We have mould in our bedroom on 1 wall...?

Question

So we've stripped off the wallpaper. The plaster underneath is blue with yellow in it.

At the moment we're leaving the wallpaper off and letting it air for a few weeks then painting it.

How do we know that the mould won't come back?

What colour should the plaster be? Blue or yellow?

Answer 1

There's damp in the wall.  You may need a new damp course, or the walls may need to be replastered (with new plasterboard put underneath).  Find yourself a reputable joiner/builder to have a look and give you a quote.

Answer 2

Plaster on many old houses looks white to yellowy whereas more modern plaster is either greyish (almost blue in some cases) but it can also be redish in colour. You are right to let the wall dry before you paint, when you do paint, apply a mold killing/reducing primer to the wall first.

The cause of the mould should be investigated too you may have some dampness getting in or it could just be a lack of ventilation - you must have air flow in bedrooms because of what you breath-out while asleep. Mould is common in some old houses where dampness accumulates and the wall are cold.    

Answer 3

This is very common and may occur when warm wet air enters the house and condenses on a colder wall during the summer. it can happen over a short time or take years to become noticeable.  using mold resistant paint and air conditioning the room will help limit this. Leaving the windows open on warm or wet days will potentially make things worse.

If there is a source of water vapor in a nearby room, such as from a bathroom, then try to vent it with a fan or open window.

Answer 4

Mould is caused by excess moisture in the air. To prevent it, open the windows every day for a good few hours, to allow the air to change.

Even on rainy days, just open them all a tiny bit and the house will breath.

When cooking, always have the kitchen window wide open, the steam will escape and not dampen your walls and cause mould.

Modern wall paper pastes have anti-fungal, anti-mould chemicals in them, so let the rooms breath for a while and everything will be ok.

Answer 5

You need to investigate where the moisture is getting in or it will certainly come back.  Check roof for leaks or outside walls for cracks and missing pointing.

Answer 6

You have'nt said if you have checked the outside wall where the damp patch is inside. You might find that your guttering is blocked or is leaking onto the wall. Have a few roof tiles moved above the damp patch, as that would let water in? Have you checked in the loft above the damp patch?

I wouldn't be inclined to paint that area in you bedroom until you have located the cause of the problem.

If you can't find anything, you need to consult a reliable and knowledgeable builder. He can find the cause and if you want, you can do the work to put it right or leave him to do it, for the right price.

Answer 7

Has the outside wall been re-pointed with cement mortar?

Is there a gutter/roof tile problem?

Is it an area behind some furniture preventing air circulation?

Is the room adequately heated?

Moisture on the outside wall soaks in through the brick and breathes out through the lime mortar. Very important on walls without a cavity. Always re-point with lime mortar, never use a water sealer and never render over. When people see damp on a wall, this is the first thing they do, seal the outside wall. Means that ant moisture in the house can't breathe out either. Seen this quite a lot.

Answer 8

Plaster does not last forever it is perishable, over some 30 or 40 years.

Get someone to check the cause of the damp.

Answer 9

stop having food fights in the bedroom! and clear it up properly when you do!

Answer 10

You need to tap the plaster with your hand, if it sounds hollow then it needs to be replaced. Otherwise it will come back.

If it sounds solid then dry it out with a heater for a week or so and paint over with undercoat first they a top coat.