we have tried out a few different lime render mixes, but we keep coming back to a lime/sand/sawdust mix.
We have a bag of builders hydrated lime powder which we mixed with about equal parts water and after a couple of days soaking it forms a thick creamy putty with the excess water floating in the surface. Render made with this lime is a lovey consistency to work with - almost like buttercream frosting.
We learnt from a local renderer how straight forward it is to slake quick lime, and he told us this lime would make a stronger render, so we made some more trials. We were trying out various colour options including local red dirt, oxides designed for tinting cement, and iron sulphate (which is sometimes an anti-fungal additive to home-made paints) While also experimenting with other additives to improve working texture or finished strength and flexibility.
1 part slaked quicklime and 3 parts sand is the most basic render (#2 in image below) but it was like working with plain wet sand. Adding flour paste (think wallpaper paste) gooped it up a little, but it didn’t stick to itself so was very sloppy to put on the wall. These all adhered to the earthen render really well.
Next day I pulled out our lime putty and played around with different combinations. My favourite TEXTURE is definitely using half slaked quicklime and half hydrated lime putty and swapping out some of the sand for sawdust which is #5. this did always grip right onto the earthen render, unless I first dampened the wall with lime water (skimmed from off the top of the lime putty) then the lime render adhered readily. The colours all lightened dramatically as they dried, my favourite colour for the outside of the house is #6.
1slaked lime, 3sand, .5flour, .25iron sulphate
1 slaked lime, 3sand, no colour
1 slaked lime, 3sand, .5flour, .5red dirt
1slaked lime, 3sand, .5flour, .25sandstone oxide
1Cup slaked lime, 1Cup Lime putty, 4C sand, 2C sawdust, 1/4 tsp brown oxide
1C slaked lime, 3C sand, 1 egg white, 1/8 tsp black oxide, 1/4 tsp sandstone oxide
1C slaked lime, 1Cup Lime putty, 6C sand, 1tsp brown, 1/4 tsp sandstone oxide
1C slaked lime, 1C Lime putty, 6C sand, 1tsp brown oxide
1/2 cup slaked lime, 1/2 cup Lime putty, 3C sand, 1/2 an egg white, 1/8tsp sandstone oxide
1/2 cup slaked lime, 1/2 cup Lime putty, 3C sand, 1/2 an egg white, 1/8tsp black oxide
1/2 cup slaked lime, 1/2 cup Lime putty, 1.5C sand, 1.5C sawdust, 1/2 an egg white, no colour
1/2 cup slaked lime, 1/2 cup Lime putty, 1.5C sand, 1.5C sawdust, 1/2 an egg white, 1/8 tsp sandstone
Next step was to make a wheelbarrow If my favourite render mix (#5) and tint it with variations on our preferred colour from the above trials (#5) We had been talking about our inside walls being a warm white, but the sandstone and red soil tinted lime renders were so beautiful we tried a series of variations on them for potential inside colours too.
Again, the colours are up to 20x lighter once they are dry. Anything with lime in it is going to dry significantly paler because the lime is so white.
Inside colours (top row) each in 2 cups of base mix:
6tsp red soil, 3tsp sandstone oxide
3t red, 1t sandstone
1t red, 1/2t sandstone
4tsp red soil
2tsp red soil
1tsp sandstone
2tsp sandstone
1/2tsp sandstone
1tsp red soil
Talking through how we are planning to use colours inside, we realised we definitely want the bevels around our windows to be a warm white, and we don’t want to change colour where window bevels turn into walls. We also want to try using homemade casein lime paint on both the rendered straw bale walls AND the conventional plasterboard internal walls. So we will actually use untinted lime render inside and tint our casein lime paint to a warm white.
Outside colours (bottom row) each in 2 cups of base mix:
1/8tsp black oxide, 1/4tsp sandstone oxide
1/8tsp black, 1/8tsp sandstone
1/4 tsp black, 1/2 tsp sandstone
1/2 tsp black, 1 tsp sandstone
1/8t black, 1/8t sandstone, 1/4t red soil
1/4t black, 1/4t sandstone, 1t red soil
1/4t black, 2t red soil
1/2t black, 1/4cup red soil
1/4t black, 1/2t sandstone, 3t red soil
#9 is our favourite. Now to try some casein/lime/linseed glazes over top to increase weatherproofing and eliminate dusting off.
Comentarios