Saturday, November 16, 2013


Wall cladding is the material or component of the wall assembly that 
forms the outer surface of the wall and is the first line of protection from 
the exterior environment (sun, wind, rain and temperature). It is also an 
important part of the appearance of a building. As with all other exposed 
portions of the building enclosure (windows, roofs and balconies), regular 
review and maintenance of the cladding is important to ensure intended 
performance and appearance.

Types of Cladding

The type of cladding used on buildings is dictated by the architecture 
and by Building Code requirements related to combustibility. Wood-frame 
buildings (combustible) are typically clad with combinations of wood siding, 
vinyl siding, fibre cement board, masonry (brick) or stucco. The latter two 
cladding types are also commonly used on concrete frame (non-combustible) 
buildings. Other popular claddings for non-combustible buildings are metal 
panels and exterior insulation and finish systems (EIFS). The nature and 
extent of maintenance and renewal activities varies significantly for different 
cladding types.

Why Must the Cladding be Maintained?

Cladding is the first line of defence in a wall assembly. It is critical for 
protection of the more sensitive components of the wall assembly and the 
interior of the building. Proper maintenance of the cladding will reduce the 
likelihood of water penetration and preserve the appearance of the building. 
 Wear and tear on cladding is expected since it is continually exposed to 
sun, rain, wind and temperature changes. In addition, cladding is subject to 
damage due to accidents, vandalism and excessive vegetation growth.
The durability and expected lifetime of each type 
of cladding will vary as will the ease and cost of 
maintenance. For example, masonry walls are very 
durable, but are difficult and costly to replace. 
While vinyl siding can be more easily damaged, 
it can also be more easily repaired and replaced. 
Regardless of the type, cladding must be properly 
maintained to retain the general appearance and 
performance functions of the building and to 
reduce the likelihood of premature failure that 
could result in an expensive wall repair.
 Wall assemblies that utilize a face seal water 
penetration control strategy require regular 
maintenance and repairs to the cladding. This 
single line of defence strategy means that water 
that penetrates past the cladding can quickly lead 
to damage within the wall. 

What Maintenance Must be Performed?

Cleaning of the wall cladding is important to
maintain the aesthetics of a building. It also helps
expose any damage, such as cracks requiring
review. Cleaning methods will vary for each
type of cladding; the cladding manufacturer’s
recommendations should be followed for each
case. Cleaning should be performed carefully to
avoid damaging sealant joints, masonry mortar
joints (brick wall) and cladding finishes. Removing
organic debris will reduce moisture retention
in any cladding joints. In general, cleaning
of cladding should be performed with nonpressurized
water. Inappropriate use of pressure
washing can damage components of the wall
assembly and introduce water behind the cladding
and into the wall assembly, especially with face
seal or concealed barrier designs.
Annual reviews of the condition of the cladding
should be performed by somebody knowledgeable
regarding building enclosure performance.
A maintenance contractor or trade contractor may
be appropriate for this inspection. The review of
the cladding is extremely important for face seal
walls as the rain penetration performance of these
walls is sensitive to maintenance of an effective
exterior seal. Concentrated staining of cladding is
an indication of high amounts of water runoff, and
may raise concerns of water ingress into the wall
Recoating the cladding is particularly
important for wood siding, but is also necessary
for fibre cement boards and stucco cladding.

The durability of wood cladding is dependent on
the coating as wood itself is quite vulnerable to
weathering when used in exposed conditions.
Poor maintenance for exposed wood products
can result in irreparable and permanent damage
such as cracking and warping.
Fibre cement boards and stucco are made
from compositions that rely on paint for protection
and to reduce the effects of staining. Recoating may
also seal any minor cracks that develop in cladding.
However, recoating should not be relied upon as a
crack repair procedure to prevent water ingress.
Sealants are typically used at joints between
the cladding and penetrations, such as windows,
doors, lighting fixtures, and vents. It is at these
locations that the vast majority of water ingress
occurs. Therefore, it is highly recommended
that sealant joints be properly maintained and
repaired. Joint profiles, preparation of substrate,
and selection of an appropriate sealant product
are important variables in determining the
effectiveness and durability of sealant joints. Help
from an experienced contractor or consultant is
Metal flashings and fasteners also form
part of the cladding and are susceptible to
deterioration over time. While corroded fasteners
can sometimes be replaced with minimal
disruption to the cladding, this is not usually
possible with metal flashings. Repainting of
flashings is usually a very short-term measure
to improve appearance. When renewal of the
cladding becomes necessary, highly corrosion
resistant fasteners and metal flashings should
be used. These elements need to be at least as
durable as the cladding itself.

How Often Does the Cladding Need to be Reviewed and Maintained?

The checklist on the right lists a number of 
relevant items that should be performed as part 
of the maintenance plan.

Renewal or Replacement of the Cladding

Proper maintenance will prolong the life of the 
cladding and reduce renewal costs over the long 
term. Eventually the cladding will need to be 
renewed either because maintenance is no longer 
cost-effective, or because the performance or 
appearance of the cladding is not acceptable. 
 Renewals projects should involve building 
enclosure consultants to examine alternatives for 
cladding renewals, help ensure that appropriate 
construction details and appropriate materials are 
used, and to verify the quality of the construction. 
Enclosure consultants can also assist in the 
selection of qualified contractors to perform the 
renewal work.
 Life expectancies of the various types of 
cladding can vary depending on exposure 
conditions and the level of maintenance 
undertaken. Cladding renewals programs should, 
therefore, be integrated with plans for windows, 
balconies and decks as well as an overall building 
maintenance and renewals plan for the building.

 Action Plan Tips

  • Report any water ingress at exterior wall 
 locations immediately to your building manager.
• Cladding condition should be reviewed every 
year by a knowledgeable person and every 
 2 to 3 years by a building enclosure consultant. 
• Develop a review and maintenance plan for 
the cladding and walls. Keep a record of all 
cladding warranties and a record log of any 
review or maintenance activities.
• Retain a building enclosure consultant to 
develop a renewal program for the cladding.

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