Cromar Building Products | Damp Proofing
Cromaprufe is a cold applied rubberised bitumen emulsion that dries to provide a tough, black flexible coating.
Cromaprufe will provide a waterproof membrane on concrete and brick foundations, retaining walls and bridge abutments. It also protects concrete structures against attack by sulphates present in soils.
Cromaprufe can be used as a waterproofer for floors and walls. It is also highly effective as an adhesive for bonding wood block and wood mosaics, expanded polystyrene and cork tiles, and provides a key for plaster on difficult surfaces.
Available in 5 Litre and 22.5 Litre Containers.
Take the usual labour hygiene into account.
PPE should be worn during application. See our Safety & PPE Products.
Consult label and material safety data sheet for more information.
All surfaces should be sound, stable and free from dust, dirt, grease, oil and all loose matter.
Cromaprufe may be applied to damp but not waterlogged surfaces. Porous and hot dry surfaces should be dampened with clean cold water to assist the application of the product.
Stir well before use.
Apply by brush. Do not apply to external surfaces in wet weather or if rain is threatened. Allow good
ventilation in confined areas. In multi-coat applications, each coat should be allowed to dry completely before the next coat is applied.
Waterproofing and Protection of Structures, Foundations, Retaining Walls & Bridge Abutments:
Apply 2 coats, each at 2m² per litre. When treating foundations, the coating should be taken to meet the damp-proof course provided in the base or wall.
Cromaprufe may be applied to green concrete surfaces immediately after the shuttering has been removed to act as a curing membrane.
It is recommended that 48 hours be allowed to elapse before back-filling.
Cromaprufe may be used to provide a damp-proof membrane on concrete beams and columns before they are clad with rendering, masonry or brickwork. Two coats of Cromaprufe should be applied, each at 2m² per litre.
When the second coat has become tacky it should be blinded with 1 to 2 mm stone chippings or clean sharp sand.
If rising dampness is at all suspected, the best method of prevention is the insertion of a damp proof course or the repair of the existing one.
Remove all dirt, dust and grease. If the surface is uneven it should be levelled using cement mortar.
Bare brickwork should be covered with a thin skin of cement mortar, which should be allowed to dry.
Apply three coats of Cromaprufe each of 2m² per litre. The final coat should be blinded with clean sharp sand while it is still tacky.
Remove the wallpaper, loose distemper paints, dirt, dust and grease and make good any damaged or perished plaster. Lightly dampen the prepared surface and apply two coats of Cromaprufe each at 2m² per litre.
A section of the wall (about 300mm) should be left untreated so that any trapped moisture may evaporate away. When decorating over Cromaprufe do not use gloss paints or other oil based products.
Emulsion paints and wallpapers may be used after first hanging a lining paper, fixed with cellulose paste. Do not use wallpapers based on vinyl.
Not advised for interior walls below ground level. It is recommended to treat on the outside as Cromaprufe is unlikely to resist exposure to free water or water pressure, conditions which are often found in basements and cellars.
Sandwich construction - severe conditions and penetrating damp: Apply two coats of Cromaprufe onto the smooth, clean concrete subfloor, each at 1m² per litre.
Whilst the second coat is still tacky, blind with clean sand, as a protection against foot traffic and to provide a good key for the top screed.
It is important that the Cromaprufe membrane is taken up walls to marry with the DPC and that the dried film is not punctured or damaged.
Apply the top finishing screed to a thickness of at least 50mm and allow to dry out thoroughly before laying a floor covering.
Where severe dampness is unlikely to occur, a surface treatment with Cromaprufe will prove an efficient precautionary measure (however, the sandwich construction as described above should always be undertaken if conditions are severe and damp to penetrating).
Apply of priming coat at 7.5m² per litre by diluting 1 part Cromaprufe with 6 parts clean cold water and allow to dry thoroughly.
Two coats of Cromaprufe each at 1 m² per litre should then be applied. Each coat should be taken up to joint with the existing DPC and the dried film of Cromaprufe should not be punctured or damaged before the floor covering is laid.
Note: Rubber tiles, pure vinyl tiles, vinyl sheets, rubber foam backed carpet or any floor covering containing appreciable amounts of solvent or plasticizer should not be fixed with, or applied over Cromaprufe.
If damp conditions are expected, first treat the floor as described above in 'floors' section. Ensure that the surface is level and clean. Lightly prime but do not over wet the surface with clean cold water.
Pour some Cromaprufe into a shallow tin and dip each wood block separately into the adhesive, coating only the underneath and half-way up the sides. Press the blocks home firmly, taking care to exclude air.
When fixing wood mosaics panels, spread Cromaprufe onto the screed at 0.8m² per litre and immediately place the panels into position.
Note: On non-porous floors, allow the film of Cromaprufe to become tacky, (30 to 45 minutes before laying the panels). Where underfloor heating has been installed, this should be turned off and the floor allowed to cool prior to laying blocks or mosaics. Allow 48 hours before turning back on again.
Cromaprufe may be applied to surfaces which have poor keying properties e.g gloss painted walls, old tiles, to permit the application of plaster.
The surface, which should be free from grease and dirt, should be coated with two thin layers of Cromaprufe (4.5m² per litre each).
Whilst the second coat is still tacky it should be blinded with clean sharp sand and allowed to dry for 48 hours before plastering according to Plaster Manufacturers recommendations.
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