Reducing height from top of founds to floor level

[cwr]

Hi Folks

 

Our strip foundations were poured this week. All very exciting but due to various reasons the top of the concrete is higher than ideal for our target ground floor level. This just affects one end of the house as there is a 1m drop across the site and the concrete is stepped.

 

I had envisaged at least 800mm from top of concrete to GF to allow for drains to pass through the footings. In the localised ares of concern don't need to worry about drains so may get away with the below detail? Or can I lower the GF even more by having a course of the Quinn Lite blocks cut and the sand sitting on top of the concrete?

 

Thanks

[PeterW]

Bin the oversite and the sand, double the thickness of the screed to 100mm and use concrete and then drop the PIR onto the MoT1 and the DPM. 
 

It has gained you 100mm min already. 

[cwr]

Thanks PeteraW, that is an option.

I was equally concerned about comprising the Quinn Lite blocks, tho prbly ok for a few m at the higher end of the site to have one 215 and one 100mm course, which would be needed with either floor make up.