Damp
Proofing
Introduction to
Dampness in Buildings
Dampness in buildings
can be caused by defects to roof coverings, flashings,
internal or external plumbing defects,
heating and ventilation, external
renders or the lack of an effective
damp proof course, thus resulting
in penetrating damp, condensation
and rising damp. All of which ultimately
can lead to the deterioration of the
fabric of the building i.e. timber
decay, defective internal and external
wall finishes, brickwork, stone or
mortar deterioration.
Identification
of Dampness in Buildings
The use of an electrical
moisture meter will only confirm that
a level of dampness is present, analyzing
the profile of the readings gives
an indication of the type of dampness.
In some cases samples of the structure,
plaster and salts will need to be
laboratory tested. LSE Preservation
surveyors are able to test for salts
on site and advise on the implications
of the findings.
In conjunction with
the meter readings taken the inspection
will need to take into account the
age and type of construction of the
building, the geographical location,
any defects that may be contributing
to the damp problem i.e. rainwater,
plumbing, roof coverings, external
weathering, rendering, pointing and
condensation.
Types of Dampness:
Penetrating
Damp
Where moisture from
the external elevations penetrates
through the structures of the building.
Condensation
At any given temperature
the air can hold a given amount of
water vapour, the warmer the air the
greater the amount of water vapour
that can be held.
Should warm moisture
laden air become cooled it reaches
a temperature where it can no
longer hold the water vapour. When
this temperature is reached the air
must release the water vapour; this
is seen as condensation usually
appearing as droplets of water on surfaces.
However, the most tell-tale sign of
condensation is the frequently associated
development of mould growth. The appearance
of the mould may be black, white,
yellow, green i colour, depending on the
specific type of mould and the surface
on which its growing.
Damp Proofing Methods:
For a long time
now the chemical damp proof course has been seen
as the cure for all damp problems.
At LSE we specify and carry out work
on a whole range of buildings. Many
of them are traditional built buildings
of cob and stone or flint and brick.
For these buildings a chemical damp proof course
is unsuitable.
The LSE Answer to the Problems:
Penetrating Damp
 Our surveyors will look at all of
the sources of moisture into the fabric
of the building and discuss the affects
of the moisture ingress the long term
plans for the property and then propose
the most suitable course of action
for the building and the occupant.
LSE Surveyor testing
for salts
We will recommend the correct repairs
for the obvious defects.
We will recommend
on going maintenance.
We can monitor
the property confirm that it is drying
or implement a drying solution and
monitor to confirm that the source
of ingress has been cured.
In extreme cases we can Install external
ventilated cavity membranes and render
over them.
Lime Render
We might recommend the
removal of sand cement renders and
replacement with a lime render which
will allow the walls to breathe and
shed moisture,
We Do Not Recommend:
Too often we see brick faced houses
coated with cement based applied coatings
as a cure for penetrating damp. In
most cases the houses are not even
damp and have not been professionally
checked. Cement based coatings can
often cause problems.
We very rarely recommend any form
of external spray applied siliconate
treatment. It is rarely effective
or necessary.
We very rarely recommend wholesale
re-pointing. If mortar joints need
chasing out then they do not need
re-pointing. Most re-pointing is carried
out with sand and cement.
If the house was built prior to 1900
it was almost certainly built with
lime mortar. Pointing a traditional
built house with cement can cause
damp problems.
LSE would match existing lime mortars
and carry out localised pointing if
really necessary.
Next >>
|
