Bricks, Masonry, Asphalt and Concrete - Using Sonotubes with Flared Footings
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DavidH1156
07-26-04, 03:52 PM
I’m building a deck and have dug a goodly number of 10 inch diameter holes, 42 inches deep, and flared the bottoms to about 12 to 14 inches to provide better support. I’m inserting 10 inch diameter Sonotubes in the top 30 inches or so, suspending them about a foot over the bottom so the concrete, when poured, will fill the footings. A number of the holes end up slightly larger than 10 inches -- there may be as much as 2 or 3 inches of space on one side or other of the Sonotube. I’m holding the tubes in place with scrap wood supports.
Here’s my question. What happens when I put the concrete into the tubes and level it off at the top of the tube? Will some of it flow back up into the gaps on the sides of the tubes over minutes or hours, causing the level in the tube to drop? I’m hiring a pump system to deliver the concrete, so I have to pour everything at once and don’t have the luxury of pouring footings separately, or topping off tubes hours later. I can’t just backfill the holes without the dirt filling the space I made for the footings. Should I plug up the holes as best I can with something like foam rubber or scrap insulation and then backfill with dirt? Or will the concrete just stay put and I can stop worrying. Any wisdom on this topic would be most appreciated.
-- Dave
Here’s my question. What happens when I put the concrete into the tubes and level it off at the top of the tube? Will some of it flow back up into the gaps on the sides of the tubes over minutes or hours, causing the level in the tube to drop? I’m hiring a pump system to deliver the concrete, so I have to pour everything at once and don’t have the luxury of pouring footings separately, or topping off tubes hours later. I can’t just backfill the holes without the dirt filling the space I made for the footings. Should I plug up the holes as best I can with something like foam rubber or scrap insulation and then backfill with dirt? Or will the concrete just stay put and I can stop worrying. Any wisdom on this topic would be most appreciated.
-- Dave
homebild
07-27-04, 07:42 PM
One approach would be to do two concrete pours. One for the footings then once hardened, another for the sonotubes placed down on top of the footings.
This approach would remove any of the guesswork and problems facing your current technique.
Otherwise, you can simply pour the footings as you descirbe them in a single pour. It is unlikley that any concrete will push up and under the sonotubes and get behind them, but so what if it does?
If concrete ettin behind the tubes makes them difficult or impossible to remove, you can leave them below grade and simply backfill them in place.
You can use a utility knike to cut the sonotube away above grade for appearance sake.
This approach would remove any of the guesswork and problems facing your current technique.
Otherwise, you can simply pour the footings as you descirbe them in a single pour. It is unlikley that any concrete will push up and under the sonotubes and get behind them, but so what if it does?
If concrete ettin behind the tubes makes them difficult or impossible to remove, you can leave them below grade and simply backfill them in place.
You can use a utility knike to cut the sonotube away above grade for appearance sake.