Paint blisters and peels

[saiinnocent]

I started to paint the spare room to treat the condensation. To start off i removed old wall paper and filled in the holes to prepair for painting. Sanded down any excess plaster and scraped off paint to give an even finish to the room.
Due to the condensation in the property i washed the walls with the fungal wash allowed it to dry. On the third day i started to paint the undercoat which i added anti condensation treatment mixture into and painted with a brush, because there are some uneven patches due to previous paint. This treatment was advised to paint on twice before applying the last coat of paint without the treatment mixture.

Today the third day whilst i was painting over the undercoat with the roller, the paint started to bobble up and start to peel in some areas. Why is this and what can i do to fix this? Have i missed anything out that i need to do?

 

[LJW61]

The new plaster or filler shouldve had a 'mist' coat - thinned emulsion 25-30%

 

[saiinnocent]

The new plaster or filler shouldve had a 'mist' coat - thinned emulsion 25-30%

The area which started to peel and blister was not the area i filled in with filler.

 

[opps]

I have to agree with Ljw that it sounds as though the paint has dried on the surface rather than soaking in.

You say that you removed the old paint, this would have left exposed plaster that would have needed a mist coat to reduce the suction- additionally I think that it is very likely that the original paint had not been applied properly.

The only solutions are to remove all the paint or roll on Zinnser BIN (or something else). it is alcohol/shellac based and so will not reactivate the paint. It can be tinted to the colour you want or you can over coat it with your paint.

It dries extremely quickly so do not over roll as you will end up with too much texture. It is also very runny so I use a rad roller- doesn't take long to apply.

Recoat time with emulsion is about an hour or so at this time of the year.

In your case I would probably have mist coated the wall with emulsion and then used BIN. Other than wall paper paste I dont like using products with fungicide as they can release them into the room.

To clean your brushes and roller after using BIN use household cleaning ammonia. BIN does smell like a wino's armpit but the smell goes after about 15 minutes.

If you find the smell unpleasant use a charcoal filter mask (AEBK) about a tenner from a decent decorator's merchant.

Cost wise you are looking at about £45 for a tin but you will save £££s in labour costs and time.

 

[malshep]

hello sai

I decided to make a comment which may or may not be welcome. I’m not a painter (yet) - that’s why I’m reading this forum. However I can see ANOTHER problem.

Condensation (film of water) forms when warm moist air meets a cold surface. If condensation happens often enough, a black fungal mould will tend to form on the surface. The treatments you have currently applied are not “anti-condensation” treatments but anti-"black mould” treatments. The only ways to reduce condensation in a bedroom are:

1) Introduce less moisture into the air by having fewer people sleep in the room
2) Remove the moist air by improving the ventilation eg install an air-brick, leave a window open or install an extraction system. The drawback with all these approaches is that they will make the room colder.
3) Increase the temperature of the wall surface through insulation.

In the good old days you used to be able to buy rolls of 2mm thick polystyrene - you “papered” the walls with the foam, then wallpapered on top of the foam. This was a cheap way of slightly improving the warmth of the walls. Unfortunately your actions so far - taking off wallpaper and replacing it with paint, will I suspect do the opposite - you will get colder walls and more condensation with your painted wall than you did with a papered wall (but at least it won’t go black).

So if you want to tackle the underlying condensation problem but can’t improve the ventilation (because it makes the bedroom too cold) and can’t install cavity wall insulation, then you may need to consider internal wall insulation - ie a wall-liner on your external walls. In which case, you obviously need to think about that before you go any further with your decorating!

http://www.energysavingtrust.org.uk...Home-insulation-glazing/Solid-wall-insulation

[[ I see "opps" has tackled the decorating problem ]]

 

[opps]

malshep is correct.

Airflow- at a minimum, is key, especially in corners

You can get paint additives that have thermal properties- have never used them myself

http://www.thermilate.com/product-overview/domestic-coatings/additive

http://www.greenbuildingforum.co.uk/forum/index2.php?DATEIN=tpc_ibyajmsjt_1155209638

 

[malshep]

"opps" has got me intrigued about this Thermilate paint additive thing! The claims for it's performance seem absolutely outrageous! However it seems a reasonable price and as I'm just about to paint my kitchen external wall, I've just GOT to give it a go!

A google search for "thermilate" reveals an on-line supplier offering it at £16.62 for the first packet, sufficient for 5L of paint.

For a more conventional (and reliable) route to warmer walls, saiinnocent should perhaps google for "insulation plasterboard"

 

[opps]

Hi Malshep

I too would recommend the plasterboard option but it is expensive and might require new skirting, socket extensions, hacking of radiator pipes, new cornice, plastering, carpet refitting and so on.

Mind you though in the long term it might pay for itself in recovered heating costs.

As I said earlier I have never used the thermal additive and would be grateful if you could post back your possible future experiences of it

 

[saiinnocent]

Hi Malshep

I too would recommend the plasterboard option but it is expensive and might require new skirting, socket extensions, hacking of radiator pipes, new cornice, plastering, carpet refitting and so on.

Mind you though in the long term it might pay for itself in recovered heating costs.

As I said earlier I have never used the thermal additive and would be grateful if you could post back your possible future experiences of it

I did research on the thermilate additive first online, seemed like all my problems would go away with just using this item. There is a massive amount different items available and it can actually get very confussing of what you should buy.

However i did buy Thermilate powder which you have to mix in to any colour of paint you like. You can add some water to the paint as this product makes the paint very thick.

Once the additive is mixed in well with paint you can apply to walls twice, before the last third coat is applied without the Thermilate mixture. Very Time consuming . The question to be asked is if this item really works?....... Well only time will tell.

 

[opps]

[quote="saiinnocent";p="1458539The question to be asked is if this item really works?....... Well only time will tell.[/quote]

Please post back once you know- good luck