SINGLE LEAF MATERIALS CLASS II MOTAR CLASS III MORTAR
1:1:6 Clay only 1:9 Clay&Calsi 1:2:9 Clay only
Half brick FBS/ Half brick NFP One brick NFP Half brick Maxi One brick Maxi
Round off cement and lime Quantities to the nearest full pocket and sand quantities to the nearest 0.5m3
SMOKE AND SOOT
For the record, to produce 1000 litres (1m3) of mortar requires
Scrub with a household detergent. The more stubborn patches
can be pulled from the brick pores using a poultice based on
trichlorethylene, although good ventilation is essential indoors.
1:6 – 6.8 pockets cement: 1,34m3 sand1:1:6 – 5,8 pockets cement : 5,8 pockets lime : 1,16m3 sand
LIME BLOOM Class III
Lime bloom and streaks may be present from the autoclaving
process, and will tend to mask the colour of the brick. The
1:2:9 – 3,9 pocket cement: 7,8 pockets lime: 1,17m3 sand
recommended brickwork cleaning process is as follows:-Wet a 1 to 2 metre width of brickwork with clean water. N.B. For mortar mix requirements for Calcium Silicate Bricks
-Immediately scrub wetted area thoroughly with a diluted
please contact the Building Advice Bureau.
solution of a proprietary acid cleaner (1 part cleaner: 20parts water). CLEANING OF BRICKWORK
-Immediately wash down the scrubbed area with fresh clean water. LICHENS AND MOSSES CHECK LIST
These can be killed with a 10% copper sulphate/water solution;
DO Protect bricks and unﬁnished brickwork from becoming
or a proprietary weedkiller recommended by the makers.
There will usually be an obvious black residue of dead of dead
DO Ensure that all safety measures are taken when handling
material which should be removed by scrubbing with water.
and using chemicals and that ﬁrst –aid measures are
Vegetable growth is generally indicative of damp brickwork and
may reappear if this basic cause is not cured. DO Identify the nature of the masonry to be cleaned and the type of stain or deposit to be removed. DO Consult Corobrik in case of doubt.
Wash down with a solution of oxalic acid (1 part to 10 parts of
DO Carry out trials on small areas of masonry well before the
main cleaning operation is started. DO Ensure that the masonry is adequately wetted before TIMBER (brown or grey)
surface application of chemicals, and, unless stated to the
These stains are due to water spreading tannin or resin from the contrary, remove all trace of the chemical afterwards.
timber across the bricks and motar, and they can normally be
DO Allow efﬂorescences to disappear away naturally whenever
removed by scrubbing with a 1:40 solution of oxalic in hot water.
possible. DO Ensure a high level of ventilation when chemicals are used
Water running regularly down the surface of brickwork produces
DO Protect vulnerable metalwork and other materials and plants
pattern staining which frequently can be removed by scrubbing
from chemical liquids, fumes and spray.
after wetting with a high pressure mist spray of cold water. If this DO NOT Clean brickwork which is exposed to hot sunlight.
is not effective, the treatment recommended for motar should be DO NOT Use wire brushes or other abrasive methods on brick
faces. DO NOT Allow chemicals and washings to contaminate
As much as possible should be removed, ﬁrst by scraping, then by scrubbing with water and emulsifying detergent. Allow to dry, then, if necessary, poultice with parafﬁn. Do not wet brickwork ﬁrst. RUST OR IRON GENERAL PRECAUTIONS
Wash down with a solution of oxalic acid (1part to 10parts of
Staining can mar the appearance of brickwork, but incorrect
cleaning techniques can cause permanent damage; consequently, any proposed method of cleaning should be left
(Brown staining which does not respond to this treatment,
far as long as possible, but at least a week or so, to judge the
particularly at the junction of the brick and mortar is probably
results before the whole job is tackled.
The techniques given here are intended for ‘do-it-yourself’ work in removing relatively small areas of staining. A specialist
contractor should be engaged for cleaning large areas of
Brush the stain with a solution of 1 part acetic acid and 1 part
brickwork, for example general cleaning of industrial grime from
hydrogen peroxide in 6 parts of water.
It is preferable to use wooden scrapers and stiff ﬁbre brushes to avoid damaging the bricks; but where chemicals are to prevent
Where possible, remove larger pieces with a scrapper, then
it absorbing the chemicals, and rinsed thoroughly with clean
wash down with a dilute solution of a proprietary acid cleaner.
water afterwards. Adjacent features such as metal windows
The manufacture’s instructions must be strictly followed.
and the area at the foot of the wall should be protected from
To remove mortar smear from brickwork having a potential
to exhibit vanadium staining, the following procedure is recommended:
In places where it is not possible to make a mess or where the stain is very localised, most of the cleaning liquids can
1. Wet the brickwork thoroughly with water.
be applied by thickening them with an inert ﬁller such as talc, bentonite or powdered chalk.
2. Remove any mortar with a proprietary acid cleaner. Many of the chemicals recommended are caustic or
3. Remove any residual acid in the brickwork by
poisonous, so that care should be taken and protective clothing and goggled should be worn. Volatile solvents should only be used indoors under conditions of good
4. Treat the brickwork with a 10% solution of caustic
soda or a 2% solution of potassium carbonate to prevent the reoccurance of stain.
Cleaning technique differ in some cases for clay and calcium silicate bricks, so it is necessary to identify the brick in question.
It is also essential to identify the type of stain or deposit before
Follow treatment recommended for “Mortar”.
any cleaning operations are undertaken. CLAY BRICKWORK
Except where bricks are liable to surface damage, remove
Remember to thoroughly wet the brickwork with clean water
excess with a scraper, then scrub with water and an emulsifying
before applying any chemical, and wash down with clean water
detergent. If necessary, ﬁnally sponge or poultice with parafﬁn.
Do not wet brickwork with water ﬁrst. EFFLORESCENCE CALCIUM SILICATE BRICKWORK It is always advisable to consult with us before embarking upon
any cleaning of Calcium Silicate brickwork, particularly where it is needed to use an acid.
This usually disappears rapidly from new brickwork due to the action of wind and rain. Brushing or sponging down the wall
Remember to thoroughly wet the brickwork with clean water
at times of maximum efﬂorescence will also help. The salts
before applying any chemical, and rinse with clean water
brushed off should not be allowed to accumulate at the base
of wall; otherwise they may be carried back into brickwork by subsequent rain. OIL Scrub with an oil emulsifying detergent in water. Allow to dry VANADIUM (green)
thoroughly; then, if necessary, poultice with white spirit, carbon tetrachloride or trichloroethylene. Good ventilation is essential
Wash down with a solution of the sodium salt of ethylene
diamine tetra acetic acid (1 part to 10 parts of water) or a 10% caustic soda solution. Do not wash the wall with clean
water afterwards. (Hydrochloric acid should never be used on
Apply commercial paint remover or a solution of trisodium
vanadium stains since it ﬁxes them and turns them brown. Such
phosphate (1part to 5parts water by mass); allow the paint to
brown stains can sometimes be removed using a strong caustic
soften and remove with a scraper. Wash the wall with soapy
soda solution, but there is a risk of damaging the bricks.)
water and ﬁnally rinse with water. In very bad cases it may be necessary to grind off the face of the brickwork in the affected
MORTAR Larger pieces of mortar should be removed by means of a bolster.The balance of the mortar may then be removed by
either scrubbing down with a diluted detergent (Teepol) or by means of a high pressure waterjet. A range of portable high pressure units have proved.