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FREQUENTLY ASKED QUESTIONS

I. Masonry Cleaning
II. Masonry Construction
III. Specifications, Fire Ratings, and Testing Standards
IV. Versa-Lok Retaining Wall Systems

I. Masonry Cleaning

What is the best way to clean decorative concrete masonry?

Typically the use of bucket & brush cleaning with a detergent masonry cleaner is the best way to clean decorative concrete masonry.  ProSoCo has a wide range of cleaners for different types of decorative concrete masonry.  Always do a test panel prior to commencement of the work.  Always use the cleaner recommended for the specific type of decorative concrete masonry.  Please read all directions from the manufacturer of the cleaner and be aware of all safety precautions.  Do not use high pressure water to clean decorative concrete masonry.  Basic cleaning procedures are outlined below.

Products:  ProSoCo Custom Masonry Cleaner or approved equal.  Detergent masonry cleaner.

1. Follow all manufacturers’ recommendations of the Approved Masonry Cleaner

2. Do a test panel to determine acceptability of dilution of product.  Always test each surface and type of stain for suitability, dilution and results before overall application.  Apply cleaner according to manufacturer’s recommendations.   Let surface dry thoroughly before inspection and approval

3. Pre Soak walls with liberal amounts of fresh water under low pressure.

4. Apply cleaner under low pressure, bucket and brush recommended.

5. Allow cleaner to sit on wall for 3-5 minutes.  Excessive mortar droppings may require additional agitation with a stiff nylon brush.  Reapply cleaner under low pressure, bucket and brush recommended and then rinse liberally with clean fresh water under low pressure.

 

More information can also be found on cleaning concrete masonry by referencing NCMA Tek Note 8-4A Cleaning Concrete Masonry

II. Masonry Construction

Do you make a 16” tall bond beam?

Yes, we make a two web knockout.  Or, you can use an 8” solid bottom bond beams, put rebar in them, lay a course of 3 web knockouts, add rebar, and fill solid with grout.

How do I turn a 12” corner and maintain bond?

Use an 8” square end to turn the corner and plug the extra space with a 4” brick.

Can I use 4” blocks for building a foundation?
No, unless you also use a 4” veneer.  According to the NC Building Code you must have an 8” wall to be load bearing.
Can I use a precast lintel over an opening that’s longer than 12’?

No.  12’ is the maximum distance for using a precast lintel.

Does Prestige Brick need reinforcing wire every 16” like you do for regular block?

Yes, for both structural and veneer Prestige Brick.

What mortar should I use with my masonry veneer?

Please check local building code requirements. Typically Type “N” Mortar is the desired mortar for masonry Veneers.  It is easier for the mason to work with, cleans up better and has less shrinkage cracks typically than a Type “S” Mortar.  Please reference NCMA Tek Note C 9-01A for additional information on mortar.

How many block per square foot of wall area?
Typically you would calculate 1.125 block (typically 8x16 face shell) per square foot of wall area.  For additional Information please see NCMA Tek Note 4-2A Estimation Concrete Masonry Materials.
How much mortar do I need to lay block?

Typically 3 bags of mortar per 100 block is a good rule of thumb for estimating mortar.  For additional Information please see NCMA Tek Note 4-2A Estimation Concrete Masonry Materials.

How often do I need control joints in concrete masonry?

In the empirical method control joints should not be spaced more than 25 feet apart.  Other factors may require closer spacing.  Please note it is possible with and engineered design to increase or do away with control joint spacing.  Please refer to the NCMA Tek Note 10-1A Crack Control in Concrete Masonry Walls, Tek Note 10-2B Control Joints for Concrete Masonry Walls and Tek Note 10-3 Control Joints for Concrete Masonry Walls (Alternative Engineered Method)

Do Clay Brick and Concrete Block move at the same rate?

Clay Brick move differently then concrete block. The general trend for clay brick is expansion in the wall.  The general trend for concrete masonry units is shrinkage in the wall.  For more information on movement see NCMA Tek Note 10-1A Crack Control in Concrete Masonry Walls

What’s the best way to paint paint-grade splitface?

Apply a block fill followed by an elastomeric paint.  Follow manufacturers’ instructions and be sure to use the suggested amount of paint for the surface area.

III. Specifications, Fire Ratings, and Testing Standards

Does the density of the concrete masonry unit affect the compressive strength?

It is possible to achieve a wide range of compressive strengths in each of the density classes.  Please see NCMA Tek Note 2-06 Density Related Properties of Concrete Masonry Assemblies for more information.

What is the difference between ASTM C144 and ASTM C 90?

ASTM C 90 is the performance requirements for concrete masonry units including compressive strength, shrinkage, dimensional tolerance and absorption.  ASTM C 144 is the proscribed test method to determine what the actual performance of the concrete masonry unit is.

Does an 8x8x16 Regular Block have a 2 hour fire rating?

Fire ratings for concrete masonry are based on the materials the block is produced with and the equivalent thickness of the units.  High Performance Aggregates such as Stalite provide superior performance in fire tests.  Please reference our fire rating matrix for specifics <Link to 2.2.1 Gray CMU>  For additional information please see NCMA Tek Note 7-1B Fire Resistance Rating of Concrete Masonry Assemblies.

What is the difference between Type 1 and Type 2 Block?

A Type 2 Block is a non moisture controlled unit.  A Type 1 Block is a moisture controlled unit.   This type of unit is typically not achievable in the field.  Basically it means the moisture content of the unit is controlled from the time of production to being covered in the wall.  The amount of humidity in the south east climate can typically take a block out of the Type 1 specification, not to mention the issues of producing one and keeping the moisture level from exceeding the requirement.  Several years ago Type 1 was removed from the ASTM C 90 Specification because the advantage of a Type 1 block was less shrinkage and therefore fewer control joints for crack remediation.  Since it was so hard to achieve in the field if you designed for a Type 1 unit there was an increased chance your project would be more likely to have cracking issues do to the difficulty of maintaining the properties of a Type 1 unit in the field.

IV. Versa-Lok Retaining Wall Systems

What colors are available?

Versa-Lok retaining wall blocks are made from regional aggregates and therefore vary by manufacturing location.  Please view product details for color sections.

Do Versa-Lok walls require concrete footings below frost?

No. Versa-Lok walls are installed on shallow, non-rigid leveling pads consisting of well-compacted gravel. The flexible nature of the walls allows them to accommodate minor earth movement without damage.

Can I install Versa-Lok walls myself?

Yes. Many do-it-yourselfers discover solid, pinned Versa-Lok systems are actually quite easy to install.  View our list of recommended contractors if this is not an option.

Do I need to order special corner pieces for Versa-Lok walls?
No. Corners, curves and steps may all be constructed using one unit, a major advantage to working with Versa-Lok systems. Units may easily be modified using a hammer and masonry chisel or mechanical splitter, when necessary.
Should I use mortar between units?

No. All Versa-Lok walls are mortarless! Units are dry stacked and aligned using Versa-Tuff pins. Mortarless construction allows walls to remain somewhat flexible and accommodate minor earth movement (such as that caused by freeze/thaw cycles) without damage.

How tall can Versa-Lok walls be built?
Generally, Versa-Lok walls can be built to any height. However, factors such as wall height and soil loads should be carefully considered before determining how you construct your wall.
How are Versa-Lok units connected?

Units are connected using Versa-Tuff non-corrosive pins. Two pins are used per unit, inserted through the front holes in the upper course units into rear slots in the lower course units.

 
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