Repainting concrete where paint has fallen off

[The Deerhunter]

Had a house built 3 years ago and they refused to do the painting to the standard I wanted.  We only got one very thinned down coat of concrete primer round the edges of the plastered concrete block walls as they hated using a brush. "Roller or nothing and rollers are too had to use near edges." 

That and the lack of a dampcourse membane between foundation and blocks has (I presume) caused white powdery efflorescence and paint bubble off near the floor on the outside of the house.  I have done one section a year ago and it seems OK now but I need to do a lot more.  I intend to gently waterblast (pressure wash for you Americans) the damaged paint off and am wondering about pretreating the concrete surface before repriming it.  As the efforescence is likely alkaline in type how about I pre treat the exposed render with diluted white vinegar or similar.  Any ideas or advice?  Also, what is the best primer-sealer-undercoat to use in these circumstances that is available at Homepro or Thai Watsadu?

[Rimmer]

Moved to DIY forum

[The Deerhunter]

14 minutes ago, Rimmer said:

Moved to DIY forum

That is where I thought I put it.  Sorry.

[eyecatcher]

I wouldnt use a pressure washer. Efflorescence is chrystalised salts that have been left on the surface after water has or is still trying to evapourate.

further use of water simply exxacerbates the problem.

Use a wire brush initially to clean the surface then continue to let the wall dry out for as long as youre happy.

If its ground water thats rising thro the concrete its too late to stop that but you can treat tge surface with a silicone wash first.

I dont like to do that as it just seals the walls and encourage damp to take another route.

If there is such a producr here ad a microporous breathable primer then start with that, and follow up with a similar topcoat.

Your typical tubs of mixed paints claiming 5,7,10years are crap and are no different to enamel paints in that when water gets behind them they can be peeled of in pieces.

[seajae]

20 minutes ago, eyecatcher said:

I wouldnt use a pressure washer. Efflorescence is chrystalised salts that have been left on the surface after water has or is still trying to evapourate.

further use of water simply exxacerbates the problem.

Use a wire brush initially to clean the surface then continue to let the wall dry out for as long as youre happy.

If its ground water thats rising thro the concrete its too late to stop that but you can treat tge surface with a silicone wash first.

I dont like to do that as it just seals the walls and encourage damp to take another route.

If there is such a producr here ad a microporous breathable primer then start with that, and follow up with a similar topcoat.

Your typical tubs of mixed paints claiming 5,7,10years are crap and are no different to enamel paints in that when water gets behind them they can be peeled of in pieces.

all great suggestions, lime coming out of the concrete is normal here, the moisture just keeps dragging it out. Unfortunately I seriously doubt they will have the required material in Thailand, I have been trying to find certain paints here for years(it was my trade for over 30 years) to enable me to do certain work on our house but they simply dont stock them. Even if the walls were neutralized with an acid wash I doubt you would be able to stop the lime build up, rendered walls really need a block filler applied but due to the quality of the builders in Thailand and the lack of quality paints I doubt there is a lot that can be done about it, even with me doing the right thing here we have lime problems inside and outside our house on the bottom of the walls, moisture is just a part of thai life

[The Deerhunter]

17 hours ago, seajae said:

all great suggestions, lime coming out of the concrete is normal here, the moisture just keeps dragging it out. Unfortunately I seriously doubt they will have the required material in Thailand, I have been trying to find certain paints here for years(it was my trade for over 30 years) to enable me to do certain work on our house but they simply dont stock them. Even if the walls were neutralized with an acid wash I doubt you would be able to stop the lime build up, rendered walls really need a block filler applied but due to the quality of the builders in Thailand and the lack of quality paints I doubt there is a lot that can be done about it, even with me doing the right thing here we have lime problems inside and outside our house on the bottom of the walls, moisture is just a part of thai life

Durn it!!!  You offer pretty disappointing news.  Also I was wrong about the repairs I did last year.  They are peeling off already. Pic x835 below is from last year's repair and it is showing bare concrete under a loose paint skin already.  Pic x849 is part of the 28 lineal metres that at least need current repair from the original paint job 2 or so years ago.   We are moving back to my home country to live soon so what I do not do in the next 8 weeks will not be done by me.  I am a fair bit older than my wife so it is likely she will come back to live here in a few (or not-so-few) years, and I was hoping the paint could be still on her retirement home when she got back after my eventual demise.  Is there nothing that will give a repair beyond a year or so?  I have had to use a low powered water blaster as 30 metrs with a wire brush on my hands and knees in this heat is beyond me and in our area labour is almost impossible to find.

[The Deerhunter]

18 hours ago, eyecatcher said:

I wouldnt use a pressure washer. Efflorescence is chrystalised salts that have been left on the surface after water has or is still trying to evapourate.

further use of water simply exxacerbates the problem.

Use a wire brush initially to clean the surface then continue to let the wall dry out for as long as youre happy.

If its ground water thats rising thro the concrete its too late to stop that but you can treat tge surface with a silicone wash first.

I dont like to do that as it just seals the walls and encourage damp to take another route.

If there is such a producr here ad a microporous breathable primer then start with that, and follow up with a similar topcoat.

Your typical tubs of mixed paints claiming 5,7,10years are crap and are no different to enamel paints in that when water gets behind them they can be peeled of in pieces.

Please see also my most recent post on this disappointing matter.  

[eyecatcher]

On 3/14/2019 at 1:46 PM, The Deerhunter said:

Please see also my most recent post on this disappointing matter.  

The wall needs to dry out.....again now that you have soaked it!

Dont use water on a building again, water is the biggest cause of damage in buildings.

 

I surmise that as typical proceedure here, render the wall then paint three days later and piss off before the paint falls off.

Because its hot and sunny everyone assumes a wall is dry in 24hrs its not.

i reckon the dry line at the bottom is the original cocrete ring beam then the problem startrs with the block or brick which would have been hosepiped before rndering. Most of the water will have collected in the bottom course.

 

I would think after drying out you can repaint it again, the problem isnt happening higher up.

 

Other checks to make.

1.make sure you dont have a water pipe running along that wall internally that could be leaking.

2. Try to minimise rain splashback from that concrete area that is potentiaally keeping that plinth area wet.

[The Deerhunter]

On 3/16/2019 at 7:10 PM, eyecatcher said:

The wall needs to dry out.....again now that you have soaked it!

Dont use water on a building again, water is the biggest cause of damage in buildings.

 

I surmise that as typical proceedure here, render the wall then paint three days later and piss off before the paint falls off.

Because its hot and sunny everyone assumes a wall is dry in 24hrs its not.

i reckon the dry line at the bottom is the original cocrete ring beam then the problem startrs with the block or brick which would have been hosepiped before rndering. Most of the water will have collected in the bottom course.

 

I would think after drying out you can repaint it again, the problem isnt happening higher up.

 

Other checks to make.

1.make sure you dont have a water pipe running along that wall internally that could be leaking.

2. Try to minimise rain splashback from that concrete area that is potentiaally keeping that plinth area wet.

I have nearly completed my waterblasting of the affected areas, some for the second time.  Waterblasting was essential as wire brushing this area would have been nigh on impossible and if done with machinery, even more destructive that water blasting with the weakest machine Karcher make.  The house has extreme overhang of over 1.5 metres and wide surrounding walkway with a second foundation in the perimeter to protect the main wall foundations in heavy rain.  It is on a slope and we get lots of water rushing through in rainy season,.  There are no water pipes in the walls to be leaking and I am sure the main problem is a result of the lack of a dampcourse membrane.   After a week or two of drying (and the lower edges of the house walls get lots of direct sun), I will tidy up with sandpaper and a hand wire brush.  Lacking advice for suitable products available here I am using the two products shown below.  Sealer first perhaps several coats after wife translates the directions, then a different brand primer that used originally or last time.  We leave LOS in May to live overseas and I am trying to keep the property reasonable for when she may want to return after I shuffle off.  I do not expect it to be a 100% success but hope for better than the one, two or three years as we have now seen.  Also the water table even in wet season is over 5 metres deep so I was surprised at the amount of water uptake in the walls.  Hope for the best and will be somewhere else in 2 months, anyway.

I am not very good at this adding pictures thing.

Edited March 23, 2019 by The Deerhunter

[kamalabob2]

The OP might check with DR Fixit line of repair solutions in Thailand. The MD of this building materials company attended High School and University in Texas. He told me that they will soon have a cost effective line of floor coating for grow rooms in Buriram Thailand. His focus is to provide solutions to construction challenges in Thailand. The woman I buy Dr. FixIt wall and floor coatings from in Buriram speaks Thai German and English. Dr. Fix it has catalogs in English as well as Thai language. Global House, Hardware House and independent builders merchants stock this brand which offers solutions to problems as outlined by the OP. 

[The Deerhunter]

21 minutes ago, kamalabob2 said:

The OP might check with DR Fixit line of repair solutions in Thailand. The MD of this building materials company attended High School and University in Texas. He told me that they will soon have a cost effective line of floor coating for grow rooms in Buriram Thailand. His focus is to provide solutions to construction challenges in Thailand. The woman I buy Dr. FixIt wall and floor coatings from in Buriram speaks Thai German and English. Dr. Fix it has catalogs in English as well as Thai language. Global House, Hardware House and independent builders merchants stock this brand which offers solutions to problems as outlined by the OP. 

Thanks but job done now.

[seajae]

when you have a rendered wall to paint normally you let it dry completely then block it to remove all the loose surface then apply the correct coats of paint, this simply doesnt happen here  as they want everything done straight away. The peeling paint is at the bottom of the wall which is the natural place for moisture to travel in the cement render taking all the lime with it which in turn caused the paint to bubble then peel. Moisture guard is designed for exterior walls to stop water penetrating the walls not coming out of the wall, you need to allow the rendered walls to dry fully then clean them off to stop the lime problem

 

[Andrew Dwyer]

when you have a rendered wall to paint normally you let it dry completely then block it to remove all the loose surface then apply the correct coats of paint, this simply doesnt happen here  as they want everything done straight away. The peeling paint is at the bottom of the wall which is the natural place for moisture to travel in the cement render taking all the lime with it which in turn caused the paint to bubble then peel. Moisture guard is designed for exterior walls to stop water penetrating the walls not coming out of the wall, you need to allow the rendered walls to dry fully then clean them off to stop the lime problem
 

So, are you saying that after removing all the loose peeling paint the surface can be simply repainted using paint only ?
The reason I’m asking is my house was last painted 2 to 2 1/2 years ago , I moved in just short of 2 years ago, and in many places lower down the paint has bubbled and peeled off. It’s all protected from rain now and has been for around 1 1/2 years and am getting ready to repaint.

[The Deerhunter]

On 4/5/2019 at 5:37 PM, seajae said:

when you have a rendered wall to paint normally you let it dry completely then block it to remove all the loose surface then apply the correct coats of paint, this simply doesnt happen here  as they want everything done straight away. The peeling paint is at the bottom of the wall which is the natural place for moisture to travel in the cement render taking all the lime with it which in turn caused the paint to bubble then peel. Moisture guard is designed for exterior walls to stop water penetrating the walls not coming out of the wall, you need to allow the rendered walls to dry fully then clean them off to stop the lime problem

 

If what you are saying is correct then I should be alright except for water still coming up from the concrete path.  It did dry out properly before painting.  Direct Thai sun for  a number of days before sealing and painting.

[sometimewoodworker]

2 hours ago, The Deerhunter said:

If what you are saying is correct then I should be alright except for water still coming up from the concrete path.  It did dry out properly before painting.  Direct Thai sun for  a number of days before sealing and painting.

A number of days won't dry it out, it needs weeks.

[The Deerhunter]

5 hours ago, sometimewoodworker said:

A number of days won't dry it out, it needs weeks.

 

5 hours ago, sometimewoodworker said:

A number of days won't dry it out, it needs weeks.

A big number of days, well into two figures.   It was only old concrete that had been water blasted.  The concrete would have been hot to the touch for at least 6-7 hours a day.  I have a plane home to catch and a lot of work too try and future proof much of the property for hopefully some years before she returns alone.   Hint:  She is quite a bit younger than me, 

 

Still lots of painting to "arrange" and new spouting to get installed over an internal courtyard.

[justin case]

there is no being proud of your work here ... new built houses and condo's already have problems before being sold and a quick paint is the solution here , to cover it up, long enough so the units are sold and then it is your problem...

 

houses sold with a 1 year guarantee... I remember it was 10 to 30 years back in the west

[crazykopite]

Could be lime in the mix that causes the white and flaking . It appears it’s tradition in Asia when painting to add up to 50 % water to save money so I do it myself . Can I suggest if you want good quality you do it yourself or get a Thai and you supervise but this means standing watching there every move . I suggest you do the following :

 

1. Wash the walls down taking all the loose paint and white away I suggest using sugar soap.

 

2 . Get a good quality stabiliser new or old paint I use Nippon Flexiseal primer not cheap but good I recommend you add between 5/10% water and give a good stir and roller it on leave for a few days to dry out.

 

3 . Use a high quality acrylic top coat paint semi gloss/ sheen as it is washable I used I use Nippon weatherbond advance its all singing and dancing stops chalking like you have is anti fungi but it does cost money around 2000/2500 baht for its just under 10 ltr once again thin it 5/10% water . My property is on the beach i painted it over 2 years ago and it’s as good today as then accept when a bird decides to do a flying squirt hence why I recommend get a sheen as Matt paint is not very good if you have to wash it .

 

hope this helps

 

ps you need a good two coats of top coat well I do as I live on the beach  just took this pic it’s exterior wall painted more than 2 years ago Persian Blue.

[PerkinsCuthbert]

On 4/5/2019 at 6:07 PM, kamalabob2 said:

The OP might check with DR Fixit line of repair solutions in Thailand. The MD of this building materials company attended High School and University in Texas. He told me that they will soon have a cost effective line of floor coating for grow rooms in Buriram Thailand. His focus is to provide solutions to construction challenges in Thailand. The woman I buy Dr. FixIt wall and floor coatings from in Buriram speaks Thai German and English. Dr. Fix it has catalogs in English as well as Thai language. Global House, Hardware House and independent builders merchants stock this brand which offers solutions to problems as outlined by the OP. 

The building engineer in the middle could certainly fixit for me.....

[transam]

I bet your internal floor level is just above where the paint is peeling off....????

[connda]

I just treat it like other home maintenance like trimming the trees.  Every two or three years you need to scrape the lower walls of the house down to concrete and repaint, preferably during the height of the hot season when the moisture content in the ground and concrete are at their lowest.  We just finished this year.
When it starts peeling again - scrape, paint, repeat...  It's elbow grease and some paint. 

[Andrew Dwyer]

I just treat it like other home maintenance like trimming the trees.  Every two or three years you need to scrape the lower walls of the house down to concrete and repaint, preferably during the height of the hot season when the moisture content in the ground and concrete are at their lowest.  We just finished this year.
When it starts peeling again - scrape, paint, repeat...  It's elbow grease and some paint. 

Would you recommend primer ?

[transam]

14 minutes ago, Andrew Dwyer said:

Would you recommend primer ?

This ploblem works from the inside out, bit like British Leyland car rust....????

[Farangwithaplan]

34 minutes ago, Andrew Dwyer said:

Would you recommend primer ?

Always use a quality primer. Not only does it act like a sealer, it gives the top coat something to connect to. Always use two coat of quality acrylic top coats.

 

[gunderhill]

On 3/13/2019 at 7:34 PM, eyecatcher said:

If its ground water thats rising thro the concrete its too late to stop that but you can

Probably dont have it  here but silicone damp proof could be injected  by normal silicone  gun, drill holes  every 6  inches or so, its  like a thick paste  in a tube .

[gunderhill]

On 4/9/2019 at 12:57 PM, sometimewoodworker said:

A number of days won't dry it out, it needs weeks.

Probably wicking up from the ground, will never  stop  unless you used concrete with GANZUM  in  like I did at my  house, they don't  use dpc's here at  all.

[Fruit Trader]

1 hour ago, transam said:

This ploblem works from the inside out, bit like British Leyland car rust....????

Yes and no amount of super space age nano coating will stop its mission to reach the surface and break the final coat bond.
 

[basinview]

You actually have another three options

 

First option - After allowing the walls too properly dry out, apply an epoxy water based primer and while it is till wet apply the first coat of acrylic top coat over the primer and then allow that too dry properly before applying the additional top coat

 

Second option as the affected area would appear to be a ''reasonably straight '' - horizontal line, saw cut ( scribe )just above the damaged section and then paint the damaged section in a different shade or colour and accept that this will be an ongoing maintenance issue, as this way you do not have to repaint the entire wall

 

Third option, install tiles over the damaged section by pinning the rear of the tiles into the wall

 

Good luck with whatever you decide

[boonchu]

We have two buildings side by side, one building I put in a damp course the other no damp coarse. The buildings were built within a year of each other, the one with a damp coarse being the newer. Both buildings now over 12 years- the building with NO damp coarse is showing large signs of paint peeling, the other building is not showing any signs of damp in the wall or effervescence. I brought the damp coarse from Australia. 

[RJRS1301]

• Needs to be thoroughly cleaned using something like sugar soap . remove all flakes of paint and all dust. allowed to fully dry out, at least 48 hrs or more.
• Then cleaned with an acid wash concrete cleaner, again allowed to dry at least 48 hrs. Primer concrete paint ( 24 hrs to dry)
• At least two coats of concrete paint ( not house paint) 24 hrs between coats.
• Have to vacuum all dust of area between each coat.
• If the moisture is "wicking" from under the ground, this will need to be done on a regular basis