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(including compressed fibre cement sheets)
New concrete floors must be allowed to cure for a minimum of twenty
eight days prior to painting.
Acid etching is the preferred surface preparation and can only be
done using professional tradespeople - contact
Resene.
Some new floors may have had a curing membrane applied, or may contain
additives which harden the surface. These treatments result in a surface
which is usually resistant to dilute acids and require alternative preparation
by mechanical abrasion or captive shot blasting.
All concrete floors must be checked for excess moisture before
coating. In the case of new concrete the test is carried out after the
minimum recommended curing period.
Surface preparation:
To Test
for moisture on new concrete:
Tape a 0.1mm clear plastic sheet (45x45cm) to the concrete surface.
Taping must provide an airtight seal between the concrete and plastic
sheet. Check the underside of the sheet after 24 hours for signs of
condensation. Darkening of the concrete covered by the plastic sheet
compared to surrounding areas also indicates presence of moisture. Allow
an additional drying/curing time of fourteen days and repeat test. If
moisture is detected on second test, the surface cannot be successfully
coated.
If painting an existing concrete floor the following surface preparation
steps need to be taken:
- Remove powdery layers and efflorescence:
Remove any powdery layers, laitance or efflorescence by vigorous wire
brushing or preferably water blasting. Sand off any protruding fibres
from fibrous cement.
- Special attention needed:
Fibre reinforced cement may contain asbestos. The removal and/or
disposal of asbestos containing materials (or just the cleaning down
of them) may require special permission and a licence. Contact your
local Council offices to determine your obligations under their bylaws.
Free asbestos is likely to be released during surface preparation
and therefore suitable dust masks or respirators must be worn by all
operators involved in surface preparation and disposal of waste. Special
care must be taken to contain all debris and this should be kept wet
and disposed of in a land fill. This material must not be left to
dry out. Professional tradespeople must be involved.
- Degrease and clean surfaces:
Thoroughly degrease by scrubbing or bushing down with detergent to
remove all dirt, dust, grease, chalk, cobwebs and other contaminants.
Rinse clean with copious amounts of clean water and test surface is
degreased by wiping with clean cotton wool. Repeat process if necessary.
- Remove all moss and mould:
Thoroughly clean down to remove all loosely adhered material. Treat
areas of moss or mould infestation with Resene
Moss & Mould Killer, correctly diluted with clean water.
Leave for up to forty eight hours to achieve full kill. For heavy
infestations further applications may be needed. Wash thoroughly with
clean water to remove residues.
- Waterblast 3000 psi:
This may not be necessary, but waterblasting will ensure an excellent
surface for painting.
Carefully waterblast at 3000 psi to remove all dirt, chalk, moss and
mould residue and any other contaminants. Allow the surface to dry
out for at least twenty four hours.
- More
information on Preparing Concrete Floors for Painting
First coat:
If your new or old concrete
floor is in poor condition and/or very porous it will require sealing
with a full coat of Resene
Sureseal applied at an approximate spreading rate of 10-16 square
metres per litre depending on surface texture.
If the concrete surface is smooth or glossy, then seal with a full coat
of Resene
Smooth Surface Sealer applied at an approximate spreading rate of
11.5 - 12.5 square metres per litre.
If the flooring surface is already painted and/or in good condition,
then you can go straight to Topcoats below.
Topcoats:
For interior concrete floors
apply three coats of Resene
Sidewalk at approximately 12 square metres per litre or for a waterbased
option apply three coats of Resene
Aquapoxy at approximately 11 square metres per litre depending on
surface texture.
Various paint effects can also be achieved by using Resene
Scumbling Glaze - contact Resene for
further advice on the paint effect you desire.
Exterior driveways can be upgraded using Resene
Concrete Stain. Resene Concrete Stain is designed specifically for
revitalizing concrete, pressed concrete and other cementitious substrates
forming a low sheen finish.
Resene
Blacktop is a heavy-bodied slip resistant topping for rejuvenating
aged or worn asphalt.
Follow label instructions at all times.
Cleaning up:
Cleaning up waterbased paints is different to solventbased paints -
click here for detailed instructions
on clean up.
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