Can I plaster straight over trunking?

[easyrider]

I have cut out a channel in my wall for the AV wires and have fitted plastic trunking in the recess.

The plasterer is coming on Thursday.

Can he plaster straight over the plastic trunking?

or do I need to prepare it with filler or something?

Thanks

[albriscoe]

Hi mate

just plaster straight over it

[ldoodle]

I filler'd over my chases as when taking off the wallpaper 98% of the plaster came with it so was down to sand/cement!

But, any decent plasterer will do that for you if needed.

[Sanders79]

Yep indeed, just plaster over (use a bonding coat first before the finish coat if there is enough space).

[wese007]

Wickes *–*Building Materials*–*Plaster*–*Bagged*–*T histle Bonding Plaster

this is what he wants to be using,its ideal for plastic, give the trunking a rub down with a rough grade sandpaper if you like,will help it key better as well,but like Sanders79 said,if you have enough space to use a bonding coat prior to a finish coat,if not i would defo give the tunking a rub down,

your plasterer may have a different way of doing it, in saying that,im a plasterer and have just done my trunking,i had no bonding in the house so i used board adesive,this stuff really sticks to the wall,rubbed down the tunking like i said,and will key to the surrounding area no problem,

your plasterer will advice you im sure,unless hes one of these plasterers who became one on a one week course

[Sanders79]

Agree with all of the above!

I think there are two really important points to consider to avoid cracking of the finish coat:

Make sure the trunking is properly secured in the wall (I have used 8 screws and plugs for a 1 m section). This ensures it doesn't try to wobble around and flex in the wall when you're pulling cables through etc.

Mak sure there is enough space for a sufficiently thick coat of plaster on the top.

Wese007, might it be an alternative to use scrim tape if there isn't space for a bonding coat? Just to give a good key...

[wese007]

good old scrim tape,good stuff,and will do as you say mate,lets hope he comes back here and the plasterer has done him a good job,will only really know once hes painted it though,as this is when he will see any imperfections,hollows etc,

we given him some help,the rest is up to his plasterer now,

hope its all good easy-rider,unlike another member who had to sand his walls down after the plasterer did his trunking,

another little tip for you mate,when it comes to painting it,no need to use these special primers for new plaster,just use watered down matt paint,whatever you do,dont use vinyl silk straight on top as it will just sit on top of the plaster,and will just peel of,

and dont do it pink

[easyrider]

Thanks for the tips guys

He's been and gone and things look ok to me.


what do you think?

[easyrider]

[wese007]

looking good batman didn.t know you was getting it boarded out,looks like he put the boards upside down just kidding

on your first coat of paint,paint ceiling first then walls,as any drips,splatters on the walls you will see then wipe of,instead of drying as runs on the walls,if you get me,

[deckingman]

Sorry to jump in but how long should you leave fresh plaster before painting?

[wese007]

about 5 inches is ok, some say it takes months to dry, others days,you know how it is

me personally,as soon as it all goes a light pink in colour,i will paint it, its only mm in thickness and soon drys out,
couple of days it should dry out,unless the room is cold and loads is done like in the pics,as the whole room will be full of damp air,

just dont be temted to whack your heating on full to dry it out quicker or it may crack

[GlynG60]

If you get trade paint for new plaster you can paint it sooner. This paint breathes and lets the plaster continue to dry and also adheres itself to the freshly plastered surface better than other paint. Regular emulsion tends to seal the wall a bit more so as you have better wipe clean properties. If you wipe paint for new plaster with a damp cloth it will start to remove the paint.

Having said all of that I would hire a dehumidifier and put it in there for a day or so - it makes a big difference.

[wese007]

GlynG60 im not going to argue over your point,but no way would i use a dehumidifier ,just let it dry at its own natural pace,you could run the risk of taking the moisture out to quick and cracking it,just open a window, at this time of year anyway,,im no expert on paint so cant comment, but again disagree with your method of using trade paint on wet plaster,

another tip i hear some is to pva the plaster before painting it,i disagree with this one as well,When you use PVA you stop the emulsion primer being able to soak in


easy-rider this may be confusing you now, you could always get on a building forumn and ask for advice or just ring some pro painters out yellow pages,hear what they have to say,you may still get mixed opions,but im sure you will be able to make your own mind up whats best,and if unsure,just dont take any chances with some ideas that dont sound right

[deckingman]

Did a bit more research and there are no hard and fast rules - depends on too many things like plaster thickness, room temperature etc. Seems the best approach is to let the plaster dry slowly to avoid cracking, so keep the humidity up and the temperature low and leave as long as possible.