Concrete Masonry FAQs

1.  Why are round columns preferred over other shapes if they are exposed?

•  Less view obstruction.
•  No sharp corners to chip and break.
•  Easily finished.

2. What are some of the advantages of Sonotube forms over other types of concrete masonry forms.

•  Minimum bracing required.
•  Lightweight – easy to handle.
•  Good quality finish.
•  Can be cut on the job with a hand saw or circular saw.
•  With a form for each column, job progress can move as fast as desired.
•  Costly concrete trucking charges are eliminated due to the ability to schedule
   multiple pours in one day, as opposed to fiberglass or steel forms which
   require multiple days to pour, depending on the number of columns.

3. When are Sonotube forms more economical than steel and fiberglass forms?

•  When speed of job is critical for concrete masonry.
•  When different diameters are required on the same job.
•  When different lengths are required on the same job.
•  When the exterior finish is of prime concern.

4. If a Sonotube form has a fairly large dent because of handling damage, will the dent straighten out when filled with concrete?

 No, the dent should be removed before concrete is poured.

5. Do we recommend a maximum rate of pour?

In most cases, pouring can take place in one go. For columns higher than 6 meters, we usually recommend to pour in 2 times minimum. Pouring rate usually has an impact on the quality of the finish on the surface. The slower the pour, along with appropriate vibration, the better the results.

6. Is steel banding or other supplementary support essential for Sonotube forms?

No.

7. Can Sonotube fibre forms be used in water?

No.

8. State precautions to be taken for pouring concrete from the top of very long Sonotube form.

Bracing here is very important to hold tube in position. Use a long sleeve and , if needed, attach the vibration needle to the sleeve. Concrete should not be dropped from the top.

9. Should the contractor apply some sort of release agent to the inside surface of all Sonotube masonry forms before pouring?

Release agents are not necessary.

10. What is the minimum stripping time allowed by most engineers or architects?

Usually 24 hours, but concrete masonry specifications will dictate. Maximum allowed time before stripping is five days.

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11. Does the Sonotube form have to be stripped from the column after the concrete has cured?

Removal of the form is general practice for exposed column surfaces.  In applications below grade, there is no specific need to strip the form unless it is required by local building code. The Sonotube Round form contains no hazardous chemicals and is biodegradable except for the 1-2 mil thick plastic liner on the inside of the form.

12. If a contractor wants to leave the Sonotube form on the column for an indefinite time to protect the column, what should he do?

Remove in halves or larger sections and wrap the sections around the column – tie with tie wire or straps.

13. Can a contractor splice together two pieces of Sonotube forms?

Yes. Use a piece of same diameter tube 50 cm long – slit vertically and fit over two sections to be joined. Strap above and below joint or run sheet metal screws through wall.

14. What are the basic requirements for bracing Sonotube forms?

The tube must be securely braced to hold it in position, top and bottom, as well as making sure it will not bend or break in the middle. Generally, lengths up to 4 meters are usually only braced at the top and bottom. Lengths over 4 meters usually require additional bracing in the middle of the form.

15. How do you form a vertical drainage hole through the center of a column where they are used for canopies?

Use a small diameter tube or pipe with spacers to hold it in position prior to pouring concrete.

16. How long does it take for concrete to take an initial set?

Approximately one hour, but it varies with temperature and concrete mix.

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Jump to:

1.   Why are round columns preferred over
       other shapes if they are exposed?
2.   What are some of the advantages of
       Sonotube forms  over other types
       of concrete masonry forms.
3.   When are Sonotube forms more
       economical than steel and fiberglass
       forms?
4.    If a Sonotube form has a fairly large dent
       because of handling damage, will the
       dent straighten out when filled with
       concrete?
5.   Do we recommend a maximum rate
       of pour?
6.   Is steel banding or other supplementary
       support essential for Sonotube?
7.   Can Sonotube fiber forms be used
       in water?
8.   State precautions to be taken for pouring
      concrete from the top of very long
      Sonotube form.
9.   Should the contractor apply some sort
       of release agent to the inside surface
       of all Sonotube masonry forms before
       pouring?
10. What is the minimum stripping time
       allowed by most engineers or architects?
11. Does the Sonotube form have to be
       stripped from the column after the
       concrete has cured?
12. If a contractor wants to leave the Sonotube
       form on the column for an indefinite time
       to protect the column, what should he do?
13. Can a contractor splice together two
       pieces of Sonotube forms?
14. What are the basic requirements for
       bracing Sonotube forms?
15. How do you form a vertical drainage
       hole through the center of a column
       where they are used for canopies?
16. How long does it take for concrete to
       take an initial set?

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