Filling in chases after re-wire

[A3Y55]

Hi, whats the best for filling in the chase channel after a rewire?

Some people have mentioned patching plaster or One Coat plaster.

I've recently had some plastering done in one over the rooms and the plasterer suggested using Thistle Bonding Coat that was left over.

Whats do people usually use and where I can buy some from?

Thanks

 

[JohnD]

I normally use an ordinary plaster. The patching plaster I tried seemed to stick to the trowel. It is easiest with a plasterers trowel or a broad-bladed metal filling or stripping knife with quite a stiff blade. You can press this hard against the sound plaster on each side of the chase to press the new plaster to the right level. This is easier if it is quite a soft mix.

Thistle bonding will fill the chase, but it is a backing plaster so may be difficult to get the surface smooth. Left-over plaster deteriorates with age, and this can make it set so fast you don't have time to put it on.

It often cracks, so allow for two coats - one to fill it in nearly to the top, and one thin, creamy skim to smooth it off once the first one has hardened, dried, shrunk and cracked. Once the finish has firmed, splash it with water from a brush and you can polish it smooth with the plasterers trowel. If you are going to paint the wall, roughen up the polish with a rough cloth. If you put on too much, scrape it off quickly with your broad filling knife. It is much easier and cleaner to scrape off than to try and sand it.

if you give the whole wall a coat of matt white emulsion, it will be easier to spot any blemishes that you need to fix. Do this before you start proper decorating.

I prefer finish plaster, but plasterboarding jointing plaster is supposed to be very good for these little jobs.

You can buy plaster at any DIY shed or builder's merchant. I'd start with a small plastic sack as it doesn't keep well. Multifinish or Board finish would be better than Bonding or Browning undercoat plasters

If you need to plaster round metal wall boxes, you can get a special plastic guide that fits into them. On ebay as "Electrical Back Box Plastering Guide".

 

[1john]

ok here is what i always do, always! dampen the chase and.or pva it with a watered down mix, depending on how much suction the wall has. Fill out with patching plaster or one coat plaster, make it slightly proud and then run a trowel or scraper over to push it in flush. once the one coat has set it will prob be a little rough so i always sand it back with some 120 grit paper and then a coat of jointing compound, leave it set and then add another coat, once the second coat has dried you can rub this back flush with the original plaster. I have tried many other ways of doing it but this one seems the best in my experience.

 

[lasors]

I used a bucket of ready mixed plaster which is quick and simple. I had to work it back with a little water as it went a bit dry on the shelf, but it was very easy to use and cost about a tenner from B&Q for, I think, 5 litres. Found in the trade section, retail stuff like Polycell is the same just more expensive. It did shrink a little into the gap, though.

When dry I sanded back any rough bits then put on a skim of Red Devil OneTime filler which I absolutely rave about as it's a fantastic product. It sands very easily and very smooth and it's super light weight making application simple. Best filler I've ever used. You'll get it from decorators merchants like the Dulux centres.