Rendering loose

[hughnique]

I had the front of the house rendered back in 2016, had a couple of problems with a couple of areas, which culminated in the Macon not answering my enquiries. So up to date I have, in an area of about 2 square metres, a few bits dropping off so thought I would try and get the original artisan's insurance details. I contacted the concilliator at the local dept of justice whom I have been involved with a couple of times before. He turned up with the original artisan today who has told me it is because the main structure of the building is Tuffeau, and that is what is causing the stuff to drop off. Well hold on a mo, I paid god knows how much to have a premier coat of something or other, think they call it degrossaie or something, to form a barrier between the Tuffeau and the final decorative coat. He says he will do something to rectify the unsightly look in September, and FOC, which is good, but I still feel he is talking crap about the Tuffeau causing it, hasn't happened elsewhere, YET!!

[RobertArthur]

@ hughnique, about rendering: Le tuffeau & les enduits. Not knowing what this artisan exactly did it is hard to make a judgment. For reference, in English, echos from the past about lime mortars. The Romans managed to render their buildings and even today the use of medieval techniques, without Portland cement, is still possible.

I suppose this artisan has used un enduit à la chaux (lime mortar). The wall should be dry, not always the case after removing an old layer of cement based render. It takes at least six months for the hidden moisture to evaporate - exit blocked by cement based render - before rendering.

[hughnique]

I am unaware of the product he used as a scratch coat, only that it was a bagged up product, not a mixed up on the driveway sand and lime mixture, I know he put that plastic grillage in the first render, which as far as I can see is still in place and firmly stuck to the existing wall. The enduit, as I call it, coloured powder in a sac, is the material that is detaching from the initial coat, which in itself is isolated from the original Tuffeau wall

[RobertArthur]

There are excellent bagged up products available in France for une rénovation de façade traditionnelle. Almost twenty years ago I rendered a wall using Procalit F, made by Weber. Time consuming, old wall, old school manual labour. Still in good condition, kitchen side and the rest.

This is what Weber has to say about these special products: " Certains enduits Weber contiennent jusqu’à 90 % de chaux aérienne et permettent aux artisans de simplifier les temps de préparation sur chantier. En effet, ils sont dans des emballages adaptés, livrés sous forme de poudre prête à gâcher et s’appliquent soit mécaniquement, soit manuellement. "

Several other good products available. The professionals prefer sometimes the spray applied render method. Special equipment and after a manual finishing touch also good results.

[elsie]

Possibly not relevant in this case and just for general information, rendering and the decennial guarantee has been the subject of several legal decisions defining when the 10-year guarantee is relevant
https://www.mv-avocat.fr/actualites-jur ... decennale/