cementing garage foundations and floor

[karaman]

hallo,

dug 70cm x 30cm garage foundations. the floor has been covered by rubble for a year so it is well settled.

builder wants to concrete trenches and floor of the garage at the same time.

Question
is it ok to carry out work at same time? should the concrete in the trenches not dry first before the floor is laid? or would the dry concrete in the trenches not provide a key for the garage floor to be concreted later on?

your thoughts appreciated - thanks

sue
the spirit never dies

 

[noseall]

Are you/the builder casting a toe reinforced raft or slab?

 

[karaman]

hallo noseall,

no idea what that means - i believe we are going to use a concrete mixer mixing cement plus pebbly material to fill the trenches, adding rubble and tiles from previous bathroom floor as we go along filling the trenches.

the floor of the garage has been covered with rubble for a year so it has bedded down nicely and is ready for the concrete but cant help feeling concerned the trenches and the floor should not be concreted on the same day. builder says it is better this way as otherwise the floor would not have a sufficient key to stick to the top of the trenches.

having a heatwave at the moment 35 degrees set to last until work is done. am also concerned the stuff will dry out too fast unless i rush around with a watering-can every hour.

i have to say he is a good little chap with proper qualifications and has done good work for me in the past so perhaps i should trust his judgement. but no harm in asking for a second opinion.....

thanks

karaman