Damage to buildings by sea water
Apart from the mechanical destruction resulting from wave action,
strong currents, flooding and the like, buildings, parts of buildings and
furniture may also be damaged merely through the presence of water.
Wood will start swelling and may even rot, glued joints will come apart,
ironwork will rust, etc.
Like the inundation of the island of Walcheren during the war, the
floods of 1st February, 1953, again showed that the corrosive action of
sea water is much more severe than that of fresh water. Consequently,
serious difficulties are being experienced in connection with repairs to
buildings which were flooded by sea water.
In the first place these difficulties are due to the fact that during the
last few centmies at least inundation by sea water of such vast areas
has not previously occurred, so that there is no experience to fall back on
with respect to the repairing of this type of damage.
Secondly, the damage to materials such as brickwork, concrete, plaster-
work, gypsum, sand-lime brick, etc. resulting from the action by sea
water is of such an undetermined and varied nature at least immed
iately after the building has fallen dry that it is often hard to rec
ognize. In many cases the effects are not noticeable until after some
considerable time has elapsed (sometimes a number of years!). This means
that in such cases all the money and labour expended on repairs has been
wasted.
Thus, before the repair work on a damaged building is taken in hand
(the visible damage may vary between damp spots on the wallpaper and
the total loss of the building), it should first be ascertained whether there
is any chance of salt-water damage revealing itself in the future. This
chance is greater according as the salinity is higher and moreover depends
on the duration of the inundation. There are yet a number of other factors
which may play a part, but their effects are either still unknown or can
only be assessed by approximation.
The most common types of sea-water damage to brick buildings and
houses are the following:
peeling off of wallpaper and plasterwork (new wallpaper and new
plaster will also come off very quickly)
precipitation of salt in the form of crystals or powder on walls and
ceilings
blistering of paintwork
rusting of hardware
damp houses (drying out by stoking does not help);
warping of doors
flaking or powdering of brickwork
rusting of reinforcing steel, etc.
In most cases such dwellings are almost uninhabitable. As a result of
the damp atmosphere food soon goes bad and damage is caused to clothes
and household effects, while the health of the inhabitants is also impaired
(rheumatism)
Experience gained after the reclamation of the island of Walcheren in
1946 has shown that the repairing of salt-water damage to buildings in
volves considerable financial sacrifices on the part of the owners, while
the results are by no means satisfactory in all cases. In practice the build
ing is demolished down to the main structure and all the walls are coated
three or four times with a bituminous preparation of special composition,
whereupon the house is rebuilt.
It is often cheaper to demolish the house altogether and to build a new
one, even though at first sight it seems practically imdamaged.
In view of these difficulties and the considerable economic consequences
involved, "Bouwcentrum" (International Information Centre for Building
and Architecture in Rotterdam) has taken the initiative to set up a research
group, which also has an advisory task. This group will on the one hand
study the problems involved and, if possible, work out cheaper solutions,
while on the other hand it will give advice both in general (publications,
lectures, reports, etc.) and in individual cases.
Apart from 64Bouwcentrum", the "Foundation Ratiobouw" and
various institutes of the Organization for Applied Scientific Research are
represented in this research group. A preliminary investigation into the
expected salt-water damage and the measures to be taken, as well as a
number of laboratory experiments, are already in progress, while an
extensive research programme is being worked out.
Right and opposite: After the dikes had
been breached in February 1953. As it
was before the floods and as it will be
again. Two aerial photographs of the
village of Dreischor.
