in the Southwest where a significant amount of the residential labor (in both custom and tract built homes) are ‘undocumented’ and being paid significantly less than commercial, usually union, carpenters. With modern code, Zip R sheathing is almost required and would eliminate thermal bridging. Given the other advantages of steel, for me it is that it is STRAIGHT, there are significant savings in downstream trades, and ultimate finish quality. I am seeing multi-million dollar ($10,000,000.00 to $100,000,000.00) homes being built here in Las Vegas using wood stud walls, OXB sheathing and building paper (Tyvek) wrap with “blue” paper as flashing. It almost makes you ill to see. Slightly off topic, but they are also building almost 5 story 100+ unit apartment buildings, in wood. To wrap up, I would advocate to move all structural to steel stud (which is also recyclable) and use wood for real finishes, to bring the nature inside, instead of hiding it in the walls.
Discussed this with a commercial contractor in the US. Doing interior work. Is cheaper for them to do metal studs. the advantages of steel studs are. Pack of studs easier to bring to job site. Easier to wire and plumb the wall. Sheers kept in the pocket can be used to make adjustments. Versus Weight of wood. Not to mention shipping costs. Have to use a saw to trim. Not to mention the dust. For this contractor is cheaper to do. And quicker.
@2:56, steel stud for structural application is readily available. Wood stud is structural only when not dry-rot or termite infested. Residential building built with steel stud last much longer than one built with wood stud. Why do homebuilder insists on wood stud? Lower initial cost. Who bears the long term cost? The home owner.
Cavity insulation with steel studs is not a good use of insulation. With steel studs, it’s better to put all the insulation on the outside. Also, that R7.1 number for a steel 2×6 with cavity insulation didn’t indicate the gauge of steel. A 12 gauge stud is about three times thicker than a 20 gauge stud, so it’s about three times more conductive. One more thing: 16 inch spacing with 2×6 steel studs doesn’t make any sense in residential construction — even with extreme wind and seismic loads. Reasonable spacing would be 24 inch OC.
I finished my basement with steel studs. I found it very easy to work with once I got the hang of it. Measurements were easy and squaring off with a magnetic level did the trick ! Bulkheads were easy too, I went to Home Depot to get them to precisely cut the rungs of the bulkhead “ladders ” Everything came out nice and square . No mess of sawdust and no warped wood ! ( hockey sticks) . The basement was pre insulated !
@6:17, While steel stud reduces the R value of a wall, it is non -combustible. For Single-family residential construction the Building Code doesn’t require fire-rating the structural components, such as wall, column, floor, roof, or shaft. Such construction is commonly designated as VN construction. However, a multi-residential building requires a minimum fire rating of 1-hour. 1 hr fire assembly using steel stud can easily satisfy than wood stud whose fire assembly is a tad more complicated.
I have built with metal stud in domestic applications in the UK for over 20 years. Either for partitions or with thicker gauge to infill on concrete frames. Recently I have used it structurally for a panelised house system. 100mm studs filled with earth wool. Sheathed with OSB then 125mm PIR wraptite membrane void formed with a steel top hat section and then a cement board for either brick slips or render. Plasterboard finish internally applied after fitout on site. This system passed all the necessary fire tests and has minimal thermal bridging and great U (r) values. Light weight and stiff with no shrinkage!
Thank you for the insulation comparison. Another big reason not used in residential construction is NON-LOAD bearing structure. There usually isn’t enough NON-LOAD bearing walls in a residence to justify using both stud styles. They are more expensive and require a different toolbox. It could make sense in a remodel adding in walls though.
Maybe when you get time you could let me know what this bucket of rubberized mat that you can roll on we are very curious to where we could purchase this or if any of the big box stores like Lowe’s or home Depot carry something similar to roll on the outside as it rubber coating could you get back to me and let me know??
Incorrect. Exterior wall studs are a much higher gauge than those you show. I’m in commercial construction. You’re using studs intended for interior walls. You are correct that most commercial construction use I-beam or reinforced concrete construction and a lot of smaller buildings, such as schools, use concrete block construction. However, in places between the steel or concrete columns, a heavy gauge stud is used. Many times, a building often has a grand entrance with high ceilings and it’ll be completely framed with thick rigid structural studs. Most modern commercial construction uses either Rockwool or spray foam exterior insulation. Fiberglass is mostly used on interior walls for acoustic reasons between rooms.
Exterior walls Three things 1. Rain screens to drain any water that gets past the veneer. Many sidings are just decorative and require this. 2. Vapor (edit not Air) permeable weather barrier. Moisture going to be in the wall. Needs to get out to avoid moisture issues. 3. Continuous Insulation outboard the wall. All or greater than half the r value outboard. whether wood or steel. Cavity insulation just isn’t as effective. Higher degree of installation faults.
Being that I am late to the party, I might be repeating many comments and concepts. This is not going to be a quick read. Sorry about that Matt. Whether you use Cold Form Steel (metal studs) or wood-based products, there are many pros and cons to carefully consider. My comments will focus on the metal framing for a residential home that is energy efficient and built for today’s ever changing weather conditions. Feel free to have your opinion and conclusions on this topic. A health conversation is the best thing. To begin with, using a 3 5/8 or a true 4 inch metal stud in either 16 gauge or upgrading to 14 gauge stud is the optimal size and strength based on the gauge. Yes, they are straight. The width of the metal stud known as the flange size is typically from 1 3/8 to 1 5/8 inches depending on the manufacture. Larger flange sizes are available and will increase the cost. Depending on your load requirement and distance, a header can be from 18-12 gauge. Again, depending on the engineering requirement, you can use a metal stud or switch over to a metal C-Joist that has the same characteristics as the metal stud. The standard flange size for a C-Joist is 2 inches. Each manufacture has various options for blocking from flat stock to u-channels. You can go either 16 inches or 24 inches on center. Based on today’s pricing, a metal framing members are more expensive than a conventional wood stud, but, not still in the range of a engineered wood product (“EWP”). Just like Builder’s First Choice Ready Frame service using wood products that Matt mentions alot, there are the same for metal framing from various sources and can be found on the web also.
This is good information, 25 years ago I built and all steel residential home, but the climate I was in didn’t have the condensation issues so I didn’t see wet inside the walls. Fast forward to today and seeing the improvements made to residential construction I would follow a different design methodology that removes the issue with thermal bridging. (Think metal SIP) There is a company that does this called Thermasteel but they were in bankruptcy and I don’t know if they are out of it yet. If I could make two other points, the steel house was sound reflective, I would definitely use sound proofing in more places. Also TRIM is a pain in the arse have you ever tried to set base board in a metal track… it sucks. I would definitely adjust the height of the house walls so I could put a strip of wood along the base (thickness matching the wallboard) and if necessary along the top for crown molding so trim goes on with pins, there is still a shoot back from the nailer possible, but having wood is Sooo much better than steel track. Oh and buck the windows with wood too. -MG P.S. metal floor joists need a de-greaser, the roller form used for manufacturing sometimes leaves oil.
Do you still need a moisture barrier on the inside in a very cold climate? I would think you would want to keep the moist air away from the steel even if it is better insulated. Another reason to go with steel framing for multiunit residential is the number of arson events on those building sites, at least that’s true in the SF Bay Area.
I soon will be moving from California into a brand new house in Chile framed in steel. It has 4 inch EPS on the exterior then covered in stucco. The wall cavities have fiberglass. The walls have no sheathing and instead use steel straps/bracing for rigidity. The second floor is a poured slab on some sort of corrugated metal. Its supposed to be much more energy efficient than most tract housing in that country. It was very interesting to see something so different than what im used to here in the US.
So your statement that curtainwalls dont use structural metal at 6:54 is not accurate. They are always structural and the stud gauges are dependent on load data determined by the engineer. Like you said, IBC 2018 dictates CI minimums. Here in NC the min is R-7 in the CI, this overcomes the Thermal transmission issues. These minimums are market specific to address regional factors. It is not enforced in all markets, so our conversation should revolve on adoption and compliance to IBC.
8:25 Canadian Mortgage and Housing Corporation . It is a Crown corporation created shortly after WW2 to increase the housing supply for returning veterans and their new families – ie. the start of the Baby Boom. Over time its responsibilities have grown to include things like construction research, loan assistance, and mortgage backed securities.
I would use 2 x 6, or larger wood studs and 5/8, or thicker, plywood sheathing for structural strength. After my experiences in hurricanes (including Hurricane Andrew) I will avoid all oriented strand board. They are poor with water and wind driven debris. The Prosoco R-GUARD waterproofing looks like a good product to use on the sheathing. Rockwool Comfortboard exterior insulation and James Hardie Siding makes the wall complete. The Prosoco masonery anchors look good. Is their an equivalent product for attaching siding? I like ICF structures as well. I would always use ICF for basements. Thank you for all the good ideas.
How about the LVL/Versa studs? Or using wood studs inside steel (strengthening)? I guess overkill but I’ve built some steel walls for interior with wood as reinforcing without issue. Ofcourse insulation wasn’t as critical since not exterior walls… so much easier building in steel but then a whole different trade!
Speaking of metal, I want to know the community and Matt’s thoughts on container homes. They have gained mass popularity as of late and my primary skepticism is the amount of insulation as well as possible moisture / condensation issues due to the difference in temperatures. Especially in northern climates such as Canada. I would love for you professionals out there to shed some light on these types of homes…..
I don’t think heat loss on the steel studs (thermal bridging) is that big of a deal considering the thickness of the studs. They actually create a larger space for insulation. Condensation is a really good point- I had never heard of that study before. The big issue with steel studs is they warp when heating up which can pop the boards right off of it. Engineers in Canada are starting to build much taller buildings out of wood now because in a fire the really thick structural wood members burn on the outside, but will stay strong inside, and don’t warp.
Metal a nightmare: to work with, to cut, virtually impossible to screw anything into(other than a high powered sheet rock gun which eventually will rust). A nightmare to carry safely, can bend over your knee(most of the gauge used in residential homes); not to mention hanging anything. Kitchen’s a nightmare hanging cabinets, barn doors, or shiplap. Metal studs. Good for one thing: the scrap heap.
From the point of view in the fire service, steel buildings fail and collapse at least three times faster than wood buildings. Also charred wood tends to start resisting further fire damage for a longer period of time. Both steel and wood off gas under heated conditions and steel off gassing of the galvanizing is more toxic.
@10:28, The steel stud’s heat transfer is greater than a wood stud, however, in a matter of a few hours all the wall materials will reach the same equilibrium temperature. Condensation will occur regardless you used steel stud or wood stud. The steel stud will sustain some self -terminating rusting but not dry rot as in wood stud. Note: Canada is a big producer of framing lumber such as Douglas Fir, hence, don’t be surprised by the study’s conclusion favoring wood stud construction.
I’ve been drywalling a lot of steel frame houses this year in Australia, here steel is used primarily for termite and fire resistance, and the age old argument that “steel is dead straight”, yes the STUD is straight, but then add the nogging and a diagonal brace or two and then electrician screws his switch plates on with a button head screw, which all cross over right where the drywall joint is and then you have a big bulge in the wall, and there is not much you can do about it.
Matt, wouldn’t it be better to build with ICF’s all the way around?? I mean, I think it’s great that all these products are available, but all those added materials cost and so does all the labor.. Aren’t we better off with insulated Concrete Forms?? Topping everything else, I don’t think you can beat the strength of them and for places like here in Florida, I think it’s a no brainer!!!
Matt, I think you have a few disingenuous arguments there in trying to compare the same construction details between wood and steel; obviously the wall detail needs to be adapted to the materials you are using. Aside from sound insulation I would be surprised if any experienced builder thinks batt insulation is useful in a metal stud wall today. But, they likely appreciate having the stud bays free for trades, and if they really need the extra insulation then a staggererd stud wall with a rock. wool layer between the studs can get you an extra R19. Also, one of the great benefits of light-gauge metal framing is being able to roll the sections on-site. I’m still not sure if steel is a “better” material in general terms compared to wood, but the insulation is likely not the best place to start the comparison.
Hey Matt, if you’re ever in the Baltimore area and want to see a weird all-steel house, let me know. Steel roof, steel frame, steel studs, and steel siding. Oh, and TERRIBLE build quality. I have the thermal cam images to back up what you’re saying about thermal bridging. My walls are close to a foot thick but with no external insulation the thermal bridging is atrocious. It was built in 2005 and the builders gave zero thought to air sealing. Seriously, where the front porch roof meets the front of the house… there’s no wall. It’s open to a 2 1/2 foot crawlspace between the first and second floor!
Steel studs are not for use on structural walls, and pretty much all exterior walls are load bearing to some extent. Thus, it makes no sense to discuss steel studs and insulation factors. One place where steel studs make sense in homes is on walls that require extra flatness and stability, such as any bathroom where you want a large mirror on the wall.
Nearly 100% of American houses have been remodeled (100% because some houses are remodeled several times). Most of us do not have the tools or the ability to ‘work’ with steel studs. I would also have no idea how to hang a mirror or picture with metal studs. But the worst is the ‘fire demonstration’. Studs almost never come in contact with an open flame as an initiator of a fire. If the open flame is on the wooden studs, it is way past ‘starting’. The fact is, almost all house fires start in the kitchen and almost all kitchen fires start on the cooktop. So the solution is not to build with steel but to install induction cooktops which are almost impossible to start a fire.
Nope. Don’t attach the insulation. As soon as you add it to the outer wall it’s reflective property is no longer. It will then bridge the temperature from your outer wall. As it’s only a vapour barrier you need to be careful about dew points and condensation. So really you want a vapour control layer as mention by others. You really want a 1″ air gap between both faces and any substrate and all joints sealed.
I have just had remediation work done on a basement suite. There was poly on the concrete foundation, framing and batt insulation between the studs. There was then a layer of poly on top of the works, and drywall put on top. It was done long before I owned the property. A lovely sandwich for water ingress. This in Alberta, Canada. Ensure you state what location and what climate your solutions are for. A vapour barrier is not recommended on concrete foundations in some climates.