Most of the causes of dampness in buildings are not completely
solvable later on.

by

VED PRAKASH


1. As there can be breakage of D.P.C (Damp Proof Course) by Plumbers, so the cast iron sanitary
and rain water pipes should be erected before laying the DPC. The plain Cement Concrete
once broken will never reunite. Even a hair crack leads to dampness in walls due to capillary
action.
2. Unequal floor levels within a house or between two houses, and not providing vertical D.P.C.
plaster along the inner side of walls from horizontal D.P.C. (Laid on the wall at the lower floor
level) up to the higher floor level i.e. the depth which needs to be sealed from dampness of
underneath floor. If this very dampness is not sealed, the same will enter in the wall from the
sides of higher floor and appears in the walls on the side of lower floor.
3. Not providing permanent treatment of dampness with effective chemical in the basement floor
slab & its outer walls from the bottom slab of floor upto the filling. The water proof treatment is
required to be provided on the sides of filling & not on the inner sides. The basement R.C.C.
slab under floor should be laid before the R.C.C. side walls.
4. Flooring if laid above the level of horizontal D.P.C. results to dampness in walls from the underneath
brick ballast concrete and sand/earth filling. If any one wants to raise any floor level than the
already laid horizontal D.P.C. , then he should must apply vertical D.P.C. plaster (prepared with
water proof chemical) from Horizontal D.P.C. up to the higher proposed floor level on the side of
higher floor.
5. There may be Dampness in cupboards & Kitchen Cabinets i.e. under the working slab. It is due
to absence of Horizontal and Vertical D.P.C's. 4½" or 3" thick walls are generally constructed
later on & masons usually forget to lay the Horizontal D.P.C. on them. More over their floor
levels are also raised upto the skirting level. So, the horizontal D.P.C on the walls and vertical
D.P.C. plaster along with the walls upto the raised floor level is necessary.
6. There will be Dampness under the terrace floors if laid other than brick tiles. Hair Cracks do not
occur in joints of brick tiles terracing when these will definitely occur in concrete, crazy and stone
floors in summer on account of their thermo behavior. For such floors, necessary remedial
measures must be taken during construction as per detailed papers & sketches.
7. a) If separate walls instead of common walls are constructed between two houses, there will be
crack between two walls at top on a/c of different loads on them. During rains, the water will
enter through the crack between two walls. Common walls should be preferred. Moreover
foundations of both the houses will also remain weak due to one side footing.
b) In case of unequal floor level between separate walls, dampness will travel from the side of
higher floor if ¾" thick vertical DPC plaster is not done from the DPC laid at lower floor level to
the higher floor level DPC. There should be grouting of ¾" to 1" thick cement mortar in (1:3)
prepared with Damp Guard between the separate walls of two houses to seal dampness from
either side.
8. Where dampness exist in the already constructed walls of a the neighbourer and a new wall is
proposed to be constructed adjacent with the existing wall, dampness will travel in new wall due
to capillary action. To avoid dampness, remedial measure should be taken between two walls
above the horizontal D.P.C. Dampness will travel in the already constructed house if the side
wall is not made water proof.
9. There will be dampness on a/c of cracks when expansion/contraction and construction joints are
not provided in he R.C.C slab or alongwith beams at required distance and place. Cracks with
the parapet on outers walls is common sight which can be all together avoided if 3/8" to ½"
expansion joint is provided between the R.C.C. slab and masonry wall.
10. There will be dampness in external 9" thick wall if effective water proof chemical is not mixed in
the cement plaster/cement paint or snocem.
11. Leakage in the water storage tanks of masonry /concrete is often due to inside chipping with
stone chips or en-facing glazed tiles etc. Cracks are liable to occur when tank emptied in summer.
Cracks on the glazed surface are not repairable where as on the cement plaster surface, the
same are repairable.
12. There will be dampness in walls behind stone Butch face work if laid without waterproof chemical
in the cement mortar.
13 When Sanitary and Rain water cast iron pipes are not of standard quality and not checked
before embedding in walls and their joints are not fully filled with molten lead. The PVC and
H.D.P.E. pipes which have high thermal expansion, are not recommended in hot region.
14 Dampness/Leakage will happen where Inverted/hidden beams are provided in the roof slab.
15. a) There will be Dampness in toilets & kitchen due to Carelessness in fittings of water supply
and sanitary fittings by plumbers. Vertical DPC plaster upto floor level must be done inside the
bathroom and kitchen of intermediate floors so that dampness may not travel on the other side
of walls.
b) Often there is menace of dampness in walls of toilets where bathing tubs of PVC are
erected. Whenever there is over flow of water from PVC tub, the water penetrate through the
joints of PVC sheet and walls which can not be sealed permanently. Generally, the base and
sides of tub is not completely water proofed mathedologically with brick ballast cement concrete
bed and cement plaster by mixing water proof chemical to the perfect shape of the tube. Moreover
the PVC bathing tub does not remain adhesive with the base and the side walls and after some
period, the same is loosened and begin to swing (to move to and fro or vibrate). To have cool
water during summer one should construct bathing tub cast in situ in the ground i.e minimum 9"
below the floor level of ground floor.
Note :-
1. Keep in mind that the dampness can be treated/sealed from where it starts/originates and not
from where it appears. Damp Guard has the properties to stop and seal the leakage/Dampness
2. Sketches how to stop/prevent dampness/leakage for the above causes have also been prepared.
The Character of PCC (Plain Cement Concrete) is not trust worthy for water proofing as it creates
problems where ever it has been used as a water proof measure.
Dampness can be permanently sealed side by side during
construction only by the masons of the contractor at work and not
by the water proofing applicators and firms.
Plinth Level and Dampness
Most of the dream houses constructed with hard labour and hard-earned money are
sickeningly damp due to unequal plinth/floor levels between two houses having a common wall
or separate walls.
The plinth level of the row of houses in a street has either not been fixed by the Municipal
Corporations, Municipalities, Improvement Trusts or any other house building authorities or
they have no control over its implementation in most of their own or approved colonies. Everyone
is free to keep the plinth level as high from the road as he wants without bothering about the
dampness from their raised plinth/floor level to the wall of their neighbour. In addition to this, the
high plinth/floor level from the road has another problem i.e. the approach/entry to the higher
floor level of houses. Ramps are made in the area of road which not only lead to traffic hazards
but also obstruct the flow of rain water during heavy rains. Some times storm water enters the
houses having lower plinth/floor levels. The much higher floor level entrance having steep slope
of ramp causes inconvenience especially to get the vehicles in and out.
The common or separate walls between two houses where there is difference in levels of
floors, the problem of dampness will become a permanent headache because the dampness
from the higher floor will enter the wall, above the DPC of the lower floor and in some cases goes
upto the roof level of ground floor due to capillary action. If technical precautions are taken
during the construction by the owner who starts the construction at later stage and keep his floor
level higher than already built neighbour house, the dampness can be sealed by providing vertical
DPC as shown in the sketch i.e. from the DPC of already built house upto the raised DPC. The
owner of already built house should be very careful when a new house is going to start,
adjoining his house. He should either not allow his new neighbour to keep the floor higher than
his floor along with his wall or get the vertical portion of his wall from his floor (DPC) level to the
raised DPC level of new house under construction sealed with permanent treatment of dampness
by providing vertical DPC to his satisfaction. It is the moral duty of the new builder to seal the
dampness from his raised floor to the neighbour wall otherwise he will also suffer from dampness
due to the contact of each other's walls. If he (new owner/builder) does not agree to provide
permanent damp-proof treatment on the portion i.e. to the height he intends to raise the floor,
then his neighbour, the owner/builder of the existing building can get stay order from the civil
court with the apprehension of dampness from the higher floor of the new building adjacent to his
walls. Higher floor, whichever type it may be, will lead to dampness in the walls of lower floors if
not sealed by providing vertical DPC on the wall with the side of higher floor. In case of seperate
walls there is another method i.e. new builder should lay the Horizontal DPC at the level of
already constructed house and provide vertical DPC plaster on his side up to the purposed plinth
level as shown with dotted lines in the sketch also.
It is a matter of regret that most of the masons and contractors do not have the knowledge
of the occurrence of the above explained unsolvable dampness and those who know it do not
bother to carry out or execute the vertical DPC in the interest only to save some labour cost.
Inhabitants, mostly layman, do not have the knowledge of this dampness which later on becomes
a headache and irritates them. Costly paint applied on walls begins to wither off. "Shora" will
appear on the walls. Where there is dampness, there will be "Shora". Otherwise "Shora" cannot
appear. Moreover, termites also make their homes in damp condition. Some contractors have
told that they are executing the building work on lumpsum labour rate which are very low due to
competition and the owner will never pay them if such extra items are executed by them i.e. to
seal the dampness by providing vertical DPC.
Actually a single common wall between two houses is required to be constructed. Where
separate walls are constructed, problem of dampness also occurs from the top of the lower
parapet. Cracks at the top between two walls will occur due to their unequal settlement on
account of different loads on them and other expansion and contraction factor also. The foundation
of these walls becomes unsafe during Earth Quake due to unbalanced footings if laid in brick/
stone masonry.
In consumer houses where concealed sanitary/water supply pipes are to be laid, then the
reinforced tie beam in foundation should be laid at least 20-22" below the entrance level of the
house from where sewer line is to pass. With this arrangement there will be no hollowness in tie
beam and no breakage will happen to pass sanitary pipes otherwise very purpose of the tie
beam to the extent it required will not be achieved.
Dampness can be treated from the place from where it originates and not from the place
where it appears. That is why aforesaid causes of dampness are not solvable afterwards. The
waterproof chemical which is to be used in cement should not be acidic or basic but should be
neutral i.e. having PH value 6-7. Permanent treatment should be applied and not the bitumen or
tarfelt etc. which is not entirely satisfactory because of the vast difference in temperature in most
of the Northern and Eastern regions of India. The bitumen expands in summer and contracts in
winter which leads to cracks and decay with lapse of time. The polythene sheet is also not
dependable because it cannot become part of the concrete/plaster surface. The water can
penetrate underneath its whole area even from a single escape.


HOW TO TREAT DAMPNESS WHICH OCCURES ON A/C OF UN-EQUAL FLOOR/PLINTH LEVELS
BETWEEN TWO HOUSES IN CASE OF COMMON WALL OR SEPERATE WALLS?


Civil Engineering Community should be conscious to their
foremost duty to maintain the quality of works


Day by day unfortunate degradation in the building construction industry is growing in general and
particularly in private consumer houses and buildings. On one side, we talk of new technology and in
certain quarters, the same is being adopted but in many cases the basic needs (equipments and
instructions) to maintain the quality of works is being ignored. Some of the glaring negligencies noticed
in construction methodologies are as under:
1. in many cases permanent benchmarks are not fixed outside the excavation of foundation to check
the centre lines of walls during construction of foundations while giving layout of buildings. In many
cases centre to centre excavation is not done and checked side by side. Usually after cement sand
brick ballast base concrete is laid, the centre lines of masonry walls are checked by the masons. In
most cases, the offsets of concrete on both sides do not come out equal and thus the required
base underneath the masonry wall is not available throughout the length. In some cases footing of
walls cross the base concrete and brick masonry is laid after some cutting of soil. In many cases
masons do not feel it necessary to check the level of bed of excavation before laying base concrete.
2. In many cases, the foundation base concrete of more than 6" thick is not thoroughly compacted in
layers. Loose concreting and unequal width of base concrete causes the settlement of foundation
which results cracks in masonry walls later on. What one expects to mix the brick ballast concrete
in a mechanical mixture, even the required dry cement and sand is not mixed properly before
mixing the base concrete. In many cases of private construction simple dry brick ballast is laid and
compacted without the mix of cement mortar. The cavities in brick ballast become hidden cells for
termites which will also result to settlement of foundation.
3. In many cases, no mixing trough/"houdi" for mixing the cement mortar is arranged/constructed at
the site of work. The cement sand mortar is often mixed on the open platform or even on the
streets/roads where cement slurry used to flow hither and thither.
4. In many cases measurement box/boxes of standard size i.e. 0.35 cubic meter or 1.23 cubic foot for
batching the volume of aggregates are not used. Even for big projects, the batching is done with
unequal size of steel 'Tasla's' for mixing cement sand mortar and concrete for masonry and
reinforcement work respectively..
5. In most cases, the foundation masonry upto 18" width is done haphazardly without caring to lay the
bricks in specified bonds. The bricks are simply laid on cement sand mortar bed & the sides of
bricks are not lipped with mortar with the help of trowel. In general, the top surface of bricks is
grouted with cement sand mortar by adding water in the already prepared mortar, which weakens
the strength of mortar considerably.
6. To have a homogenous and pores free rich concrete (P.C.C.), the proper grading of aggregate i.e.
fine & coarse sand and coarse aggregates are not fixed prior to the mix of concrete. Similarly no
importance is given to the water cement ratio which is very important factor to achieve the desired
strength.
7. In case of manual mix, the water should be added in dry mix of cement & sand for mortar and
cement, sand & bajri for concrete until uniform colour of dry mix is not achieved.
8. In many cases 4" thick sand filling is not laid under the floors of ground floor. Moreover lean brick.
Ballast concrete is laid under floor instead of cement sand concrete (1:8:16). Under such floor
termites make their way and that by most of the houses are termites effected. Such practice is
going on where the work is given to the petty labour contractors as they do not want to employe
labour to remove the extra earth filling and prepare proper mix of base concrete.
9. In many cases due care is not given to the use of cement mortar or cement concrete within half
hour after adding the water. It is very disheartening to see that most of the masons who lay the
stones and ceramic tiles etc. for flooring/skirting, prepare the mortar twice a day in summer and
once a day in winter. They use very rich and thick cement mortar without preparing proper bed of
the base concrete of brick ballast. The base of concrete bed is not brushed with steel broom brush
to have key joints between the base concrete and mortar bed. Even in many cases, lean brick
ballast concrete without any mix is laid. They use more than 2" thick cement mortar for laying of
stone/ceramic tiles when the same should not be more than 3/4" thick.
10. Where there are difference in floor levels within a house or between two houses, some of the petty
contractors do not lay the horizontal DPC on walls at the lower floor level and avoid the item of
vertical DPC plaster to seal the dampness in walls from the side of higher floor.
11. Many masons do not bother to make bonds with the existing masonry walls which are required to
be made in alternative layers to avoid any later on cracks with the junction of walls.
12. Joint must be provided between the load bearing wall and non-load bearing wall to avoid crack
between them. Where Joint is not provided, one can see a crack between the compound and main
wall of building which becomes a source of dampness. The thickness of wall facing with the
compound wall should be plastered in rich cement mortar to avoid any dampness before constructing
compound wall.
13. Due attention is not given to lay the brick masonry with thin joints. The joints should not exceed
3/8" thick (8mm to 10mm) in any case in the interest to achieve good binding and as well as to save
mortar. The side of bricks are rarely lipped thoroughly with cement sand mortar
14. Key-joints (grooves) with raking tool are rarely made on the plain side of masonry wall side by side
when the cement mortar of masonry is still green i.e. to provide proper keys for adhesion of plaster.
As far as possible, the steel gurmala should not be used for plastering unless otherwise it is specified
for sake of smooth surface. It should not be used on outside exposed wall plaster work because it
bring out more cement slurry on the outerside of plaster than the wooden gurmala and becomes a
cause of micro hair cracks on the outer surface of plaster.
15. Thans 6 to 8 ft. high (wooden or steel straight edge) is seldom kept at site to check the equal height
of walls during the construction. Often, the top levels of walls are corrected with thick layer of
cement sand mortar or concrete (P.C.C.) before laying the slabs.
16. Before the start of laying concrete in slab/beams, the footpath of wooden/steel planks or challis are
seldom erected for the labour so as they can easily move without disturbing the binded steel.
Similarly, chowkies are not arranged for masons to work. In absence of above, the binded steel
get jerks by the movement of labour and masons which also goes in the fresh laid concrete of slab.
Due to non arrangement of the above, the cranks provided for negative steel reinforcement often
bent down during the process of laying slab and the very purpose of cranks is marred. Even due
care is not adopted to put the concrete gently for laying of slab. Such carelessness can endanger
the underneath centering and shuttering and effect the concrete cover also. Vibrator should not be
used to such an extent that cement slurry may come out on the top surface.
17. Due time is not given to stripping/loosing the centering and shuttering under the RCC slab and
beams just to save the rent of same. In normal temperature minimum time to loose the centering
is one day for per foot length of span in case of slabs. Now many contractors do not give 50% of
the required time and that's why some sagness in slab often occurs during loosing the centering
and shuttering which weakens the slab. Any accelerator (Admixture) for quick setting of concrete
or any other admixture in structural works is also harmful.
18. Mostly, the petty contractors engage second class masons who have not requisite technical
knowledge and skill of their profession and they do so many wrongs during construction. During
inspection, necessary check should be made on them or may not be allowed to work.
19. Except urban estates of PUDA/HUDA etc., now in most cases separate walls instead of common
walls between two houses are constructed. In colonies of PUDA such practice is also there. Some
invisible settlement of foundation always happened. In case of separate walls, a crack between
two walls due to unequal load on them becomes a source of dampness and leakage. The inhabitants
losses space and spend more either due to lack of technical knowledge or noncooperative attitude
even knowing the demerits. The foundations of such walls become unbalance due to one side
footing and can endanger the safety of building. This practice should be sincerely and strongly
discouraged by the Engineers and Architects. .
20. In many cases, 4½" thick brick wall are constructed by petty contractors as load bearing walls and
where sperate walls are constructed, they save some labour cost. They prevail upon the owner
who is layman with the reason that ultimately it will become 9" thick wall. The 4½" thick single layer
brick wall can not with stand against earthquake.
21. In many cases, compaction of earth filling is not done to the required density under the ground
floors and also underneath the terrace floor which result to settlement. Further to save labour, the
petty contractor avoid to mix the toori/pushka while preparing mud plaster for laying of brick tiles on
the terrace floor. They misguide the layman with the reason if toori (pushka) is mixed in the mortar
the ants will enter in the roof which is contrary to the reality. The mud mortar without pushka (toori)
will rise upward during the tamping of tiles and thus the joints between the tiles will not be thoroughly
filled during the cement sand grouting. Through these empty joints, the ants make holes in the tile
terracing. During rains, the water penetrate in the roof which results to leakage and dampness
especially during rain in summer
22. The character and behaviour of materials is seldom counted for in constructions. Where the clay
burnt tiles or Dholpur stone etc are to be en-faced on brick masonry walls, the mortar should be
prepared by adding water proof chemical because these are prone to absorb water. Stone cladding,
some times disintegrate during hot summer due to bending of mortar because same are not laid by
fixing proper size of brass dowels and clamps in the masonry joints. Disintegrated stones from the
wall face some time causes fatal accident. During summer, stone/tiles partially disintegrate from
mortar. Water penetrate in walls which results to dampness in walls. Similar is the case of terrace
flooring laid other than brick tile terracing. Refer detailed paper at page 89-91.
23. Some contractors prefer to provide hidden beams to save extra cost evolved on centering and
shuttering of T-beams.
24. In many cases the client wants their construction completed within short period. Cracks will happen
where the pace of work is too fast and rich cement mortar and over dia or excess steel is
used.
25. Petty Contractor prefer to provide single flight stair without any landing in between of steps which
is a unhealthy and dangerous practice going on in almost small houses and even in big houses also.
The main reason of degradation in construction industry is mostly due to the execution of private houses/
buildings by the agency of labour contractors on lump-sum plinth area rate basis contract and not on
item rate basis. The labour contractors try to save the labour expenditure wherever they can. Even the
very important item of vertical DPC where there is difference of floor level within a house or between two
houses is ignored. Most of the masons become contractors after a certain period because they do not
feel it difficult to calculate their payment of work done at the plinth area basis. Most of them lacks in
systematic planning to reduce the expenditure of labour and that is why the above pointed out basic
needs to improve the workmanship are ignored. Most of the some contractors go after the quantity
and not quality. But they are ignorant of the fact that the bad workmanship always increases the
cost of labour in addition to wastage of material.
We should not forget the recent Gujarat earthquake and consequent loss of life and property. If we
continue to overlook the above formal basic needs to maintain the quality of works, then the created
assets of individuals and public will not be upto the mark (durable). It is worthwhile to mention that in
many cases some basic needs to maintain the quality of works are not even followed in to-to in government
and semi-government departments also where there is no dearth of technical supervisory staff.
The Engineers and Architects who supervise the works should realise their foremost duties and make a
point to get the basic needs complied/adopted during construction while providing other technical guidance.
If degradation is continued, in execution of works, then it will not be out of mention that the engineering
community in general is not fair to their profession.