Have Your Cavity Wall Ties Begun To Corrode?

1
Have Your Cavity Wall Ties Begun To Corrode?
2

• For as long as they have been in use, cavity
  walls have presented a unique problem to
  builders, and while they are a vital addition to
  the design of modern households, in some
  instances, they can be weak. Damp-proofing a home
  and giving it the ability to be better insulated,
  cavity walls are useful, but problematic. But
  why?
• Cavity walls and wall ties
• The inner leaf of a propertys wall is supported
  from inside of the home by all of the walls and
  floors that are attached to it, but the outer
  wall generally stands alone, and unsupported.
  Without any additional support in the form of
  cavity wall ties, the outer part of a homes wall
  could fall down in an extreme weather event, or
  following prolonged harsh weather conditions.

3

• Cavity wall ties are designed to stabilize the
  inner and outer leaf of a propertys structure,
  and make the entire structure more robust
  overall. Depending on the age of a property and
  the skill with which the wall ties were
  installed, however, some problems can commonly
  occur.
• Nowadays, wall ties are usually made from
  corrosion-resistant materials such as stainless
  steel, plastic or composite materials, while in
  days of old, they were made from materials that
  were far more likely to rust, and deteriorate.

4

• Cavity wall ties and corrosion
• When a substance wears away in its entirety,
  softens or dissolves, due to a chemical
  interaction between the environment and the
  metal, corrosion has taken place. One type of
  corrosion is known as rusting, and this
  particular reaction is caused when water, iron or
  steel interact together when oxygen is present.
  Although solid in form, the hydrated oxide that
  is rust, is still very weak and brittle.
• Older cavity wall ties made from corrosive
  materials will eventually succumb to this, while
  newer, stainless steel, galvanized wall ties will
  be far stronger and more resistant, for far
  longer.

5

• Which homes are more at risk from cavity wall tie
  failure?
• If your home was built between the years of 1935
  and 1981, it has a higher chance of wall tie
  failure. This is mainly because houses built
  before that time didnt have cavity walls, and
  also because older cavity wall ties simply
  werent durable enough and prematurely corroded.
• The British Standards Institute addressed the
  problem in 1981, by tripling the thickness of the
  wall ties zinc coating.

6

• What can speed up the rusting process?
• There are a number of factors that can accelerate
  the speed at which cavity wall ties rust or
  corrode, and they are as follows
• Use of aggressive chemicals
• Sometimes added to mortar to colour it black,
  black ash is a byproduct of the coal mining
  industry, but its high content of sulphur, when
  wet, produces a weak sulphuric acid, which can go
  on to attack galvanised coatings

7

• Chloride salts
• If added to a mortar as an accelerant, chloride
  salts can speed up the process of corrosion, even
  in very small amounts
• High levels of moisture
• Whether the entire building, or certain sections
  or elevations of it are exposed to high levels of
  moisture, corrosion can occur at a faster rate.
  Its common that the part of the wall tie in the
  outer leaf will experience the most rusting due
  to moisture penetration, but even condensation
  can cause wall ties to rust.

8

• Cavity wall ties have a tendency to rust, and if
  youre concerned that your older home may be
  experiencing problems with aging ties, a thorough
  inspection from a local expert can help put your
  mind at rest, and if necessary, get the problem
  fixed
• NorthWest Wall Ties is a small family-run wall
  tie company based out of the heart of the
  Northwest. We specialize in offering cavity wall
  tie replacement and high-quality workmanship that
  is designed to last. We have been in business for
  over 20 years, and our experienced team of
  professionals has provided countless customers
  with reliable and affordable wall tie solutions.
  If you are looking for wall tie specialists,
  contact Northwest Wall Ties at 01942 933821 or
  emailnorthwestwallties_at_yahoo.com.