Taking 75mm from the top of a dense concrete block

Discussion in 'Builders' Talk' started by deanomc, Dec 7, 2016.

  1. Plan to go down more than the 75mm required especially if the removal method you choose is likely to leave a rough bumpy bottom as SDSing would do.

    If you were able to side-cut it with an angle grinder, however (tho' I understand this is unlikely...), then you'd stick close to the 75mm you are after 'cos you'd know it would be a neat, accurate cut - perhaps 80-odd mm.

    With the core drill method, there will still be some 'bumpiness' as the cut cores will still need SDS chiselling out, so I guess 90-odd mm makes sense?

    Summat like that :)

    Good luck - take it steadily - lots of breaks if needed - and please post back on your progress :)
     
  2. deanomc

    deanomc Member

    Will do. Hopefully be able to post finished pics on Sun/Mon
     
  3. deanomc

    deanomc Member

    So..... Job done. To be honest it wasn't as bad as I thought considering the awkwardness of the job and the fact I was cutting into dense concrete block.

    It took be the best part of 4hrs to take 85mm from the top of just over 6 metres of concrete block. ( two doors and a bifold). I also added a layer of cement, DMP sheet then 75mm insulation.

    If anyone else needs to do a similar job in the future here is what I thought worked best.

    I first tried using a core drill but this was taking a long time so I opted to drill lots of holes ( 12mm bril bit). I marked 85mm depth on the drill and went for it. Not sure my drill appreciated half hour of full on drilling as it was very hot when I finished.

    Next step was to attached a chisel on the drill and knocked it into hammer mode . Starting off with a small chisel then finish off with a wider one to level off.

    Brushed up the brick work and cleaned down.

    I then added a mixture of sand/cement to the bottom of the cavity to level off.

    Cut and fitted a layer of visqueen DPM sheet on top of the sand cement then added the insulation on top of that.

    I then rested some bricks on top of the whole lot until the cement has dried.


    NEXT JOB......

    I will add a 25mm insulation around the edge to stop the cold bridge between the door and floor, prime the floor then pour on Self Levelling Compound over the whole lot. door_01.JPG door_02.JPG door_03.JPG door_04.JPG
     

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