Suction control

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Fatarm

Trainee mod
Just been to quote for a job,90year old building,Walls are extremely dry,old lime-sand plaster.Walls are very sound for age .reskimming existing Walls and ceilins previous experienced this type of job in the past and had some nasty problems with suction, dryin out to quick."as dry as a nuns @&@t " as my old tradesman used to say.sometimes pva just won't do, gyprime very expensive, I have used neat sbr 20-30quid 5 litres,roll it on let it dry for 24 hours then pva and skim while tacky,works a treat, found out that solution from my old tradesman god bless im
 

lucius

Well-Known Member
Stabilser then PVA but it will still crack in places because of the lime background
 

srp

Member
i used thistlebondit otherday half thistle bond half pva reduce,d suction on an old plaster sand lime horse hair atreat
 

DannyMac

Private Member
SBR, PVA and water. Make it quite strong mix, about 1:1:4. Throw in a load of cheap vinyl silk.

That seals really well, then a coat of bonding agent (used blue grit last time). That is the equivalent of about 5 strongish PVAs.
 

lilharbs

New Member
The best solution I have found is neat sbr,but that sounds very expensive wherever your buying it.im sure I pay approx 15quid for a gallon normally.
 

Fatarm

Trainee mod
As I said in my post had some nasty problems with suction on old lime plaster,ie crazin and crackin like a road map lol. But using sbr method has eliminated the crackin problem.as long as the original lime plaster is structurally sound. If not sound then I would hack off loose or unsound and apply an undercoat before skimcoat.alternative is to tell the customer u need to take it right back to the bare brick,tell them the cost,tell them about the mess, then stand back an watch the colour drain from thier face.lol
 

Fatarm

Trainee mod
I get my sbr from sometimes b&q, wicks 15-20quid or unfortunately when I feel like gettin shafted I pull my boxers and take a shaftin 25quid an upwards :RpS_tongue:
 

Fatarm

Trainee mod
No question my friend just discussing the merits of sbr for suction control on old lime plaster"taking the sting out of the original plaster"
 

NPS

Private Member
oh right,, i thought you was asking something then all of a sudden it turned out you was telling us something

i do alot of 90+ year old walls and all i do is pva it straight away then get all my gear in and ready to mix up then give it another coat

just out of interest how much do you lay on in one go i only mix a bag or just a little over, not many walls in a house take more than one bag
 

Fatarm

Trainee mod
Sorry, wasnt askin somthin or suddenly telling u anythin just like to hear other guys views on suction control on very dry backgrounds.as for how much I lay on in one go depends on size of wall and how quick it's going to dry before lay in. Some times pva just won't do on very dry backgrounds such as old lime-sand plaster, no time to flatten first coat before it's screamin for a lay in. When sbr is used it makes a big difference it hangs back allowin larger areas to be worked before lay in lilharbs and Dannymac above Have obviously had the Same probes in the past
 

lucius

Well-Known Member
I get my sbr from sometimes b&q, wicks 15-20quid or unfortunately when I feel like gettin shafted I pull my boxers and take a shaftin 25quid an upwards :RpS_tongue:
Didnt know Wickes sold SBR. my branch certainly dosent.
 

glowkeeper

New Member
By putting sbr, pva, vinyl silk et all on a lime plastered wall, you are in effect 'sealing' what was once breathable. And by doing so, you might be causing structural problems down the line because you could be creating damp. There are products that are better than PVA in such situations (by which I man the treatment of lime plastering in old buildings). Check out Baumit DG 27, for instance....
 

Nisus

Elite Member
For me it's stabilising solution, then pva or bonding agent on these walls. (mainly if limewash/distemper is present)
Fibres in 1st coat of skim if walls are bad, or if really bad a tight coat of bonding 1st, or if really really bad hack it all off & start again :RpS_thumbsup:
 
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CeeVee

Well-Known Member
PVA x 2 then skim. Never had a problem in 15 years. Never.

Re. how much mix....I always mix one bag at a time, and do a little rolling set so each set I use about 3 bags, or two walls and maybe some reveals in an old house....
 

twitcher

Private Member
try mixing the pva with the stabiliser and a bit of water if it needs it.

works a treat, cuts out some time and effort too
 

henry

Private Member
By putting sbr, pva, vinyl silk et all on a lime plastered wall, you are in effect 'sealing' what was once breathable. And by doing so, you might be causing structural problems down the line because you could be creating damp. There are products that are better than PVA in such situations (by which I man the treatment of lime plastering in old buildings). Check out Baumit DG 27, for instance....

There taking the piss with the price of D27
 

dm79

Member
most 90 year olds i know have a suction problem.
i would suggest simply taking out their dentures:RpS_thumbup:
 
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