Stone support column

[Steve]

I am finishing up a 8 x 12 screened porch that has two of its sides attached to the house. That leaves one corner that needs support. The porch is inset into the corner or the house (one story) so the weight of the roof and the porch will be bearing on the column. It is about

9' off the ground. The plan was to have a mason build a 18" x 18" granite column to support this corner. I want to use granite to match the foundation which is granite. A builder friend of recently told me that the granite column really isn't strong enough to hold up the porch and that I should use a 4" steel post because it would be stronger. For me a steel post is not acceptable because of the looks unless it it encased. Anyway, my feeling is that a properly built stone column is WAY more than adequate but before I proceed I though I would check and see if this builders argument has any merit or should I just dismiss it as bad advice.

Is there anyone here who might have some insight into this question?

Your thoughts would be much appreciated.

Thanks,

Steve

[Steve]

Squarish cut pieces somewhat irregular in shape is what I see mostly around here. I'm guessing they're roughly 8x10x12".

[EXT]

Depends on how he was planning on building it. If you want granite boulders, round rocks will not stack strong enough to hold any weight. If the stones are to be cut and dressed, not veneer but solid masonry, it should hold most anything.

[Edwin Pawlowski]

He has a valid point. Just look at the condition of the Parthenon. It is crumbling away after only 2000 years. Had they used steel columns and some aluminum siding, it would look much better today.

[Walter R.]

LOL

[Michael Daly]

If you're using round rock, there's nothing wrong with using a steel column inside and using the round rock as a veneer. 18" - 4" = 16"/2 = 8" so you could use rocks up to 8" in size. If this is significantly smaller than the granite you're trying to match, you're stuck.

Mike

[William Brown]

First, you need to calculate how much weight is involved.

If you go with masonry, you probably need to get a structural engineer or an architect to do some calculations, and find a mason that will comply with the specifications they give. I.e., if the rock is strong enough, but the mortar isn't, you may have problems.

An alternative might be to use a steel post, framed with rock. You can look up how much weight a given steel post will support, and the framing rock would not be structural.

You should also give careful consideration to what will be supporting this column; you will need some kind of foundation that meets code. The same goes for the top of the column; you likely will need some sort of plate to spread the load.