Concrete type to level hearth

4 Oct 2012
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United Kingdom

I recently had engineered timber flooring laid on top of my existing floorboards. The flooring installer cut this around the existing concrete constructional hearth.

Therefore the hearth now sits 17mm below the level of the flooring.

I now want to infill this void, and inside the fireplace itself up to this level, and then overtile with some slate/granite tiles. I then will use the fireplace to burn wood on a standard grate, and then in the future install a woodburner.

Can someone confirm the best type of concrete to use as will be exposed to heat, and is anything obtainable from the big DIY stores ready mixed? Ideally I don't want to be bulk buying different materials to mix myself.

The hearth is 1100mm wide, 360m deep to the face of the fireplace, and inside the fireplace it's 500mm x 350mm, so not a huge area.

The maximum depth of my concrete pour inside the fireplace to bring it level with the floor will be c.30mm.

With thanks.

This pic will give an idea of what I'm doing (taken prior to the floor installation)

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From what i can gather, you intend to set your hearth on a combustible material ie. the wooden floor.

Given the tricky and variously changed regulations ref hearths and open fires in recent years, you would be well advised to pay a HETAS person to come around and give you a heads up.

I hate regulations, and admire people who are willing to have a go at DIY, but, FWIW, any work on or changes to a fire opening or chimney system is notifiable to BCO.

I've been advised previously that "as it's being sat on top of the original constructional hearth, it will be fine. The "returns" to the sides of the fireplace are on the borderline of the Building Regulations for new build properties".
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From what i can still gather, it is partly sat on the construction hearth, but, at your dimensions, it's overlapping on to wood.

The only person who can advise on Blg Regs is BCO.

To raise your back hearth, a tacky wash of S&C followed by a semi-dry mix of S&C.

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