• Looking for a smarter way to manage your heating this winter? We’ve been testing the new Aqara Radiator Thermostat W600 to see how quiet, accurate and easy it is to use around the home. Click here read our review.

Decorating gone wrong

Joined
10 Feb 2025
Messages
8
Reaction score
1
Country
United Kingdom
Hi All,

I wonder if someone would be able steer me correct after some advice to took with decorating has gone a bit wrong.

I moved into a 3 bedroom house a few years back. One bedroom and bathroom is in an extension and the other two rooms on opposite sides of the main house. I noticed that the bathroom was starting to get some black mould on the ceiling in the bathroom that at first wiped off, but was beginning to be a problem and there were signs of it in all three bedrooms too (no trickle vents in the new windows when we moved in which I expect doesn't help). On the advice of a local handyman who has done a few general jobs for me, I painted all three rooms in a coat of Zinsser perma-white anti mould paint. I left that on the bathroom ceiling, but in the bedrooms on the external walls I painted the Zinsser and then a general emulsion from homebase over it.

Fast forward a few months and while it looked fine at first its starting to take a terrible turn. The paint on the bathroom ceiling is starting to peel off and some mould is coming through again. This is supposed to be for high humidity so not sure what I've done wrong. The paint at the junction with the wall is starting to have a cracking effect.

In the bedrooms on the external wall, there is a really odd paint running effect that's appeared about the window and around the lintel area. I can only assume it's the Zinsser, but I don't where were to go from here. I've attached some pictures so if anyone had any advice it would be helpful and make my wife a lot happier with the outcome.

Many thanks!
 

Attachments

  • IMG_20250112_174351.jpg
    IMG_20250112_174351.jpg
    232 KB · Views: 74
  • IMG_20250112_174528.jpg
    IMG_20250112_174528.jpg
    88.4 KB · Views: 71
  • IMG_20250112_174537.jpg
    IMG_20250112_174537.jpg
    144.4 KB · Views: 74
  • IMG_20250112_174629.jpg
    IMG_20250112_174629.jpg
    91.9 KB · Views: 64
  • IMG_20250114_154253.jpg
    IMG_20250114_154253.jpg
    102.2 KB · Views: 70
Fast forward a few months and while it looked fine at first its starting to take a terrible turn. The paint on the bathroom ceiling is starting to peel off and some mould is coming through again. This is supposed to be for high humidity so not sure what I've done wrong. The paint at the junction with the wall is starting to have a cracking effect.

You have a serious need to address the moisture level issue in that room. Add an automatic extract fan.
 
Hi Harry,

Thanks for the input.

The bathroom is fitted with an extractor fan that I'm told is fairly decent and moves a reasonable amount of air for a bathroom extractor fan. The windows were new when I moved in and don't have trickly vents which is rather annoying. I try to keep a window open after showers etc, but the family aren't always great at remembering. Maybe there is something beyond an extractor fan I could have fitted, though I'm not sure what that would be? Something that has a sensor for the amount of humidity instead of the standard light switch timber?

It might be two different issues, one in the bathroom and one in the bedrooms, but both involve the basecoat of Zinsser and were done within the same few weeks.
 
Maybe there is something beyond an extractor fan I could have fitted, though I'm not sure what that would be? Something that has a sensor for the amount of humidity instead of the standard light switch timber?

I'm not a great believer in trickle vents, I have none, and yet no damp/mould issues. Your fan needs to come on, irrespective of whether the light is turned on, and run for at least twenty minutes after the bathroom has been vacated - which means a PIR triggered fan with a timer. A useful option on top, would be a humidity sensor - so PIR, timer, and H sensor.
 
Do you think then doing a repaint with the Zinsser, after installing that and pulling off the areas of flaking paint, is in order or am I just going to make it worse and should use something else?

Any thoughts on the odd streaking in the bedroom corners? An insulation problem with cold coming through the walls maybe? Has anyone seen something like that happening and knows how to deal with it? The green and purple walls are both bedrooms, one in the new extension and one in the original house. One bedroom is totally fine, so I'm not sure if I've caused a problem with the Zinsser as a base coat or if it's showing up an under lying problem, but these issues were not there when we moved in and it took me a long time to get round to painting as the colours were nice. I'm unsure why the original paintwork didn't have this issue.

Thanks for all the help!
 
Do you think then doing a repaint with the Zinsser, after installing that and pulling off the areas of flaking paint, is in order or am I just going to make it worse and should use something else?

Paint, is not my area of expertise... Sorry.
 
Get your windows open on a regular basis

You can have the best extractor fan in the world but if there's regularly a lot of moisture in a room it's eventually going to cause problems

In terms of the decorating of the room it looks to me that it was damp when it was done and not clean

Put those two together and maybe not leaving time for coats to harden off and bobs your uncle ......flaking

Start again , get the room as dry as you can , get the flaking paint off then , in a dry environment .....stick on 2 coats of a good adhesion primer ......zinser cover stain , crown px4 ......let that harden off for a day ......then paint with a specific bathroom emulsion or eggshell
 
Hi Michelangelo,

Thank you for the advice.

Do you think it was damp that caused the running of the walls in the bedrooms too (green and purple rooms)? I was doing each coat about a day apart, then the streaking effect didn't appear till a few days later. Looked perfect and then my wife called me in as she had noticed it. There the paint isn't flaking there, it just looks like someone has poured water down the wall, but I did give the room a coat of Zinsser while I was at it.
 
Hi Michelangelo,

Thank you for the advice.

Do you think it was damp that caused the running of the walls in the bedrooms too (green and purple rooms)? I was doing each coat about a day apart, then the streaking effect didn't appear till a few days later. Looked perfect and then my wife called me in as she had noticed it. There the paint isn't flaking there, it just looks like someone has poured water down the wall, but I did give the room a coat of Zinsser while I was at it.
Yes , moisture, damp ......definitely

I would concentrate on getting those walls as dry as possible ....heat , dehumidifier , opening windows etc


Then get a decent adhesive primer on there .....zinser cover stain , crown px4 , zinser bin

then a decent white trade matt from leyland or johnstones x 2 coats to give you an idea of the state of the walls

A day between coats

Then your chosen finish .....again noting drying and recoat times

My advice would be wait until the spring if you can ?
 
Great thanks for the advice I will give that a try.

Yes I can wait till Spring as it's not an inconvenience and probably easier to deal with then as the weather is better.

Many thanks for everyone's help with this.
 
Hi, you need to sort out your damp issues BEFORE decorating. I would suggest getting at least one or maybe 2 good dehumidifiers and put one in the problem rooms. Meaco make good dehumidifiers. If the rooms are heated get a compressor type they are quieter an cheaper to run than a dessicant type (these are best suited to colder places like a garage). Also buy some hydrometers to monitor the moisture levels in the problem rooms. Amazon sell them and don't cost much, get some which show the high and low moisture levels. I would say put the dehumidifiers on a high setting until the walls have dried out then a lower setting to keep moisture levels below 70% any higher the mould will return. Then leave them on, most good dehumidifiers have built in sensors and turn off automatically at the desired humidity levels. I personally regard dehumidifiers as an essential household item for any property with mould issues. I see it in the news about all these properties suffering from mould and they always blame the local authorities or landlords for neglect. The problems isn't always the property but could just be condensation created by breathing, cooking, showering, drying clothes etc.. And dehumidifiers are rarely even mentioned as a possible solution.
BTW I don't have shares in any dehumidifier company. This is all from personal experience and advice I was given. I used to have mould problems in the house until I got a dehumidifier. I would never be without one now (just like I wouldn't be without a fridge or TV).
 
Last edited:
Hi, you need to sort out your damp issues BEFORE decorating. I would suggest getting at least one or maybe 2 good dehumidifiers and put one in the problem rooms. Meaco make good dehumidifiers. If the rooms are heated get a compressor type they are quieter an cheaper to run than a dessicant type (these are best suited to colder places like a garage). Also buy some hydrometers to monitor the moisture levels in the problem rooms. Amazon sell them and don't cost much, get some which show the high and low moisture levels. I would say put the dehumidifiers on a high setting until the walls have dried out then a lower setting to keep moisture levels below 70% any higher the mould will return. Then leave them on, most good dehumidifiers have built in sensors and turn off automatically at the desired humidity levels. I personally regard dehumidifiers as an essential household item for any property with mould issues. I see it in the news about all these properties suffering from mould and they always blame the local authorities or landlords for neglect. The problems isn't always the property but could just be condensation created by breathing, cooking, showering, drying clothes etc.. And dehumidifiers are rarely even mentioned as a possible solution.
BTW I don't have shares in any dehumidifier company. This is all from personal experience and advice I was given. I used to have mould problems in the house until I got a dehumidifier. I would never be without one now (just like I wouldn't be without a fridge or TV).
I think that's spot on

Get it dried out

If it's damp and you decorate again ....it will emerge somewhere else

You could hire a dehumidifier
 
I think that's spot on

Get it dried out

If it's damp and you decorate again ....it will emerge somewhere else

You could hire a dehumidifier
I would definitely buy at least one dehumidifier to control humidity levels on an ongoing basis. I guess hiring an industrial dehumidifier to dry things out quickly but if it dries too quickly it might cause cracks in the walls and ceiling so maybe not a good idea? Here a photo of my hydrometer.
 

Attachments

  • 20250219_184538.jpg
    20250219_184538.jpg
    153.7 KB · Views: 32
I would definitely buy at least one dehumidifier to control humidity levels on an ongoing basis. I guess hiring an industrial dehumidifier to dry things out quickly but if it dries too quickly it might cause cracks in the walls and ceiling so maybe not a good idea? Here a photo of my hydrometer.
Again I think you are right
 
Hi Dave,

Thanks for the added input.

I will defiantly get a hydrometer as that looks really helpful to guide when to do the painting. I'm in no rush so I can afford to allow it to dry out and maybe wait for the summer months. It never occurred that the moisture levels would be an issue in the bedrooms so I just went ahead and did the decorating. I do have a dehumidifier for doing the washing (funnily enough in a room that has no issues) so I can get that bringing the humidity down prior to the work. I think I have a number of steps to take care of in the bathroom as you have all mentioned above, but you guys have been very helpful. Fingers crossed I can get it all under control.

Many thanks!
 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top