Pressure treated vs not pressure treated
akadrew98
| Posted in General Discussion on
A fellow builder and I have a disagreement on the use of pressure treated (PT) stair stringers. I don’t like to use pressure treated material for stair stringers because it seems inferior in strength and quality of material to plain douglas fir(DF) . I feel the PT has to many nots and defects to be strong enough to use for stringers. Additionally after all the material for the stair treads is cut away a good deal of the PT material is removed exposing raw wood. Granted a copper sulfate coating can be applied after the cuts but the same proceedure can be done for regular DF.
Any thoughts?
Drew Hunt
Replies
Not PT? Great, more rot repair work for me down the line. It would help to know where you are, in AZ it might not matter, down here in Florida even the PT stringers rot.
We use PT stringers on a regular basis.
You do need to pick and choose a bit to avoid knots, etc.
Jim
Most PT is made from the craapiest wood available; it is so bad, I wouldn't frame a garbage bin with it let alone a set of stairs.
Go for untreated #1&2 DF; just take whatever measures are necessary to see that everything drains properly after being wetted. If you do that, it'll last fine.
Except in Florida, of course. There, the only thing that doesn't rot is concrete. Or so I'm told....;o)
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Been using PT stringers routinely for a long time. Granted, not every 2x12 in the pile is stringer material. Pick and choose, then arrange layout of cuts accordingly. PT around here is SYP. I understand that on the west coast, PT may be Doug Fir, which I understand may not take PT process as well as SYP, hence the concern about exposing interior wood.
Been thinking about trying PT LVLs for a future project.
Are you kidding?
That advice would get you red-tagged just about anywhere I've ever worked. PT is mandatory for deck frame, stair stringers, etc. here. And if you're choosy, there are some decent 2x12's to be had, though harder to come by at a big box than a true lumberyard.
I don't care what you treat it with, new growth DF in contact with or close to the ground will rot in short order.
To the op, Good .40 treated PT syp will be treated all the way through, so when you cut it, it's the same color at the back of the tread. It will last a long time, too. I've got stair stringers going on 22 years at my Mom's house, solid as a rock.
Bing
PT is mandatory for deck frame, stair stringers, etc.
That's scary right there.
You are in a world where abestos abatement and lead paint removal have become big businesses because of the potentially harmful effects these substances might have on somebody who decides to chew on or inhale them...but at the same time, you have a code-writing authority requiring you to install poisoned wood where it will leach into the ground, poison your groundwater, and be exposed to casual skin contact on a repetitive basis.
Yep, scary is the word.
I would fight any such 'red tag' as high as necessary to get it overturned.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I respectfully disagree.
I think that the amount of chemicals leaching from a pressure treated frame is comparable to the amount of oil your truck leaks in the driveway....minimal (non-existent) danger to health....
As far as the framing members and the stair stringers on a deck, I'm not sure how much "casual contact" there would be. I would suggest none. Different story if the decking were pt, but thankfully that's pretty rare these days.
As far as fighting the red tag? Sorry friend, but you would be fighting it to the top of the Massachusetts dpartment of safety, and you would lose. It's part of the Mass state building code, and it's not ambiguous, it's quite clear. You'd be told, "If you want to build it, it will be pt, or you're not building it!" period.
Ground contact=pt
Contact w/ concrete=pt.
Doug Fir=rotten
Bing
It's part of the Mass state building code, and it's not ambiguous, it's quite clear. You'd be told, "If you want to build it, it will be pt, or you're not building it!" period.
Bet me.
Building codes are minimum standards, not immutable laws unto themselves accountable to no one but the little tin gods who wrote them. If I want to build something that exceeds code, and can get somebody with the appropriate state license to sign off on that, the AHJ would have a very hard time refusing to allow it to be built.
And I submit that designing a building where the wooden framing members do not come in contact with the ground is a superior design, and thus exceeds code requirements.
As far as contact with concrete, that's just plain silly. There's only about a hundred million houses in the US and Canada with plain SPF sole plates sitting on mudsills and slabs, and most of them have already lasted longer than the PT industry has even been in existence. I would challenge the code authority to provide their evidence for making that requirement. And if they refused, I'd take their silly a$$es to court. And win. The existing empirical evidence against that requirement is overwhelming.
Cripes. Next thing you know, some twerp with a bowtie and a blackberry will be requiring LVLs instead of solid lumber for framing.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I don't even know where to start. Sure, they would allow you to build it. But that little twirp with a Blackberry and a badge would hand you a red tag on your framing inspection. I'm guessing that sill sealer or something keeps you off of the concrete? Good idea, it just doesn't meet code. Some guy with a state license, an engineer? You still have to submit your plan to the Building Department and get it approved by the state's engineer, and just because he OK's sill sealer or whatever, doesn't mean that the inspector will like it.
I don't think that I have pulled out one SPF (you realize that stands for more than one species, don't you?) mudsill that wasn't rotten. Do you actually believe the stuff that you type, or are just trying too hard to get us to?
We are required to use treated wood on concrete here too - even with foam sill sealer below, which I always use too.
BTW - anyone have any opinions on the MCQ treated?
Micronized, the stuff Home Depot's got, right? I bought some of it to build a fence with. It doesn't seem to grey near as fast as the dark green stuff does. I think it might be better.
>> Micronized, the stuff Home Depot's got, right? << Exactly. It doesn't seem to contain as much treatment though.... I think it might hold paint better though...
What about a metal termite shield - would you still need PT?
Yes.
Why not use borate treated (non-toxic) mudsills, rather than ACQ.I think eventually all "treated lumber" will be more benign than the copper-based stuff. Products like Timbersil and Thermawood will become more common:http://www.termawood.com/products.html
That Thermawood looks very interesting. How long has it been out? Availability? What is the pricing like? I'm guessing it is high dollar, especially considering it is available in several species.
Stupid question time ....
Are there other materials, like Trex, available for use in this application?
I posted the original question which had to do with stair stringers. Trex is not structural and not available in larger sizes.
I have not used it, but have seen posts about it on the forums (fori). Those who used it as trim said it was priced like Azek. In our Minnesota temp extremes, I don't like the expansion/contraction of Azek though, so I am interested in it.
Does it actually say PT or does it some something like - naturally rot resistant wood or chemically treated.That allows lot more options for both the species and the type of treatment.And it probably also says - when in DIRECT contact with concrete.But that often gets shorthandled to must use PT, when is far from that..
William the Geezer, the sequel to Billy the Kid - Shoe
"And I submit that designing a building where the wooden framing members do not come in contact with the ground is a superior design, and thus exceeds code requirements."
I'm with you on the first part, but our code mandates PT for all exterior structural members within two feet of the ground.
A deck beam made of built up D. Fir or Cedar lasts less than ten years here in the PNW. Much as I dislike PT wood, I hold my nose and use it out of necessity.
Bro, I know the Great North Wet is, well, wet...but it ain't the Amazonian Rain forest, even so. I honestly don't understand what could be causing that kind of rot.
In my experience here, Western red cedar is damn near indestructible, even in poorly built and badly drained structures. I just finished a 'paint job' (after 7 weeks of rain; talk about wet weather!!) that was more of a cut-out and replace job. (We're talking years of neglect and quite a few 'shortcuts' in the original construction, too.)
There were places the siding was laid directly on OSB sheathing--no furring, felt, or anything else. The osb and the framing under it rotted...but the cedar siding showed no signs of rot.
There was another spot where the topsoil cover on a small hill had mud-slid over the years and buried the bottom six inches of the west wall of the house. The furring, homosote sheathing, and sole plate of that wall all rotted out...but the cedar siding over them looked fine, except for the paint.
And it wasn't even backprimed!
Yes, this is the same house where the PT balusters and handrails all rotted out in less than 20 years. I rebuilt them with red cedar...and I don't expect them to rot...not before I do, anyway. (Which, if I behave myself even a little, shouldn't be for a while, yet....)
If cedar (from out your way!) can survive conditions that destroyed PT in less than 20 years, what the heck is going on in your area that causes it to die in less than 10?
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
A couple of things:
There's Cedar and there's Cedar. The plantation grown non-old growth simply doesn't have the same density or levels of tannins. Some of the old houses around here have had their roof shakes reversed after 20 odd years and are good for another 20. You won't get that out of new ones.
Until you live here it is hard to understand the stress moisture puts on materials. They are continuously wet for months on end and when you disassemble the vulnerable parts where two members are sandwiched, such built up beams, it isn't uncommon to find the mated surfaces wet even in mid-summer.
I have had enough scares, including a deck less than 10 years old on which the beam rotted and sheared off at the post leaving the deck and hot tub suspended by the joist hangers, that I can't in all conscience use anything but PT for vulnerable structures. Wish it was otherwise.
Yer right; I guess you gotta be there to understand it. But, if it's that bad, I'd either move...or use concrete. ;o)
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Well I'm not too keen on moving, but you are onto something about the concrete. The climate, although wet, is very mild. It is a rare day when you don't want to be outside as long as you can keep dry. The ideal solution seems to me to be partially covered at grade concrete patios. Whenever the site permits it, that is what I build.
Yah, the way you guys are talking about the climate up there, y'all better wear PT socks and skivvies so's ya won't get crotch-rot and phungus 'tween yer tootsies....
;~)
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Don't they already have webbed feet?
View Image
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Don't laugh. Cathedral Grove, an old growth forest that tourists like to stop at, has a deadly air-borne fungus "Cryptococcus" that has killed several people.
Cryptococcus="Mysterious germ" or "Hidden seed". It's a yeast-based fungus that is common enough for most people to have developed an immunity to it. But it's deadly to anyone with AIDS.
Maybe you oughta wear PT prophylactics....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I think that the amount of chemicals leaching from a pressure treated frame is comparable to the amount of oil your truck leaks in the driveway....minimal (non-existent) danger to health....
Even less, I'd think. The oil leaks in the driveway could wind up washing into the water supply (and likely do in many cases). Spread a leak out over millions of vehicles=potential problem.
Whatever chemicals leach from PT lumber would seem to me to be 1) Minimal; 2) Confined to that area. Of course, I could be wrong.
I priced out some PT LVL's last week. Sit down and hold on. I wanted to use the LVL to replace a built up beam, 5" X 12" X16.' 3, 2 X 12's were $80.00, the LVL was $387.00. Even my salesman thought it was stupid.
Wow! I had no idea they were that much. Looks like I'll be using regular PT for a while more
Is this interior or on decks?
Exterior - definitely PT. If you can't get good stuff, use more of them of add 2x4 under or sister to inside.
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Besides Piffins quarry about interior or exterior, (I think everyone is assuming exterior) you didn't state your location. Reading between the lines you live west of the Mississippi. (roughly). The reason I mention it is that many of us are easterners and our lumber is different. You mentioned DF so that probably tells me you are a westerner. Here, in the east our PT lumber is made of SYP (Southern Yellow Pine). For one thing it absorbs the treatment chemicals much better so a 2 x anything is fully saturated. Even 4x4s are mostly fully saturated, but not 6x6s. Although some SYP can be knotty, generally it is not so much so, and I can get PT in whatever grade I want to pay for... or at least up to #1. Even used to be able to get something called #1 dense that were specially graded boards. I haven't been back to that yard in a while, so I'm not sure if they still sell that (or actually if they are even still in business - these days:-( ). Anyway, my point being that from reading here, and even some pics that people have posted the western PT is cr@p, but we can actually get some pretty nice stuff here on the right coast.
I've seen nicer PT when visiting down south than we get up here too.
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I was looking some for maybe use as decking.HD has Radiance (IIRC the name) available as special order. I saw it when there was a rep with sample of it and also Azek.He said that I would have to get a quote from HD, but expect in the range of $1.80 to $2.00 per running foot for 2x6. But note that it ends up smaller than standard. A 2x6 ends up 1 1/4x5.Just for reference 5/4 PT decking runs close to 0.50/ft.I was at a deck supply company and they had Purewood. Don't remember the exact price, but it was something like $2.50.
William the Geezer, the sequel to Billy the Kid - Shoe
Maybe eventually they will get the process better perfected for these non-chemical woods and they will become more popular and therefore cheaper.
BTW, you have to go father west than the Mississippi to not get SYP as PT.I think west of the Rockies, but not sure..
William the Geezer, the sequel to Billy the Kid - Shoe
I didn't know that. Maybe in the future I should just say "out west".
Here the PT is mainly Hemlock.