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FAQ

The following are Frequently Asked Questions (FAQ) addressed to clay brick manufacturers:

 

 


 

What is the difference between a clay brick and a calcite brick?

A clay brick is manufactured by forming natural clays into a brick shape and firing the shape in a kiln at temperatures exceeding 1000ºC.  The clay undergoes a ceramic transformation into a permanent brick, which is colour-fast.  Calcite is another term for concrete brick, which is moulded from concrete and coloured with pigments.

For further information please refer to:

Manufacture of Clay Brick
(The Clay Brick Association of Canada's Technical Notes)

Manufacturing of Brick
(Brick Industry Association's Technical Notes)

 

Why is there an air space behind brick walls?

The airspace is part of the rainscreen wall system, a triple protection layer against moisture penetration.  Any wind-driven rain that finds its way through the brick wall will drain down the inside of the cavity and is directed out by the base flashing through the weepholes.  The cavity is ventilated top and bottom to allow air circulation and drying.  The third layer of protection is the building paper on top of the sheathing over the framing.  This wall system is considered by the National Research Council of Canada to be the best possible wall system.

For further information please refer to:

Moisture penetration through brickwork
(The Clay Brick Association of Canada's Technical Notes)

 

What is the difference between a cavity wall and a brick veneer wall?

Cavity wall is a construction of brick units laid up with a cavity between the wythes. The wythes are connected together with ties or bonding units and are assumed to act together in resisting lateral loads, but not to act compositely.
Brick veneer consists of one wythe of brick laid up with mortar and that is tied to a structural backing with suitable brick ties that are placed in the mortar joints of the veneer.

For further information please refer to:

Moisture penetration through brickwork
(The Clay Brick Association of Canada's Technical Notes)

Brick Masonry Cavity Walls
(Brick Industry Association's Technical Notes)

 

What is that white powder that appears occasionally on brick walls?

This is called efflorescence and is a deposit of soluble salts. Although unsightly, it is usually easily brushed or washed off.  Often, efflorescence will occur on newly built walls as they dry out ("new building bloom").  Recurring efflorescence can be a cause for concern in that it indicates moisture in the wall which can ultimately cause deterioration of the wall system.  Common sources of moisture include leaking roofs or downspouts, sprinkler systems, runoff from horizontal surfaces, and interior moisture leaking through the air/vapour barrier.

For further information please refer to:

Efflorescence
(The Clay Brick Association of Canada's Technical Notes)

Efflorescence - Causes and Prevention
(Brick Industry Association's Technical Notes)

 

 

What is a good specification for residential brickwork?

The general requirements for good masonry practice are set out in section 9.21 of all provincial building codes.  At a minimum, the clay brick should comply with grade EG (Exterior Grade) of CSA A82.1.  The specification should also identify the manufacturer's name, colour, texture and size of brick.  The recommended cleaner for that type of brick should be included (ask the manufacturer).  The specification should identify the type of mortar (generally Type N for veneer brickwork), the style of joint (e.g. concave-tooled)

For further information please refer to:

Genuine Clay Brick: A Home Owner's Guide
(This Clay Brick Association of Canada brochure outlines the benefits of clay brick construction for home owners.)

Guide Specifications for Brick Masonry, Part 1
(Brick Industry Association's Technical Notes)

Guide Specifications for Brick Masonry, Part 2
(Brick Industry Association's Technical Notes)

Guide Specifications for Brick Masonry, Part 3
(Brick Industry Association's Technical Notes)

Guide Specifications for Brick Masonry, Part 4
(Brick Industry Association's Technical Notes)

Guide Specifications for Brick Masonry, Part 4 Continued
(Brick Industry Association's Technical Notes)

Guide Specifications for Brick Masonry, Part 5, Mortar and Grout
(Brick Industry Association's Technical Notes)

 

 

How high can a brick cavity wall (90mm units) be built without support?

11 m (36ft.) is the maximum height allowed above the brick wall's bearing support.

For further information please refer to:

CSA S304.1-04 "Design of Masonry Structures"- Clause F.5.1 "Height and thickness of Cavity Walls"

 

 

What max. height can masonry veneer be built above its bearing support?

Brick veneer with a total height exceeding 11m above the top of the foundation wall shall bear on masonry, concrete, or other noncombustible bearing supports located at each floor level, but not more than 3.6 m.(11.8 ft.) vertically, starting at the second floor level.


For further information please refer to:

CSA S304.1-04 "Design of Masonry Structures" –Clause F.10.1 "Veneer"

 

 

What vertical expansion joint spacing should be used on a straight brick wall?

About 7.5 m.(25 ft.) for 10mm (3/8") joint; 12 m.(40ft.) spacing for a larger 7/8"joint

For further information please refer to:

Movement Joints
(The Clay Brick Association of Canada's Technical Notes)

Accommodating Expansion of Brickwork
(Brick Industry Association's Technical Notes)

 

 

What maximum spacing should be used for brick ties?

Max Vertical Spacing Max Horizontal Spacing
400 mm (16”) 800 mm (32”)
500 mm (20”) 600 mm (24”)
600 mm (24”) 400 mm (16”)

 

For further information please refer to:

CSA S304.1-04 9.1.3.1 "Tie spacing and pattern"

 

 

What distance above grade should brickwork be installed?

150mm or 6'' above grade

For further information please refer to:

Genuine Clay Brick: A Home Owner's Guide

National Building Code Clause 9.15.4.6 (available from: nationalcodes.nrc.gc.ca)

 

 

Do bricks leak?

No, walls leak. Brick is the densest part of the wall so typically moisture penetrates through voids in the wall, such as poorly bonded or unfilled mortar joints.

For further information please refer to:

Moisture penetration through brickwork
(The Clay Brick Association of Canada's Technical Notes)

 

 

Are water repellants necessary for clay brick masonry?

No. Good quality brick, combined with proper design detailing and installation, do not need any coatings to produce a long lasting wall. Some repellants have been found to cause premature deterioration of the brick by preventing fast drying out of the masonry.

For further information please refer to:

Use of waterproofing sealers
(The Clay Brick Association of Canada's Technical Notes)

 


What is the life expectancy of clay brick produced to CSA Standard A82?

Clay brick will last as long as the useful life of the building - given proper design and installation performed in compliance with building codes and proper maintenance.

For further information please refer to:

Sustainability
(The Clay Brick Association of Canada's Technical Notes)

 

 

Does clay brick enhance a home's resale value?

Yes, studies have shown an average of 6% better resale value than other claddings

Learn more about why Home Owners choose brick at: www.gobrick.com

 

 

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