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Deck or porch footing & pier construction FAQs:
Questions & answers about how to build & prepare concrete piers for porches & decks, using form tubes & other materials.
This article series explains how to prepare deck footings or piers using cardboard tubes, reinforcing steel, post connectors, and concrete. We describe using a SonoTube concrete form to pour the concrete piers or footings that will carry deck posts.
These questions & answers about preparing the hole & using form tubes to build concrete piers for decks & porches were posted originally at DECK PIER CONSTRUCTION - topic home.
On 2017-07-28 by (mod) preparing the bottom of the pier hole
Sorry for the delayed posting, Ian, the Comments Box security software is nervous about comments that it thinks contains links.
For the very bottom of the hole into which you're putting a sonnotube there are a couple of options - a solid 4" block on solid soil or 2" of item 4 sized gravel
You'll want to see https://inspectapedia.com/decks/Concrete_Mixing.php where we discuss DECK PIER CONCRETE MIX
Let me know if you need more help.
On 2017-07-28 by Ian William Polnick
I am located in Elliot Lake Ontario. I am constructing an overhang roof over a patio, in clay soil which is susceptible to frost. On one side the overhanging roof is attached to the house by means of a ledger board.
The opposite side is to be on concrete piers made with the aid of sonotubes, I understand that you have to go bellow the frost level. My question is how do you make the very bottom part, that the sonotube sets on?
Can you please explain this to me? My e:mail address is firstname.lastname@example.org. Thank-you for your help.
Ian William Polnick
On 2016-08-11by (mod) Tips for removing concrete form tubes:
Tips for removing concrete form tubes:
Sure, it is certainly permissible to remove plastic or paper concrete form tubes, but you may find removing plastic or paper form tubes no fun as the tube can be pretty tough. People cut with a utility knife or try to unwind the paper following its spiral. I avoid using a power saw because I don't want to cut/gouge into the concrete pier.
But here is Quikrete's advice for form tube removal:
If forms are to be removed, do so within 24 hours. Cut the QUIKTUBE™ with a sharp knife or power saw set to the correct cutting depth. Simply peel the form away from the concrete. - https://www.quikrete.com/pdfs/projects/quiktubepillarfoundations.pdf
Sakrete.com says their forms can be removed after a minimum of 48 hours. http://www.sakrete.com/uploads/downloads/Sakrete%20Form%20Tube%20Tech%20Data%2011-12.pdf
In my OPINION waiting that extra time is safer from a structural point of view.
If the concrete contractor used a release agent or if one was included on the form interior that'll make peeling it away easier.
Below-grade there is of course no need to remove the concrete form.
Watch out: Never remove a concrete form before the concrete has cured enough to carry its load - else the pier will collapse.
Concrete form tubes such as Sonotubes should in fact be removed where fire rating is important, as the form tubes themselves are not fire-rated.
On 2016-08-11 by Anonymous
Can I remove the old paper concrete forms from my concrete deck piers and paint the concrete directly?
On 2016-04-06 by (mod) how to use helical piers or screw piles
Helical piers ("screw piles") are discussed at
On 2016-04-06 Geoff; Capital District NY
We too have very wet soil conditions. The screw piles seem like a good alternative. Do you know of any drawbacks?
Have you ever used screw piles instead of sonotubes? I live near Saratoga Springs, N.Y. My neighbors deck was installed in one day. He had 8 footings installed in under an hour and he was able to start building immediately.
On 2016-03-14 by (mod) concrete systems that will set under water
Phillip there are concrete systems that will set under water, else you'd have to build an enclosed tube bottom, anchor it in the hole, and pump out the water.
WATCH OUT: Sonotube points out that their tubes should NOT be set in standing water. (They do have a system that can tolerate wet weather and rain for up to 72 hours) (http://www.sonotube.com/resources/faq.aspx)
If you cannot get your pier holes deep enough (with the tube in place) to stop water from flowing into the tube you'll need to consider the extra details below. If you can get the tube down to below the water entry point you can pump the water out.
I think Burk concrete form tubes may tolerate setting in water using "plastic cement based concrete" and perhaps additional driven re-bar to secure the tube and the pier itself.
Some contractors use a vibrator, normally used to remove excess air, to bring excess water to the tube top as well. Keep your concrete mix as dry as you can lest it not displace the water. YOu'll probably have to increase the concrete cure time as well - consult with your concrete manufacturer or with a local engineer who is familiar with underwater pier construction.
On 2016-03-14 by Phillip
We live 150' from the river and set the tubes but they are filling with water. How do we fix
On 2016-02-21 by (mod) deck piers do not, in most soil conditions require additional horizontal footings.
Eva individual deck piers do not, in most soil conditions require additional horizontal footings.
On 2016-02-21 by eva marie
hello, our patio with the roof above is l-shaped, wide/front 32ft x 20ft on side.....but my serious question is if it was done right in the first place by contractor, because first winter lifted about 1-2" flag stones on top and around the 6x6"pillers, which they are sitting on sonotubes, deep down 46"-48" on so called solid soil- ground.
.than each pillar is sitting in that metal boot, than entire outside edges of covered patio is done with boulders, than filled up with soil to the level, where the top layer is screening, maybe 5-6" and on that is flag stone, steps in front to garden,
my questions to you, if you will be so kind,
is it required to pour concrete footings across the width and depth of covered patio structure before sonotubes are placed in ground or no footings required there, if SOLID GROUND IS UNDER SONOTUBES,
to mention diameter of sonotubes is 19inches and
second part of my question is : these 6x6 pillars( high 12 ft to reach the bottom of the roof structure) have cracks , random, from top down, do we have to worry for next 30 years of collapse?
becauce they will split ? or just to exchange them for load bearing fiberglass slopes, sold in special stores, if you will be willing to give me your opinion, that will be very valuable, thank you eva marie
On 2014-07-20 by Mario
Who in the Chicagoland area specializes in drilling residential deck pier holes 10"in diameter by 10 ft in depth?
On 2014-06-23 by (mod) 4x4 connected above ground to the top of a masonry pier is a longer-lived construction
Larry an authoritative answer needs to come from your local building officials who doubtless have an opinion.
But generally, so long as the connections are properly made, including post to pier and among all of the other deck framing structural members, a 4x4 connected above ground to the top of a masonry pier is a longer-lived construction.
Even pressure treated wood is not immune to insect damage or rot, though in the best cases of optimum soil conditions and perfectly-treated wood you may get a couple of decades of service.
Where wind uplift is a concern there may be additional structural connections required in your area.
On 2014-06-22 by Larry Altman
I plan to build a 3 sided free standing deck around a swim spa.
Can I keep the 4X4 posts above ground anchored to concrete tubes below frost line? The area is subject to windy conditions.
Would it be better to install the 4X4's in the ground on top of 10" of concrete below frost line?
Which would be a better pressure treated or Ipe
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