Plastering Technique - sponge

by Carl

Hi Paul. I made a mistake today - I applied a skim over bare Plaster and with only a single coat of PVA applied beforehand. Consequently the 1st coat was drying too quickly. (The backing coat was sand and cement sealed with SBR but it would seem a couple more coats PVA beforehand was still needed). I decided to bite the bullet and continue with the 2nd skim coat anyway. As there was nothing to lose I did 'reactivate' the 1st coat by flicking with water and then dampening with a sponge. This worked a treat, the 2nd coat stayed workable for very long time. Is this the correct way to get out of this situation? I realise I shouldn't have got myself into it in the first place, but there must be times when even the experts get the suction wrong - is this the reason for having a sponge float?. I've seen you can buy these from Wickes. I also used the sponge to soften a couple of trowel ridges that I'd negelected, so it's proven to be handy Thanks again ,Carl

Hi Carl,
The text book reason for using a sponge float would be for finishing a sand based plaster - such as to obtain a smooth render finish or for use when skimming with lime. The sponge float is not a standard tool to use on gypsum plaster in order to obtain a finish. However if it works then it is definitely good to use. The way in which you used it sounds ideal - as you say better to control the suction in the first instance but we all get it wrong sometimes. This method actually sounds like a good tip for anyone who may be struggling with a high suction wall where the plaster has become dry and needs invigorating. It may well have it's limitations for large areas, but all sorts of points for and against can be raised - I'm of the opinion that it's good to use any method if it works and helps to achieve good results.
If you develop any more new tricks feel free to share your thoughts.


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