paint reaction

[Belle427]

I have 2 problem areas, 1 in the kitchen and 1 in the bathroom both on dot and dabbed walls.
When the walls were originally plastered i allowed them to dry for a couple of weeks before applyng 1 mist coat of white matt emulsion. I then applied 2 coats of dulux kitchen/bathroom paint.
The bubbling of the areas didnt occur until 18 months later and only in 2 small patches. Ive recently started redecorating so i scraped all the loose paint back and gave the area a good sand, i then applied a coat of alkali resisting primer. The primer seems to have taken but around the edges of the patch the paint has started to bubble again, the walls dont appear to be damp.
Any advice on what may be causing this?
The pictures show the area after the paint bubbling is removed.

 

[TheDec]

Difficult to say at this time, could be a moisture/condensation issue perhaps these primers really only fail when there is moisture beneath them. Try increasing the area of application of the primer and see if that cures it, by the way where are those pics.

Dec

 

[Belle427]

View media item 37260 View media item 37261
here you go!

 

[TheDec]

Well looking at the pics to be honest there does not appear to be any sign of a mist coat being applied, I would as said extend the area of the primer and see if this sorts it out.

Dec

 

[Belle427]

i will rub it back again and re apply the primer, will report back and let you know how it goes

 

[Growler]

Damp.

 

[Belle427]

could be i suppose. bathroom problem is on an external wall which has been dot and dabbed (not correct but i trusted the plasterer wrongly)

 

[Growler]

Go to e-bay. Type.."damp meter".
There's cheap ones on there for a little over £6 with free postage and more than adequate for what you need.
Every home should have one. Stops any ooohing and aahhhhhing and ...could it be or couldn't it be or what do you think it is.

 

[Belle427]

will do that, dont want to repaint until the issue is cured.
Thanks

 

[Belle427]

damp meter arrived today and ive done some testing, sadly i think it is damp as the patchy areas are coming back at around 38%. A good piece of drywall (in a bedroom partition) is 20%
anyone know what sort of level is considered too much?

 

[misterhelpful]

The cheaper meters usually say anything over 30% needs investigating and over 70% requires essential treatment. They are not very accurate and can give false readings. If you search the Building forum you will find lots of debate on the issue of damp so it might be worth asking a question there.

 

[TheDec]

Never had any experience with these so could'nt really offer you any help, did you recieve any form of instruction leaflet with the product?

Dec

 

[Belle427]

only useage instructions, no advice on readings etc

 

[TheDec]

Thats a shame, perhaps Growler may be able to shed more light on the subject. Perhaps you should use the search facility to see if you can find something that would be of help to you.

Dec

 

[Growler]

This is was what I was referring to...

http://www.ebay.co.uk/itm/DAMP-DETE..._Measurement_Equipment_ET&hash=item3cb45623f2

I use it all the time..new plaster, walls etc.

It has an audible scream In fact I used it last week at my sisters in the hallway. It screamed at skirting area, up to about half a metre then stopped. Further inspection outside showed that it was the soil pipe..(long story).

It will show whether you have moisture content or not and it's for you to determine what's causing it.