Plaster and Best Before Dates?

[AndrewSchofield]

It was news to me last year when i learnt that plaster has a 'use by date'. Someone at the time told me that it does become unusable but the date on the bag is a little conservative and is so to save the plaster manufacturers skin if it all drops off the walls and you've laid it after the use by date. Does anyone know how long it is safe to use it after the date on the bag, or should i just scrap it the day after that date?

If i've got to buy new, anyone know where i can get rid of it? Should my local 'refuse amenity site' (tip) take it?

Thank you.

 

[Richard C]

How long it will last generally depends how it’s stored but I wouldn’t use it if it’s expired or, this time of year, if it's very close; I don't even bother to save a ½ used bag or so, once opened unless it's going to be within a couple of days as it will absorb moisture much more quickly. It wont fall off the wall if you can manage to get it on there before it goes off but once it’s gone, it can set virtually as your mixing it or even worse, just as you’ve laid it on. You only ever "chance it" once as I did but the stuff is so cheap, it’s really not worth the hassle of getting caught out.

If you have a lot of it stored, you could try mixing some up & just see how it behaves; if it’s OK then use it. My local refuse site takes mine, just goes in their landfill skip.

 

[AndrewSchofield]

Thanks Richard.

Will probably get some new to be on the safe side. The previous lot i got were multifinish but i've got a price for board finish as well - what's the difference and can board finish (as the name suggests) only be used to skim plasterboard?

 

[Richard C]

I rarely use Board finish & always use Multi; it’s formulated for use on all suction backgrounds & is perfectly OK for boards & will even give you a little more time over Board Finish. Board finish, on the other hand, is specifically formulated for use on low/medium suction &, do you know, I've never actually used it on anything other than boards! I suppose it should be OK but may take a little longer to go off. I don't know; I’m sure Rough or Roy could advise for sure.

Price wise, have you checked out your local B&Q Trade Centre? I get practically all mine from there @ £4.68 a bag, it’s one of the cheapest places I know, even cheaper if they have one of their 10+ bags deals going; it’s also stored well & I’ve never had any dodgy stock going off to quick, unlike from the local BM’s mostly damp tin sheds!

 

[marshman]

When Siraphite got scarce board finish was the plaster to use, used it on any backing same as multi is used today, as the alternative was carlite wall finish and that was ****e.
There is not much difference between the two now.
when the plaster is getting old you'll find the finish surface looks a bit like an eggshell when troweling up and slower setting,
as it gets older still it changes and will reach a point where it will set before you can get it out of your bucket.
any bag that's been open more than a week is skip fodder.

 

[AndrewSchofield]

any bag that's been open more than a
week is skip fodder.

Well thats one thats going tonight then!!! Got a part bag from before xmas!

Cheered me up on the price Richard - i'm buying for just over £4 a bag for multi!!!

Thanks guys. Better get me tape measure out and start working out how much i need again.

 

[Richard C]

i'm buying for just over £4 a bag for multi!!!

That's good, who's supplying you and does it include VAT?

 

[JohnD]

if you live in an area with a heavy clay soil, discarded plaster raked into the surface will lighten it and make it drier and more crumbly.

keen gardners will be pleased to have it once they have given it a try.

(true)

 

[AndrewSchofield]

Richard - £3.80 + VAT from a local builders merchant. That's delivered too!

JohnD - will ask my grandad if he wants any for his garden then!

 

[kjacko]

I had a brand new bag from a local BM it was going off as i was mxing it! So it promptly went back for an exchange.
I use B&Q as well, unless i'm already at a BM and i know i'll be plastering very shortly i'll get it from there, as cost is only a few pence and i only do smaller projects taking maybe 2-3 bags of multi-finish up at most.

 

[Richard C]

Richard - £3.80 + VAT from a local builders merchant. That's delivered too!

Ahh the local builder’s merchant. I had one which I used regularly when I lived in Essex; keen prices, usually delivered same day if you rang before 11am & free delivery. When we moved here, sadly, the only local choice is the big 3; most of the prices are the same & all are a rip off even with the discount (up to 60% in some cases), delivery when they feel like it & charged & I’m only a couple of miles away!

 

[AndrewSchofield]

I have a rough stone wall in the storage part of my loft which i want to 'face-up' to make it even and cleaner and to stop drafts blowing through it which seems to occur when its very windy? I don't want to paint it or anything decorative like that and i'm not bothered about it being smooth so long as it is flat (ish). Would there be any mileage in using my old out-of-date multifinish for this or would it just drop off? Maybe even mixing it in with a sand & cement render to do the job - literally just to use it up?

 

[Richard C]

What do you mean by a "rough stone wall" Multi is a finishing plaster, intended for over plastering a base coat plaster or render; it’s not really suitable for applying directly onto stone or brick. Also, it should only be used in 3-5mm thickness; you can cheat a bit & even build it up in layers but if applied too thickly it will craze, lift & possibly fall off; Bonding or even Hardwall may be more suitable.

Having said that, if you can get it on the wall & reasonably flat before it goes off, it should be OK but it may not look very good; never tried mixing it with render Personally I wouldn't be arsed with it & chuck it but, with the new landfill regs. from April 1st, looks like you cant even dump it down the tip any longer!

 

[roy c]

I have mixed finish with sand and cement when putting screeds up walls (internally) that need to be built out 2" or more. This helps it to go off a lot quicker and helps you level up your screeds to your "dabs" and devil
it up ready for when you have filled in and devilled that ready for skimming. I have known "boys" put it in the mix outside when putting beads on , but I wouldn't recommend that......

 

[Richard C]

I have mixed finish with sand and cement when putting screeds up walls (internally) that need to be built out 2" or more. This helps it to go off a lot quicker and helps you level up your screeds to your "dabs" and devil
it up ready for when you have filled in and devilled that ready for skimming. I have known "boys" put it in the mix outside when putting beads on , but I wouldn't recommend that......

Something else I've learned