Rendering

[KrisK]

Hi Guys

We have a room that has about 45% bare walls, ie just brick with mortar falling out. The rest is limestone rendered.

We have a quote to render the entire room, I put to the builder the possibility of just rendering the barewalls and leaving the existing limestone in place. The builder said that if you render it half in concrete and leave the existing limestone, the render will shrink and there will be hairline cracks in the work. He suggests is best to strip the entire walls (which we wanted to initially anyway) and render the entire room correctly

I agree with the builder 100% but I have a woman telling me to not overcapitalise and that hair line cracks are fine, we'll just fix them as they come up. The total cost to render the entire rooom is $2200. Not heaps.

Can someone tell me

a) is the hair line cracking thing true
b) does concrete render shrink with limestone butted up to it

Which is the best option?

 

[Rockstar]

Cement render will shrink so a crack will appear between whatever it butts up to Kris. Are you painting over both surfaces?

 

[KrisK]

Hi Rockstar, I see

Yes, we will paint it. This is our living room

 

[Rockstar]

If the base is all continuous brick for both renders then you may be able to wait a couple of weeks for the new render to dry and then fill any hairline crack with sikaflex and then paint. The only concern I would have is the difference in texture between the two renders. This would show up I would imagine.

 

[Rockstar]

Hi Guys

I have a woman telling me to not overcapitalise

Who is the woman?

 

[KrisK]

Ah yes, of course. the limestone is very smooth indeed, definitely a different texture! THanks Rockstar

 

[KrisK]

the gf, expert builder and professional renderer too now

 

[James Allen]

Your other option that will keep costs down, is unlikely to crack and will give you a similar finish to the lime render once painted is to stick plaster board to the brick. I know it sounds a little dodgy but is done often by tradesman. It may not be the answer for you but is worth exploring, it may save you a bit.

This site will explain it better, it's an australian site

http://www.how2plaster.com/stickonplaster.html

 

[Nathan]

jutst put some thin wall studs in and plaster, better finish, and probably same price or cheaper.

 

[KrisK]

Sorry guys, rather render the walls with concrete. Not a fan of plasterboard in this house... rather keep it original.

 

[Celeste]

jutst put some thin wall studs in and plaster, better finish, and probably same price or cheaper.

Hi Nathan

Just thought I would let you know, you do not need to put studs my plaster sticks the gyproc straight on to the brick... works fine and is cheaper.

 

[J Martin]

Hi Nathan

Just thought I would let you know, you do not need to put studs my plaster sticks the gyproc straight on to the brick... works fine and is cheaper.

If you follow this advice, just make sure you don't have any damp in the brickwork. Gyprock is a absolute sponge for moisture...

As long as you have a dampcourse, and the exterior brickwork doesn't abut any structure like pavers, soil etc on the outside above the dampcourse, you should be ok with this method.

 

[RumpledElf]

Surprised noone has said this so far, but I'm assuming you have an old house that is damaged - why not just use the original materials? They still sell them

We put in some doors through an old wall and it turned out one side of the wall was rendered back in 1876 by an incompetant so several square metres of the old render fell off and we had to re-render vast tracts of wall.

It is quite simple - put a base coat of cement based render on (our bloke mixed it up himself with sand and cement as he hates the too-dry packet premix mortar). Might need more than one coat to get the depth, needs to be notched or hatched or whatever you call it so the next coat keys in and sticks. You make the final coat so it is barely 1/2cm lower than the render you are trying to match up to.

Then you go over the top with lime render as a skim coat. This stuff is made of a mixture of hydrated lime and hardwall plaster (NOT plaster of Paris), which you can find in any hardware store that is in an area with a lot of old houses. You soak the lime overnight and then mix up the right ratios with plaster just before you use it. More lime makes it softer, shinier and rubberier, more plaster makes it more brittle, duller and harder to work with.

It is NOT a job for amateurs though, you'll need a proper hardwall plasterer in to do it. It is quite tricky to get it smooth, and you need to do a final run over it with a smooth tool when it is partly dry, which is what gives that lovely smooth and sort of shiny finish. You don't sand it at all.

 

[KrisK]

We've now decided to get in a plasterer who is going to rerender the entire walls

 

[MCS_80]

Anything to do with Render, speak with this company.

They manufacture the stuff and have applied it to polystyrene. If it wont crack on such a flexible base like that, it will not crack on anything else.

Click Here >>> QuikCote

 

[KrisK]

Our plasterer is working on the walls, day 5 of 5 so far. Only starting the whiteset now, seems like a slow process but he's basically doing it alone and truely under quoted us!!! He's put in far more work then his price suggests.

 

[Cartoon]

hehehehehe im currently teaching my self how to render.
its not easy trust me

 

[RumpledElf]

Yup, our tradie was here for quite a while too. And it really isn't easy to get solid plastering just right - tidying up the joins in gyprock is WAY easier, I've done a reasonable amount of gyprocking and it looks fine, but solid plastering? Argh.

I have an entire wall in the bathroom that is currently just loose rubble from removing a chimney/fireplace, solid plastering is so painful that we're planning to just roughly render or bag over the raw stone and dirt mortar to keep it all in place, and then put gyprock over the top on battens.