Filling back hearth and raise area just 15mm (pics)

Discussion in 'Builders' Talk' started by Mark_s, Mar 5, 2021.

  1. Mark_s

    Mark_s New Member

    I've exposed our fireplace and removed the rubble from the rear hearth area, it's just earth and flint in there now and about 200mm deep.

    We plan to lay flooring so I need to fill the back hearth and then raise the whole lot to be level with the 15mm shuttering I have fixed.

    I was going to:
    1. Whack down the rubble in the hole
    2. Add layer of sand
    3. DPM bottom and sides of hole, try and underlap the remaining bitumen DPC in the walls
    4. Fill the back hole level with ballast/sand/cement mix
    5. raise the remaining area to the 15mm shuttering with 3:1 sand cement mix + SBR

    My questions:
    - The whole area is very dry, no signs of moisture or damp, is DPM required? Doesn't appear to be one under the existing floor
    - Is 15mm too thin and will it probably crack? Should I maybe dig the remaining concrete substrate out a bit and use a floor levelling latex?
    - Is it overkill!?

    Once this is done I plan on using tile adhesive to lay the decorative granite hearth on top.

    It's a job for this weekend as the HETAS guy is coming end of next week to fit the log burner.

    Screenshot-2021-03-05-at-08.25.09.jpg Screenshot-2021-03-05-at-08.25.02.jpg
     
  2. Wayners

    Wayners Screwfix Select

    Don't find dpm in fire place as the heat could melt it..

    Could use a couple of layers of cement board to build up but I'd just go with sand and cement. I've seen a slurry of cement and water to seal and after 10mins sand and cement over vs sealer as I've seen that done but I used thin 5-1 pva a few times before concrete or cement.

    Not my area of knowledge so I'll back out as all I know for what it's worth

    Oh. I'd concrete that hole
     

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