An alkaline concentrate for hand-cleaning clay and concrete roof tiles of long-standing soiling: grease, soot, algae, fungi, moss, wax, honeydew and leaf marks. Lightly foaming, diluted to suit the state of the roof.
Surface
Facades and roofs
The surface the manufacturer intends this preparation for.
C-11D is an alkaline concentrate made for roof tiles alone - clay and concrete. The manufacturer lists what it is meant to shift: years of mineral and organic soiling of fatty origin, soot, algae, fungi, moss, wax, honeydew and leaf marks.
Two limits matter more here than anything else. First: hand washing only. Second: the surface being washed must not be warm - the manufacturer advises working in the morning or the evening.
The product foams lightly. Dwell time 15-20 minutes, then rinse with clean water, ideally under pressure. The dilution is matched to how soiled the roof is; the ratios are under "Technical data".
The facade is the one category where the order of work can ruin the result whatever the product. A sealer applied over live algae seals them in.
Work out of direct sun and with a forecast free of rain. The manufacturer states how long the surface has to be protected from rain; it is under "Technical data".
Before sealing the whole area, test on a patch hidden by a planter or in a corner of the patio. The same product can read differently on two batches of the same material, and on a surface with old coating left on it, it will not bond at all.
It should not, and that is not how it works. Water-repellent products limit the ingress of water from outside while leaving the pores open to water-vapour diffusion. Manufacturers state this as diffusion resistance; we quote the figures in the technical data.
Wash it off first with a product for organic soiling, rinse thoroughly and dry the wall, then seal. Sealing without washing traps the growth under the treatment.
Yes, if the product lists roof tiles among its recommended substrates. Roof tiles are washed by hand only and on a cool surface - early or late in the day, never in full sun.
We do not claim that, and neither do the manufacturers' data sheets. A sealer acts on the water uptake of the surface, not on heat transfer through the structure.
A 1:4 dilution means one part product to four parts water - a litre of concentrate gives five litres of working solution. Where the ratio is given in ml per litre of water (the C range), work the other way: 50 ml per litre means 20 litres of solution from one litre of concentrate.
The manufacturer allows rinsing with water under pressure, but the application and scrubbing are to be done by hand. On a roof the point is not to force water under the covering or to damage the surface of the tile.
Once rinsed and dry, the covering can be sealed - for clay and concrete roof tiles the product is VD-1, whose data sheet gives a water-vapour diffusion resistance of Sd = 0.0 m.
The product works on what is on the surface. Moss rooted in a joint or in a damaged tile usually has to be removed mechanically before washing, and the damage made good.
The technical sheet and safety data sheet will be available after approval.
This product has no stated coverage yet, so we cannot work out the requirement.
The calculator starts once the manufacturer states the coverage.
Go directly to the right category. We do not imply compatibility across materials.