Can anybody supply some convincing info or a link regarding the required
footing depth for a cinderblock wall that will be two or three courses in
height? I'm talking about 8x8x16 blocks that will be mortared in place.
North Carolina. The real question is, even though the wall will be
relatively light, does the footing still have to be the code-approved depth
because of frost potential? The contractor already poured a 3.5 to 4-inch
footing (after we agreed on 6 inches) and I have to decide whether to get
him to rip it out and go deeper. Thanks.
My first reaction is to withold payment and have him do as he agreed or
send him on his way.
At the same time, you ask about footing depth, then describe footing
After wondering about that, I would like to know about horizontal and
If it were my wall, I would want to have a footing placed below the
local frost line, a minimum 7 inches deep and extending two inches
beyond the masonry on each side. I would, for such a light wall
consider a single reinforcing bar at the center of the footing cross
section and extending the fool length. I would place vertical
reinforcement every 24 inches to keep the masonry from overturning.
How do you intend to protect the top of the masonry from water
intrusion and freezing?
A 2 ft high wall that doesnt support a structure doesnt even need a
footer, So what if it sinks a bit. A block wall suporting a small
10x10 shed doesnt need a footer. A footer on a garden wall a waste of
I'd check out websites for garden block manufacturers. Plus, I'd use
that type of product, not cinder block, as they are very attractive and
available in a variety of styles, go together without cement, etc.,
while cinder block is about as ugly as you can get. I think you'll
find that the manufacturers generally don't require footers, the
product is designed to go on a well drained, compacted base. Anchor
concrete is a supplier here with a website.
I can only give you my experience with walls. I built field stone walls 2.5
ft high for the purpose of flower beds. that was 3 years ago. I am now
rebuilding each one the right way. Field stone or cinderblock, it doesn't
matter. Freezing water will move them. You can either set a footer below the
frost line or supply drainage under the shallow footer with
gravel(preferably pea gravel) to remove all water. The theory is the soil
below the gravel will push up when frozen but the gravel will compact before
the wall moves assuming the weight of the wall is is enough to push back on
the gravel. Sorry, I wish I could be more scientific. Another point is if
you are building a wall, you are probably holding something back(soil?). Now
you have a horizontal push. It will tip your wall ! Again, backfill you wall
with gravel to remove the water. I know a professional wall builder who
insists on a backfill of 3 ft! I did 1 foot and have been ok so far(2
winters in Pa....frost line is 4 feet where I live). I have no idea what
your frost depth is in North Carolina, but I'm sure you do. If it's not that
deep or other provisions made for the removal of water, you'll spend the
next summer or two doing what I did! Trust me, it cuts into your beer time.
In general, the footing needs to be on undisturbed(*) earth,
and below the frost line for your area. some kinds of soil
heave around seasonally with different water content, and
those present special problems.
(*) Undisturbed or packed down by someone who knows
what the hell they're doing, which someone's you and I
are not among.
I am not a wall expert but I did a good bit of research on this topic about
3 years ago.
Blocks laid with mortar are not your best choice for any type of wall. Dry
laid blocks which allow the water to pass through are your best choice.
In my area which seems to stay about 1 year behind the latest codes, there
are no code requirements for "non-essential" retaining walls. A garden wall
is "non-essential". That said if I were to build it I would build it to
last. I would use the same standards as a normal retaining wall.
The footer should be below the frost level for your area, six to eight
inches thick and at least twice the width of what you are going to lay up on
top of it. In this case and 8" block would need a 16" front to back footer.
In your case, if you contracted for a 6" thick footer, that is what you
should have gotten. How you handle it is up to you. Contact your local
building inspection department if you need a source to cite for your
actions. Or use this link for 665 hits of reading pleasure:
That would be OK, if it sank or heaved evenly, but that's unlikely,
given moisture and other differences along the wall. As an alternative
to removing the present footing, the OP might look into "frost
protected warm foundations," and lay horizontal foamboard in a shallow
trench outside the wall, then backfill the trench with soil.
I would consider not mortaring any wall and using real stone or the
manufactured paver types so water will flow through. Ive seen many walls
built some 50-70 yrs old that are fine without mortar or even footers.
Building a solid sealed wall will fail, a breathable wall wont. Water
pressure will destroy it and the stone you cement to it.
Nick if the wall is properly angled it will stay even , drainage is key
through the wall, Settling, unless soil is different, changes in
composition from area to area which is unlikely, there is no reason for
any settling difference.
replying to B, Maxx wrote:
It should be atleast a 1' by 1' footing with 2 bars of Rebar running parallel
with footing should have uprights every 24" in footing tied to the running
rebar.those should be set on 2"X2" concrete adobes You need a base of some sort
to hold wall from eroding. Do it right and you won't have to fix it when it
shifts years from now.
On Wednesday, September 7, 2016 at 5:14:04 PM UTC-4, Maxx wrote:
This thread goes back to 2005. unfortunately the OP didnt go back and fix the footer. a couple years later he was napping by the wall, and got crushed when it fell over......
hiskids are suing the person who put in the footer for a billion dollars.........
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