Is this Lime? And some advice

[Kasheen]

Hello all

I'm wondering if anyone would be able to help me figure out the anatomy of my bathroom wall a bit here!

Basically over the past few weeks I've been trying to turn our bathroom into an office - part of which involved removing some wall tiles. Sadly, careful as I was trying to pop the tiles the wall was coming apart pretty fast as it seems that all the plaster underneath has become dry and crumbly.

Anyway, I'm wondering if anyone can tell me if this type of plaster is lime (picks below), it seems to be in 3 layers: 1 layer with keying which is attached to the brick (backing?), 1 layer of thick soft crumbling plaster which has some hair in it (backing pt2??), and a final layer which is very thin and still tough and white in colour (finishing). The middle layer seems to have hair in it so I assume that this is all lime plaster, am I correct?

I was hoping to replaster (or attempt to replaster) the wall myself but would I be in over my head working with lime? Would I need to take the keyed layer off, it is very dry but seems pretty sound, although you can see the bricks in some places. And finally is there anywhere to easily get this type of plaster such as Jewsons, Wickes, B&Q etc? I had been hoping it was a case of strip it back, backing plaster, finishing plaster but it seems I can't use gypsum in an old house because the walls need to breathe properly.

Sorry it's a mammoth post as usual and thanks in advance and added for any help!

TL/DR for those who want the less loquacious version : Is the plaster in the photos lime. What are the layers. Do I need to remove all layers or can I patch up the backing layer then skim finishing. Where can I get lime plaster easily. Is this far too difficult to pull off with almost no plastering experience.

 

[stevethespreader]

brick houses do not need to breathe that much here are some old post that you may find helpfull //www.diynot.com/forums/viewtopic.php?p=1463027#1463027

 

[joe-90]

Only ground floor rooms with no damp course need to breath (evaporate the damp).

 

[Kasheen]

Thank you both Steve and Joe.

That post was quite helpful steve thank you. The room is kind of a ground floor and kind of not, the house is sort of built into a hill if that makes sense so that what is the ground floor on the front is actually 1 storey up at the back. This room is therefore 1 storey up but it is above a basement room which has a minor damp problem but I think that is just the design of the house.

Anyway, the room its self has no dampness problem however I think I'd prefer to follow the original materials as much as possible as since there is no problem now then as long as I don't change anything there wont become a problem!

So following that theme - I already know about a range called Limelite which has a backing plaster and a finishing plaster (and I think my local jewson's sells it although I don't know the cost). Is this the right stuff to use? Namely "Limelite Cement Backing Plaster" and "Limelite High Impact Finishing Plaster". One thing that worries me is that it says "Cement", I thought cement stopped breathing and moisture... surely if you have lime you are using it because you don't want cement or impervious materials? (the spec sheet says "Effect of Moisture
Limelite Cement Backing Plaster skimmed with Tarmac High Impact Finishing Plaster is not impervious to water vapour, but will resist the passage of soluble salts.")

Anyway, assuming this is the right stuff should I just remove the old plaster back to the keyed coat, repair and patch with the limelite backing and then skim limelite finishing after damping it all down or should I take everything back to the brick?

Thanks again for anymore insights!

And once again the TL/DR since I've been told my mouth hinge needs less exercise : Room is 1 floor up and has no dampness. Want to use limelite to be on the safeside is this the correct stuff even though it says "cement backing plaster" which I thought stops moisture. Should I patch up the original backing coat and skim finishing or should I go back to the brick and do 1 full backing and 1 skim finishing?

 

[stevethespreader]

ive just read the spec sheet of limlite and it says its made up of lime and cement with Perlite lightweight aggregate replacing the sand. im not sure what advantages the perlite is going to give you, because your house is brick and not damp i would use s&c ,if you really want to keep it as close as possible to the old lime plaster surely you have to use render with sand in it? looking at phils8340 old post who says he used it on a barn he says it was nothing like lime plaster and he still had the salts coming through further more he states that it has gypsum in it but i couldent find this on the spec sheet, perhaps someone else whos used limelite can help here? tbh i had never heard of limelite i see the old post

 

[Micilin]

I've used limelite and have to say I'd rather sand and cement as it is cheaper, and gives you the properties you need.

The limelite finish is a bit 'tougher' than multi/board finish , although you can skim it using them as well.

The main advantage of limelite ? Off the top of my head

- it will go off more like a plaster unlike sand and cement, so you can build it up in coats where you would perhaps have to leave s/c for a day between coats to build up thickness.

- It is lighter and 'stickier' so easier on the arms or for working overhead for the inexperienced.

- comes in bags so can be loaded out in the area you want it and mixed there

- uniform mix as it is pre bagged

- make the manufacturer some money when it is specified.

When using it make sure it is well floated and all angles etc cut well , and in good time, as it sets harder than gypsum plasters

A sand cement and lime float coat with multi skim will do you okay on ordniary prepared brickwork. Leave at least a day to skim, you may have to wet wall to kill suction if it is too dry.

If any damp, no lime and add waterproofer as per spec, then skim at least day after, no need to wet down..

 

[thatbloke]

you will need to mix lime putty with sand , have a look here.
http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=11005&hilit=lime+plastering

lots more in this forum if tyou search for lime

http://www.periodproperty.co.uk/forum/viewforum.php?f=1

the other end of the country but this will give you an idea of what you need

http://www.mikewye.co.uk/mikeprices.htm#limeputty

if you have lime on there then you should only replace with lime really especially if the ground level is higher on the outside of the building.

edit - also , be aware of what you use to paint over this with , no point in having a wall designed to evaporate moisture then sealing it with modern bathroom paint.

 

[Limespred]

Strip all the stuff off,then do a scratch coat of;3to1,3sharp sand and 1 NHL 3.5 hydraulic lime,then a float of the same and top that off with a coarse lime skim,FP14 is quite a good top coat skim.