Selection of plasters and renders for salt laden masonry substrates

The choice of a repair plaster or render by architects often appears to be the result of fortuitous circumstances, such as prior experience with a plaster or a recommendation by a producer. Seldom is the choice based on a sound assessment of the state of the building and the wall that is to be repaired. The service life of the repair plaster...

Development of a new accelerated salt crystallization test

TNO Built Environment and Geosciences has developed, in cooperation with other institutes in the European project Compass1, a new accelerated salt crystallization test. In this paper the design process leading to the definition of this test is described. Preliminary tests studying the influence of the environmental conditions on the damage...

Aspects of salt and moisture transport in restoration renders (plasters)

There is a need for obtaining more knowledge about renders (plasters) used in restoration because of cases of damage observed in the field. The currently applied and available restoration renders do not always meet the requirements By analyzing damage cases it becomes clear that the performance of modern and traditional renders, under salt load...

Reinigen, voegen en impregneren van monumentale gevels

Hoe verminderen we schade aan pleisterwerk in monumenten? Bevindingen uit Europees project Compass

Een steeds weer terugkerend probleem in monumenten is het ontstaan van scahde aan het pleisterwerk als gevolg van zouten (foto 1). Dit zorgt voor veel overlast een vormt een grote kostenpost. Het voorkomen van zoutschade aan pleisterwerk is al tientallen jaren een belangrijk punt in de monumentenwereld. Samen met enkele Europese partners heeft...

Aspects of salt damage in restoration plasters and renders

This paper reports provisional test results and their analysis on moisture-salt transport in restoration plasters obtained in the EU project COMPASS. First, some basic notions regarding salt damage in plasters / renders (plasters) are treated. Subsequently, using various simple as well as advanced experimental techniques (porsuring a...

Historic trass - lime mortars with expansive reactions: Characterization and repair strategies

The characterisation of two ancient mortars in historic bridges, suffering damage due to thaumasite and other swelling compounds is described. Characterisation was part of the analysis of damage occurring to the brick masonry structure. Expansive reactions were found to have taken place, being the cause of the damage to the masonry. In both...

Laser cleaning of black weathered Obernkirchen sandstone

Hechtsterkteontwikkeling in kalkzandsteen metselwerk

Vervuiling and reiniging van natuursteen

Verweringsprocessen, zowel natuurlijke als onder invloed van luchtvervuiling, resulteren vaak in verkleuring van natuursteengevels in onder meer monumenten. Dergelijke processen worden vaak simpelweg aangeduid als 'vervui-ling', en als esthetisch storend ervaren. Van bedreiging voor het voortbestaan van de gevel of het monument is veelal geen...

Richtlijnen moeten zoutschade aan pleisterwerk verminderen. Europees project COMPASS onderzoekt zoutbestendigheid mortels

Zoutschade aan pleisterwerk is een groot pro-bleem omdat traditionele, maar ook speciale restauratiepleisters na verloop van tijd vaak toch kapot gaan. Om dit probleem te verminderen, loopt momenteel het driejarig Europees onderzoeksproject COMPASS. Het project moet uiteindelijk leiden tot richtlijnen die betrokker partijen helpen de juiste...

Thaumasite swelling in historic mortars: Field observations and laboratory research

The formation of thaumasite in historic mortars was found to be a recurrent problem in cases of conservation of historic masonry in the Netherlands. Several case studies in which mortar swelling occurred were performed. In this paper two case studies concerning thaumasite formation are briefly described, focusing on the damage patterns observed...

Laser cleaning of Rakowicze sandstone

Decisions about the cleaning of natural stone should always be made within the awareness of direct and indirect damage that may be the result of cleaning. During the last decade, laser cleaning of objects and monuments of natural stone has become increasingly popular. Whereas a considerable amount of literature has been devoted to the effect of...

Efficiënt restaureren. Een duurzaam resultaat door samenwerking volgens een stappenplan

Beoordeling van reinigingstechnieken

Er zitten veel aspecten aan het reinigen van gevelmaterialen zoals natuursteen en baksteen. Teneinde bij een reiniging er zeker van te zijn geen aspecten uit het oog te verleizen, kan gebruik gemaakt worden van het RDMZ-stappenplan. Hierin zijn alle stappen opgenomen waarin de

Thaumasite swelling in historic mortars. Field observations and laboratory research

The formation of thaumasite in historic mortars was found to be a recurrent problem in cases of conservation of historic masonry in the Netherlands. Several case studies in which mortar swelling occurred were performed. In this paper two case studies concerning thaumasite formation are shortly described, focusing on the damage patterns observed...

Non destructive monitoring in laboratory. Understanding of damaging processes by the use of NMR on masonry

Moisture content in laboratory specimens is generally determined by weighing the complete