Advanced Structural
Designs ACN 097 789 87
92 Vasey Cres CAMPBELL ACT 2612 Telephone 61612171 Facsimile 61612170 Email mal@structuraldesigns.com.au
How can I tell if a
rendered masonry wall has been cracked in the past?
If a good quality repair job has been carried out, the owner is hoping
you cannot tell that there was ever a crack there but in 95% of cases the signs
are still there if you know what you are looking for.
If the paint on the wall is a number of years old and there are no signs
of cracks in the wall the chances are that there never have been any problems,
as most cracks will reappear with seasonal moisture variations. When looking for cracks your eyes need to be
very sensitive to the staggered pattern of most movement cracks and zero in on
any variation in surface texture or alignment that may give away the
repair. It is also useful to look carefully
at the areas they are most likely to occur such as from the corners of windows.
The usual mistakes tradesmen make are as follows
- Failure to
exactly match the coarseness of the sand in the mortar is a common
shortcoming as coarser sands were generally used in older renders than we
would use today.
- Matching
trowel swirl patterns is the next most common giveaway as a circular
action is required to work the mortar into the
surface but the final trowel direction should match the direction of the
original work.
- Slight
overlaps of the old and new renders even if it’s the thickness of a grain
of sand can be a dead giveaway.
- With severe
cracking the surfaces can move out of alignment by between 1 and 5
mm. A good patch on this type of
crack will be up to 1 metre wide in an attempt to disguise the step in
alignment.
Mal Wilson has carried out some near invisible repair work in the past
on friends and neighbours homes so if you need a second opinion from a
practical structural engineer in Canberra ACT or the surrounding district give
him a call at Advanced Structural Designs Ph 61612171.