Hole in hallway floor. Fill it or Limecrete the whole thing?

[Sikes]

Hi all, looking for advice. House is from 1919. The hallway floor has always been bowed. Covered in clay tiles on a soil (I think) mixed with lime. Many of the tiles where cracked and damaged. The previous owners had but a cement screed over it. I took all the tiles up. Started laying new tiles in lime. Then my foot went through the floor. The hole is about 10cm deep and the hollow area is about 20 X 20cm. The soil feels dry, I mention this as a cast iron water pipes runs under the hallway. Can I fill it with something? Or is it a whole new Limecrete job?

 

[Sikes]

After having a think. I've come to the conclusion to check for more weak spots. If don't find any I'll fill the hole partially with gravel. Topping up with a 1:2 mix of NHL5 & sand. I think that sounds ok

 

[Stevers]

We've got a lot of that stuff around the house (literally), and I would describe it as cinders, as in cinder track. Some of it trends towards tarmacadam and may have been laid hot, but a lot of ours is loose and under later concrete. I've rammed it down and successfully used it as a foundation for paving and concreting. I'm interested that it's been used indoors as ours has a strong tarry smell when disturbed. It may have been one of many by-products of your local gas works.

Your plan seems sound to me, except that I would use All-in Aggregate (the name varies) rather than sand to make limecrete for the top layer.

 

[Sikes]

Thank you for the advice @Stevers. Good to know I'm on the right track. I'm in Wales, so they seemed to mix coal dust in with everything