essexandy
The Lake Governor
Sorry mate I misunderstood the question. I won't skim Hardwall until it has set. Just asking for problems doing it too soon.OK to skim after a couple of hours then?
Sorry mate I misunderstood the question. I won't skim Hardwall until it has set. Just asking for problems doing it too soon.OK to skim after a couple of hours then?
Sorry mate I misunderstood the question. I won't skim Hardwall until it has set. Just asking for problems doing it too soon.
Same day is perfectly safe. Just skim in roughly the same rotation you float in.Cool. Next day safer then?
Same day is perfectly safe. Just skim in roughly the same rotation you float in.
You're most welcome.Thank you sir x
When I was working for a damp firm we always skimmed the next day and guess what .....yes it always cracked but damp firms don't give a fook just get in and get out.Ok, so how many on here skim s&c next day? I always have done.
You're most welcome.
The invoice will be in the post.
By the way that now makes you more qualified than lurpy.
I always pva or SBR before skim as I don't trust it even when cured. Last substantial job I skimmed onto s& c was probably getting on for 10 years ago anyway. Bonding or hardwall and finish same day is the norm.I can guarantee that loads of your skim won't be attached to the S&C backing within days of you finishing. I witnessed it plenty of times where the skim has just stood there shelled for years and years before it gets noticed. I've also seen it where it has been noticed almost straight away.
S&C shrinks, fact, and no amount of devil floating will make the gypsum finish plaster, which is rigid and brittle, move with it.
What exactly don't you trust about cured S&C?I always pva or SBR before skim as I don't trust it even when cured. Last substantial job I skimmed onto s& c was probably getting on for 10 years ago anyway. Bonding or hardwall and finish same day is the norm.
I just don't believe that after 5 days s&c is fully cured. It may have set and changed colour but the curing will go on longer than that. It's probably enough for a reasonable bond but I just don't trust it, multi could sit there for years and then suddenly shell, seen it too often. I just like to be sure, which is why I mesh the lot too.What exactly don't you trust about cured S&C?
As a company I've done around 800 houses in S&C, always allowed to cure and never sealed prior to skimming.
Shelling of the finish happens because of shrinking as in the evaporation of the moisture from the mix which should be done in a 4 to5 day period depending on conditions . Curing means that the mix just keeps getting harder which will take much longer but the mix no longer contains water so the shrinking will stop .I just don't believe that after 5 days s&c is fully cured. It may have set and changed colour but the curing will go on longer than that. It's probably enough for a reasonable bond but I just don't trust it, multi could sit there for years and then suddenly shell, seen it too often. I just like to be sure, which is why I mesh the lot too.
Ok, shrinkage is one thing. But when cured the finish will have no chemical bond with s&c, you are then relying solely on key and in my book that makes me nervous. When using bonding or hardwall you have a gypsum chemical bond which is more reassuring. Don't just rely on key alone with s&cShelling of the finish happens because of shrinking as in the evaporation of the moisture from the mix which should be done in a 4 to5 day period depending on conditions . Curing means that the mix just keeps getting harder which will take much longer but the mix no longer contains water so the shrinking will stop .
What exactly don't you trust about cured S&C?
As a company I've done around 800 houses in S&C, always allowed to cure and never sealed prior to skimming.
You are wrong my friend. skimming does not need a chemical bond how do you think it sticks to plasterboard . when the skim drys on sand and cement it goes through a shrinking process also, and when this happens it grabs into the groves left in the rubbing up process .If your skimming is not adhering to the floating then you may want to re asses you rubbing up of the backing coat .IMO.Ok, shrinkage is one thing. But when cured the finish will have no chemical bond with s&c, you are then relying solely on key and in my book that makes me nervous. When using bonding or hardwall you have a gypsum chemical bond which is more reassuring. Don't just rely on key alone with s&c
I can probably count on one hand the number of s&c I've done. I've nearly always used bonding and hardwall. I came into plastering just after I'd heard about multi shelling and it put me off. The plasterer may have skimmed it too early, who knows, but I will never trust relying solely on key, hey I'm probably wrong. Paranoid?.... definitely.You are wrong my friend. skimming does not need a chemical bond how do you think it sticks to plasterboard . when the skim drys on sand and cement it goes through a shrinking process also, and when this happens it grabs into the groves left in the rubbing up process .If your skimming is not adhering to the floating then you may want to re asses you rubbing up of the backing coat .IMO.
OK to skim after a couple of hours then?
You are wrong my friend. skimming does not need a chemical bond how do you think it sticks to plasterboard . when the skim drys on sand and cement it goes through a shrinking process also, and when this happens it grabs into the groves left in the rubbing up process .If your skimming is not adhering to the floating then you may want to re asses you rubbing up of the backing coat .IMO.
Do you skim sand and cement without a bonding agent?Gypsum sticks to gypsum even without a key tbf
But snc needs the key
I've been shot down before about using PVA on sand and cement Being told to skim too early (as far as I was concerned) and when I started floating s/c on my own always left for a week at least ,used PVA , no scratching ( devil ), don't think I'd use SBR as would act too much as a moisture barrier but each to their own,Do you skim sand and cement without a bonding agent?
Yes mate I wouldn’t use a bonding agent but hey do what ever feels best I’ve enjoyed reading this thread everyone has there waysDo you skim sand and cement without a bonding agent?
How long is your mixer going to stay that clean and shiny?. Smile face.I trust you on this for sure but I'm the same as above, I worry the finish is going to shell off so will glue up also! Probably as I've scraped finish off rendered walls a few times where it hadn't took to the scratched surface very well! Infact I have one to do this week.. do I PVA or not.. lol
Brand new mixer too, fed up hiring! View attachment 29404
with hardwall and browning it depends on the background suction when you can skim. on very high suction we may float and set twice a day. on very low suction we may leave it over night. if it looks to dry we would mist it with water.
You just shouldn't be skimming S&C next day, full stop. Should be left five days summer, seven days winter.
Even if not 100% cured I definitely couldn't measure any further shrinkage after the fourth day at 18mm thickness on Celcon blocks in early summer.I just don't believe that after 5 days s&c is fully cured. It may have set and changed colour but the curing will go on longer than that. It's probably enough for a reasonable bond but I just don't trust it, multi could sit there for years and then suddenly shell, seen it too often. I just like to be sure, which is why I mesh the lot too.
How long is your mixer going to stay that clean and shiny?. Smile face.
I love floating with hardwall DOn't do it enough as plasterboading is cheaper and quicker :-(