please help plastering victorian brick walls..

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#1
Guys,

I'd appreciate your help please - I've done loads of jobs using gypsum plasters, but have been advised not to use gypsum in my victorian solid brick walled semi to let it 'breathe'. I believe all the walls are still of original lime plaster although some of the ceilings have been boarded and skimmed (gypsum).
I bought some mixed lime finish coat and did a couple of walls, but it ain't great and takes 6 weeks to harden off.
Is it really necessary to use lime? I've been in loads of period places that have used gypsum, but am hesitant to use it just in case...(although I can't be bothered with the lime again!)
Also, there are a few sections where the plaster has blown. Is it ok to use bonding/hardwall, or lime once again?

Thanks very much.
 

Danny

Administrator
#2
Hello,

I personally have know idea..... but in a few hours I am sure you will get some answers.... Looking for the *cough* more wiser *Cough* (older) members :)
 

ljm

New Member
#3
ok, not sure if this is as such the 'right' answer but here goes... I would of thought the main reason for not using lightweight plasters in a solid wall construction is mainly due to damp bridging. Gypsum plasters are very porous and as such any damp that penetrates can reach the top coat and the paint. They usually installed air bricks/vents etc to allow 'breathing'. We have quite a few victorian properties this way and generally we don't use lightweight plasters on external walls. We usually s/c them with waterproofer in (sometimes SIKA 1 if needed) then top over the s/c. Personally I only use lime for certain circumstances ie. pebble dashing but I know a lot of people on here use it in most render mixes. That's going to be a matter of personal preference. Is the building listed at all? If so, obviously you will have to use suitable materials to match the existing. Of course, if external walls are rendered and sealed then all this is irrelevant and I can't see any reason that gypsum plasters couldn't be used :RpS_biggrin:. Hope this in some way helps unless I've completely missed the point in which case I will hang my head in shame!!:RpS_blushing:
 
#4
thank you!

Thanks for the replies. It is not listed and not rendered on all walls. I've tried to research this a lot, but there seems to be a lot of conflicting answers. On top of all this, the lime pplasters should be painted with natural paints to allow the breathing (yes, to stop damp), but my walls are covered with thick wallpaper and what I guess is emulsion anyway.

I'm sure it'll make no difference what I use, but the thought of using gypsum, getting damp and scraping it all of gives me a serious headache!!!

Any more suggestions or advice would be gratefully (and desperately) accepted.

Thanks again.
 
#6
not 100% sure if its not a listed property dont need 2 use lime based plaster if any damp or conserned about damp due 2 solid walls u can use gypsum dri coat which is a light waight plaster & vapour barrier & stops hydroscopice salts which draw in damp finish with board finish or multi finish put air duct in room 2 draws out moister we all exhail moister in the day & night HOPE THIS HELPS :RpS_thumbup:
 
#7
cheers

Thanks guys,

I took a photo of one of the walls, but it just looked like a typical plastered & painted wall so I won't bother to upload it.

It is not a listed place, so I can do what I want - but I just don't want to get it wrong. Neither do I really want to put extracors in the rooms if I can help it.

I can't believe that all victorian solid wall houses are skimmed with lime products these days....or do they all have gypsum.....and damp problems?

Maybe i'm just being a bit anal?
 

flynnyman

Private Member
#8
Thanks guys,

I took a photo of one of the walls, but it just looked like a typical plastered & painted wall so I won't bother to upload it.

It is not a listed place, so I can do what I want - but I just don't want to get it wrong. Neither do I really want to put extracors in the rooms if I can help it.

I can't believe that all victorian solid wall houses are skimmed with lime products these days....or do they all have gypsum.....and damp problems?

Maybe i'm just being a bit anal?

Victorian houses never had central heating or double glazing so a vent is a must, whats wrong with sand and cement and normal finish also mentioned was drycoat and you could use limelight backing.
 

superspread

Private Member
#9
hi, as long as the brickwork looks dry and theres no smell of damp i would go for hardwall and multi .hardwall replaced renovation plaster and a lot of the speces i work to recommend hardwall for (inside) outside walls,also where hardwall is softer than s/c its more forgiving so hopefully less cracking,hope this helps.
 

flynnyman

Private Member
#10
hi, as long as the brickwork looks dry and theres no smell of damp i would go for hardwall and multi .hardwall replaced renovation plaster and a lot of the speces i work to recommend hardwall for (inside) outside walls,also where hardwall is softer than s/c its more forgiving so hopefully less cracking,hope this helps.
I wouldnt go near any gypsum products on a wall with no cavity and i dont ever remember hardwall replacing renovating plaster in all my days, but i might of been on holiday that day ;)
 

bubbles65

Private Member
#13
I reckon superspread is right about Hardwall replacing Renovating Plaster.
Although BG might not have said anything, I'm pretty sure Hardwall is the same as Renovating Plaster. Maybe it's just me but - get this - it's the only plaster that makes me burp/belch!!!! So did Renovating!......And it smells the same.........And cats always target it to sh*t in:-0 - same as they did in Renovating! I put that down to some kind of fungicide that is probably in cat litter. I'm no chemist, but the coincidences are enough to convince me that it's the same - or very similar - stuff. I reckon they needed to change the name to avoid people (chancers?) from believing it done what it said on the tin...........
 
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superspread

Private Member
#14
British gypsum tech dept told me that renovation plaster didnt sell well ,they reckon hardwall was the same,like i said architects ive worked for recommend it for outside walls in old properties, dont shoot the messenger.
 
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superspread

Private Member
#15
i rang british gypsum tech dept today just to confirm what i knew already.they told me hardwall did replace renovation plaster as they were basiclly the same
and you can use hardwall on external solid 9" walls just as long as the walls are dry,if the walls have had an injection course ,they recommend dri-coat.
TO FLYNNMAN AND A D PLASTERING YOUR BOTH RIGHT THERE IS A LOT OF CHANCERS ON HERE.
 
#17
:RpS_lol: thanks superspread give your self a kick up the arse or a pat on the back its up to you but thanks again m8 :RpS_thumbsup:
 

flynnyman

Private Member
#18
i rang british gypsum tech dept today just to confirm what i knew already.they told me hardwall did replace renovation plaster as they were basiclly the same
and you can use hardwall on external solid 9" walls just as long as the walls are dry,if the walls have had an injection course ,they recommend dri-coat.
TO FLYNNMAN AND A D PLASTERING YOUR BOTH RIGHT THERE IS A LOT OF CHANCERS ON HERE.
basicly the same? lol aslong as they are dry lol and if they have had an injection course are they damp? and why would they need an injection course if its a 9" wall? yep makes no sense.renovating plaster is cement based unlike gypsum based ive been out tonight so cant be arsed looking but i think they are pulling your leg if you were using renovating plaster there would have been a problem with damp in the past ie salts coming through so hardwall would be no use ie damp involved.
 

superspread

Private Member
#19
flynnman you obviously aint been in this game very long, B G use to make a gypsum based renovating plaster ,but stop producing it about 10 years ago approx. stop talking about things you no nothing about,mainly plastering, if you think im talking bollocks ring BG yourself you obviously know it all .( B G 01159456123).what do you mean ,why would you need an injection course in solid 9" brickwork,well you dont really need it in cavity work do ya. youve got to be winding me up.
 
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flynnyman

Private Member
#22
A D Plastering i take no pleasure in always being right,lol.

LOL you may be right on this one lol hardwall and toughtcoat are nearly the same and they probably did replace renovating plaster they also have the same smell but me personelly would not use it on a solid wall coz of potential problems that ive seen in the past ie cold walls drawing in damp.
 
#23
I wouldnt go near any gypsum products on a wall with no cavity and i dont ever remember hardwall replacing renovating plaster in all my days, but i might of been on holiday that day ;)
lifes one big holiday for you mate hahah only joking how are you doing anyway... well anyway to answer the lads question... its all down to cost and time, to be honest a 2 or possibly 3 coat lime render should be carried out... however this is expensive and time consuming... just for the amount of time between coats to allow the lime render/plaster carbonate... if its a case of penetrating dampness then i would look at the external wall first as they may have been pointed with sand and cement allowing the water to penetrate and not escape... if so remove the cement pointing and re-point with nhl2.5 mortar... if its rising damp... then the problems may lie below ground level so check for leaking pipes etc... if there are no obvious signs as to where the problem lies then get a damp meter and check the walls out thourghly... if you get readings above 1 mtr high its probably condensation due to the lack of ventilation... under 1 mtr high its rising damp... or a combination of both... if it was my hoose i would re point or render the outside wall with nhl2.5 lime mortar replaster with nhl2.5 lime render/plaster and put a couple of airbricks in
 
#25
back in the old days it was a s/c mix using salt free washed sand with a water proofer added to the mix.Problem in some cases was render being a cold surface it caused condensation on solid walls.I havent been in the rising damp/woodworm/dry rot biz for 25 years now so things have moved on alot I guess.Steer well clear of bonding on a wall thats damp,it will suck every bit of moisture out of the brickwork and hold it for weeks!
 
#26
back in the old days it was a s/c mix using salt free washed sand with a water proofer added to the mix.Problem in some cases was render being a cold surface it caused condensation on solid walls.I havent been in the rising damp/woodworm/dry rot biz for 25 years now so things have moved on alot I guess.Steer well clear of bonding on a wall thats damp,it will suck every bit of moisture out of the brickwork and hold it for weeks!
Finally some ones on the right track, as has been mentioned stick with dri-wall, limelite, wykemol lightweight lime based or cementitious plaster when renovating older property's without a cavity, always steer clear of any gypsum based plaster (even hardwall ) as these do have additives to reduce the risk of moisture being absorbed from the atmosphere, but not sufficient enough to combat penetrating damp,condensation etc, i am not saying any one is wrong in their recommendations here, but maybe a little mis- informed by a) the architects (who know sweet fa half the time) and by so called techy helplines (who have never moved from their cosy office and reading the answers from a comp screen) and as render say's lime mortar is too expensive and time consuming (although ideal for most applications where renovation on older property's are concerned) and off course there are airbricks , but these don't actually prevent the problem from happening, but just help to dry out the affected areas , unless you use a passive vent which then rely's on positive air pressure forcing any damp warm air out and not let any cold air in, but then things do start to go off track and you end up buying s**t to solve a problem that you don't really need, babble babble babble, sorry chaps.
In short dri-coat or limelite
 
#27
our local b and q was selling dri coat for £1 a bag the other day and they had a full pallet. maybe i should have bough some ..... hmmm
 

owls

Private Member
#28
pricey stuff is that if it was a quid a bag id have took the pallet load, you can use it months out of date.

i give 17 quid per bag limelite the other week.
 
#29
lifes one big holiday for you mate hahah only joking how are you doing anyway... well anyway to answer the lads question... its all down to cost and time, to be honest a 2 or possibly 3 coat lime render should be carried out... however this is expensive and time consuming... just for the amount of time between coats to allow the lime render/plaster carbonate... if its a case of penetrating dampness then i would look at the external wall first as they may have been pointed with sand and cement allowing the water to penetrate and not escape... if so remove the cement pointing and re-point with nhl2.5 mortar... if its rising damp... then the problems may lie below ground level so check for leaking pipes etc... if there are no obvious signs as to where the problem lies then get a damp meter and check the walls out thourghly... if you get readings above 1 mtr high its probably condensation due to the lack of ventilation... under 1 mtr high its rising damp... or a combination of both... if it was my hoose i would re point or render the outside wall with nhl2.5 lime mortar replaster with nhl2.5 lime render/plaster and put a couple of airbricks in
At last. Someone that knows about lime plasters.
 

lucius

Private Member
#30
There are a few on here competent in lime morters Brendan the question on its uses are often asked and the answer always the same if you can afford it use it other wise we recomend alternatives. The widespread use of NHL morters a product being pushed by the big producers was discovered by the Romans i believe to work underwater not for general house building, true lime morter is made with putty.
 
#31
British gypsum tech dept told me that renovation plaster didnt sell well ,they reckon hardwall was the same,like i said architects ive worked for recommend it for outside walls in old properties, dont shoot the messenger.
Architects don't know their arse from their elbow. Years of uni training to graduate as a fully qualified tw*t.
 
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