Skimming Chimney Breast

[Ric]

Hi there,

This weekend I will be embarking upon my first ever plastering related project. I am going to skim a chimney breast! I have a brand new hawk, a float (not brand new but nice and clean looking), a bucket, a bag of Wickes Universal Finishing Plaster and last but by no means least a Wickes good idea leaflet telling me how to do it. I aim to do the following and I invite people to contradict me where experience dictates:

1) Preperation - this part is important I am told. The breast is currently very uneven and patched but for the most part is covered in grey cement plaster type stuff. I intend to brush this down with a stiff brush to remove lose particles and prime this with a 5:1 PVA:Water mix and give this plenty of time to dry.

2) Putting beading on the corners - the corners are presently badly defined with wooded beading - I would like to use some angle beads to re-create the corners - and this brings about my first question: Which angle beads do I need? I have bought some but I am concerned that they are too deep for skimming and are probably more suited to plastering from scratch. Is there a special bead that should be used for skimming existing plaster or am I worrying over nothing and should I just put the stuff I've got up and see what happens? Which leads me on to my second question - what should I use to fix the beading to the walls?

3) I am then going to apply a 3:1 PVA:Water mix to the walls and allow it to go tacky, during which time I will mix the finishing plaster as per instructions in said leaflet. I will then attempt to skim the breast, again as per said leaflet. Will one coat be enough or should I plan to do two?

Any tips/help/advice muchly appreciated but I fear that in the end it will come down to weather or not I am any good at it! We will find out in good time I am sure!

Thanks, Ric.

[Andrew Gabriel]

That's not a good move -- I suggest you start by replastering the inside of the cupboard under your stairs or a garage wall, not the focal point in your living room. ;-)

I presume you mean a trowel (metal) and not a float (wood or plastic). A new trowel is difficult to use -- a used one is much easier, but make sure there are no nics in the long edges. If there are, you can polish them out using house brick with a good flat surface -- use a motion like trying to saw through the brick with the trowl, but hold the trowl at a 45º angle. If the corners or edges are sharp (as with a new trowel), polish the sharpness out on the brick too. (This is one reason why a new trowel is bad news for a plasterer.)

You should use plasterboard beading, which is indended for taking a skim coat. Plaster beading (as opposed to plasterboard beading) is intended to go in the scratch (base) coat which you aren't replacing, so they won't be useful.

Some people nail them (nails are supposed to be galvanised to stop rust marks coming through the finished paintwork). I actually just use the plaster itself -- a smear all down the groove, and then push it into place. Make sure it's well seated on the corner and not springing away.

Always plan for two. Sometimes having done one, I decide it's good enough to polish up, but this requires that the wall behind is in good condition (almost good enough that it barely needed replastering).

I and others have posted loads of tips -- check back on google.

[Mark]

A few practical bits........

2Lt water makes about 4Lt by volume of plaster, which is sufficient to skim coat, an 8x4-sheet plasterboard so if your chimney has a fire surround, thats about the same size. Mixing more then 4Lt by hand is hard work trying to get the lumps out, I sometimes use an elec kitchen whisk on *SLOW* speed for small jobs. Get a straightedge and concentrate on getting it level, surface imperfections can sorted once the plaster has set, waviness cant. Make sure you put covering down on the floors were you are working and don't reuse any plaster that ends up there.(as it will).... :-)

-- mark

[chris French]

In message , Andrew Gabriel writes

Indeed, brave man. The suggestion made previously here about getting a sheet of plasterboard and practising on that would seem to be good advice.

I've always seen heard them called 'Thin-coat beads'

My plasterer uses drywall adhesive

My tip would be prepared to be immensely frustrated :-( I've not done anything major in the replastering line, but it really is much harder to get a good finish that it looks (IME)

[Wisefrog]

I too embarked on my first plastering project this week using the wickes guide. Definitely practices, on plasterboard first! A couple of sheets both sides.

Having spoken to a few people and done a few test runs, I found doing it in two finishing coats with the later in a more diluted mixture (so you can only just make peaks in the mix) applied about 30-45 mins after the first gave me the best finish. Also, I ditched the Wickes universal finishing plaster for standard finishing plaster. I find it easier to smooth out after the initial application.

Make sure you get a good level/flat surface to apply it too using bonding plaster first.

And some form of electric mixer is well worth while. Mixing be hand can get very tiresome and frustrasting when you still have lumps in there. The attachments you can get for a drill work well but prepare for the mess! In fact prepare for mess full stop. I'm still getting plaster dust on everything I touch a week later!

But I'm still w>

[Andrew Gabriel]

It should be runy enough so it easily runs off the trowel if you hold it vertical. Scratch coat is thicker -- it should stay on a vertical trowel unless you give it a slight vertical jolt to make it slide off.

Also watch the drill temperature -- it's easy to burn out a cheap drill with a plaster mixer. Torque is quite high, but speed to too low to adequately cool the drill. It kind of relies on rest periods whilst you are plastering before you mix up the next load to cool down.

It's used to transfer plaster from your board to the trowel, and to size and shape the plaster on the trowel. I'd love to explain, but my descriptive powers aren't up to it. Actually, I couldn't do it even having read how to and looked at the pictures -- it only worked for me once someone had actually shown me how to use it and then it was easy.

I've seen someone plastering (not a professional plaster) by using the trowel to directly scrape the plaster from the mixing bucket. If you can do this with finish coat, it's far too thick (I didn't see the end-result in this case).

[Ric]

Well, I did it and its not too bad - I probably would have been better practicing but I did the two sides first to get me going. I think I have a bit of a nack for it and I'm sure I would get better with practice! I even got cocky and did the wall next to the chimney breast as well as it was a bit dodgy. I will certainly attempt it again as I continue to decorate the house!

I just wanted to say thanks as well for all the advice as it helped a lot - not just the responses to my post but the tips I got by googling this group.

Cheers, Ric.