plastering

homer1982

I am putting insulated plaster boards on the external facing inside walls, as for my other inside walls one of the plasterers I have gotten to quote me a price said that I should slab the other walls instead of scratching it and plastering it, he also said that it would be cheaper.

What does anyone think of this?

But I was told that the slabs can show up any bumps or hollows of the wall after plastering them as opposed to scratching the walls and plastering them then.

plasteritup

trust me as a plasterer i can tell you that,putting sand and cement(scratchcoat)on ur internal walls,is cheaper.cost of slab and adhesive to sand and cement,no comparison.if he slabs them be sure they are stuck correctly.and also it should not matter regarding the finish on the wall,if he is any good the skimmed walls should all be immaculate.

Mr NoTV

I'd slab the inner walls as well as the outside facing ones. Eliminate the cold surfaces if you can. Sand and cement inside a room is a recipe for condensation, if you do want to smooth dress the walls, skim a coat of bonding then a finish.
We are renovating a 100 y/o cottage that has sand/cemented walls and concrete floors (why???) - I lowered the ceilings and applied 12" insulation which warmed the house up no end. This caused the walls to run with water as they are so cold. Experiments to one room have proved that correct insulation on the walls works beautifully. Avoid sand/cement - it's only good for the outside or for hallways of blocks of flats.

I'm no builder or plasterer but never find the need go back on any of my jobs - I ensure they are done correctly in the first place. Good luck.

paddy147

plasteritup wrote: »

trust me as a plasterer i can tell you that,putting sand and cement(scratchcoat)on ur internal walls,is cheaper.cost of slab and adhesive to sand and cement,no comparison.if he slabs them be sure they are stuck correctly.and also it should not matter regarding the finish on the wall,if he is any good the skimmed walls should all be immaculate.

can I ask you a question?

I had my chimney breast recently replastered.1 month ago infact.

No plasterboard,just the brick of the chimney breast and then the plaster,er replastered it.It was then painted about 10 days later

The fireplace has not been used since it was replastered and painted.

There are now long cracks everywhere,on the front and sides of the plaster on the chimney breast.A friend of mine said something about shrinkage,but I didnt get what he was saying.



Can you tell me what may be causing this???:mad:

Thanks.

plasteritup

it looks to me that sand cement scratch coat was not finished properly,and the bond with the skim has failed,but hard to tell from pic,although this is the most likely reason.

plasteritup

mr notv,
i would imagine the fact that the cottage walls are running with water has a lot to do with the age of the building,what condition is the building in?proper ventilation roof etc etc.

on the slabbing of internal walls,if you use lets say 70 half inch slab at 9 euro a slab 630 euro
30 bags of adhesive at i think 12 euro
360
so material is 1000 euro.
compared to material of sand and cement lets say 500 euro.
already double the price and not days work done.
most plasterers i no charge more for slabbing tan mortaring
walls are much more solid,look as for condensation im not sure,never came across any problems,pros and cons for both,but the finish on the wall should defo not differ.

PaleRider

It is hard to tell from photo what is going on, however, i will try. The wall would appear to be scudded, this is a good sign. It gives the next coat of sand and cement a grip. This all looks good. But there can be a number of reasons for failure. There was paint on the chimney prior to scudding. Mix was to strong to much cement. Sand was very poor . Second coat was too deep/thick. All of these can cause cracking. Tap the wall with your knuckle to check for hallow sound, if there is a hollow sound it may be poor adhesion of sand and cement coat. It takes a bit more skill to re-plaster old walls. There would need to be more detail to get to the bottom of this. Hope its of some help.

plasteritup

just a thought,but if your plasterer did not scratch the second coat(a rake like tool that scratches into sand and cement coat,to help the skim bond to the mortar)this could also be a reason.so the sand and cement bonds to scud fine,but bond to skim fails.either way dont put up with it,very poor show,your job i would consider a basic plastering task,and if i was leaving work after me like that,i would sell my tools and give up.:)

paddy147

plaster,er came back today and filled in all the cracks with some sort of flexi filler stuff.

he said something about the shrinkage happening from the sand and cement mix that went on 1st.

he also knocked around the entire chimney for about 5 mins with his hands and said that the plaster wasnt going to fall of,so not to worry about it.

Hes getting a painter to come around on Monday and repaint the chimney breast.

PaleRider

Lets us know how it all pans out. It might work out. When you start to use the chimney, it will test it. But lets us know goog or bad, i would be very interested. Regards

plasteritup

hope it all goes ok paddy.