Lime to repoint chimney breast

[LJohno13]

Afternoon all

Could someone tell me what sort of lime I ought to be using to repoint an internal chimney breast?

It's a Victorian, brick chimney breast. I have raked the old lime out so that it is ready for repointing but I'm confused about what I should be using to repoint it/ where to buy etc etc. Obviously don't want to be using modern cement to repoint as it would look totally out of place.

Any tips would be gratefully received!

Thanks in advance.

 

[ree]

Hydrated lime - comes in powder form in plaster like bags. Get at any Builders supply yard.
Mix with sand at 3:1 S&L or 4:1 S&L.

If the flaunching and brickwork are in need of attention then hold back any pointing.

Pics would help?

 

[jeds]

There are two main aspects to lime mortar; it has to be strong enough to do the job and it has to look right. Because original lime mortars were generally made from local sands they tend to vary considerably across the Country in shade, colour and texture. Often there is a yard somewhere fairly nearby that stocks those local sands so I'd look there first to see what they have. To get the desired look you might have to trial two or three mixes until you get something pleasing.

As for strength, use a hydraulic lime - either natural or lime putty - in a ratio approximately 3:1. Hydrated lime isn't recommended on its own because it won't provide a strong enough finish but some people do use it mixed about 50:50 with cement. Not really a traditional lime mortar though.

 

[LJohno13]

Ree - It's the actual chimney breast in my dining room inside the house, thankfully the exterior work was done around 4-5 years ago before I bought the house. The brickwork itself is in decent nick as it had been plastered over and left that way for around 50 years (on my best guess) - I'll try upload some photo's tonight.

Jeds - thanks for that tip - I'm in York as it happens but essentially the only pointing that will be on view will be that which I repoint - I've raked all of it out and what I replace it with will be the only pointing left on show - in other words I shouldn't need to match it to anything, just need to find something pleasing/traditional/in-keeping.

I'm getting stuck on the hydrated and hydraulic/non-hydraulic issue - what are the differences?

 

[theprinceofdarkness]

As far as I know, Hydrated lime is always used with cement as a plasticiser. Non hydrated lime, or lime as we know it, is available in two forms, powder or putty. While hydraulic lime, which is a fast setting lime which is stronger and waterproof is only available as a powder.
The sand /lime mix is dependent on the finish you want, loads of lime, very white and smooth (look out for lime plasterwork in your house) less lime and using sharp sand a rougher but more rain tolerant finish. Because I use lime inside and out, I use hydraulic (1part) with 2 1/2 parts sharp sand.
Google "the lime centre" , they supply the stuff and have instructions also "SPAB" who advise on ancient building restoration with lime.
Frank

 

[LJohno13]

Cheers for that Frank, that's really helpful. So for the interior I need to be going for a non-hydrated lime and working out whee I want the colour to be, cheers. I've posted a few pictures below:

 

[ree]

Apologies for not reading your post correctly.

Just go to a builders counter and ask for a bag of builders lime & a couple of bags of builders sand - the lime will be NH.
The ins and outs of the lime and sand are irrelevant - any old sand will do.
Do you think that the old guys from the last two or three thousand years made a fuss about where the sand and lime came from? No way: they used what was handy. And what wonderful work they did.

Dont entertain using lime putty.

FWIW: your rake outs are looking shallow here and there - rake out min of 25mm.

Use a just wet mix, and fill the beds level with the brick face. When its firm and drying run a brush over it, dont strike it with a tool (i learned that on here from someone).

As it dries it will lighten in tone.

Your flue needs sweeping, and the fire back need cleaning.

Do you intend to actively use the fire opening?

 

[LJohno13]

Thanks Ree - when you say NH do you mean Non-hydrated or Non-hydraulic?

Tips on cleaning the back would be welcome - I've tried all sorts to clean the black off: wire brushing, oven cleaner, wire wool, all sorts, even tested bleach on it at one point and it didn't make a dent. Unless there's a relatively cheap and straightforward way of doing it that I haven't found then I'm probably happy to leave it looking used and worn, as long as the rest is clean(ish) and repointed.

I'd like to put a swans nest grate in there - chimney draws well from a few test fires I've done but will need a sweep, that's the next thing to deal with!

 

[ree]

Keep wire brushing - only wire brush. i know that its difficult to shift but dont use any liquids or chemicals.
If you install a solid fuel fire then the soot stained bricks are not important.

Your front hearth is not Regs size - google stovesonline or fluesonline (or something like that) for info on hearths.

 

[Yukster]

Any chance LJohno13 can upload a pic of the pointed chimney breast? Thanks