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preserving wood

topic posted Tue, June 3, 2008 - 4:28 PM by  yadda yadda
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Between tearing down the shed and ripping out walls, I have a crapload of old 2 X 4s. These things are so old and rock hard that I can't get a nail through them. I had to attach all the new drywall with big honkin' screws. I'd like to use them doubled as fenceposts. Some folks say to use linseed oil and others say to use a deck perservative.
Any thoughts?
Don't say, "go buy pressure treated lumber". Its not in the budget so if I can't use the 2 X 4s, the fence won't get built.
posted by:
yadda yadda
Nashville
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  • Anything that seals out the water ( on the buried part) will work. Let the above ground part breath, and it will dry out on it's own.
    • in climates with high humidity and not that much UV (i.e. sunlight) it is advisable to put deck sealant on it,- as otherwise funghi will rott your wood.

      I've had good success with outdoor furniture treatment,- though I need to touch it up every couple of years or so,-
      • Oh, I should've said. I live in a place with med/high humidity and plenty of sunlight. We get a hard freeze two or three times in the winter and the summers are HOT. At 8 o'clock this morning it was 79 degrees with 74% humidity. ick. I'm talking mostly about the part of the post that goes beneath the ground.
        • Unsu...
           
          I'm assuming that this is Douglas Fir? You can treat it with copper preservative that will resist rot and repel wood eating insects longer than any water seal or wood oil (linseed or teak oil).

          If you are going to use them as posts I'd recommend digging and pouring piers (with post attaching hardware). DF won't last long in the ground.

          If you must do it quick and dirty, put some gravel in the bottom of the hole so the water doesn't pool up in the post.
          • I first thought fir or spruce, but then she said it was old, and that it is very hard so it could well be oak. That's what was used around here 50 years ago and even more recently. Out of an old shed around here, it could be anything from poplar to walnut.

            Do you know what kind of wood it is, Amy? Perhaps you can post a pic. Makes all the difference.
          • I second this.

            Don't let the wood touch dirt. Don't create an area where water will gather against the wood. If you do, it will eventually rot.

            You can also set the posts in concrete. Just make sure to put a couple inches of gravel in the bottom of the hole, put the post in place, then pour concrete around it, and go an inch or two higher than the dirt so that the concrete doesn't eventually cover with dirt and hit the wood.

            Ya, and use a water sealant on the finished product.

            I guess just like everyone else said, i just wanted to chime in.
            • I thought that wood being set in concrete is as bad as putting it in the dirt, perhaps worse. Not positive, but that's what ive been thinking.

              If you are going to use it in a greenhouse, it is a good idea to put some white latex paint on it, maybe a few coats. There is a lot of condensation. White because it reflects light. that's what i'd do, anyway.
              • Thanks. I'm exploring all options. I have these materials and a list ( a long one) of projects that need doing around here. So I'm trying to find out which materials go best with which project.
              • It's only bad if you create a cavity in the bottom of where the wood is set that gathers/collects water. The trick around this is the gravel at the bottom, which allows the water to pass through, rather than collect.

                Wood against concrete is done all the time. 90% of all homes (foundations) are done this way. Concrete foundation, with wood being built on top of that. The key is that you don't want any dirt to touch the wood. Dirt holds moisture, which causes rot. Concrete doesn't.

                But yup, a little white latex paint will help. You can even water it down and use a thin solution of this (often called white-washing).
                • Wood is not allowed to come into contact with masonry unless the wood is treated. That's code everywhere there's code.
                  • This is the maximum depth. Additional responses will not be threaded.
                    We don't have much in the way of codes. But I don't want the fence falling down after the first year.
                  • This is the maximum depth. Additional responses will not be threaded.
                    Now that's just not true. I think you're slightly confused with the facts. I think by masonry, you mean dirt. Wood houses are usually built on concrete foundations. On them. They don't float in space and they arn't built on pressure treated wood.
                    • The plate that goes on top of the block or concrete foundation, or the bottom plate for the walls have to be salt treat. That was the code when i was learning of such things in the early 70's and it is the code now, but, more importantly IMO, it also is the sensible way to do this, since i've seen the effects of untreated softwood up against masonry firsthand plenty of times, and it rots very quickly. There's some sort of wicking action going on, i think.
                      • Concrete has a way of absorbing, holding, then releasing moisture. Metal does not hold water but may generate a bit of condensate. Some codes will advise metal interface between concrete and wood structural members...like sheetmetal, steel support brackets joining beams to foundation, etc.... Or else one could use a vapor barrier of heavy gauge mylar for that needed separation between concrete/wood.

                        For Amy's purpose, however, the setting of the fenceposts in concrete is unnecessary. Virtually none of the millions of miles of agricultural & ranch fence still standing after generations is set in concrete. It's just set in raw dirt. If you are doing a fence or guardrail for heavy duty industrial applications, with machinery moving around it, then you need to put it in concrete, otherwise not. Planting garden fenceposts in oversized postholes over a few inches of gravel, and then with a gravel backfill surround, should take care of the drainage issue and then some.... even if you don't do the crankcase oil dip - which all by itself would make a bombproof fencepost against water, bugs, microorganisms, whatever.
  • Unsu...
     
    Etheline Glycol will kill fungus, powder post beetles, and anything else in the wood.

    I have used boiling VOC's and tar pitch - works better than anything else I've used.

    A good long soak in Used Motor oil works Messy though.



    • Good idea, Wil. I posted two photos, one of the wood in the house and the other of the wood from the shed.
      • They all look like pine to me. Perhaps fir or spruce, but softwood, and no good much for posts without treatment for sure. Not as good with treatment either. I would think they would be more valuable used somewhere high and dry on another DIY project. But i understand you don't want to spend any money on the project.
    • Unsu...
       
      "A good long soak in Used Motor oil works Messy though. "

      This is what my wife's dad does for fence posts on his ranch. Soaks the ends going in the ground in large barrels of used motor oil for a couple weeks (or more). There is always a barrel full soaking in the barn.
      • Best cheap/free low-tech appropriate-tech solution?: soak posts in spent crankcase oil in drum or 5 gal. bucket. Just let sit a few days. Works esp. well with dried lumber. Oil saturates into dried woodgrain thus rendering it impermeable - water can't displace the oil. Then drain back excess into container. Oil will totally repell sub-grade bugs. Fungus won't even try. For good measure plant posts in oversize posthole, then gravel backfill -- gravel surround will drain down groundwater. Have treated portion come to a few inches above grade.

        Oil soak also works reliably when setting metal toolheads onto wooden handles .... like hammers, picks, sledges, axes... soak toolhead overnight to swell up metal-wood interface..... even if head is not yet loose. Rag wipe oiled tools before use.
    • A yes, the motor oil trick. Kinda ghetto, but some people swear by this. I've been told that you take a gallon of diesel, add a quart of thick motor oil to it, and spray it on (multiple coats). Never tried it myself. Contractors do this all the time to preserve wood that will be used repeatedly for forming retaining walls.
      • ain nothin ghetto to it boy. its n ol cowboy trick... of which I have plenty. always plenty old used black oil layin round in buckets waiting for rats to drown in the barn. recycle. SOAK, not any little diletante multiple sprayjob stuff. Thick hearty bombproof soak saturated in to 1 cm depth. What's better? all else is costly, all else leaves a huger carbon footprint in its production. This is american country recycling son.... not ghetto (??!!)

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