Adding porch posts — how to do?
A client needs to have additional 4 x 4 porch posts added to an existing porch in order to install gates as required for her at-home preschool. The existing posts have those approx. 1″ high feet (aluminum?) to keep the post bottoms out of water, and I’d like to match them.
I’m not sure how to do this as a retrofit. If I fasten the feet to the floor, I can’t slide the post in on top. If I fasten the feet to the post, I can’t fasten them to the floor. If I try to raise the roof, it will pull the existing posts loose.
This looked simple at the time (they already have the matching posts), but now I’m not figuring it out.
Help?
Thanks in advance!
Sue
Replies
Are the existing post bases bolted to the porch? The low profile bases with no 'sides' to fasten to the post's sides are usually nailed onto the post prior to installation, then gravity/building weight hold them in place when installed. Twenty years ago, those were the modern answer to rot prevention, but are now well out of date.
I don't like to use those, as the base isn't bolted down, creating uplift concerns. (I live on coastal CT.) If you have to use it, I would jack the beam up slightly to ensure positive force on the post to keep it in place. I have seen posts on these bases knocked well out of plumb. A deck I rebuilt this spring had one of three 6x6 posts sitting on a similar base knocked completely off the pier from a falling branch.
There is another 2 piece base out there, though I haven't used it. The steel base is bolted to the foundation and a second piece to screwed to the bottom of the post. A screw at the bottom of the post slides into a matching slot in the base, keeping the post in place on 3 of four sides. Not the best solution, but miles better, in comparison.
Incidently, our BIs will not pass any new decks/porches with those low profile bases, due to wind up-lift concerns, amoung others.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
I'm not sure, but I suspect you're right that the roof weight is holding the posts in place. I'm not concerned about retro-fitting to prevent uplift. I would like the installation to match the existing. Since these new posts aren't structurally necessary (for the roof), but rather are needed to give support to gates and railings, I'm not going to worry about anchoring, except that I don't want them waving in a breeze, of course. Sue
There is also another option similar to the one I described. You nail on a plastic shoe to the bottom of the post. The shoe has a slot machined in it. At the post's dead center on the porch, sink a screw. The shoe on the post mates with screw when slid into place.
But probably not exactly the same as the original.
You're right, though, not structural. So use the low profile base similar to existing, attach it to the post, size it, cut it about 1/32-1/16" long, and pound into place. The uplift on the beam shouldn't be enough to lift the beam off the existing posts. Viola, you're done.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
Possible option: cut the post 3/4" short and put a simple 3/4" trim block at the top as a shim.
Or cut it a bit short, shim tight and just trim out the top. You could trim out the existing posts to match...