A Digital Construction Manual to Support Earth-Built Heritage Resilience in Southern Morocco
Mud Bricks
Rammed Earth
Credits
Authors: Giamila Quattrone, Claudia Briguglio, Soumyen Bandyopadhyay, Raquel Peña López
Design & Layout: Pasquale Larosa, Kate Eleanor Dodds, Haiyun Zheng, Georgia Young
Photographs & Videos: Claudia Briguglio
Video Editing: Haiyun Zheng, Claudia Briguglio
Drawings: María Galán Martín, Zhouxinyue Deng
3D Animations: Georgia Young
English & Arabic Translations: Kenza Belahnech, Rim Yassine Kassab
Copyright: ©ArCHIAM
FUNDING SUPPORT
Research England (University of Liverpool Participatory Research Support Fund)
University of Liverpool (SotA Research Development Initiative Fund)
PROJECT PARTNERS
All rights reserved. No part of this manual may be reproduced in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without permission of the copyright holders.
This manual supports the transmission and application of the traditional earth building know-how of Southern Morocco. It aims to improve technical practice and make structures less vulnerable to decay, natural disasters and climate change, while ensuring this intangible heritage is preserved and transmitted to future generations.
Drawing data co-produced with local builders, the manual describes earth building crafts step by step, from the sourcing of materials to the preparation and application of mixes, from the making of components and building elements to the execution of finishing layers, including the labour, materials and tools required.
We are indebted to El Bashara Tajar (Kabila coordinator), Abdellah Elgharri (project coordinator), Said Bahnini, Abdellah Elghani, Abdeslam Lakhlij, Abdelkader Mahassine (master builders), Abderrahim Elatmani (site coordinator), Mourad Ben Chaiba, Nabil Chaiba, Jamal Chekri, Mohamed El Ghani, Abdelhakim El Ghani, Faissal Haddi, Hamada Lakhlij, Abdellah Zaabal (apprentices) and Khalifa Marzi (translator) for their contribution to the documentation.
Our sincere thanks go to the local institutions, the Caidat and Commune of M’Hamid, and to Abdessamad Samlali for the support provided, and to all the participants in the ”Restoration and Documentation of Architectural Heritage” Workshop, 22nd-29th January 2023, Ksar Ouled Driss.
Mud Bricks
Introduction
Mud bricks (tob) are moulded and sun baked on site, and typically used to build discreet architectural elements such as columns and domes, to create decorative patterns, for which rammed earth is not suitable, and sometimes to build the upper sections of walls. Depending on the size of the mould, bricks are manufactured in two different sizes: 25x12,5x7 cm – the traditional size, good for fillings and decorative patterns – and 40x20x15 cm – the more recent size, good for walling and keep the verticality of walls.
Material Mix & Provenance
• Sandy and clayey earth (sourced from the gardens)
• Water
• Straw from wheat crops or diss (optional)
Material Properties & Characteristics
The earth must be a bit sandy in order to avoid cracks in the bricks and make it easier to remove them from the moulds. If the earth is not of good quality, straw is added to the mix to reduce shrinkage during drying and increase the adhesion of the mud to the mould. The crops are gathered in a place called nwader, where they are left on the ground, to be later threshed. In the past, cereal grains were manually threshed with a spade (‘etla or madira) and the help of animals. This produced long and thick straw fibres. Nowadays, tractors are used, generating shorter, thinly chopped straw fibres.
Mud Bricks
Preparation
Mud Bricks
Making
Mud Bricks
Labour & Skills
One person is required to manufacture mud bricks but with two people the work proceeds faster. Once the mixture is ready, one person ‘cuts’ it, i.e., takes the required amount out of the mound, and hands it over to the second person, usually the master, who places and compacts it within the mould. Only basic skills are needed to make mud bricks: the main skills are to know how to ‘cut’ the right amount of mixture and how to press it inside the mould.
Weather Requirements
They can be manufactured any time during the year, although this is preferably done in winter as they are more mouldable.
Socio-Cultural and Religious Practices
There are no socio-cultural or religious practices associated with making bricks.
The Role of Women
Women cook for the workers so they can undertake the job without interruptions. Sometimes, they bring water to the site for the manufacturing of the bricks, but they never make the bricks.
Rammed Earth
Introduction
Rammed earth (tallouhat or Iouh) consists in compacting successive horizontal layers of moistened earth inside temporary wooden formwork (wraq or tabout) using a wooden ram (merkez). The formwork consists of two side boards (tafraout) made of horizontal wood planks, and two cross boards (tajbat) made of vertical wooden planks. The formwork is held up in place by three pairs of stakes (timndat) tied together by rope at the top and keyed at the bottom. If the mixture is not adequately selected and prepared or if the earth is sandy, the wall will collapse soon after the formwork has been removed. Depending on the height of the wall, building can be labour intensive.
Moist clayey earth, including stones (sourced from the site or the gardens).
The earth needs to be clayey, as sandy earth can cause structural failure. To ensure that the earth has absorbed enough water, it is soaked for two to four days prior to using it. On the day of the construction, the ground is excavated for circa 30 cm to build the wall foundations.
Material Mix & Provenance
Material Properties & Characteristics
Rammed Earth
Preparation
Rammed Earth
Making
Rammed Earth
Labour & Skills
The number of people required to build a wall depends on its height. If the wall is circa 2 m high, it can be built by two or three people. One person stands within the formwork to pour and ram the mixture, while the others fill buckets with earth. In case of higher walls, the number of people required on site can go up to eight. Building rammed earth walls requires at least a few months of training.
Weather Requirements
Rammed earth walls can be built any time of the year.
Socio-Cultural and Religious Practices
It is common to praise God and the prophet Muhammad when starting building a wall. Occasionally, as the construction progresses, the person standing within the formwork boards says “Allah, rabi, Allah rabi” (Allah, my god, Allah, my god), to give rhythm and motivate the other people on site.
The Role of Women
In the past, women used to participate in rammed earth construction when the master or builder did not have anyone to help on site. In these cases, they helped by watering the earth or transporting small mud bricks to be placed above the keys (shkoul), which are cross timbers that run through the width of the wall holding the formwork boards together.
Tadelakt
Introduction
Tadelakt is a water-resistant lime plaster used to coat interior walls, ceilings and floors, which can have either a shiny or matt finish. The technique is originally from an area in the lower Atlas, near Marrakech, where limestone is still quarried. Both the technique and the material are called tadelakt, which means ‘to rub in’ in Berber language.
Material Mix & Provenance
• Lime (brought in from Marrakech)
• Earth sourced from the site or its surroundings (optional)
• Colouring powders (optional)
• Olive oil-based soap (black soap)
• Marble powder, added to the mixture when the lime is coarse in order to make the mixture softer and facilitate the finishing of the plaster
Material Properties & Characteristics
The lime comes as either rocks or powder. The limestone rocks are either dissolved in water and sieved in their humid form or soaked in water inside a metal barrel and mixed to produce limewater. This, also called milk of lime, is later mixed with sieved earth. The two techniques produce the same results.
Tadelakt
Preparation
Tadelakt Application
Tadelakt
Labour & Skills
One person can do the job. If a large wall needs plastering, it is important that the whole area is done in one day in order to avoid cracks that might develop where the work was stopped and resumed. There may be up to 6 people working on the same wall. Experience is important as well as acquiring the profession’s secrets, which can only be learnt by practicing the craft.
Weather Requirements
Working with tadelakt is preferably done in winter and in places with high humidity levels. If the weather is dry, you need to use excess water in the mixture in order to have enough time to work it, and results are not as good.
Socio-Cultural and Religious Practices
No specific rituals are associated with tadelakt. The practice may include saying “Bismillah”, literally meaning “In the name of God”, before plastering a surface and praising the prophet Muhammad a couple of times by saying “Sali ‘ala sayidina Muhummad”.
The Role of Women
Women sometimes participate indirectly, for example bringing water to the site or transporting the mixture.
Mud Finishings
Introduction
Mud renders and plasters are applied to earth walls to protect them from erosion caused by the elements, namely wind, sand and water. Straw must be added to avoid excessive cracking, which would accelerate water infiltration. Recently, ash has been introduced into the mix to improve waterproofing. In the absence of eaves at the top of walls, mud renders are fundamental to ensure that the walls are adequately protected. Typically, re-rendering is required every few years to prolong the life of buildings.
• Clayey soil (from food-cultivated areas)
• Sandy earth (from places close to the desert sand dunes)
• Straw
Two types of earth are used in mud finishings (tamlissa). The first type contains organic matter and straw, is clayey and hard, and is used for the base coat of renders. The second type is inert, sandy and soft, contains less straw and is used for the finish coat of renders and for plasters. Recently, ash has been introduced into the mix to improve waterproofing.
Mud Finishings
Preparation
Mud Finishings
Mud Finishings
Labour & Skills
Ideally, three people are required to execute mud finishings: one person mixes up the earth, one person passes the mixture and one person applies it to the wall. A lot of practice and a good reputation is needed to guarantee the quality of the work as well as ensure the safety of workers as well as occupants. A building craftsperson becomes a master only after a lot of people have recommended his services.
Weather Requirements
The best time for rendering is June and July because the base coat dries out quickly, so it is possible to complete the job with the finish coat straight after that. In winter, instead, it is necessary to wait a couple of days before applying the finish coat.
Socio-Cultural and Religious Practices
It is common to praise God while building or sometimes start dancing and singing rokba. This can happen anytime if people decide to gather and do it together.
The Role of Women
Women used to be involved a lot in rendering by carrying the earth to the site, watering the mixture, passing it to the men doing the rendering or, at times, rendering themselves, especially the roofs. Nowadays, this is not common as women are more into weaving.
Wall Head & Foot Pathology
Wall Head & foot Repair
Erosion from splashing water.
The lower part of the wall is heavily eroded by the splashing of rainwater as is the upper part by direct rain. This causes a considerable loss of material and wall section.
1. Clean and remove dust.
2. Rebuild the lost wall section and reinforce it in the lower part with round stones bedded in lime mortar, and in the upper part with stabilized mud bricks and lime mortar, and a finish that allows correct moisture evacuation.
3. Apply a mud finishing layer over the repaired wall.
Note: if the wall is very deteriorated, it is recommended to clean it by applying a layer of lime (liquid solution obtained mixing 1 part of lime with 4 parts of sand and water). This should be applied from a distance using a natural brush.
Wall Head & Foot Pathology
Wall Head & Foot Repair
Roof-Wall Junction Pathology
rammed earth wall
earth screed
palm tree leaves
tamarisk branches (d: 7-10 cm)
palm tree trunk (d: 20-25 cm)
water damage
Loss of material due to water ingress.
The wall is eroded around the junction with the roof floor slab due to the lack of gradient in the latter. This causes waterlogging and water seepage inside.
Note: it is usually caused by execution errors such as, recently, inappropriately inserting the plastic sheet into the roof, which detaches leaving a gap through which water enters.
Roof-Wall Junction Repair
rammed earth wall
lime mortar
palm tree fiber + limewater mud bricks
mud mortar
earth
palm tree leaves
tamarisk branches
palm tree trunk
mud bricks
mud finishing
1. Clean and remove dust.
2. Rebuild the lost wall section with mud bricks.
3. Reinforce the roof-wall junction with mud mortar and mud bricks, creating a bevelled corner that enables water drainage.
Palm tree fibres are added to the top layer of mortar to allow expansion without the junction cracking.
4. Finish off with a layer of lime mortar.
Catalogue
Roof-Wall Junction Pathology
Roof-Wall Junction Repair
Wall Corner Pathology
Wall Corner Repair
A crack develops in the upper part of the wall, which normally advances in a vertical direction.
It is usually caused by execution errors when the two adjoining walls are not correctly interlocked or due to a settlement of the ground at the corner.
1. Clean and remove dust and all loose material. If the wall is disintegrated, apply limewater repeatedly until the wall regains consistency. 2. Remove at least 25-30 cm of rammed earth on each side of the wall and insert tamarisk (or local wood) branches every 50-70 cm vertically. 3. Rebuild the lost wall section with mud mortar, reinforced with fibres. Where the loss of material is substantial, place standard or stabilized mud bricks. 4. Apply a mud finishing layer over the repaired wall.
Wall Corner Pathology
Wall Corner Repair
Glossary
Bala: shovel.
Blana: plastic float used to apply and even out the tadelakt.
Chetaba: brush.
Diss: stem of a local plant similar to reeds, which grows in riverbeds.
‘Etla (or madira): spade with which cereal grains are treshed.
Fertas: wooden float.
Fes: pickaxe.
Germata: container used to store the mud render mixture before applying it to the wall.
Hajra: smooth river stone used to polish the tadelakt surface.
Melasa: metal trowel.
Merkez: wooden ram used to compact the earth inside the tabout
Mizan: plumb bob used to check the perpendicularity of the wall.
Nwader: place in the gardens where the wheat crops are gathered for threshing.
Plastica: small piece of plastic, which can be hard or soft, used to smoothen tadelakt surfaces.
Ponja: sponge.
Qaleb: mould used for making mud bricks
Qeneb: rope used to hold the sticks together.
Qiyas: jig used to hold the vertical planks of the tafraout together and establish the desired wall width.
Regla (or listouna): wooden joist used to smoothen the wall’s surface.
Rokba: music and dance with chanted interludes, generally performed in rows by men and accompanied by drumming
and hands clapping.
Shkoul: cross timbers that run through the width of the wall, used to hold the tabout boards together.
Tabout (or wraq): temporary wooden formwork used to make rammed earth walls.
Tadelakt: water-resistant lime plaster used to coat interior wall surfaces.
Tafraout: side boards made of horizontal wood planks used to close the tabout lenghtwise.
Tajbat: cross boards made of vertical wooden planks used to close the ends of the tabout
Tallouhat (or louh): rammed earth construction obtained through successive ramming layers of moistened earth inside the tabout
Tamlissa: mud finishing.
Timndat: wooden posts that hold up the tafraout in place.
Tob: brick made from mud mixed with straw, moulded by hand and sun baked.
A Digital Construction Manual to Support Earth-Built Heritage Resilience in Southern Morocco
