Clarification re render after tanking

Status
Not open for further replies.

Chrisamyphillip

New Member
Just completing tanking coats and looking to overcoat render. Have used Everbuild Febtank.

Their data sheet states Renovating Plaster OR Cement Based Render:
SUBSEQUENT OVERCOATING: FEBTANK SUPER is suitable for overcoating once correctly and thoroughly cured.
Plaster: If plaster is to be used it must be ensured that cement based “renovating plaster” is used. Gypsum plasters must not be used.
Cement based render: Use a slurry bonding coat consisting of 2 parts sand, one part cement gauged to a brushable paste with neat FEBBOND SBR. Apply render whilst bonding coat is still tacky.
Final Decoration: Allow 6 months minimum to elapse before final decorative finishes are applied.

Whats the pros/cons of Renovating Plaster versus Cement Based Render?

I'm a little bemused as I though that it HAD TO BE Renovating Plaster for its chemical resistance to salts etc. but then again I suppose the tanking slurry 'should' have blocked all of that?

Can't find a Renovating Plaster in usual b7q's / wickes….

 
Thistle dri-coat, vandex both usually need to be ordered in dri-coat will be pallet quantity only.

Sent from my Nexus 6P using Tapatalk
 
use s&c, the waterproofer I'm using atm has a salt inhibitor in it. It's top stuff too.


Sent from my iPhone using Tapatalk
 
use s&c, the waterproofer I'm using atm has a salt inhibitor in it. It's top stuff too.


Sent from my iPhone using Tapatalk
Is that based upon the cost saving - using s/c or other reason?

I think the waterproofer I have in the van is the Everbuild Concentrate (that has salt inhibitor in it).
 
stick to sand cement render, bagged plastering sand with a drop of sbr in the mix, it should be a 3/1 sand cement mix with a good water proofing and salt inhibiting agent such as sika1, rendergaurd gold or tri mix.

the use of renovation plasters are ok above ground on dry walls but unless you know what your doing then should be avoided on tanked walls, hence not many damp proofing firms use renovating plasters.

sand cement render is the cheapest option, what more can I say...
 
stick to sand cement render, bagged plastering sand with a drop of sbr in the mix, it should be a 3/1 sand cement mix with a good water proofing and salt inhibiting agent such as sika1, rendergaurd gold or tri mix.

the use of renovation plasters are ok above ground on dry walls but unless you know what your doing then should be avoided on tanked walls, hence not many damp proofing firms use renovating plasters.

sand cement render is the cheapest option, what more can I say...
Can I ask why the mix needs to be so strong(3/1) for damp works?
I know this is the norm for this but surely it's too strong and will crack?
 
Can I ask why the mix needs to be so strong(3/1) for damp works?
I know this is the norm for this but surely it's too strong and will crack?

After injection, correct re rendering is just as important and needs to be done to spec, they say a dense coat is what is required as this helps provide extra protection against moisture that is currently in the wall from bleeding through the new finish as it is more resistant to ground salts.
But that goes against any advise I've ever been given externally about the render being weaker than the substrate and the next coat always weaker than the last coat. Otherwise you can get failure and delamination.


Sent from my iPhone using Tapatalk
 
stick to sand cement render, bagged plastering sand with a drop of sbr in the mix, it should be a 3/1 sand cement mix with a good water proofing and salt inhibiting agent such as sika1, rendergaurd gold or tri mix.

the use of renovation plasters are ok above ground on dry walls but unless you know what your doing then should be avoided on tanked walls, hence not many damp proofing firms use renovating plasters.

sand cement render is the cheapest option, what more can I say...
Renovating plaster is spec'd as part of the tanking system if your not dabbing insi boards. I use it all the time rather than traditional S&C. It's a better product in that you can top it after 24 hrs, you get less shrinkage. It's a better insulator and it's more forgiving if you need to build it out. The only negative is the price imo

Sent from my D2303 using Tapatalk
 
Renovating plaster is spec'd as part of the tanking system if your not dabbing insi boards. I use it all the time rather than traditional S&C. It's a better product in that you can top it after 24 hrs, you get less shrinkage. It's a better insulator and it's more forgiving if you need to build it out. The only negative is the price imo

Sent from my D2303 using Tapatalk
Thanks for everybody's help - much appreciated.

I've finished the slurry aspect (including fillet with FebTank Plug) and about to use Limelite Renovating Plaster. Reading the spec on it, it is expected to shrink a little and also to crack due to the lime content (manufacturers data). They say to complete the job with Limelite High Impact Finish. Excuse my ignorane, but is this totally necessary if I don;t end up with too many slight shrinkage cracks?

BTW - I paid £21.50 + vat for Limelite Renovating and been quoted £14 + vat for the high impact bags. All from Jewsons.
 
Just use board or multi finish unless your issuing a guarantee

Sent from my D2303 using Tapatalk
 
Status
Not open for further replies.
Top