To blind or not to blind

[duffsparky]

Hi All,

I'm replacing the concrete floor in my shower room/toilet. The floor's had to be replaced as it had subsided (poor oversite).

I'm using polystyrene sheet (jablite) to insulate the floor with the dpm on top of the insulation. The final layer of hardcore has been finished off with selected finer rubble pieces and finings, therefore, is it necessary to blind the hardcore with sand prior to laying the insulation?

Also should I wrap the plastic soil pipes, which will come up through the concrete slab, with anything prior to laying the concrete?

Regards,

duffsparky.

 

[jeds]

No and no. The purpose of the blinding is to protrect the dpm from damage - in this case the poly does that. Plastic waste pipes are fine in concrete.

 

[duffsparky]

Thanks for that jeds

Just to make sure we're on the same wave length, I was referring to wrapping the soil pipes where they poke up through the concrete/screed for the purpose of movement etc.

Thanks in advance.

duffsparky.

 

[jeds]

I see. Do so if you think a few millimetres of play might be useful for installation later - but not necessary otherwise.