Cladding

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

assembly.

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

recommended.

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.