• About Us
• Products
• Shapes
• Photo Gallery
• Where To Buy
• Tech Advisories
• Contact Us
• Press Room

Technical Advisories

1. Basic Cleaning For All Redland Brick
2. Cleaning Moulded Brickwork
3. Flashing Brick Veneer
4. Efflorescence
5. Mortar Selection for Moulded Brick

1. Basic Cleaning for All Redland Brick...

(back to top)

TECHNICAL ADVISORY #99A - Cleaning Procedures For All Redland Brick

THE #1 RULE - The cleaning method is much more important than the cleaning agent!
Note: Always contact the mortar manufacturer for recommendations to avoid discoloration of mortar joints.

--------------------------------------------------------------------------------

CATEGORY A:

1. KF SWB (ANY SURFACE TREATED BRICK)
2. HARMAR AND KF SAND FACED BRICK
3. KF TUMBLED BRICK
4. CUSHWA AND ROCKY RIDGE MOULDED FACE BRICK

METHODS: Follow technical advisory #94A "Cleaning Moulded Brick" (High pressure over 300 psi not allowed)

CLEANING AGENTS:
We recommend EaCo Chem Inc. NMD80.
Good results have been obtained with careful use of Vanatrol, or Vana-Stop. Red only brick have been cleaned successfully with SureKlean #600 or Diedrick #202, but Redland willl not accept any responsibility for efflorecence after these are used.

CATEGORY B: HARMAR AND KF FACE BRICK - NOT SANDED OR COATED

METHODS: Follow BIA Tech Note 20. "Bucket And Brush" method recommended. High pressure allowed if appropriate precautions used.

CLEANING AGENTS:
We recomment EaCo Chem Inc. NMD80.
Good results have been obtained with careful use of Vanatrol, or Vana-Stop. Red only brick have been cleaned successfully with SureKlean #600 or Diedrick #202, but Redland willl not accept any responsibility for efflorecence after these are used.

CATEGORY C: CUSHWA AND ROCKY RIDGE MOULDED PAVERS

METHODS: No cleaning is recommended. Contact your local distributor for site inspection and advice.

CLEANING AGENTS:
Site inspection by local distributor required.

CATEGORY D: HARMAR AND KF PAVERS (NOT TUMBLED)

METHODS: No cleaning is recommended. Contact your local distributor for site inspection and advice.

CLEANING AGENTS:
Site inspection by local distributor required.

CATEGORY E: KF TUMBLED PAVERS (CANAL STREET)

METHODS: No cleaning allowed.

MOST COMMON CLEANING PROBLEMS / MISTAKES

1. IGNORING "THE #1 RULE"

2. Whitish "scummy" or "milky" appearance after cleaning:
Not enough clean water used prior to applying agent. Dissolved mortar has been absorbed into the surface pores of the masonry. Contact EaCo Chem Inc. or ProSoCo for assistance in removing white scum.

3.Discoloration of mortar joints:
a) Use of inappropriate agent (too harsh).
b) Leaving agent on the wall too long.
c) Not rinsing the wall thoroughly.

4. Overall discoloration, or streaking discolorations: Too much pressure from pressure washing nozzle, or inappropriate nozzle or technique.

5. Green and/or brown stains on white, buff, brown, or gray brick mean the agent (acid) was too strong or the method used insufficient water for pre-wetting and/or rinsing.

2. Cleaning Moulded Brickwork ...

(back to top)

TECHNICAL ADVISORY #94A - Cleaning Moulded Brick and Sand-Finished or Coated Extruded Brick

(Revised July 2006)

New brickwork is cleaned to remove excess mortar from brick faces. The cleaning agents designed to do this are sometimes called "detergents", but they are all some type of buffered acids. Only acid will dissolve the cement in mortar to release it from the brick faces. All of the cleaning agents (acids), even the mildest ones, have the potential to damage masonry. This is why the method of cleaning is critically important. However, Muriatic acid is NEVER permitted in cleaning any masonry, ever!

There are three methods approved by Redland Brick for cleaning new brickwork constructed with Cushwa moulded face brick, Rocky Ridge moulded face brick, and all Harmar and KF sand-finished or surface treated face brick.

--------------------------------------------------------------------------------

METHOD 1. - No Cleaning (Building Clean Walls).

If certain precautions are taken, objectionable amounts of excess mortar on the brick can be completely prevented, or, at least, minimized so that water and chemicals are not required. This is by far the best approach to clean, beautiful brickwork. Careful work is not much slower, nor much more expensive, than haphazard work. And, any extra cost is far less than the cost of chemical cleaning; and far, far less expensive than solving problems later caused by poor chemical cleaning.

METHOD 2. - Chemical Cleaning with Bucket and Brush.

If the brickwork must be cleaned of excess mortar, beyond what was accomplished with Method 1, the next best method is the use of proprietary cleaning chemicals, applied by brush, not by pressure-spray equipment.

---

Remember, controlling the method of cleaning is much more important than which cleaning acid you use. Improper cleaning methods often cause efflorescence, and can cause many other types of damage to masonry.

---

METHOD 3. - High Pressure Cleaning with Chemicals.

Extreme caution, and a limited definition of high pressure, are required with this method. Pressure spray equipment has become popular because of ease of use, speed, and economy. Pressure spray equipment has also ruined many brick projects.
The success of high pressure cleaning relies not only on limiting the pressure, but, also, the nozzle type, distance from wall, angle to wall, and operator technique. Experience and good judgment are critical. Planning, testing and control are essential.

---

Remember, controlling the method of cleaning is much more important than which cleaning acid you use. Damage to masonry is typically caused by the cleaning personnel, not the cleaning chemicals.

---

3. Flashing Brick Veneer...

(back to top)

TECHNICAL ADVISORY

#94B Flashing Brick Veneer

Brick veneer is not waterproof. Every brick veneer, no matter which brick or which mortar, can be expected to let water into the wall system under some conditions. Leakage can occur at joints between brick and mortar, allowing water to get behind the brick veneer into the wall system. This is why through-wall flashing (with weep holes) is required for all brick veneer design. All professional organizations in the industry either require or recommend the use of through-wall flashing, including:

American Institute of Architects ("A.I.A. Graphic Standards")
Brick Industry Association (BIA)
B.O.C.A. Building Code
National Association of Home Builders.

Because some jurisdictions do not have building codes applicable to residential construction, or they ignore requirements for wall flashing, houses are often constructed without through-wall flashings. The "lucky" houses either don't have leakage or don't show leakage, because they may not have severe exposure, or any water penetration may get absorbed or lost in foundations or walls. The unlucky ones have water problems.
Waterproofing brick walls has become a major business over the years, partially because of the common lack of proper wall flashings. Water in or behind brick veneer is not a problem by itself. Only when it is directed inside the wall, due to the lack of wall flashing, is water a problem that requires correction.
Think of a brick veneer wall as a "drainage cavity wall," where the cavity between the brick veneer and the sheathing allows water in the wall to drain downward. Therefore, wall flashing is required at every location that the cavity is interrupted, such as at the foundation and window and door lintels. Also, brick walls that "enter" into the interior of a building, such as chimneys and walls above lower roofs, require wall flashing above the roof. Suggested details are found in BIA Technical Notes or AIA's "Graphic Standards."

4. Efflorescence...

(back to top)

TECHNICAL ADVISORY

#93A Efflorescence in Masonry

Efflorescence on masonry walls is almost always made up of carbonate and sulfate salts. Although some brick may contribute to the formation of these salts on some occasions, when a significant amount of efflorescence appears on a wall, the source is almost certainly cementitious materials, such as mortar, concrete, or concrete block. These salts dissolve in water which has soaked into the cementitious material. The "salty" water then migrates through the masonry to the surface where the water can evaporate, leaving the salts behind on the surface. This is why efflorescence shows up on brick faces, even though the brick is not the source of the efflorescence.

For efflorescence to occur, there must be (1) a source of salts, (2) water, and (3) evaporation.

1. SALTS: Portland cements and masonry cements contain components which contribute to efflorescence, partly because it is simply not feasible to manufacture pure cements.

A major contributor to efflorescence is often concrete block. To limit this efflorescence:
- provide a clear cavity between the brick and the block, or
- provide a water-resistant membrane between the brick and block - prevent water from reaching concrete block by flashing under copings and sills, and waterproofing exposed cmu

Mortars can be providers of efflorescing salts:
- All types of cements may contain these impurities.
- Some people are concerned about the "secret" ingredients and inert fillers that are used in masonry cements as proprietary additives to the portland cement base.
- Mortar proportions and mixing procedures should be carefully controlled to make sure the cements become completely hydrated and cured as quickly as possible.
- Sand for mortar must be washed in accordance with ASTM C144. Unwashed sands could contribute potentially efflorescing salts.
- Sand should be properly graded in accordance with ASTM C144, in order to create tight and well-cured mortar joints.

It is the contact between the brick veneer and wet concrete components that allows the dissolved salts to migrate into the brick. Therefore, any such contact should be avoided, through the use of cavities, waterproof membranes, or wall flashings. Where contact cannot be avoided, the availability of water should be limited, since without water, efflorescent salts will not dissolve or migrate.

2. WATER: It takes a fairly significant amount of water over an extended period of time to dissolve enough salts to create an efflorescence problem.

Water is necessary during masonry construction to mix mortar and to provide cement hydration in the mortar. Excess water required for mixing, but not for hydration, may dissolve efflorescing salts and migrate into brick units. This is especially true in winter when evaporation is slow and the water remains in the masonry longer.

During construction, walls are exposed to precipitation.

- Keep walls covered until all masonry work is complete and all openings are closed.
- Seal or protect all expansion joints immediately.
- For composite walls, drape or protect all concrete masonry from exposure to precipitation.

After construction, efflorescence would only be caused by excess water continuing to enter the walls.

- Use good copings, sills and other materials, with proper flashings and detailing.
- Specify Portland/lime mortar Type N for best watertight bonding.
- Maintain sealants and repair cracks judiciously.

3. EVAPORATION is important to the proper performance of a masonry wall. The concept of preventing evaporation to prevent efflorescence is dangerous. Water trapped within a wall system can do all types of damage. Therefore, limiting salts and water penetration, as discussed above, are the only good solutions to preventing efflorescence. Water repellents which are "breathable" may be used, but they are only temporary, they are expensive, and they may have side effects such as discoloration or damage to other materials. We suggest repellents not be used, except in extreme cases as a resolution to faults which might otherwise require drastic solutions such as demolition.

4. OTHER ISSUES RELATED TO EFFLORESCENCE.

- "New building bloom" (efflorescence on new construction) is fairly common during winter and spring, because cold weather slows evaporation of the water which entered the walls during construction. It is especially critical, therefore, to cover walls during construction to prevent precipitation from EVER saturating the masonry.
- Masonry cleaning solutions (to remove mortar on new construction) can greatly increase the dissolution of efflorescing salts. Therefore, they must not be allowed to soak into the masonry. The proper cleaning process includes completely wetting the surface with clean water prior to applying a chemical cleaner, and thorough rinsing quickly after cleaning.
- The fact that brick are the only masonry materials required to be pre-tested for efflorescence has misguided some into believing that they are the cause of efflorescence. Yet, brick that have been proven to be non-efflorescing are used on many walls that effloresce terribly, pointing out the reality that brick are NOT the cause of efflorescence.

As a final reminder, the following cannot be overstated:

NEVER ATTEMPT TO CLEAN EFFLORESCENCE FROM BRICK MASONRY !

There is a great deal of misunderstanding about efflorescence. We are giving, and getting, a lot of bad advice, the kind of advice that could turn simple efflorescence into an impossibly permanent stain!
Efflorescence is never limited to what you can see on the surface of masonry. It starts inside the masonry, and it REMAINS inside the masonry, for years, if not indefinitely.

THEREFORE, EVEN IF YOU COULD CLEAN EFFLORESCENCE OFF THE SURFACE, YOU WILL NOT HAVE REMOVED THE EFFLORESCENCE FROM INSIDE THE MASONRY, AND THAT INSIDE EFFLORESCENCE WILL COME TO THE SURFACE LATER!

The ONLY good advice for efflorescence is to do absolutely nothing to "clean" it. The source of the water causing the efflorescence should be found and stopped. Nothing else. (In some extreme cases, concrete may have to be removed from contact with the masonry.) If the efflorescence does not go away on its own in a few months or a year, it will not be going away at all! But, "cleaning" will NOT make it better - only worse!
Read BIA Technical Note #23 and Redland's Technical Advisories.
(In some severe cases, efflorescence "control" systems are available. They chemically neutralize alkali content in the masonry, and then add another treatment to "block" the efflorescence from getting to the surface to be seen. Call ProSoCo or other suppliers for these "systems.")

NEVER ATTEMPT TO CLEAN EFFLORESCENCE FROM BRICK MASONRY !

5. Mortar Selection for Moulded Brick...

(back to top)

TECHNICAL ADVISORY

#95B Mortar Selection for Moulded Brick

Moulded brick are still made the "old fashioned way" - they are shaped in mould boxes made of wood. The nature of this process requires that the end product usually has a strong absorption. This means that mortar used with moulded brick should be selected with this in mind, and this almost always means a high lime content, low cement content, Type N mortar.
Type N mortar is the best mortar for almost all brick in non-loadbearing applications. Type S would be used only where extra strength is required for loadbearing or structural applications.
The combination of Type S mortar and moulded brick can have a very negative effect on the performance of the masonry. While increasing the load carrying capacity of the masonry, the joints are likely to allow more water penetration than with Type N mortar. In order for Type S to develop more compressive strength, the portland cement content is increased at the expense of a reduction in lime content. Without sufficient lime, the mortar will not retain its water well while laying and curing. Then, the strong absorption of moulded brick can dry out this mortar so fast that it will not bond properly to the brick, the masons will not be able to lay the brick properly, the mortar will not cure properly, and proper tooling can be virtually impossible, leading to a higher probability of water penetration. It is also more likely that the appearance of the wall will be affected by uneven coloration of the mortar.
The high cement content of Type S also leads to shrinkage of the mortar while curing. This contributes to water penetration.
There is seldom any reason to use Type S mortar in brick veneer applications. Although Type S develops higher compressive strengths than Type N, brick veneer can support itself hundreds of feet high with Type N mortar. When high flexural strength of brick veneer is desired, such as with metal stud backup in high rise construction, if moulded brick is used, it is still better to use Type N than Type S because of the curing and shrinkage problems of Type S, noted above.
Type N mortar actually bonds better to moulded brick than Type S. Since it is actually dangerous to use Type S mortar with moulded brick, as pointed out above, Redland Brick recommends only Type N mortar for use with Cushwa and Rocky Ridge moulded brick.
We recommend "Type N portland/lime" mortar with the highest lime content allowed by ASTM C270 (1 or 1-1/4 parts Lime to 1 part Portland).

CAUTION: Pre-bagged Type N Portland/Lime mixes are sometimes prepared with only ½ part Lime, the same as Type S. Therefore, Masonry Cements may be preferable to Portland-rich (less than 1 part Lime) pre-bagged PCL mixes.

(back to top)