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gerry coffey
best trees for lally columns

Hi,
I'm building a 22x25 camp and have access to plenty of trees so I'm wondering what type would be best for lally columns. I have the foundation done and footings poured for the lally columns. I have cedar, spruce, hemlock, maple and pine trees available. Also I would assume the column should match the size of the caring beam. So a 6 inch beam should have a 6 inch tree column, true? Thanks

dj1
Re: best trees for lally columns

I thought lally columns were steel.

Posts should be 4x4 at a min. Check your local code for the other dimentions.

ed21
Re: best trees for lally columns

Sort of a vague open ended question. I would say it probably doesn't matter. Are you building a simple open or covered roof?
Columns don't necessarily have to match the beam width, but sure, why not.
White pine around where I am seem to attract boring insects when they set in the wood pile, so I wouldn't use them.

A. Spruce
Re: best trees for lally columns

Keep in mind, if you're doing a log cabin (stacked log ) structure, that the logs will settle over time, a column won't! You have to be able to account for that settling or you will risk damage to the structure.

JLMCDANIEL
Re: best trees for lally columns

Cedar would be the most rot resistant.

Jack

Mastercarpentry
Re: best trees for lally columns

I'd go with the cedar for posts as well, but I'm curious- you mentioned "trees", which if they aren't already harvested, cut, and drying means you're a long way from starting the structure. "Green" lumber and timbers aren't going to keep their shape, especially if used for beams. Back to the trees, spruce is not as rot-resistant but has good strength and if it's not weather-exposed would make better beams than cedar. Here in the south Pine is considered pretty much 'trash' lumber but old-growth pine is a different matter and might make good beams too so long as you don't have pine borers and beetles where you are. I don't know enough about the Hemlock to comment, but maple might be useful though I'd want it for finish work rather than framing- it's a valuable wood down here.

Whatever you use other than Cedar, you're going to need to treat it with something is it's weather-exposed and even cedar can benefit from something to help keep the wetness out. Column width can be wider than the beam but never narrower- if you will see them in the finished building stout-looking columns look nice and are stronger against lateral wind forces too. Do some reading about Timber Framing to get ideas and to learn of the best way to use the inherent strengths of the wood. And check to see if you need permits, inspections, etc.

Phil

Phil

Sombreuil_mongrel
Re: best trees for lally columns

http://en.wikipedia.org/wiki/Post_in_ground
This is the article about this type of building method. A lot of historic first-generation settler structures were built this way along the Miss. R. from LA to MO.
Casey

Fencepost
Re: best trees for lally columns

What Phil said.

I'd add that there is a significant difference between old-growth and second-growth cedar even within the same species. Second-growth isn't nearly as rot resistant or strong as old-growth cedar. Where you might get by without preservatives on old-growth, they are a necessity with second-growth.

Also, every species of tree has two types of wood:

  • Heartwood -- in the center of the tree; this is the "old" wood that has hardened and doesn't contribute much to the life of the tree. It is naturally stronger and more rot-resistant.
  • Sapwood -- toward the outer rings of the tree; this is the "young" wood which carries sap to the living parts of the tree. It is softer; more likely to warp, crack, and check; and has poor rot resistance. It isn't nearly as strong as heartwood.

In most species, sapwood and heartwood are different shades (lighter/darker). Generally speaking, the tighter the grain, the stronger the wood. For each "ring", there is summer wood and winter wood. The winter wood is harder and darker and more rot-resistant; summer wood is softer and whiter, and usually wider. Part of what makes old-growth better is that the ratio of summer wood to winter wood is lower, so the percentage of hard, strong winter wood is higher. Dense forest canopies and competition for nutrients is what causes "old growth" to grow slower in the summer than second-growth, yielding the tighter grain.

Mastercarpentry
Re: best trees for lally columns
Sombreuil_mongrel wrote:

http://en.wikipedia.org/wiki/Post_in_ground
This is the article about this type of building method. A lot of historic first-generation settler structures were built this way along the Miss. R. from LA to MO.
Casey

And how many are still standing? It can be done this way but better ways exist- and the OP spoke of foundations and footings already being in place, rendering this option out of the picture. There's a lot of farm structures around here built this way using locust or cedar for the posts which serve their purpose well enough, but they were built this way for a lack of money to do anything else. I'd hope the OP wants a more permanent structure :cool:

Phil

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