Placing post on footing before slab pour
BDohrn
| Posted in Construction Techniques on
I am a self-builder — above average skills and experience, but still, I don’t so this often.
I face this situation: I have two footings that will carry a post for a roof that covers exterior covered entry areas. These areas will have a slab poured for their floor. Weather and needs for ground settling does not allow the slab to be poured now. However , I could use to place the posts ( 6 x 6 wood. PT? ) and get moving with the roof work. How do I do things in this order, in terms of the post getting embedded in concrete later. I see things in Simpson catalog, but really not sure what’s best.
Thanks in advance for your help.
Replies
Unless you're relying on the concrete to provide lateral stiffness, you generally don't want a wood post embedded in concrete. Something should be used to hold the post above the level of the finished slab. (Often the footing for the post is finished to the height of the finished slab for this reason, and because the footing and slab should be able to move vertically independent of each other.)
If you do end up embedding the post, at the very least wrap it with something to prevent direct contact with the concrete.
Will your slab be poured over the post footing positions?
You might consider using Simpson EPB66, set at the proper height for the later slab pour. The initial height will probably be more than the rated exposure but as a temporary start will get you going. These things will actually hold more than specified.
Thanks for the idea on the simpsons. Problem is, My footing is already there, so I can't really embed something like the EPB. But maybe I can epoxy in my bolts to the finished level and just get a regular old post base falsely elevated for now.... Hmmm
What diameter posts?Common trick in some parts of the country -- drill the footing, epoxy a piece of 3/4" all-thread into the hole. The all-thread is long enough to be past the FF elevation of the slab (to be poured later in this case)and leave enough room for a decorative post base and stick into the post a few inches.You drill a 3/4" hole in the post and set it on the all-thread.A nut and a big washer on the all-thread lets you adjust the post height precisely, then after the slab is down you apply a decorative base. Stone works nicely.It's a lot stronger than it sounds. The only consideration is uplift in high wind areas.
I would find a way to put the post in temporarily now so you can proceed with the roof work. When the time comes for the concrete, find another temporary means of supporting the roof, pour the concrete, then install the post permanently.
Why didn't I think of that? THanks. It's really not that hard to do!
<<When the time comes for the concrete, find another temporary means of supporting the roof,>>That's an intriguing thought.How do you do this? And what does the support sit on while the concrete is curing?Maybe a post kicked out at an angle past the forms? Seems I saw some remodelers do something like that one time.
I dunno, man, I can't see it from my house, but yeah, stick some temporary legs under the rafter tails outside of the forms, or stick in a temporary girder that extends out on both ends, something like that. There are times when you can't build from the bottom up, in fact I am doing just that right now.
They do that on porch roofs around here all the time.
Support the roof with temporary post setting on the porch footing. Then just before the porch is poured they will add several braces angled out away from the porch foot print and set on staked down 2x10s. The porch is then poured and finished. A week or so later they come back and set the permenant post or columns on the finished floor.
As DanH stated, wood columns are not buried below slab. Piers (concrete) sit on the footings and the column sits on the piers at slab level.
Another part of your situation is that once the footings and piers are poured, how do you plumb and stabilize the columns with loose and ungraded ground around them. It isn't impossible but needs to be addressed as part of your construction equation.
Will the columns be supporting anything other than the roof?
Frankie
Flay your Suffolk bought-this-morning sole with organic hand-cracked pepper and blasted salt.
Thrill each side for four minutes at torchmark haut. Interrogate a lemon.
Embarrass any tough roots from the samphire. Then bamboozle till it's al dente with that certain je ne sais quoi.
Arabella Weir as Minty Marchmont - Posh Nosh
Are you saying the the footing I have in place might move when the slab is poured?The post suports nothing but the corner of a hip roof. It's 8 x 14', beams, plywood, metal on top.
A. Sorry I was not clear. Never thought footing would move. I was addressing the column only, in regard to the loose soil surrounding.B. Somehow I thought you were referring to columnS, some of which were to support a ridge beam. Wrong assumptions.I guess you will be erecting the column as though is was for a second story deck. Yeah, it was the ridge beam assumption which threw me. Dunno why.F
Flay your Suffolk bought-this-morning sole with organic hand-cracked pepper and blasted salt.
Thrill each side for four minutes at torchmark haut. Interrogate a lemon.
Embarrass any tough roots from the samphire. Then bamboozle till it's al dente with that certain je ne sais quoi.
Arabella Weir as Minty Marchmont - Posh Nosh
the footer does not move, the post will and will crack the slab.so you need to block out for the post. you can reverse the block out and pour it now to slab height and then pour later too it. Do not pour the slab over the post. it will crack like crazy
I have wraped bost with 1/2" rigid foam and poured around them. After finishing the slab I dig out the top 1/4-3/8" off the top edge of the foam, and fill with a self leveling caulk .
The foam and caulk give the post room to move without cracking the slab. I did sevral like that 18 years ago and there have been no cracks radiating from the post.