Author Topic: How long does it take for non treated lumber to degrade?  (Read 15106 times)

0 Members and 1 Guest are viewing this topic.

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,469
Re: How long does it take for non treated lumber to degrade?
« Reply #25 on: April 19, 2014, 06:11:48 PM »
Yes the plates in red are the ones that need to go away. I understand and don't disagree that a tie there wouldn't hurt but most importantly there shouldn't be an unsupported hinge in the middle of a wall. The studs need to run from one point  of lateral support (the floor diaphragm) to another point of lateral support (the roof diaphragm). If you want a tie a metal strap wrapped from one sidewall top plate, across the outside of the gable studs and around the other sidewall underneath the sheathing would provide that tie. That is actually unneccessary because the rafters hang from the ridgebeam, preventing any outward thrust on the sidewalls. The rafter load becomes vertical onto the sidewall. But the metal straps won't hurt a thing and would ultimately strengthen the structure. You can buy roll strap from Simpson... you could also buy some lumber band strapping off the roll at the building supply, non code but cheap and code doesn't enter into this. I cut the lumber bands on incoming bundles of material at the band clamp and keep some handy on the job for additional ties in places, trusses tend to come with awesome strap.

The posts and beams are not Flyingvan's method yet, I'll try to draw a detail and post it. You will need more rafters, I'm assuming you're just showing the plane at the moment.

BTW in sketchup you can draw one member, select it, then click the move icon, then click ctrl and drag a copy of a member to the next layout, then type x 12 or however many copies you want at that spacing and it'll copy that many rafters or whatever member in the model, makes drawing repetitive members quick.

The posts can be 2x6's and the wall studs could be 2x4, leaving the posts as a feature element inside, they could be left like that or later wrapped in a decorative trim if desired. Just another cost/benefit thought.

The Simpson pier brackets prevent uplift but have no lateral capacity, the connection of post to pier is a hinge. If the soil adequately braces the pier then all is well. The soil is an unknown and the piers are small. If the connection of post to pier is rigid the pier cannot rotate. I know people think sonotubes and self engineered piers lightly connected to posts are adequate to support a house but pay attention to the size of piers and the connections used in parking lots to hold up just light poles and signs.

I'm not an engineer and this is their territory. This is a better connection than the Simpson's. Something along these lines is much longer and more rigidly connected to the post. The moment they are giving is the resistance to hinging at that post to pier connection.
https://www.permacolumn.com/what-are-sturdi-wall-brackets

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,469
Re: How long does it take for non treated lumber to degrade?
« Reply #26 on: April 20, 2014, 06:43:09 PM »
These show what I was thinking, I believe it is what flyingvan is showing.



Offline flyingvan

  • Journeyman
  • *****
  • Posts: 1,022
  • Welcome to the CP-Forum
    • flyingvan
Re: How long does it take for non treated lumber to degrade?
« Reply #27 on: April 21, 2014, 03:25:37 AM »
Yes!
Find what you love and let it kill you.

Offline rick91351

  • Journeyman
  • *****
  • Posts: 3,091
  • 5000' in Idaho
Re: How long does it take for non treated lumber to degrade?
« Reply #28 on: April 21, 2014, 06:00:14 AM »
WOW I like that.  Sort of a large mortise and tenon joint that is so simple.  This summer or fall planing a wood shed I might just have to try that.....
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #29 on: April 21, 2014, 09:36:29 AM »
Hmmm... only down side  I see to my design is that on mine each girder is being held up by 2 of the 3, whereas in this one it is just one of the three.  I suppose you would also add a simpson support underneath the entire assembly.

I may go to 4pcs of 2x6, and make it a structural element.  Keeping the 2x4 walls as Don mentioned, I think that would be a nice look.  4 2x6s should be more than ample, and then maybe I can do Flyingvan's approach but with 2 pieces going through.  Need to rethink...

Don, yes, I plan on having a rafter every 16 inches, and all walls will be completely framed in also at 16" on center.  The drawings here were partially drawn only... thanks for the Sketchup tips, I will work on the newest ideas this week.

I was not expecting there to be much of a hinge effect from the post to the pier mostly because the post can't hinge since it is supported all the way up.  That said, I could be wrong... my nephew is taking a welding class (top of his class) and they have access to all kinds of metal and can build whatever they want as long as it's welding.  I sent him that website and asked if he can build these.  If so, I will ask him to do 9 of them, sized for 4x 2x6's, and 10" high, should be perfect.  If he is allowed to do it, that will save me some $250 and give me all the support I need.  (Maybe wishful thinking, but it can't hurt to ask).

Offline flyingvan

  • Journeyman
  • *****
  • Posts: 1,022
  • Welcome to the CP-Forum
    • flyingvan
Re: How long does it take for non treated lumber to degrade?
« Reply #30 on: April 21, 2014, 01:51:48 PM »
   Instead of going wider, go deeper.  Like I pointed out before this will provide some sheer strength. (one 2x12 instead of two 2x8's for instance) When you run two carriage bolts through all three, it's supported by them all.   I countersink the washer and nut and use a 4 1/2" bolt so nothing sticks out at all.
    So you stand up two of your studs in the pier straps, don't worry about how tall they are.  Put a scrap block between them and just hold them in place with a clamp; you can also run a diagonal through all your uprights just held in place with a temporary wood screw. 
     Then you just shove your floor beam through, between all the studs.  You can get it exactly level, then cut the middle blocks for it to sit on.  Re-check for plumb then run bolts through.



   (Went outside to take some pics of this---let me know if there's some angle or detail you need that I didn't get)
« Last Edit: April 21, 2014, 02:29:28 PM by flyingvan »
Find what you love and let it kill you.

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #31 on: April 21, 2014, 04:33:24 PM »
Thanks for taking those pictures, it does help to visualize it.  The idea of using 4 would be to give it an almost square look (5.5" x 6") but looking at your pictures it looks nice like that as well.

I will do some more drawings this week, and see what works best for the overall plan.   

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,469
Re: How long does it take for non treated lumber to degrade?
« Reply #32 on: April 22, 2014, 02:02:21 AM »
You were concerned about the single ply at the beam ends. In a simply supported beam, a beam supported at 2 ends, the maximum bending force climbs toward the center and is very low at the ends. The shear is just the opposite and is highest at the ends... but I'd bet we are in range. This needs to be checked. for the beam I drew, a beam supported in the middle and at both ends the force is distributed a little differently. The center posts bears 5/8 of the beam load, the ends each bear 3/16 of the load... the force acting on those tennons just dropped a good bit from each carrying half the load.

The spaced column has close to the buckling and bending resistance of a solid 4.5" thick member where the post you were drawing has the buckling and bending resistance of a 1.5" column, much stronger.

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #33 on: April 22, 2014, 01:18:53 PM »
Ah... I think I finally get it.  While my other drawing may have had better weight load strength, it lacked  lot in shear strength.  I started a new drawing but got too busy at work.  I will redo this with 2x6, and submit it for final inspection later this week.  ;)

One more question... since this is a post and beam now, with all the weight being over the posts... that means the floor joists are only holding the weight of the floor and whatever is on it, so I can do way with having a girder underneath the floor joists right?  Seems like it would make for an easier build, and give me more headroom inside.
« Last Edit: April 22, 2014, 01:33:38 PM by Adam Roby »

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,469
Re: How long does it take for non treated lumber to degrade?
« Reply #34 on: April 22, 2014, 05:25:47 PM »
It probably won't be the final drawing, but I think it's evolving into something good.
The bottom sketch in my post above, in my mind would have joists on hangers between those triple girders but they could also sit on those girders. There are some advantages to sitting up on the girder though, wiring and plumbing are potentially easier, it saves on the cost of hangers and it is stronger

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #35 on: April 23, 2014, 02:51:47 PM »
I might go with joist hangers rather than the girder with rafters over top.  If I go with girders, I need to add some end pieces, and I need to brace the joists to the girders.  If I use hangers, my ends are already blocked and there is no additional bracing.  If the floor was holding up more than just itself I would not consider this, but since it is not, then I think this is the way I may go.

I need to have the joist hangers attached to the beam that is being sandwiched.  I decided to try using a single ply sandwiched on the side walls, and double beams sandwiched in the middle, so that each 8' section of floor is being supported by its own beam.



Not sure how well this will translate through an image, but this would be the first floor (I would still add some blocking in the middles to help with stability and bending.



I also designed two pier-to-post brackets based on that website, and sent them to my nephew.  He will check with his teacher to see if he is allowed to build them, and how much they will charge me for the raw material.  If it is reasonable, I will go ahead and do it. 

Oh, and these are 2x6 now.  The light blue ones are the treated lumber, the whites are non treated.  I will either build faster or tarp everything.
« Last Edit: July 10, 2019, 08:16:12 AM by Adam Roby »

Offline flyingvan

  • Journeyman
  • *****
  • Posts: 1,022
  • Welcome to the CP-Forum
    • flyingvan
Re: How long does it take for non treated lumber to degrade?
« Reply #36 on: April 23, 2014, 08:00:44 PM »
  You could extend the outer two 2x's higher than the inner ones to form a cradle to support the girder---kind of opposite what I did for the porch.  The middle 2x extends up 7 1/2" so my two 2x8's rest on the outer 2x's, making room for the diagonal supports.  Everything got filled in between the two 2x's running horizontal, forming a 3 ply beam (held together with carriage bolts)
Find what you love and let it kill you.

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #37 on: April 25, 2014, 11:46:43 AM »
I am considering different possibilities for giving the posts some lateral support.  Since the walls between the posts will not bare any weight, if I use something like this as a basic shape for each of the sections between the posts, modifying each for window and door framing, would this provide the lateral support I am looking for?  The side 2x4’s are spaced 2’ from the edge on each edge, so the triangle on each corner is what I am hoping will provide that strength. 




I could alternatively have one diagonal across the entire span, but then I can't add my window and door openings.  This should still be relatively easy to insulate, just a few more cuts.  I plan on using cedar strips/planks on the inside finish so I would also consider their spans for the framing, but essentially this would be the minimum I would have in each of the 8 sectional walls I need to build.  Once the sheathing is on it will strengthen the entire thing up, but I was hoping something like this could work as well.

« Last Edit: July 10, 2019, 08:13:31 AM by Adam Roby »

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,469
Re: How long does it take for non treated lumber to degrade?
« Reply #38 on: April 25, 2014, 03:13:27 PM »
Sure this will work if there is enough and if your bracing cannot slip. Google "fachwerk" for some historical examples of this method of bracing.

I'm assuming I'm looking at 16" oc joists, 8' post grids, a 16'x16' building. It looks like in #2 or better SPF lumber, double 2x10's will work for girders, 2x6's will work for joists. There is room under the joists to nail a 2x4 ledger on the girder to support the joists rather than using joist hangers if you wish. This would also slightly stiffen the girders. If the center posts continue on up to the ridge, the same pocket scenario would make a good ridgebeam saddle.

If you are welding the post brackets, I would weld a strap across both open sides high and low. The low strap would be a bit off the bottom to allow a drainage slot. This would give a bit of lateral support in the other direction.

Offline Adam Roby

  • Senior Member
  • ****
  • Posts: 647
  • Montreal, Canada
Re: How long does it take for non treated lumber to degrade?
« Reply #39 on: April 25, 2014, 03:40:37 PM »
Heheh... I just emailed my nephew with this design and asked if it would cost less due to less metal.  Very similar idea to what you just described.



Need to put the kid to bed, will reply to the rest later.
« Last Edit: July 10, 2019, 08:11:57 AM by Adam Roby »

Offline flyingvan

  • Journeyman
  • *****
  • Posts: 1,022
  • Welcome to the CP-Forum
    • flyingvan
Re: How long does it take for non treated lumber to degrade?
« Reply #40 on: April 25, 2014, 04:23:47 PM »
Why not continue with sandwiching stuff for your lateral support?  If that wall you show has no door, you could run something corner to corner, between the left and right posts.  Or if you need the opening, run a few more verticals then zigzag them either side.
Find what you love and let it kill you.

 

Templates: 5: index (default), Ads (default), Portal (default), Display (default), GenericControls (default).
Sub templates: 12: init, html_above, adsheaders_above, body_above, adsindex_above, portal_above, main, portal_below, adsindex_below, body_below, adsheaders_below, html_below.
Language files: 3: SPortal.english (default), index+Modifications.english (default), Ads.english (default).
Style sheets: 1: portal (default).
Files included: 37 - 1124KB. (show)
Cache hits: 12: 0.00198s for 40,669 bytes (show)
Queries used: 29.

[Show Queries]