gap over fireplace

[rscho]

Hi Forum,

We're installing a space heater into an existing fireplace opening (see picture). However the original fireplace opening is quite high and when the heater is installed there will be a gap of about 60mm above the heaters' trim.

We've considered a seperate trim around the heaters trim to cover the gap but don't really want to go that way. We're planning to either paint or tile around so would like a solid base. I've though about running a metal lintel and filling with suitable mortar and plastering, however I'm worried the expansion and contraction of the metal will result in cracks in the mortar.

The option is to chisel into the masonary around the edges and fit a section of AC sheet flush with the existing rendered surface.

Does anyone have any other suggestions or comments about suitable materials or ideas?

[echnidna]

You could put thick tiles on the hearth so the heater sits higher.

[Auld Bassoon]

I like your thinking Bob!

[rscho]

You could put thick tiles on the hearth so the heater sits higher.

Hi Bob,

We considered that, however we can't lift the heater high enough to cover the gap because that black thing at the top of the photo is a concrete lintel supporting the bricks above it. We were reluctant to interfere with it too much. The trim extends only 35mm above the top of the heater.

I though about chiselling some brick away from the sides at the top and fixing a block of hebel across it just below the lintel but I couldn't find a piece long enough (about 650mm).

Now I'm thinking about fixing some angel iron across the gap and filling in with mortar. Its about 25mm deep. However I'm not sure how the metals expanding and contracting will affect the mortar. Another thought was to use two strips of 6mm AC sheet as a lintel, then fill in above it.

Any thoughts on this would be much appreciated.

[ozwinner]

Now I'm thinking about fixing some angel iron across the gap and filling in with mortar. .

The mortar wont stay there for very long, trust me, it will crack and fall out.
I cant see why you cant lift the heater, or get a brickie in to lower the lintel.

Al

[echnidna]

As you are thinking of tiling around the heater why not just fit a piece of cement sheet around the heater to mount the tiles on.

It would cover the gap yet be virtually invisible once tiled.

If you really wanted a fancy finish build a timber fireplace surround come mantlepiece to go around the outside of the tiles.

[rscho]

The mortar wont stay there for very long, trust me, it will crack and fall out.

I think you're probably right.

I cant see why you cant lift the heater, or get a brickie in to lower the lintel.

I should clarify, we could lift the heater but to fill the gap we'd have to use bricks laid on their side for a hearth which would look crap. We can't lift it high enough for a four-sided trim and normal hearth because of the lintel above. The only thing going against the bricky is probably the expense. The Finance Minister is going on about puting kids through school or something.

Bob, I think the cement sheeting is probably the way to go. What's the preferred method of fixing it directly to bricks, mechanical fasteners or adhesive, and if so which?

Thanks again

[echnidna]

I'd use tile adhesive (selleys unifix) onto clean bricks (or sikaflex)

[rod@plasterbrok]

Another idea you could use a hammer drill to fix a timber nogging, to the brick, 10mm back from the face of the wall nail a small strip of plasterboard in so it sits flush. Tape and finish the joins.

You will get a nice flush finish that way. The taped join wont crack either, (use paper tape).

Cheers

[rscho]

Another idea you could use a hammer drill to fix a timber nogging, to the brick, 10mm back from the face of the wall nail a small strip of plasterboard in so it sits flush. Tape and finish the joins.

Cheers

Rod,

Timber and plaster would have been my preferred solution, however the heater is not a zero-clearance type, it is designed to go into an existing masonary fireplace so I still have to maintain minimum clearances to things like the timber mantel. Although the timber batten is not exposed to flue gas it would be very near to the metal of the heater which gets too hot to touch.