How can I get rid of black mould in my bedroom?

Q WE are experiencing a lot of damp condensation in our bedroom and some black mould has formed around the window and ceiling — should we be concerned? Peter, Carlow A BLACK mould is a fungi which will happily grow where there is damp. This problem requires addressing fairly quickly as there are health issues associated with mould spores, even the non-toxic varieties, in particular for people who are prone to allergies or have asthma.

There are a number of likely causes and ways to prevent the growth of mould:

1. Lack of ventilation is the most likely culprit. Rooms require a minimum number of air changes and frequently there are no air vents in rooms or, if present, may be blocked up. I recommend installing permavents in all windows (which can be retro-fitted) but they must be left open all the time. First, improve the ventilation by unblocking or adding vents. If your room is next to a bathroom or has an en suite, ensure it is properly ventilated and has a good extract to the exterior with a time delay and use it. Don’t dry clothes in the bedroom.

2. Another possible cause is cracks and leaks. Check if the seals of the mastic are broken, cracked or missing. Is there a cracked drainpipe outside where water may enter the window area? Check the ceiling area — is there a fault in the roof covering? Ensure that gutters and downpipes are not blocked — they can often be the source of the mould in the ceiling.

3. You may also have a ‘cold-bridging’ issue — this occurs where areas of a building are less well insulated than other adjacent areas. As a result, the surface temperature of the cold bridge area is lower and, when in contact with the warmer moist air, damp spots are created. The junctions around windows and doors and at floor and ceiling are often where this cold bridging occurs. Poorly executed dry-lining works can also be a big issue. Check your attic for uninsulated areas at the edge and rectify if necessary, but always ensure you have proper ventilation into the attic space. If cold bridges at junctions cause the problem, you will need to have these areas properly detailed to eliminate the problem. You will need to have the mould removed. If it is extensive, have the work carried out by a specialist, and a registered architect can advise you on this. If you are competent to address it yourself (having ascertained it is the non-toxic variety), there are a large number of treatments available from specialist providers. I recommend using an eco-friendly variety. Ensure you work in a well-ventilated room and wear protective mask and gloves. Strictly follow the manufacturer’s guidelines. A lot of the systems have a mould prevention final coat. Unfortunately if the mould has taken hold in the plasterboard these treatments will not be effective in the long term and you will have to replace the plasterboard. To avoid a re-occurrence you need to identify the source of the problem and put in place measures to address it. A registered architect can advise you on these measures. Log onto riai.ie, the registration body for architects in Ireland.

Do you have a design dilemma we can help you with? Email your problem to designclinic@independent. ie.Advice provided is for guidance only and readers are advised to seek professional assistance for any proposed project.