On a recent project, Total House Construction Series – Foundation to Finish, I wanted to point out how we used precast concrete piers. The new house has a front porch and rear deck for a hot tub so we installed the precast concrete piers to support the structural framing.
Traditionally you would dig a hole in the ground, install a sonotube and then pour concrete into the hole. In theory that works pretty well but my experience over the years has been nothing short of frustrating when it comes to building piers with sonotubes. If the weather goes bad, which it does around here all the time, then the sonotubes can get wet and collapse before you get the concrete in them. Then you also face the issue of whether or not you have sufficient bearing capacity.
They have a very large base for increased bearing capacity. The piers have a threaded insert cast into the top so you can connect your porch or deck posts to them. And the best part is you don’t have to worry about the weather.
Now the flip side of this is these are really only good when you have an excavator to dig a large hole and something to pick them up with.
The piers are 54″ tall so you can have the base at 48″ (depth of frost protection here in NH) and still have 6″ above finished grade. Be sure to come back and continue to follow this series as we build this new home.
Since writing this article quite a few people have inquired about where to buy precast concrete piers. We purchase them from a local precast concrete supplier that makes septic tanks, manhole structures and misc concrete products. Some of the local building supply companies are also starting to carry them. As the popularity of these increase they are likely to be more common place.
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Hi.
Where can I pick up these concrete piers in southern NH?
They sound great for my farmer's porch rehab project.
Thanks.
Not sure where in Southern NH. I know up here they can be bought at Michie Corporation in Henniker NH and at LE Weed & Son in Newport NH. Best of luck.
Hi,
I am looking for more precise dimensions of these piers, particularly how wide the bases are. Also, what size sonotube could they be considered to replace? Thanks.
Todd,
You may have some insight into this...
I'm building a 16x20 shed in Kennebunk, Maine, and have been permitted to build it on pilings. I've dug 20 holes, each 4 feet deep. But, with all of the recent rain, the water table has risen, and there's a foot of water in 16 of them. The ground is mostly very compacted sand with a foot of loamy topsoil.
I am planning to have a cement truck deliver cement, so I will need to have each sonotube set in place and level the day before.
How long do you suppose a sonotube could sit in standing water before it loses its structural integrity?
Someone suggested pumping the hole, wrapping each sonotube in a large plastic trash bag before setting in place, and then back-filling around it. My thought on this is that as the water returns to its level, it will then push the whole thing straight up.
Any advice?
Many Thanks,
Nat Saywell
@ Nat - Sonotubes do not do well in water at all. If you drop them in the hole as you do the concrete they will work ok. This is one of the reasons we use precast concrete piers now.
I found a neat product: Ecopiers. They're polyurethane and reusable, as well as low cost (about $7-$8 per pier).
Hi, Todd,
Thanks for the great article.
Q: What is the shortest height of a precast,concrete deck pier that is available?
I doing a "floating deck" for my yard and I wanted the built up/finished height to be a short as possible- just an easy step up.
Thanks again. Regards from Long Island, NY, Art
Shortest ones in our area are 48" tall, that's due to our deep frost requirements. They may have shorter ones in your area if the frost design depth is shallower.
I have a summer camp in Sylvan Beach NY
With lots of sand. I’m having some problems with the foundation. Building is over 100 years old and new addition 10 x 12 is sitting on blocks. Can I use precast piers and level the room? A contractor told me I only had to dig 19” because weight is not an issue. Didn’t sound right as it gets very cold and snowy around here.
Any pier that's exposed to the elements MUST have frost protection....seems he may not really know what's going on.
Hi Todd,
Q: We are building a Farmers porch in front of our Gabriel House could you give me some information on what I should use for piers maybe thinking 54"concrete pre-cast piers .. what do you suggest
when setting them in if this are good to use ..should i also use a type of sand around it ??..
we live near Beecher Falls VT but in NH
Thank you
Susie & Robert
Pittsburg NH
Up in Pittsburg you'll want as much frost protection as possible....54" should do the trick. We typically install them on a bed of sand...then backfill with clean granular material. Good luck.
Good morning, I live in Prince George’s Maryland and been approved to use piers on an addtion 24x44. The frost line 30”. It’s a Gabriel style and could you give help with information on what size precast piers I should use and location where can I purchase them?
Thank you
Watson
It will really depend on what suppliers are near you. You'll need piers that are 30" plus a height to keep your framing up off the ground. Around here the shortest is 48" but we have deep frost. Maybe down there they sell a 36" or 42"..not sure.