Never done THIS before - Screeding a Limecrete Floor 

Great, thanks! We’re doing some more today so I’ll concentrate on getting level and less on the finish 😃

@@MAKEDOGROW Finer texture can also become more brittle due to expansion and contraction cracks, although it is also dependent on the mixing ratio. Don't know how NHL based mortars behave but cement based, when too weak the base "dust away" and when too strong it contracts a lot, causing it to also crack and eventually forming large lose particules in the finished base. Usually, not a big deal for tilting (adhesive bonds corrects the imperfections), but of major importance for laying laminated floors (due to the leveling issues it causes). Not that unusual to apply self leveling final mortar in the base to aggregate everything and leave it leveled. (Not an option for you I would say, since don't know any self leveling mortar that is lime based).

As this was a learning experiment - skill, confidence, lesssons learned, material ratio mix proportions, etc, may want to try the following: Using a garden spray mister, lightly dampen the sub layer to improve the bond. 2x4 form should go the full distance, need more shoring to prevent bowing, leave in place until cured - shrinkage, bowing, settling, partial collapse. Not sure if a layer of plastic as a moisture barrier is useful due to heated floors. Not sure if a floating wire mesh or reinforcing steel rods matrix is required, depending on slab thickness and applied weight bearing load to avoid cracking/settling due to varying humidity/moisture/seasonal changes. First mix too dry, hard to work. Use Guy's technique of filling an area first. Then for the top layer, depending on how wet or dry the mix is relative to temperature and humidity, try (a) misting the top surface with water from your garden sprayer, then trowel or float, (b) as in (a) lightly dust the moistened top surface with your limecrete/fine sand mixture, then trowel or float. This will determine how level, smooth your top surface can be. A little bit of trial and error. Not knowing your final top surface, a broom can be genty passed over the level top surface to create either a smooth or non skid surface. Or something to grip to that is not completely smooth. For much larger areas, ringed in formed sections or not and wearing wading or garden boots, demark level height. Pour limecrete/sand mix. Based on slab size, get the appropriate aluminum or wood float to pack, shape, level and smooth the floor. Starting from the furthest end to your exit point. If either of you have sometime, try watching some rural family home diy from Japan/China, to see simple, inexpensive techniques with very basic tools for countryside, rural or offgrid renovations. Remote, using readily available materials.

I used self leveling concrete because the underfloor heating + vinyl floor required the ground to be quite flat

We’ve seen this method and might try it out once we have all the pipe laid out 😀

@@MAKEDOGROW Yeap it works best in larger areas, you were doing it similarly but you were using the Woden ruler as your level guide and on only on one side and that made your work much harder because you had to continuously check the level perpendicularly to it... On the bright side on the kitchen you now have a level based on a good part so now you only need another side and then you level across with the ruler... You guys do a great joob.

Great advice!

Are expansive joints required?

@@roymeryman8098 with limecrete, no, it has enough flex to accommodate movement

Agreed. Wheelbarrow the concrete to the job. Shovelling into buckets is a waste of energy.

Unfortunately I don’t have the physical strength to use a heavier or larger float. The spirit level is working well after mostly getting the material into the right place

@MAKE. DO. GROW. Fair enough. I also cannot plaster with a pool trowel for the same reason. Slow and steady wins the race. Please keep on uploading, you both are doing a quality job.

better still, you can clamp the level to the material and use it as a hard guide

Better still, get a table saw.

Awesome, I was aiming for nothing more than 1mm out of level 😃

Wooden float makes that initial material handling a lot easier/smoother.

😂 our day rate is very high 😂🤣😂🤣😂🤣😂

Thanks for the kind words! From all my reading/research the suggestion is always to have a dry lime:sand mix, not sure why though … something I’ll have to look into. And you’re right, we can’t use a latex or self-levelling compound so it’s a little more important that we get it as level as possible now. There is a lime based tile adhesive but it’s not really a screed rather an adhesive for setting the tiles

I checked on the water/wetness with nhl … seems the more water you use the less strength the resultant slab will have … all to do with how the hydraulic lime sets

@@MAKEDOGROW Thanks, I’ve never used limecrete in my long career and that’s really interesting and at 55 years young a sure sign you never stop learning. You two are a real credit and if you ever get the chance should think about putting your knowledge of these processes down In a book, it may never become a best seller but would be invaluable for students in the future.

Great, thanks!!

@@MAKEDOGROW It’s probably set by the time we've seen this, but if not, tapping over the surface with a stiff brush will create a key.

@@LaReynedEpee we’re doing more today so we’ll be sure to do that 😀

We can’t actually use self levelling compound, it contains plastic … we’ve chosen limecrete (rather than concrete) as it’s a breathable solution suitable for stone buildings

Yep, that reinforcement isn’t need due to the layer under this one. The two combined layers have sufficient compressive and tensile strength. Often in cement mixes rebar or wire is added to help prevent cracking … also not needed with lime as it flexes

Why would we go to all the effort of putting in a (breathable) limecrete floor to then ruin it by using cement or a plasticiser 😳