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Hemlock posts vs Pressure treated

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  • Hemlock posts vs Pressure treated

    I'm building a playhouse - swingset for the kids & am considering 6x 6 hemlock for the posts & 4 x 6 for the beams.

    How would hemlock post embedded in concrete stand up vs a pressure treated post?

    In general, does hemlock stand up well or better to just go with PT?

    Thanks
    Graham

  • #2

    Re: Hemlock posts vs Pressure treated

    Re: Hemlock posts vs Pressure treated

    Hemlock is the same material that they used to build barns so id say it holds up very well .
    I would either wrap the wood at the end with plastic , poly or treat the end before pouring cement around it .

    Comment


    • #3

      Re: Hemlock posts vs Pressure treated

      Re: Hemlock posts vs Pressure treated

      The mistake here is placing the timber, any timber into a concrete pocket. The post will rot completely off in under 5 years right at the interface between concrete, grade and the timber.

      Put concrete in the hole, place a post saddle in the top and place the wood on the saddle.

      Hemlock is not as strong as fir but is cheaper in most cases and looks just a nice.
      Wyatt Earp
      My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

      Comment


      • #4

        Re: Hemlock posts vs Pressure treated

        Re: Hemlock posts vs Pressure treated

        I agree with Wyatt----but I used Hemlock years ago for a HUGE deck. Deep hole---(4')---coated everything in the ground with old oil and backfilled with sand and then water packed. Deck was built in '85---still standing.

        Today I would dig the hole---wrap the bottom of post in double large green garbage bags---seal top with silicone (above ground line) and back fill with stonedust and water pack. Worked great for my 15 year old fence.

        And Hemlock is cheaper and stronger thany any pressure treated
        "Born 50 years too late"

        Comment


        • #5

          Re: Hemlock posts vs Pressure treated

          Re: Hemlock posts vs Pressure treated

          Mac,

          I've never thought of those ideas before. Cool. When I built my yellow cedar fence (6 foot high and about 700 LF) I used a post auger, set the rough sawn 4x4 and filled the remainder with 3/4" washed stone. Tamped it hard and built the panel - repeated many times. Should last me 20 years.
          Wyatt Earp
          My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

          Comment


          • #6

            Re: Hemlock posts vs Pressure treated

            Re: Hemlock posts vs Pressure treated

            I agree with Wyatt. there is no reason to have the wood in direct contact with concrete, it will only come back to bite you in the ass. Use galv saddles and put some roofing membrane in between if you like. Do yourself and your kids a favour though and DO NOT use pressure treated. The sawdust is horrible for your lungs and kids being kids will touch the pt, then touch their eyes and mouth. It's bad stuff that will also hurt you down the road.

            Comment


            • #7

              Re: Hemlock posts vs Pressure treated

              Re: Hemlock posts vs Pressure treated

              Most certainly, PT (the old green stuff) is nasty. The new brown stuff isn't as bad I don't think but any chemical that can rust through galvanized fasteners and clips can't be that good for you though.

              Personally, I use Cedar where possible. After that for a deck anyway I would use Mahogany (but that really depends on budget) and then and only then consider PT.
              Wyatt Earp
              My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

              Comment


              • #8

                Re: Hemlock posts vs Pressure treated

                Re: Hemlock posts vs Pressure treated

                Someone please correct me if I am wrong, but if you cement the post in, bury the end of the post in gravel. The post is essentially standing in a bucket of water if the cement covers the bottom of the post. I wonder if the plastic might do just the same if it were buried with plastic wrapped over the end?
                you need pretty sturdy brackets to hold the post solid from the bottom if the post isn't buried. not that that is not possible, but they might add to the price?

                Kids might not want to play on it forever anyway so maybe it is better if it isn't built for forever? depends how much space you have I guess. of course it needs to be safe.


                Phil
                “The time you enjoy wasting is not wasted time.” -Bertrand Russell

                Comment


                • #9

                  Re: Hemlock posts vs Pressure treated

                  Re: Hemlock posts vs Pressure treated

                  Why not use a concrete base with a post anchor some of which are shown at this site.
                  http://www.tamlyn.com/index_files/PostAnchors.htm


                  You could have some fabricated by a local welder if so desired.

                  Takes all the buried worries away and you can use untreated lumber.
                  Egon
                  from
                  The South Shore, Nova Scotia

                  Comment


                  • #10

                    Re: Hemlock posts vs Pressure treated

                    Re: Hemlock posts vs Pressure treated

                    Phil,

                    You are correct. Concrete is a big spounge. It never completely cures and never really dries to 100%. Water is always a problem and concrete just makes it worse in this case.

                    If you auger a sono-tube in the ground and then placed as you have indicated a simpson strong tie type product in the top and started at a corner you could get a lot of strength. Trouble here being that most of these are single direction fasteners where you need to be able to secure a fence post in 2 directions for it to really do what you want. Next, you need to consider wind loading on the fence and the type of connector you use. It is therefore beter to just dig the hole place the post in the ground with gravel around it.

                    But there are many different schools of thought on this one so it really depends on if there is a bylaw or a code you are having to meet in your particular area more than anything.
                    Wyatt Earp
                    My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

                    Comment


                    • #11

                      Re: Hemlock posts vs Pressure treated

                      Re: Hemlock posts vs Pressure treated

                      Originally posted by greid View Post
                      I'm building a playhouse - swingset for the kids & am considering 6x 6 hemlock for the posts & 4 x 6 for the beams.

                      How would hemlock post embedded in concrete stand up vs a pressure treated post?

                      In general, does hemlock stand up well or better to just go with PT?

                      Thanks
                      Graham
                      Graham

                      I had to go back to the original post since there seems to be a lot of advice which would be OK for a deck or fence but when you are talking a playhouse and swingset I can see the possibility of posts being angled into the ground or at least having a lot of two directional stresses on them from the swings.
                      I would also advise against wrapping the posts in plastic or setting them in concrete since both will promote rot. Just put your posts in the ground with gravel around them to provide drainage. If they are in 4 feet they are not going to move and will be there and strong longer than the kids are interested in either the playhouse or the swings.

                      Blaine
                      "Congratulations. You've just figured out the most complicated way to hold a board 30 inches off the floor."
                      Tage Frid

                      Comment


                      • #12

                        Re: Hemlock posts vs Pressure treated

                        Re: Hemlock posts vs Pressure treated

                        Thanks for all the responses.

                        I hadn't thought of putting the posts in without concrete. I don't like the idea of using the brackets. The plan is 2 - 6 X 6 posts with a 4 x 8 or 10 beam on top to hold 2 swings. Without extra bracing I wouldn't trust brackets.

                        Re the wood choice. I called a local mill & spoke with the owner who has run the mill for decades. He doesn't carry helmock & his view was that it would rot out in < 10 years & felt it would be too rough - too many splinters for kids. He suggested spurce or pine. I know an Amish mill that usually has helmock but you can't call.

                        So, will plain spruce or pine stand up?

                        Thanks again to all
                        Graham

                        Comment


                        • #13

                          Re: Hemlock posts vs Pressure treated

                          Re: Hemlock posts vs Pressure treated

                          Unpainted or stained the spruce or pine will not last more than 5 years to be honest. Hemlock, in my opinion would last longer untreated because it is a stronger wood. It depends on the environment, the kind of temperature swings and the usage.

                          On the subject of splinters - well, having a natural splinter from hemlock or anything else except cedar is much better for you then something coated with the PT (chromated copper arsenate (CCA), ammoniacal copper zinc arsenate (ACZA) and ammoniacal copper quat (ACQ)).

                          Again, my opinion.
                          Wyatt Earp
                          My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

                          Comment


                          • #14

                            Re: Hemlock posts vs Pressure treated

                            Re: Hemlock posts vs Pressure treated

                            Without extra bracing I wouldn't trust brackets.
                            With a proper designed bracket the failure point of the post in shear and bending would be the same as for one set in concrete.
                            Egon
                            from
                            The South Shore, Nova Scotia

                            Comment


                            • #15

                              Re: Hemlock posts vs Pressure treated

                              Re: Hemlock posts vs Pressure treated

                              Cross sectional shear and not vertical or axial shear...
                              Wyatt Earp
                              My wife's Mr. Fix It. Construction Manager by day, hobbist when I find time.

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