Hi,

What should I pay extra attention to when plastering walls?

I notice some cracks on those new plastered walls but the contractor said will remove those cracks when painting...tell me don't be worry..

Is it impossible to plaster the wall and no cracks when dried? Must have some cracks on dried plastered wall and will remove them later?

Any way to prevent this? or trust my contractor?

Please advice me..

Thanks a lot..

This post has been edited by edwardsiow: Feb 24 2011, 10:37 AM

remove those cracks?? or do you mean they use filler? how bad is the crack? some pics would help..

The contractor said, when painting, they will use something like filler to smooth and remove those cracks...(not big cracks but hmm...how to explain....hmm...like small crack lines on the wall...)

currently no pic..with take this weekend...

You need to pay attention on where the lights or fan placement, have seen alot of customers complaining about the placement and it is very very difficult for them to re-do it or shall i say cannot re-do it once the damage is done.

as for the cracks, the contractor is half right. you will see no lines after them fill it up and paint it. but you'll notice it again after sometime, probably 1 or 2 years later.

So, how to prevent it or how do I want them to do so that no crack lines seen after plastered?.... I keep complaint about that, they just reply the same answer...What can I do? I already try to tell them....I afraid one day we will gaduh which I don't hope to see that...I am not professional, hard to provide the correct facts...I just hope they are honest....

First of all, you have to determine whether you're talking about the cement render coat, plaster coat or skim coat.

This is what's normally done in malaysia:
1st layer: Bricks (obviously)
2nd layer: Cement render (this means a mixture of cement and builder's sand and water, a good contractor will apply 2 thin coats of this instead of 1 thick one)
3rd layer: Plaster render (this means a mixture of cement and water only, applied in a very thin coat)
4th layer: Skim coat (this means a mixture of skim-coating powder and water. This stuff is usually white. Applied in thin coats. This is what makes the walls smooth)

Usually, the contractor will stop at the 3rd layer.
You have to ensure you and the contractor are on the same wavelength here, because if you ask for smooth walls, he will claim the plaster coating (3rd layer) is smooth enough.
So be sure to ask specifically for a skim coat.

Now back to the cracks on your wall...

If you determine the cracks are skim coat cracks, then a bit of wall filler will do the trick.

If they're plaster render cracks, then you'll have to hack out a groove on your wall and fill it up again. Basically, you're enlarging the crack.

I don't know what your contractor means when he says he'll be "covering it up" when painting because as far as I know, even the best paints
can only cover up hairline cracks. If you can see the cracks standing 2, 3 feet away, then it probably isn't "hairline" anymore.

Just remember: Paints are NOT fillers. Don't depend on them to fill up cracks. Barring special products, paints are decorative coatings only.

And just to get it out of my system, the main reason why cracks are there is because the contractor does the work in stages, mixing different batches with varying quantities of ingredients.
This makes the drying time different, thereby causing cracks when a particular area drys faster or slower than its neighbour.
Other causes would be soil settlement, whereby the earth underneath the house shifts or settles, thereby causing cracks in the walls, particularly where the walls meet the beams or columns.

Hope this helps!

thanks....great explanation...

my house is rebuilding...it seems that the walls now have been painted with the first coat of sealant..i can see that it have patches of very fine cracks..so i was wondering..isit normal?

well done ihatemynahs.

add some info..

item 2 render - plasticizer like KAPUR (white lime) add into cement sand mixture, if its over use then the wall are more prone to cracks, beware of some contractor use "Detergent Powder " to save cost, your wall 100% cracks like spider web

the same apply to item 3

The cement render is about to be done next week - the area to render is quite big-it is almost impossible to not mix in batches...what is the solution?

Also ,my contractor don't want to listen to me, say 1 time cement render instead of 2, says the trick is to water the bricks first before rendering so that it won't crack..

This post has been edited by jojozep: Mar 4 2011, 06:57 PM