Post options - strength vs cost
#1
08-12-11, 10:03 AM
Post options - strength vs cost
I have a 4" x 8" inch spot ready for a post to hold up a concrete lintel. I was originally thinking of just buying a 4x8 wood beam, but have since found out these are difficult to find. I am considering LVL, steel, and sistering 2 - 4x4 posts. Anyone have any input? Strength is still my number 1 concern.
Thanks,
Craig.
Thanks,
Craig.
#2
08-12-11, 05:52 PM
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You can have a 4"x8" board cut at a local sawmill. That would be my first choice. Second choice is to sandwich a piece of 1/2-inch plywood between a couple of 2-by boards to give the full 4-inch thickness.. You may have to go with 2x10's and rip them to size. Steel is probably the most expensive and hardest to work with of the three, and for those reasons it would be my last choice.
TJI and LVL beams are designed for use as joists and are optimized for deflection loads. Posts are best for handling compression loads.
TJI and LVL beams are designed for use as joists and are optimized for deflection loads. Posts are best for handling compression loads.
#3
08-13-11, 07:02 AM
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You're in Canada and can't find a 4x8 stick of lumber to use as a post?
If exact dimensions are critical you can furr or wrap a 4x8 which typically will measure 3 1/2" x 7 1/2".
If exact dimensions are critical you can furr or wrap a 4x8 which typically will measure 3 1/2" x 7 1/2".
#4
08-14-11, 09:15 AM
Dimensions aren't critical because it will be buried inside the wall. I cannot find 4x8 sticks here! I found one place that have 4x8 rough-sawn lumber - I was told that rough-sawn means it hasn't been dried and will shrink over time???
I am thinking of using either 2 - 4x4 posts sistered together or maybe 2 - 2x8. Opinions welcomed....
Thanks,
I am thinking of using either 2 - 4x4 posts sistered together or maybe 2 - 2x8. Opinions welcomed....
Thanks,
#5
08-14-11, 12:26 PM
2 - 2x8's with a 1/2" ply sandwich will give you the dimensions you need. Sort of like building a header, only vertical. I think the 2x8's will give better support with less chance of warpage like the 4x4's would.
#6
08-15-11, 07:14 AM
I am still trying to maximize srength, what do you think about sandwiching 2 - 2x8 with 1/4" steel plate or an I beam?
#7
08-15-11, 03:31 PM
Consider the weight the lintel will be carrying......then look at what you have at the ends. The lintel is the weakest point. Where will you stop with the strength of the support? A solid billet of 440 stainless? I don't think overbuilding the ends will justify the weakness of the middle. Any of the suggestions will work, but you have to decide which one you will use.
#8
08-16-11, 05:58 PM
Rough sawn doesn't mean hasn't been dried. It means it has been sent through a planer to get rid of the saw marks from the saw mill. I think when you get into timbers of that size, it isn't common to find them dry whether or not they have been planed. You have to ask the lumber yard about the moisture content.
