Renovating plaster/limelight vs Traditional lime plaster

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andyR

New Member
At risk of sounding liek a complete twazzock... Ive just bought a 1920's semi with solid wall construction and existing lime plaster internally. Some of this old plaster need replacing back to brick due to water damage etc. Ive been told that i need to do a 4 coat job with old lime plaster. I.e spatter coat, hair coat, non-haired then finish.
Does limelight work like normal gypsum based dri-wall then skim over?
Im asking as i dont wanna feck about with days of drying time for lime and keep overtrowelling if i get any cracks as it shrinks etc if i can do it faster with something like limelight.
Related to this, theres a spar-dash render on the outside, i dunno when it was put up but doubt theres any ads in it, wont that affect the breathablilty of the walls considering its a solid wall and have an effect on the overall performance of the lime if i should use it anyhow?
pls help before i give up n dot n dab the feckin lot....
Cheers
 

andyR

New Member
an old spread i know told me that the expansion rates between the modern backing plasters are different and will cause cracking. What i was gonna do was as i was taught, Dri-wall for backing then seal the old gear with bond-it or similar and then skim the lot with multi.
 

andyR

New Member
that shouldve read the expansion rates between the old lime gear and modern backing plasters are different and could cause cracking where the two meet.
 

henry

Private Member
Well am a old spread and I will say Bullshit to what you have been told . Dr coat from BG is a good backing coat Renderlit another good backing plaster. Trouble with us silly old buggers we think the old ways are best and it is not always true only when we want to look important.
 
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andyR

New Member
Fair one mate, thanks for that. Feel better about it now. Being told that load of twaddle kinda made me question myself for a moment. Now i know what i was gonna do is fine, so happy days :)
 

spark2010

New Member
ok, again a problem thats overlooked and needs a lot of thought.. A situation like this a lot of people would ..hack off, fix damp, (pointing, injecting etc) let plaster dry out - backing plaster - finish - job done.. technically yes but it goes a lot deeper than this.. you need to really think about this especially if its your own property....

ok.. first thing..renovating plaster? - renovating plasterers are lightweight, pre mixed & CEMENT based, and is used for the above situation instead of actually mixing sand and cement manually. The reason why its lightweight is because instead of sand, perlite is used, which behaves very cleverly compared to a standard S&C mix. Perlite is lightweight and any water trapped in the structure vaporises instead of causing problems. Perlite can also reach high temperatures without weakining. These renovating plasters are are designed to simualte a 6-1-1 mix (sand,cement,lime). they also incorporate waterproofing, salt inhibitors and fibres for strength.. To improve the resistance to water you can use SBR beforehand. Lastly and key factor is, renovating plasters have good thermal value, reducing the risk of condensation, unlike a standard S&C mix has no thermal value whatsoever. Overall - renovating plasters are a better option than standard S&C.

because your house is really old and there was lime on the walls originally, i would avoid S&C, renovating plasters is an option although cement based, the lime and perlite will overlook it as the cement is for strength.

The preferred option would be the lime road .... because the pointing could be lime, which is doubtful on a solid but u never know and lime plaster has been hacked off.
Then I would.... fix the damp problem and let the walls dry out completely. Thing to watch out for after you hack off is the presence of salt. if there is quite a bit then the pointing is S&C. If there is none present or very little then lime is present in the pointing. I wouldn't put a S&C over lime pointing where there was originally damp. Again because your property is solid walls its not cob walls so technically a renovating plaster or s&c option is still open. Most important factor is what caused the damp, was it externally, under the wall, inside moisture, high ground level etc

if your unsure why lime has been recomended by your mate, its because lime allows the structure to breathg, better for movement, any minor cracks that do appear does not need to be repaired as lime heals itself in different seasons, reducing condensation etc

a typical lime spec would be
preserve any wooden lintels and batten over with oak lath
..after dampening, scud/harl a coat of lime putty unhaired
..good coat of lime putty mortar haired to staighten the wall
..another coat of lime putty mortar unhaired and devil floated
..then finally a lime plaster unhaired (2 thin coats)

then most importanly a 2-3 coat lime wash, lime wash will allow it to breath and evaporate water,

Thats either helped you a lot or confused you even more !!!!
cheers
 
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alf

New Member
Well am a old spread and I will say Bullshit to what you have been told . Dr coat from BG is a good backing coat Renderlit another good backing plaster. Trouble with us silly old buggers we think the old ways are best and it is not always true only when we want to look important.

Well you should know that old buildings constructed with lime are no good with modern gypsum based plasters.... Read above post
 

JamieMac

Member
renovating plaster is a gypsum premixed plaster 4 walls with dampness itcontains a fungicide and it allows the background material 2 breath and dry out without letting the moisture show on the surface deal with the cause before plastering.
 

alf

New Member
renovating plaster is a gypsum premixed plaster 4 walls with dampness itcontains a fungicide and it allows the background material 2 breath and dry out without letting the moisture show on the surface deal with the cause before plastering.

stick to modern builds.
 

henry

Private Member
Alf so your saying all buildings with lime used for render and skimming should only use the same when repairs are carried out, is that what your saying. What planet are you off.
 

alf

New Member
probably because it is of cavity construction so why does it matter. hardwall and skim it with multi

maybe you should read the topic starter before you put your foot in it?

"Ive just bought a 1920's semi with solid wall construction and existing lime plaster internally"

Just maybe....
 

alf

New Member
Alf so your saying all buildings with lime used for render and skimming should only use the same when repairs are carried out, is that what your saying. What planet are you off.


I don't remember saying anything of the sort but I did base my opinion on this "Ive just bought a 1920's semi with solid wall construction and existing lime plaster internally".

You are not quick enough to try move the goal posts.
 

flynnyman

Well-Known Member
Maybe you could enlighten us all to why you would use a gypsum base render on a 1920s semi built with lime, just maybe..?

Maybe you could enlighten us to how much gypsum is in dricoat and renderlite, just maybe....?
maybe you should read what henry actually wrote before you put your foot in it? " Dr coat from BG is a good backing coat Renderlit another good backing plaster."
just maybe......?
A clever boy like you should have known all this but maybe you forgot, now lets see how quick you can move the goal posts with all that egg on your face? xxxx
 

alf

New Member
Maybe you could enlighten us to how much gypsum is in dricoat and renderlite, just maybe....?
maybe you should read what henry actually wrote before you put your foot in it? " Dr coat from BG is a good backing coat Renderlit another good backing plaster."
just maybe......?
A clever boy like you should have known all this but maybe you forgot, now lets see how quick you can move the goal posts with all that egg on your face? xxxx

Renderlite is cement based and doesn't allow for movement......


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henry

Private Member
how much movement alf? will give you time to have a google.
ping pong ping pong I can play this game all night.
 
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