Preserving a Marrakech riad: tadelakt, zellige and damp

A riad does not deteriorate while it is lived in. It deteriorates between two stays, with no witness, at the pace set by the climate of Marrakech and the hardness of its water. The owner who lives in Europe discovers the damage on arrival: a tidemark at the foot of a courtyard wall, a tadelakt shower panel gone matt and rough, a zellige tile that shifts, a joint that has hollowed out.

None of it appeared the night before. All of it follows a calendar, and that calendar is known. Here is what actually works on a riad in the medina — the rainfall concentrated between November and March, mains water at 33 French degrees of hardness, seventy-three days a year above 35°C — and then what can be done, when, and with what.

Why does an empty riad deteriorate faster in Marrakech?

Because the Marrakech climate does not work steadily: it strikes in episodes, and an empty property has nobody to absorb the episode. The 1991-2020 climatological normals of the World Meteorological Organization, Marrakech station (WMO no. 60230), give 221 mm of rain a year spread over only 29 rain days — of which 6.9 exceed 10 mm. Most of the annual water therefore arrives on a handful of days, onto flat terraces and drains nobody checks in the owner’s absence.

The rest of the year it is the heat that works: 72.9 days a year above 35°C, of which 22.3 above 40°C, with an absolute maximum of 49.6°C recorded on 24 July 2004 (recorded on 18/08/2026). A wall that drank in March dries violently in July, and the salts drawn up with the water crystallise at the surface. It is that cycle, not ordinary wear, that decides the state of a riad.

What is not checked in October is paid for in June, in render repairs.

How do you care for the tadelakt in a riad, and with what?

With warm water and black soap, exclusively — and it is an industrial manufacturer who puts it most bluntly. The Socli (Heidelberg Materials France) tadelakt sheet, recorded on 18/08/2026, states that acidic detergents must never be used to maintain or clean tadelakt, on pain of degrading it, and that black soap alone should be employed for those operations.

The reason lies in the nature of the material. Tadelakt is a lime render, and its water resistance comes not from a varnish laid over it but from the soap itself, applied and then burnished with a stone — what the same sheet calls savonite, a mixture of carnauba wax and black soap. An acid does not soil the surface: it consumes it. Routine care comes down to four steps — dust dry, wash with diluted black soap, rinse without soaking, dry. Nothing else.

Why is descaler the most expensive mistake in a riad?

Because the water in the medina is hard, hard water invites descaling, and descaling kills tadelakt. The study by El-Fadeli et al., published in the Journal of Materials and Environmental Science (vol. 6, no. 9, 2015), followed 320 samples over a full annual cycle across four areas of Marrakech: mean drinking water hardness comes out at 332 mg/L of calcium carbonate in the Medina zone, or 33.2 French degrees, against 137.45 mg/L in Chouiter.

On the hydrotimetric scale, where one French degree equals 10 mg/L, that water is classed as hard. White deposit therefore returns quickly on a shower panel, and the reflex is to reach for the descaler. Allo Maison, a cleaning company in Marrakech, says so without hedging on its rates page (recorded on 18/08/2026): a standard descaler used on a tadelakt shower wall eats the patina in a single application. One application, not a habit.

How do you clean old zellige without destroying its joints?

By treating the joint, not the tile — the joint is the weak point, and it is made of lime or cement. The Moroccan platform bclik.ma sets it out in its cleaning guidance for riads (recorded on 18/08/2026): on zellige, never use acidic products such as concentrated bleach or descaler, because they attack the cement holding the pieces in place. Allo Maison describes the same mechanism with more precision still: the glaze holds up very well, it is the lime joint that suffers, and a joint treated with acid hollows out and powders away.

The tile itself does not move: it is its support that gives way, then the tile comes loose, then its neighbours follow. The maintenance rule fits in one sentence — black soap and a soft brush, never acid, never steam on bejmat — and the monitoring rule in another: a tile that sounds hollow is dealt with straight away, not on the next visit.

Where does damp in a closed riad come from, and how do you recognise it?

From three natural sources — infiltration, rising damp, condensation — to which a plumbing leak is added, and which an owner consistently confuses from a distance. Someone who receives a photograph of a dark stain wants to know whether to send a plumber, a mason or nobody at all. The answer reads off the height of the stain, its shape and when it appeared.

An infiltration runs downwards and follows a single point — terrace corner, chimney stack, rooflight, foot of a gargoyle. Rising damp climbs from the ground, stops at a constant height and leaves a powdery white deposit as it dries. Condensation settles everywhere at once, preferentially in cold corners and behind furniture, and disappears once the house is aired. All three are treated differently, and two of them get worse if you repaint without looking for the cause.

A dated photograph, taken from the same spot two weeks apart, separates three of those four origins on its own.

What should be checked before the November rains?

The terrace and everything that carries water away, before mid-October, because after that it is too late to test. The Marrakech station normals put 29.8 mm in November and 35.2 mm in March, with exceptional months at 143.6 mm in November 2014 and 147.5 mm in March 1991: a Marrakech terrace does not handle fine, spread-out rain, it takes brief sheets of water.

Four points are enough for an owner to cover the essentials. Gargoyles and downpipes should be cleared by hand, not with a jet. Waterproofing upstands at the foot of parapet walls should be continuous, with no lifting. Low points are tested by pouring a bucket of water and watching where it goes — a visual check does not replace that test. Finally the rooflights and light wells, almost always implicated when a stain appears on the top floor, are checked joint by joint.

Who in Marrakech actually publishes maintenance guidance?

Material suppliers and cleaning companies — almost never those who hold the keys. The survey of 18/08/2026 is unambiguous: the upkeep of tadelakt, a render invented here, is documented online by French and Swiss sites — biologement.fr, tadelaktdesigns.com, maison-ecolo.com, bio-construct.ch, lamaisondestravaux.com, Socli — and by no Moroccan source at all.

In Marrakech itself, those who write on the subject are craftsmen and painters: Ateliers d’ailleurs, Travaux Peinture Maroc, peinture-marrakech.com, bati.ma, Khdemli. The concierge companies, for their part, publish “maintenance” without ever naming a material. An owner looking for how to hold a riad therefore finds cleaning on one side and renovation on the other, and nothing in between — which is precisely the upkeep that prevents the renovation.

What both halves leave out

The cheapest action of all, and the one neither of them sells: a regular visit by somebody who knows what to look at. A cleaning company cleans what it can see; a renovator arrives once the damage has set. Between the two lies the only window in which a damp stain is still treated with a brush and black soap rather than by stripping the wall back. That window is held by a calendar, not by a quote: two visits that matter, October before the rains and April after them, with a monthly technical inspection in between. An owner putting only one thing in place this year is better served by that than by another cleaning contract.

What does a repair cost when routine care has not been done?

Between 200 and 1,200 dirhams per square metre depending on the material, where routine care of the same riad is counted in hundreds of dirhams per visit. Bricolat publishes, in its riad renovation guide of 16/05/2026, the repair prices charged in Marrakech: 200 to 500 MAD/m² for tadelakt, 400 to 1,200 MAD/m² for zellige, 800 to 3,000 MAD/m² for carved woodwork, and a recommended contingency of 20 to 30% for the unforeseen.

A 12 m² shower whose patina has been eaten by a descaler therefore costs between 2,400 and 6,000 MAD to put right, before any repair to the substrate. A management commission is another calculation entirely: we recorded it company by company in what the market actually charges, and our own terms are set out on our pricing page. This is not a plea for cleaning: it is the observation that one unsuitable product, used once, costs more than a year of proper care.

How often should an empty riad be visited?

Often enough to catch an infiltration while it is still a tidemark — which, for a riad in the medina, means one visit a week and a full technical inspection each month. The weekly visit is not a clean: it opens up, airs the house, runs the water points, looks at the foot of the walls and the corners, fills the traps to keep drain smells out, and ends with dated photographs.

The monthly inspection takes the terrace, the drainage, the zellige tiles that sound hollow, the meters, the basin pump and the joinery. The calendar matters more than the frequency: the inspection that decides the year happens in October, before the rains, and the second in April, after them. That is what our experience curators in Marrakech cover for owners who are not on site, and the detail of the visits is set out in the property management mandate.

Where do you start when nothing is in place?

With October, and with the terrace — the rest can wait until spring. An owner who currently has nobody on site gains more from sending someone onto the roof before the first rains than from arranging a full clean: the expensive problems in a medina riad come in from above, and are paid for six months later in render repairs.

In seventeen years in Marrakech, we have watched the same sequence repeat — rain in November, a stain reported in February, a repair in June. The two articles either side of this one describe the rest of the arrangement: maintaining a villa from abroad month by month, and what handing over the keys to a local team involves.

Is your riad about to go through the autumn without a visit? Write to us: we carry out a condition report and a free, no-commitment assessment within 48 hours.