Hi All:
I am looking to set 6 sqaure 10″ x 10″ Permacast (hollow) columns on an outdoor concetre deck. The columns will support a porch, and are thus load bearing.
Question: The concete deck is stamped concete with a cobble stone pattern. To get a suitable load bearing surface (the cobbles are pitched / not level by design and also have the jaggies) , I will need to level 10″ x 10″ ‘pads’ for the columns to set on.
I am looking for solutions for a ‘leveling’ medum to use. I do not want to use mortar. Even the enhanced mortars (acrylic additives) I find brittle at best, and crubble with time given the freeze / that cycles. I would think that by now there must be a water proof 2 part epoxy based leveling ‘filler’, similar in consistency to a body filler.
I am even considering using short strand fiberglass filler as a substate / leveling meduim under a doubled-up 10 x 10 x 3/4 PVC trimboard. The column would sit on top of the trim board. I had consider a PT 2x 10 pad, but over time, even the PT will rot.
What to you-all recommend ? What would you use ?
Thanks !!!!
Jim D
Boston, Ma
Updated 06/15:
Thanks for the responses. For clarification, the porch slab is about 8″ thick, and is poured over a 8′ deep frost wall that was poured at the same time as the foundation.
The stamping in the concrete (the cobble stone relief) will need to be filled ranging from zero to 1/4″ in the 10″ x 10″ areas that the columns would sit on. Again, this will be to have a proper surface area for the columns rather than the columns just sitting on the highs and lows of the cobble stone texture that was molded into the concete slab.
Thanks again ! Jim
Edited 6/15/2005 5:07 am ET by JRD
Replies
Jim,
Although I am only an advanced DIY type, I think that if you are supporting a porch with the columns, the base that they sit on really needs to be a "footer" for lack of a better word. It should go down into the ground to whatever the frost depth is in your area. If the concrete deck you are planning to sit them on is only a few inches thick, and does not have a foundation below it, there is a good chance it will crack if any type of concentrated weight is put on it. I dont know what type of posrch you are planning and how high up in the air it will be, but footings for the colums would probably be best. Even down here in the "south", I have done 2 decks, both with piers 20 inches deep for the support columns, and they are basically ground level decks. I am sure some of the other regulars will also chime in.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Mr. Bill makes a good point. The precast columns I have been involved with have to be cut to length, of course. So you just need some grout under your bases to level them. We set 5000 lb beams on grout that hold up several stories of masonry. This is a special grout with an engineered psi purchased at a masonary supplier Edit : I checked today its called non-shrink grout.
Edited 6/15/2005 5:29 pm ET by quicksilver
Assuming that the columns are set over the top of the 8' deep frost wall, you don't have an issue with load distribution.
If the columns can be cut to length (most can) just scribe cut them to set plumb on the concrete deck. You can fine tune the cut to the scribe line with an angle grinder to get a near perfect fit, and assure yourself of the maximum amount of bearing surface at the columns base.
A 1/4" per foot fall in a 10" is not much. Don't make it complicated by thinking the base of the columns need a perfectly level surface to sit on.
Dave
Even if you skipped the load bearing question by putting a pipe column in the hollow p/c columns, you still need a base for the columns.
For that, what you likely need is non-compressive grout. This should be available at any good masonry or concrete supply joint.
Hmm, the "what holds the columns up" question remains. Is there any way to cantilever the porch roof over the columns? The real question, I'm thinking, is what will the building inspector say?
(If you filled in a bit of your Profile {click on your name in blue, the profile info will pop up}, some of our questions will go away, like frost depth or seismic considerations, and the like.)