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QUIK-TUBE™ rigid fiber building forms are the ideal method
of pouring cylinder-shaped concrete foundations for deck and porch
supports and other load bearing applications. QUIK-TUBE™ forms
can also be used to create attractive bases for lamp posts, fence
posts, basketball net posts, mailbox posts and other post-setting
applications. Such forms may also be required by frost line building
codes.
QUIK-TUBE™ forms allow you to place the strongest foundation
possible. The inner walls of the form are waxed. This holds in the
concrete's water content, which results in maximum curing and strength
buildup. Consider that when placed in a hole or dirt form, water
can be sucked out of the concrete by the surrounding soil. This
shortens curing time and reduces concrete strength. For this reason,
many local building codes now specify the use of forms for all footers
and foundations used in load-bearing applications.
QUIK-TUBE™ forms are available in 8", 10"
and 12" nominal diameters. Each tube is 4' long and can easily
be cut to length using ordinary power tools. They can be left in
place or stripped away after the concrete has cured for 24 hours.
For the easiest removal and the smoothest concrete finish, apply
a release agent to the inside of the forms.
Pressure-treated wood or metal posts can be secured to the footer
by anchor plates or bolts embedded in the concrete. The posts themselves
can also be embedded in the concrete to a depth that ensures complete
support. The exact method acceptable for load-bearing applications
such as decks are subject to local building codes.
For example, in areas prone to termite problems, the code may specify
the use of pressure-treated lumber attached to the footer using
anchor plates. The elevation of the footer may be several inches
above grade. These steps keep the lumber from direct contact with
the soil, a condition that reduces the likelihood of termite problems.
Flag, basketball and playground equipment poles may require embedding
in concrete to certain depths, often up to 1/3 overall pole height.
Check local codes and/or pole manufacturer recommendations.
Positioning the Form
1. The diameter of the QUIK-TUBE™ form should be at least
double the post or pillar diameter it will support. When supporting
deck posts or other load-bearing members the form should extend
down below the frost line.
2. Use a posthole digger or shovel to dig a hole to the proper
depth. Do not make the hole wider than needed to minimize backfilling.
3. Place 6" of QUIKRETE® All-Purpose Gravel on the base
of the hole to help with drainage.
4. Cut the QUIK-TUBE™ rigid form to size. In most cases you
will want to size the form so that the finished footing will extend
out of the ground approximately 2" to 6". This protects
lumber from direct contact with the ground and allows rainwater
to drain rapidly from the area.
5. Center the form in the hole. Check that the top of the form
is level using a mason's level.
6. Carefully backfill against the sides of the QUIK-TUBE™
form to support the tube and keep it from shifting during the pour.
7. When forms are placed aboveground in applications that will
be backfilled later, make sure the bottom of the QUIK-TUBE™
is properly braced. Build a bottom collar out of scrap lumber, and
keep the form plumb by adding braces above its midpoint as needed.
Nail and stake all braces firmly in place.
Positioning the Post
When the post or pillar is to be embedded in the concrete, position
it inside the QUIK-TUBE™ prior to beginning the pour. Use pressure-treated
lumber or apply creosote equivalent to prevent below-the-ground
rot. Coat metal posts with rust inhibitor. Center the post or pillar
inside the form. Brace it as needed to prevent shifting during the
pour and while the concrete sets. Use a mason's level to make certain
the post is plumb and its top is level.
Estimating the Concrete Needs
For a cylindrical form, such as QUIK-TUBE™, multiply the square
of the form's radius (one-half its diameter) by 3.1416. This gives
you the area of the QUIK-TUBE™ form. Multiply this area by
the form height to determine the volume of concrete needed. The
table given below simplifies the calculation process for QUIK-TUBE™
jobs. It lists the bags of mix needed per linear foot of QUIK-TUBE™
form for the various tube diameters. For example, if you are using
50-pound bags of QUIKRETE® Fast-Setting Concrete, to pour the
8" diameter, 4' long form that calculation would be:
1 bag per linear foot x 4' = 4 bags
If 80-pound bags of QUIKRETE® Concrete Mix were used, the calculation
would be:
3/5 bag per linear foot x 4' = 2 2/5 bags.
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# of Bags of Concrete
Needed Per Foot of Form Height |
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QUIK-TUBE™ Diameter |
8" |
10" |
12" |
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50lb. Fast-Setting Concrete |
1 |
1-2/5 |
2 |
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80lb. Quikrete Concrete |
3/5 |
1 |
1-1/3 |
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60lb. Quikrete Concrete |
4/5 |
1-1/4 |
1-1/3 |
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