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?

Our listed standard wall (12 foot length) and heavy wall (20 foot length) are designed to be poured in a single lift.  For lengths in excess of 20', call for technical assistance.

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

No.

7. Can Sonotube fiber forms be used in water?

No. Commercial forms are the preferred column form if water is a factor.

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. Concrete should be placed with an elephant truck or similar means – not dropped.  

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 but highly recommended as they will help facilitate stripping.

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 12” 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 12’ are usually only braced at the top and bottom. Lengths over 12’ 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.

17. (A) How do you go about changing specifications from a square pier or        column to a round section?
       (B) What requirements should be met?
       (C) At what stage in the project is it possible?

(A) In most cases, the architect and /or engineer must approve, but some cases the contractor can make the change.
(B) In general, the cross-sectional area of the round column must be equal to the area of the square column being replaced.  The reinforcing steel must also be equivalent.  The architect/engineer approving the change will be able to answer this question.
(C)  When job is designed – when it is bid – prior to construction.

18. How much concrete and rebar is required for my particular job?

Selection of the proper materials and design of the support system for any structure is dependent upon the full design of the structure, the soil characteristics of the job site, local building codes and other job specific details.

A licensed engineer or architect familiar with your project must provide these answers.

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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?
17. (A) How do you go about changing
       specifications from a square pier or
       column to a round section?
       (B) What requirements should be met?
       (C) At what state in the project is it
             possible?
18.  How much concrete and rebar is required
        for my particular job?

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