Refinishing interior rendered walls with a few hair line cracks?

[passingas]

When we had our house built, I was unaware of how rendering done by half-assed Thais, would come back to haunt me. It looked fine in the daylight, but when lights are put to it, the ugliness more than just shines through. It has been 5 years now and time to repaint the inside. Can these walls be...re-rendered before I repaint? We used a double wall (AAC block outside and red brick inside) but where the columns are, there is a vertical crack from floor to ceiling where every column is (no wire mesh was used and I wasn't aware that putting this in would keep that from happening...lesson learned the hard way). I'm wondering if sanding (or an equivalent process), an already rendered masonry wall is possible. I'm thinking since it has had 5 years to set up...it might be like trying to sand a rock cliff. That or can it be rendered again, over the existing crap? Any ideas from anyone would be wonderfully appreciated. pg

[meatboy]

we got a problem with one of our pillers,a crack from top to bottom,mesh was used but they forgot to fill it with mix.

so last yr.the crack was exposed to see what could be done,the plasterer done a good job,so we thought but it is appearing again.so he s comin back.

if yours is just a hairline crack,dont use that wall putty they sell in home pro,get a tub of TAO CRACK FILLER.

we aslo had a few hairline cracks that kept appearing but since useing TAO it seems to have done the job.

[IMHO]

1) Get the walls professionally plastered (i.e. UK/US style). There are some contractors around in TH, but they are rare and expensive.

2) Veneer the walls with gypsum. A little tricky around things like door/window openings, and you will lose square footage, but your walls will be uniform

3) Cover the walls in a textured wallpaper/finish that better hides the imperfections.

4) Get a contractor to chip away the existing render, and re-render properly.

Edited February 18, 2015 by IMHO

[rgs2001uk]

A photo would sure help.

there is a vertical crack from floor to ceiling where every column is

Was the birckwork tied into the column?

Tie in rods are usually inserted into the columns.

Were these fitted, could be the wall is coming away from the column.

[eyecatcher]

Not sure why the OP is making a big drama out of this and straight into the blame game?

I am going to assume you are western and remind you why you would never spout the same complaint in the West.

here's a phrase you may know: "papering over the cracks" its a decorators job.

ok I am English and 9 times out of 10 these days every wall in every house is wallpapered; not only that we go further and install coving and skirting boards; and architraves around every door...BECAUSE we dont want to see cracks. yes even with our so called professional plasterers unfortunately cracking is not their fault.

Every day on my sites the bricky would always blame the groundworker; the joiner blamed the bricky; the plasterer blamed the joiner and guess what....the guy with the easiest job the decorator; he had the most difficult job on site................and that was to make the silk purse from the sows ear. the finished job was all down to the decorator.

now here in Thailand, there is no wallpaper, there is no coving, skirting boards, architraves so the cracks will be noticeable and its simply differential movement between differing materials. a plasterboard ceiling against a masonry wall will crack; always, a masonry wall up against a concrete column will crack; always and a 10m block wall backed up by a 10m brick wall will be 1cm shorter than the brick wall after a month in the sun.(hence the need for expansion joints) the oppoisite of shrinkage cracks.

As IMHO alludes to above if your walls are in such a state you can overboard them and skim them again; big expensive job; a lot of buggeration with plug sockets/switches and t.b.f overkill.

You can buy the tubs of premix skim to fill the cracks and after 5yrs you can safely say that the shrinkage has stopped and they will not worsen. but it sounds like you simply need standard fine joint filler and then just repaint the walls.

So before you jump in and start blaming the "half assed" for not including expamet (you will never see this here) just consider other factors such as the different expansion coefficients of materials; the amount of direct sunlight; the over indulged amount of cement thrown in to a mortar mix; the lack of water in a plaster mix. the wrapping of concrete columns in polythene to control the drying out.

Then you can blame the plasterer shortly before he boards and skims you.

[Anthony5]

A photo would sure help.

there is a vertical crack from floor to ceiling where every column is

Was the birckwork tied into the column?

Tie in rods are usually inserted into the columns.

quickstart__3.jpg

Were these fitted, could be the wall is coming away from the column.

Could you point us to a location in Thailand where those tie in rods are sold?

[Anthony5]

1) Get the walls professionally plastered (i.e. UK/US style). There are some contractors around in TH, but they are rare and expensive.

2) Veneer the walls with gypsum. A little tricky around things like door/window openings, and you will lose square footage, but your walls will be uniform

3) Cover the walls in a textured wallpaper/finish that better hides the imperfections.

4) Get a contractor to chip away the existing render, and re-render properly.

I would think that someone who knows his job should be able hide most imperfections with a very this layer of Gypsum. I'm thinking about 2 - 3 mm in the worst sections, to almost nothing at some other places.

I'm thinking about just filling the depths in the wall instead of putting a layer on the complete wall.

Wouldn't that be possible, and would it give any major issues with switches and so?

[rgs2001uk]

A photo would sure help.

there is a vertical crack from floor to ceiling where every column is

Was the birckwork tied into the column?

Tie in rods are usually inserted into the columns.

quickstart__3.jpg

Were these fitted, could be the wall is coming away from the column.

Could you point us to a location in Thailand where those tie in rods are sold?

Usually they just use rebar, drilled into the columns before the bricks are laid.

[wayned]

Or, you could just "live with the cracks"! Here a crack, there a crack, not a big deal. If that's the only problem that you are having your about 10 up on me!

[IMHO]

The secret to avoiding cracks in render is actually pretty simple.

1) Wait. Give the structure and walls time to settle, shrink and cure before rendering.

2) Use high quality premix render (just add water kind).

The problem is, no-one really wants to wait up to 28 days after a wall is up before rendering it.

Unfortunately, it's a very difficult thing to patch later - even if you manage to get the exact same consistency and texture in your patching mix, you need to be somewhat super-human to be able to lay it up with the right amount of extra thickness, so that once the patch mortar shrinks the end result is perfect.

Using acrylic fillers will solve the shrinkage issue, but you will very clearly see the difference in texture between it and the original render - so using this, you've fixed one visual flaw but created another.

As eyecatcher points out, often the best solution is to get your interior decorator to hide it.

[rgs2001uk]

I dont think the perfect house has ever been built, not just Thai related.

If you expect perfect 90 degree angles, everthing straight and true and flush, forget it.

I dare say if I took a plumb line, spirit level and a right angle set sqaure into any house anywhere I could find problems.

Experienced tradesmen know how to reduce these visual horrors, rice farmers moonlighting as builders dont.

Edited February 19, 2015 by rgs2001uk

[kevvy]

This is what I done , No rendered walls

[kevvy]

A photo would sure help.

there is a vertical crack from floor to ceiling where every column is

Was the birckwork tied into the column?

Tie in rods are usually inserted into the columns.

quickstart__3.jpg

Were these fitted, could be the wall is coming away from the column.

Could you point us to a location in Thailand where those tie in rods are sold?

Anthony

On the first brick(Q-con) of every second row of the wall we cut a V shape grove into the brick and then drilled a hole into the pier and then inserted a length of rebar into the hole in line with the V cut.

[JDGRUEN]

Consider this: Fill the big cracks with filler as one poster suggested. Then find some heavy duty - high content latex paint ... Applied a couple of times this type of Elastomeric paint - stretchy - as the name implies could well do the job. In America one company advertises a exterior grade elastomeric latex paint for exterior stucco painting. I have used it and it makes a nice thick smooth covering...

[moench]

Concrete and block work are different in expansion and must cover with mesh before rendering. To repair small cracks ,I would use flexible joint filler .but before scratch the cracks and make it bigger and deeper ,fill the joint filler ,next day sanding and painting finish

[IMHO]

This is what I done , No rendered walls

I hope your Mrs is a quiet one - not much sound insulation between rooms with just sheetrock walls

[kevvy]

This is what I done , No rendered walls

I hope your Mrs is a quiet one - not much sound insulation between rooms with just sheetrock walls

Off topic but funny .

[passingas]

I was a builder of custom homes for 30 years stateside....only we did wood frame-brick veneer-sheetrock (gypsum board) interiors, etc....I'm very sorry, but I do know craftsmanship and when it is done half-assed! But back to the issue...it is not where walls intersect, but where the red brick buts up against the columns (flush on each side) and continue. Rebar pieces (1/4" size) were drilled into the column where the red brick landed...that's not where the crack is. It snakes up the face of the concrete column part. I do have two support columns hidden in the walls of my living room and that is where the hair-line cracks are. They aren't gapping crevices, just hair line cracks. And I would bet, if they had been done correctly, ie...had a fine mesh over the concrete column part (20cm), I would not have this problem. I see where one poster did encounter this, but again, I will take responsibility for that, having never done masonry walls with rendering before....I wasn't aware. However, I think anyone doing this for a living should know....but....TIT. Land of the shortcuts. So perhaps there is a paint that might do this magic? I can live with cracks, no problem, but it would be nice not to have to. I'm really not expecting properly floated and taped gypsum wall surfaces, but then I really don't care for the excessive wall acne I have as a result of this half assed job. I was fortunate in that our main builder guy, was actually a working foreman. I pretty much ran the show, however, when it got to that point in the construction there were too many irons in the fire and the rendering was overlooked until it was too late. The walls get rendered about three weeks to a month before all the lighting fixtures are in and operating that will show the imperfections. I highly recommend anyone doing a house build to take a flashlight after dark and shine it up the walls to be sure you have no ugly surprises later. Do this every evening after they've been rendering so you can get it taken care of before it is too late. I thank all for their suggestions...pg

.

[IMHO]

I was a builder of custom homes for 30 years stateside....only we did wood frame-brick veneer-sheetrock (gypsum board) interiors, etc....I'm very sorry, but I do know craftsmanship and when it is done half-assed! But back to the issue...it is not where walls intersect, but where the red brick buts up against the columns (flush on each side) and continue. Rebar pieces (1/4" size) were drilled into the column where the red brick landed...that's not where the crack is. It snakes up the face of the concrete column part. I do have two support columns hidden in the walls of my living room and that is where the hair-line cracks are. They aren't gapping crevices, just hair line cracks. And I would bet, if they had been done correctly, ie...had a fine mesh over the concrete column part (20cm), I would not have this problem. I see where one poster did encounter this, but again, I will take responsibility for that, having never done masonry walls with rendering before....I wasn't aware. However, I think anyone doing this for a living should know....but....TIT. Land of the shortcuts. So perhaps there is a paint that might do this magic? I can live with cracks, no problem, but it would be nice not to have to. I'm really not expecting properly floated and taped gypsum wall surfaces, but then I really don't care for the excessive wall acne I have as a result of this half assed job. I was fortunate in that our main builder guy, was actually a working foreman. I pretty much ran the show, however, when it got to that point in the construction there were too many irons in the fire and the rendering was overlooked until it was too late. The walls get rendered about three weeks to a month before all the lighting fixtures are in and operating that will show the imperfections. I highly recommend anyone doing a house build to take a flashlight after dark and shine it up the walls to be sure you have no ugly surprises later. Do this every evening after they've been rendering so you can get it taken care of before it is too late. I thank all for their suggestions...pg

.

Have you used a water level to check for any subsidence?

Were the posts properly cured for 28 days - if not, they could still be shrinking.

[StefanBBK]

This is what I done , No rendered walls

Looks very nice. Good job.

I see you used steel but what kind of board is it? How thick ?

I've done a couple projects with thin board and my problem was that the self tapping screws did damage the boards a bit, or I sunk them right through....

If you could, please share your specs.

[kevvy]

This is what I done , No rendered walls

Looks very nice. Good job.

I see you used steel but what kind of board is it? How thick ?

I've done a couple projects with thin board and my problem was that the self tapping screws did damage the boards a bit, or I sunk them right through....

If you could, please share your specs.

We just used gypsum board 9 mm.If you get a decent plaster team you will have no problems. After they sanded the joints I painted them half a metre each side of the joint so when the paint dried you can see if the joints we sanded properly. There is nothing more annoying to see the joints not sanded properly after painting and the team has gone. I grew up in Australia and we built with bricks and the inside is plaster on a pinewood frame. The truss roofs are made in a factory out of hardwood , but steel trusses are coming in now.

[weegee]

This is what I done , No rendered walls

Quickest way to have good internal walls is... what Kevvy is saying......Steel frame it and plaster (Gypsum ) board..

The steel frame material is now available here in Thailand at every place that sells the gypsum Board (2400 x 1200) sheets.

Cornices are not available yet here....

[IMHO]

Cornices are not available yet here....

Ke? If you're talking about what Amercians call crown moldings, they're plentiful and available at practically all big building supplies store, in your choice of gypsum, wood or polymer profiles.

[IMHO]

This is what I done , No rendered walls

Looks very nice. Good job.

I see you used steel but what kind of board is it? How thick ?

I've done a couple projects with thin board and my problem was that the self tapping screws did damage the boards a bit, or I sunk them right through....

If you could, please share your specs.

We often do small sections of internal walls in framed gypsum - things like finishing 'triangles' for enclosed bottom staircases, and partitions inside bedrooms to create walk-in closets (i.e. wall sections that do not have a supporting beam).

If we're extending a rendered block wall, we use 9mm gypsum so the overall thickness is the same, but otherwise we use 12mm gypsum just for it's added strength (and minimal extra cost). If the client really doesn't like the idea of gypsum walls, we'll use 15mm gypsum to help them pass the "knock knock" test better.

Edited February 22, 2015 by IMHO

[Naam]

A photo would sure help.

there is a vertical crack from floor to ceiling where every column is

Was the birckwork tied into the column?

Tie in rods are usually inserted into the columns.

quickstart__3.jpg

Were these fitted, could be the wall is coming away from the column.

Could you point us to a location in Thailand where those tie in rods are sold?

or a location where these rods were used?

[steve187]

This is what I done , No rendered walls

Iv'e never seen 'Jumbo studding' used that way round to support the gypsum ( plaster) board, there is no support, from where the studding is cut around the larger steel horizontal support, up though the ceiling and i assume supported by a steel out of view. .

Re the cracking have they not indented the join between the wall and the column.

[weegee]

Cornices are not available yet here....

Ke? If you're talking about what Amercians call crown moldings, they're plentiful and available at practically all big building supplies store, in your choice of gypsum, wood or polymer profiles.

Good, so now you can get it..

I havent needed any for a long time so stopped looking ages ago.

[IMHO]

Cornices are not available yet here....

Ke? If you're talking about what Amercians call crown moldings, they're plentiful and available at practically all big building supplies store, in your choice of gypsum, wood or polymer profiles.

Good, so now you can get it..

I havent needed any for a long time so stopped looking ages ago.

Well, I don't know when your "before" was, But I've seen houses older than my grandmother that have them

[passingas]

Even though we built on fill (and no...we didn't wait for a year of rainy season to settle it), but....all of the footings (1m x 1m) were dug down to original substrate and I personally wrapped every single pier, beam and column with plastic film for proper curring. Did it all stay on for the entire 28 days?....more or less. It is not a settling of the concrete columns issue (all roof lines are as true today as the day after they were wielded), but more of a shrinking chap issue where it spans the concrete column (for 20cm). That and the overall bad rendering (floating of it) that gives our walls that acne look. Sure I can live with it all, but like I mentioned at the beginning, I want to repaint now and would like to address these issues, easily if possible. pg

[sometimewoodworker]

Even though we built on fill (and no...we didn't wait for a year of rainy season to settle it), but....all of the footings (1m x 1m) were dug down to original substrate and I personally wrapped every single pier, beam and column with plastic film for proper curring. Did it all stay on for the entire 28 days?....more or less. It is not a settling of the concrete columns issue (all roof lines are as true today as the day after they were wielded), but more of a shrinking chap issue where it spans the concrete column (for 20cm). That and the overall bad rendering (floating of it) that gives our walls that acne look. Sure I can live with it all, but like I mentioned at the beginning, I want to repaint now and would like to address these issues, easily if possible. pg

Since nobody has answered the original question of can the walls be sanded. The answer is yes, using diamond surface grinding discs for a 4 ½ angle grinder. They are easily available in every supplier of angle grinding supplies, not the cheapest but not outrageous either' I've got 1 or 2. But be careful it's the surface grinding disks you need not the diamond cutting discs.

The surface grinding discs are much more substantial and have diamond on one face only.

An example is here http://www.aliexpress.com/item/4-inch-Diamond-granite-grinding-cup-wheel-100mm-marble-polishing-cup-wheel/443238905.html