Fireplace Mortar and Heart materials

[DanScarfe]

Hi everyone

After many years lurking and picking up generally good tips I have decided to join and post my first question.

We moved into a 1930s terraced property and are currently in the process of knocking the back two downstairs rooms inot a kitchen diner.

Part of this process has involved me removing the old gas fireplace and taking it back to the original brickwork. The plan is to install a 5kW multi-fuel stove in there. I have noticed that the brickwork is damaged ina few places (which I don't mind) but also that the mortar is really dry and sandy and beginning to fall out in places. Can anyone recommend what mortar I would need to repoint this with? Do I need to use something like the Vitcas Heatproof Mortar?

Secondly, I understand the hearth dimensions as stated in the building regs and currently we have a constructional hearth that is more than large enough for our size stove. However it is quite a bit lower than our finished floor level and will need building up and leveling off. Can I do this with a regular concrete?

As for the decorative hearth, I was thinking of slate or granite tiles bedded on the construction hearth, What can I use to attach these and fill the gaps between them? I know you normally have a two piece hearth to prevent cracking, will tiles be alright?

The stove install is being installed by our local HETAS installer but other work I am planning to do myself.

Sorry for all the questions, hopefully I will be able to find some answers...

Thanks, Dan

 

[measureitonce]

We've just this month had a stove installed professionally. Hearth is slate tiles, or slabs. 600mm sq, by about 20mm thick. Unfortunately I wasn't around to see what they were fixed with but I assume std mortor/concrete as they really don't get hot. the fire board side panels and roof of the insert where the stove sits are another matter however - they are almost too hot to touch.

Just a note on the stove - we have a 4kw, in a room 12ft x 15ft we HAVE to have the door open, with hot air going up the stairs, and the 3x double bedroom doors open to suck out some of the heat. we haven't yet turned the boiler on in the evening. Even then, you really feel the heat hit you as you walk in the room. Our house is well insulated, with a-rated windows - meaning no drafts or air flow to carry the heat around so it really does tend to stay in the same place making the room unbearably hot (although the wife and cat seem to like it!). If you can look at some sort of ducting in the ceiling void to transfer the heat else where in the house!

 

[DanScarfe]

Thanks measureitonce. I don't think our house is all that well insulated although we have just has new windows and doors in the room where the stove is going. We have our fitter round for a chat last week and he recommended something along the lines of 4 or 5kW. I guess we'll see

As for the hearth, am looking for something that won't look too bad with oak effect quickstep laminate flooring and also need something to differentiate and hide the joint between the two.

My main issue is what I need to repoint the brickwork with

 

[measureitonce]

Cant help on the pointin all our brickwork covered with fireboard.

We had laminate right upto the bricked up chimney breast. They used a circular saw type tool to cut out for the hearth, but made the cutout 15mm too small on all side the laid the slate as if it we sat on top of the flooring. Leaves a lovely neat edge that doesn't require any trim. If we change the flooring it will just slide out from underneath. Carpet would work the same.

Another useful tip, lay a piece of conduit under the hearth in case of need to run any cables. Our tv ariel would have to have been completely rerouted otherwise.

 

[DanScarfe]

Good tip, cheers. As it stands we have laminate on top of floor boards (with a layer of underlay between. I guess I could build up the construction hearth to finished floor level and do as you mention. I would just be a bit concerned that the tiles would snap at the edges it someone stood on it and the floor dropped slightly due to the underlay compressing

 

[measureitonce]

20mm thick slate would take some snapping, but I'm not sure what the situation is re wooden floor boards, so best to take advise from a pro.
Ours was concrete floor.

A quick google of hearth regs brought this up http://www.stovesonline.co.uk/stove-hearth-size.html

sounds like a decent stove is a must to reduce the hearth thickness from the rediculous to the realistic!

 

[DanScarfe]

Yeah, I've looked at that previously. Our construction hearth is actually full depth, I lifted the floor boards adjacent to it before starting the new flooring and I'd estimate it to be about 400mm thick so should be more than adequate.

I like the idea with the tiles, going to go to a local supplier this weekend and see what I can find.

 

[DanScarfe]

So, having decided on using some tiles as suggested above I need to bring the constructional hearth up to finished floor level.

I reckon I need to add approximately 2cm in height over the whole area. What is best to do this with? Was thinking of concrete and have read elsewhere on here that a 5:1:1 mix (ballast:Lime:cement) would be best. Any suggestions on ballast size and what sort of consistantcy I need?

Also, if anyone else has any information on what I can use to re-point the brick work within the fireplace it would still be much appreciated