Crack Stitch Repairs/Cavity Wall Tie Replacement.
Cannon Preservation Ltd
cavity wall ties, Crack Stitch Repairs
This is a project involving Crack Stitch Repairs and Cavity Wall Ties Renewal
and Isolation.Property is of around a 100 years old and built of Red Stock
Bricks and very close to the sea.
cavity wall ties
Sea salts appart from driving rain can
cause alot of damage to timber and steel fixings,once the moisture enters the
outer leaf it can then start causing issues to the Wall Ties and move around the
Property was Surveyed in April 2011 and found to have a large
crack to Gable end of around 3 metres in height and around 250mm to 500mm from
corner/Buttress of property.Cause was due to Cavity Wall Ties corroding and
causing vertical cracking in a fork like fashion,wall ties were Fishtail ties
and due to the steel Corrosion and rusting they expand and cause damage to
Work started on 9-5-2011 and completed on 16-5-2011 on
Gable end only.
Works involved were Crack Stitch Repairs over the 3 metres
in height and as per photos it involved Grinding the mortar bed every four
courses(13 in total) at 60mm deep and using Helical Stainless Steel Bars
inbedded into a 10mm/20mm bed of Resin Compound and then repointed,all cracked
brickwork was either replaced or repaired with a grout to a similar
Cavity Wall Ties: Wall ties to Gable end were found to be
Corroded and or Rusty to about 90% and in need of replacing and isolating.All
Wall Ties were located using a metal detector then mortar was removed around the
Ties by meens of a angle grinder and then all ties were isolated using a
Clam/Sleeve to stop any more moisture to affect the Steel and cause any more
expanssion. New Ties were introduced by Drilling into both leaves and being the
cavity was 75mm the Wall Ties were 220mm Helical and Stainless Steel.With a
fixing of no less than 50mm into the inner leaf these were then Resin fixed due
to the soft Stock and Lime mortar mix for a better fixture,outer leaf was a
dencer mix of sand,cement and clinker mix and also resin fixed.
, Crack Stitch Repairs