Plaster or Dry Lining?

[CivilianJenny]

Hi everyone,

We have just started trying to renovate an old 1910's terraced house. When we started to remove the wallpaper, the plaster on the wall was very old fashioned sandy/dusty stuff that just came loose with the paper. We have now removed all the old plaster from the walls and are left with the exposed brickwork. There is quite a lot of dusty residue left behind that we intend to remove with wire brushes, but the mortar in the brick joints is also quite soft and crumbly in places.

The question I wanted to ask is what might be the best option in terms of re-plastering? I was thinking that dry lining would be quickest, but thought a bonding coat might be better in terms of holding the old mortar in place? What other preparation would be necessary in this situation, do I use diluted PVA on the bricks first? And will it be more of a pain to cut the dry lining around all the socket boxes or build the bonding coat up to the required depth?

Thanks in advance for any advice.

 

[JohnD]

you may be living in an area where it is the custom to render the walls with sand and cement to about 15mm, then give a thin coat of hard plaster on top.

Just a regional practice on the coast.

I have that, it seems to work quite well and doesn't crack much. I also find it chases out easily. It is probably also more resilient in case of damp.

Your house (by its age) might be built with lime mortar which is very soft, it will probably need repointing on the outside.

IMO plastering is superior to drylining, but takes more time so is less cheap.

 

[FredFlintstone]

Hi Jenny,

It all depends on what you're after in terms of finish etc. It's an older house so if youre wanting to keep with the character then float and set is the best option. As John says, it could be a sand cement mix but you coul also use bonding, browning or hardwall. Then a skim coat on top. Downside is you'll have to wait a few weeks for it to dry fully before painting.

If however you're not bothered about the original character then drylining is an option. With dot n dab it'll be quicker and therefore cheaper in terms of labour. Once done it can be skimmed. The upside to this is it dries quicker so can be painted sooner. Usually within three days. It's also easier to make the walls plumb with dot n dab.

As for the internal mortar being soft and crumbly - I wouldn't orry about it. Internally, the mortar ain't subject to the elements so won't wash out. It's serving its purpose, sitting there between the bricks. The mortar doesn't so much stick the bricks together - it's just that it keeps the bricks a uniform distance apart. If you've got the same problem outside the re-pointing will be necessary because, open to the elements, the soft mortar willl gradually wash out thus removing the unform spacing between the bricks.

As for PVAing. If you're going to float and set then yes, you'll need a couple of coats of PVA to reduce the suction of the brickwork so the bonding coat doesn't dry too quickly which will cause it to crack. If you're drylining then the PVA won't really be necessary. And as for the wire brush - I wouldn't bother. It'll probably have no benefit and will probably brush more mortar out of the internal joints.

regards

Fred.