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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Building Questions >> Peeling Plaster https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1109513320 Message started by woodsmith on Oct 24^th, 2004, 9:40pm

Title: Peeling Plaster
Post by woodsmith on Oct 24^th, 2004, 9:40pm

I have a house with dry lined walls, about 6 years old. The plaster looks fine but if I disturb it then large pieces come away from the plasterboard. I seems that non of the plaster has adhered to the plasterboard ???

Any ideas why this has happened. This was obviously done by professionals as the finish is excellent.

Thanks

Keith

Title: Re: Peeling Plaster
Post by thescruff on Oct 24^th, 2004, 9:50pm

perhaps its a boiler and only designed to last 6 years ;D

I shall hazard a guess before the expert get here, and say the wall was too dry when the top coat was applied.

scruff

Title: Re: Peeling Plaster
Post by JerryD on Oct 24^th, 2004, 9:50pm

1) The plasterboard may have been dusty when plastered.

2) Is it grey side out or white side? �It should be white side out (plastered).

3) Is the plaster manufacturer the same as the plasterboard manufacturer? �I've heard that British Gypsum plaster doesn't like Knauf boards which doesn't like Lafarge either. �In other words you shouldn't mix and match boards and plaster manufacturers.

4) Room could have dried out too fast, either very hot weather or possibly force dried with heaters or dehumidifiers.

These are the main reasons that spring to mind.

Title: Re: Peeling Plaster
Post by billythekid on Oct 24^th, 2004, 10:00pm

i spent a large part of the summer stripping paint off plastered walls, seems it didnt stick properly coz the plaster was dusty, used to come off with blu-tak! my guess is that the same is true with the plaster in your case. it stuck to the dust, which wasnt stuck to the wall. I think I'm gonna prep the wall here with some sort of pva solution before trying to apply paint this time.

Title: Re: Peeling Plaster
Post by woodsmith on Oct 24^th, 2004, 10:16pm

The plasterboard is white side out,

It's like this all over the house and I could understand one dusty piece of board but not all of them.

I assume then that the weather must have been very hot and dried out too fast.

But? when I did some plastering on the only hot day we had this year, the plaster cracked as it was drying, so I hacked it off. The plaster in the house looks perfect no shrinkage cracks anywhere.

The plaster is white if that is a clue but no idea of the make of the boards

Title: Re: Peeling Plaster
Post by JerryD on Oct 24^th, 2004, 11:04pm

If the house is only 6 years old it should still be under the ten year NHBC warranty??

Title: Re: Peeling Plaster
Post by dj on Oct 25^th, 2004, 12:19am

sounds to me like it isn't british gypsum plaster. and that they are british gypsum boards, i think gerry could be right in his first post
if you can find out the make of the board then phone the manufacturer, a lot will go on site to find out the source of the problem.

Title: Re: Peeling Plaster
Post by Lectrician on Oct 25^th, 2004, 7:55am

I have a similar problem when I work on my house. Breeze block wall, cement scratch coat, but the plaster top coat pops easily - even when drilling a 5.5mm hole etc!!

Stripping paper or paint brings it off aswell. Once you get a little bit pop, the rest follows.

Suppose i should get each room replastered as I decorate??

Title: Re: Peeling Plaster
Post by woodsmith on Oct 25^th, 2004, 8:49am

Thanks for all the replies.

The house has an NHBC cert but if this was the trade forum I could tell you what I think about that, lets just say it's useless.

Still my plastering skills have improved since living here.

Keith

Title: Re: Peeling Plaster
Post by Robbo on Oct 25^th, 2004, 12:41pm

Any of the above could be a contributory factor but not actually very likely if that makes sense!! :-/
Ivory side down for boards yes, but if they are not it does not really make a jot of diffrence, the tapered edge of the board is ivory side out hence fixed this way.
Can I assume this is a new house on a newly built estate, if so the materials will be compatable as the deals would have been made with who ever and the full quantities delivered shrink wrapped to each house as the spreads go in.
Other reasons for this to happen include dirty gaugeing water, old past its best plaster, retempered mixes instead of fresh for second coating, and overworked finishing where too much of the splash brush has been used for polishing off but theese would normally be for the odd wall or ceiling rather than whole sale.
Therefor my opinion is that, as was common practice a few years ago when rates were poor many spreads would only one coat boardwork and if large areas were hit on one gauge they would cure quickly and need alot of splash brush to bring them bak for polishing, not great practice but the diffrence between a decent wage and half nothing. this left boardwork with a poor bond and liable to shell but the man got paid and thats all thatvconcerned him.
Lectrician your problem is the render coat has cured too much before a skim was applied so the finish would take up (dry) almost on contact with the wall, the second coat would be workable only for a little longer and could be polished up but the bond is not there initially. Browning should be skimmed the afternoon after application and sand/cement the following day.... regardless of what manufacturers may state!
Preperation is the key to good plastering!

Title: Re: Peeling Plaster
Post by woodsmith on Oct 25^th, 2004, 6:36pm

Thanks Robbo, could have been old plaster as these were the same builders who did my roof, if you remember the valley from hell ::)

Can I ask then? if you are skimming a plasterboard wall you would do it in 2 coats one straight on top of the other while still wet so that the top coat stays workable long enough to polish it? I have done it this way because it is easier for me to get a good finish.

If the plaster is applied in one coat it goes off too quickly and as they work it to get it smooth it looses its bond? Is that right?

Thanks

Keith

Title: Re: Peeling Plaster
Post by Robbo on Oct 26^th, 2004, 8:49pm

Its good working practice to two coat skimming Keith your first coat is applied and as this starts to set you "flatten" which is to take out any of the lines from the coat ....as it begins to " take up" (stiffen) the lines will go as you dry trowell it, no water at this stage, from here you "lay in " a nice tight second coat, the second coat will be far easier to lay in and trowell up to a finish if you keep to those two main rules ....... flatten the first coat and tight coat the second. Allways run some over the skrim taped joints before you lay anything onto the boards.

One coat can be ok if you work it correctly but if you take a hot day, to many metres put on then over watered and over worked then yes it will not have the same bond as good slow curing two coat work.

Title: Re: Peeling Plaster
Post by woodsmith on Oct 26^th, 2004, 9:35pm

Thanks Robbo, whos idea was the plaster's forum :-)

it was a good one.

It's odd really, if you splash plaster onto any surface nothing will ever get it off, yet it will fall off the wall, if it isn't applied properly.

Keith

Title: Re: Peeling Plaster
Post by Dewy on Oct 26^th, 2004, 10:37pm

I like the way they 'plaster' in the states from seeing a number of American building programmes.
This Old House, Hometime etc.
There they screw the plasterboard to the walls then tape over the joints.
The screws pull the board in slightly so all it needs is a skim over the joint with 'mud' (sorry Mud) and the work is finished and just needs painting.
Proper plasterers are like rocking horse droppings there as there is no training in proper plastering taught over the pond.

Title: Re: Peeling Plaster
Post by Lectrician on Oct 27^th, 2004, 7:56am

It gets done here like that a lot, you can get board with a recess on the edges to take the tape. Whats this method called?? Seen it done with that board with the polystyrene on the back.

Title: Re: Peeling Plaster
Post by dj on Oct 27^th, 2004, 3:48pm

that's tapered edge board.
up ere it's just called tape and join

dj.

Title: Re: Peeling Plaster
Post by Robbo on Oct 27^th, 2004, 6:38pm

wrote on Oct 26^th, 2004, 10:37pm:

Its very common in europe and is often used on bigger jobs in England but is never anywhere near as good as a nice skim coat, something I have never managed to fathom is why tape and jointing is used anyway. Its a three coat system with paper tape for skrim with every single screw head caulked and the whole lot sanded so as to feather into the plasterboard, have done a good bit myself but can finish a skim in less time ???????????

Title: Re: Peeling Plaster
Post by The_Trician on Nov 13^th, 2004, 6:11pm

Re-Peeling plaster -

I had a similar problem when I did my kitchen.

Old Voctorian semi with nearly nothing left of old DPC, so I replaced the first course of bricks which appeared above floor level with blue engineering bricks - a few at a time.

Thought it might be a good idea to get the walls rendered from skirting level to about a metre high.
Used cementone No2 at 'swimming-pool strength' and PVA with the render mix.

Plasterer applied this, then skimmed over the top with plaster. About 3 months afterwards, the plaster skim began to peel and crack off.

Had the plasterer back to sort it out, and re-skim, but the only reason we could come up with as to why the plaster cracked the way that it did, was because the render coat hadn't fully dried out when the skim was put on, and had continued to dry and shrink behind the skim coat.

Been redone about 3 months ago and all is fine now.

TT

Title: Re: Peeling Plaster
Post by Kesh on Nov 14^th, 2004, 1:21am

wrote on Oct 27^th, 2004, 6:38pm:

Not because it's quicker or better, just because any idiot can do it! ;D

Title: Re: Peeling Plaster
Post by bstyle on Nov 14^th, 2004, 4:45pm

I use the tape and join method all the time and find that it is very good. The main advantage is that like Kesh says you can do it yourself so you can get jobs done quicker.

Title: Re: Peeling Plaster
Post by scotspark on Nov 14^th, 2004, 6:34pm

most painters do the tape and fill thes days but it's nowhere near as good as a good platered finish. tho saying that theres a huge difference when it's done well, there is a couple of guys who are really good round here far better than most of the work you see.

Ames taping is the correct term i believe??????????????

Title: Re: Peeling Plaster
Post by bstyle on Nov 14^th, 2004, 7:39pm

If you're thinking of doing it yourself (tape + join).

The best stuff to use is gyproc easy fill, you need to mix it up yourself.

I used to use the ready mixed stuff but i find it so much better with the easy fill.

Also dont use the paper jointing tape its much easier with the self adhesive scrim.