Recipe for about 25 square meters of clay linen:

5.5 bags of clay flour of 25 kg

500 kg of sand

40-80 liters of water

4 bags of soaked, chopped flax straw of 5 kg

20 liters of glue water (400 g animal glue + water)

• Mix all the ingredients in a cement mixer, except the flax straw, until smooth. Finally, add the soaked flax straw and process for about 10 minutes. You can also stamp the clay mixture into a wooden box, covered with a strong, waterproof tarpaulin. Tough, but fun. When it’s ready, the mixture should be smooth and easily spreadable, without being watery.
• If you want to reuse old clay clay, it can be mixed with an equal amount of new clay.
• However, the material you soak must not contain
• keep wallpaper remnants, cakes of lime mortar and the like.
• The clay is the main binding agent. The amount given here is for sand-free clay flour, which is available in bags in Gysinge. Tile kiln clay cannot be used, as it already contains sand. As with all other mortars, you must keep to certain proportions between binder (clay, lime, cement, etc.) and aggregate (sand, gravel, etc.). Normally you have 1 part binder by volume to 3 parts aggregate. Too little binder results in weak mortar with poor adhesion. Too much binder causes shrinkage and cracks. So do a test first and let the clay line harden!
• The glue water is a pure binder and is prepared from animal glue. See recipe under the heading “Glue paint”. The sand should be fine-grained and salt-free masonry sand. Do not use sea sand. The flax straw must be rooted and chopped into lengths of about 5 cm. Soak the flax straw for at least a couple of hours, preferably 24 hours, before use.

The course of work – Basic stockpiling:

• Moisten the surfaces to be clayed by sprinkling water over the surface with a lime brush or paint brush. The moisture will prevent the clay from drying too quickly. First, fill deeper cavities and cracks in the substrate with mortar. Smooth out the mortar with the trowel, making sure that the clay penetrates well into all the cavities. Leave to dry until the next day.
• The clay liner cracks easily if it is laid in layers thicker than 2 cm at a time. Therefore, allow the base layer to dry overnight. However, it should not be completely dry before the next layer is laid. It is therefore advisable to moisten the walls by splashing water with a paintbrush over the surface before starting again. If old clay tiles remain on the walls, it is particularly important that the edges of the tiles are well moistened so that the clay tiles stick together. When patching old clay tiles, it is a good idea to lay the new mortar slightly thicker than the old. This is because the clay liner sinks slightly when it dries.

Cleaning:

• Apply a layer of just over 1 centimeter of mortar. Smooth it out with a trowel and, if possible, polish it with a “Spanish”, a wooden or metal disk with a handle that you move around in circles to smooth the surface. Leave to dry until the next day.

Fine-tuning:

• Add another layer of clay liner. The recommended thickness is about 2.5 cm. Smooth the surface with the trowel and spatula. Feel free to reduce the amount of flax straw in the finishing mortar, or omit it altogether, if you want a completely smooth surface, with no visible streaks in the mortar.

Tips! A professional bricklayer is often a good help in clay lathing, even if he has not clay lathed before. But he knows the technique of plastering and that’s the main thing.