What Can You Do?

Controlling Condensation

Check the structure of the building first for obvious defects:

• Check that the walls are not suffering from rising damp
• Ensure that there is an effective damp-proof course, that it is not bridged or damaged. A new damp course can installed by removing one brick at a time and inserting a physical DPC, or a chemical DPC can be injected into existing walls.
• The damp-proof course should be at least 6 inches above any outside paving to avoid heavy rain from bouncing back up and soaking the brickwork above the DPC - consider lowering the paving around the house where necessary.
• Check that any wall cavities are clear of rumble, debris can accumulate over the years - to remove it normally requires removal of bricks at each corner and racking the cavity clean. Where the dampness is restricted to one area and no other reason can be identified, it is a relatively easy task to check/clean inside the cavity.
• Check that all airbricks are clear and consider fitting additional airbricks to ventilate under suspended floors. Modern practice is to fit a duct across the cavity so that the cavity itself is not ventilated.
• Consider applying a surface finish to outside walls. Either a clear waterproofing finish (silicone) which can be brushed on or a paint/textured finish, which will cause most of the rain to run down (check that you are allowed to change the outside appearance of your house before you start doing so). Evaporating water from the outside of walls can remove heat from the wall making it considerably colder.
• Check the roof to make sure that it is sound and directing rain into the guttering, not into the structure of the building.
• Check the guttering and down pipes, make sure that they are carrying the water away and that there are no damaged/blocked gutters or drainpipes causing the external wall to become soaking wet.
• Check solid floors to ensure that they are dry and free from condensation. If not they may need a damp proof membrane and insulation below – potentially a big job.
• Check that there are no leaking water tanks or pipes within the house.

 Once you are happy with the structure of the building, look to the occupation life style. You may need to educate your tenants as to how to avoid condensation.

• After a bath or shower, the room should be ventilated to the outside, not to the rest of the house - just opening a window (and closing the door) will help. Fit an extractor fan.
• Dry clothes out of doors or in a cool area of the premises - this latter suggestion may sound strange, it will take longer but less moisture will be held in the air at any one time.
• While drying clothes indoors, ventilate the room. Dryers should have external air extraction.
• When people come in with wet coats, they should be hung outside the living envelope to dry. A good reason for a porch.
• Try to increase the rate of change of air in the premises - increase ventilation. Add forced ventilation/extraction to areas which produce a lot of moisture (kitchen, bathroom). Extractor fans are available with an air-moisture switch so that they operate automatically while the moisture in the air is above a set amount. Other units (more expensive/complicated) are available which remove the moist air but reuse the thermal energy that would otherwise be wasted.
• Consider changing the fuel you use. Electric is the driest, paraffin probably the wettest.
• Consider using a dehumidifier - domestic types are now available and can remove a surprising amount of water from the air.
  

If condensation persists after you have sorted out the basic structure of the building, made life style changes, and suitable modifications to the property, there are still some other changes to try.

• In Britain, condensation will almost always occur with single glazed windows. The inside surfaces of these windows can be almost the same as the outside temperature. Overnight in winter their temperature can drop below freezing and often the inside windowsill will be awash first thing in the morning.
• Simple secondary glazing consisting of little more than a sheet of glass (or plastic) screwed to the window frame with a seal in between can be fitted.
• Alternatively new double-glazing windows can be considered. Although much more expensive than simple secondary glazing, there are additional benefits: existing wooden or metal windows will need continuous maintenance and repair whereas new double glazed units are low maintenance.
• Some decorative materials always have cold surfaces, (i.e. ceramic tiles, mirrors etc.) and are well known for the formation of condensation. Unfortunately we tend to use tiles in the kitchen and bathroom, two rooms where high humidity is likely. There is not much you can do where this occurs other than keeping the room (and the tiles) evenly heated or improve by ventilation.
• Some wall surfaces can also be a problem. Where the wall is papered the situation may be made worse if there are many layers of paper, (this can act like blotting paper) so strip off all the layers and re-paper the wall.
• Things can also be improved by lining the wall with thin expanded polystyrene (normally available from your wallpaper stockist) before you hang new wallpaper.
• Painted walls have a cold surface. If you do not want to paper it, consider lining it with wooden panelling or another material such as cork tiles.
• Alternatively a wall can be insulated by fitting a false wall with a layer of insulation behind and the front either being panelled or plasterboard so that the new surface can be papered. However, remember that with all these 'covering up' methods, they possibly just hide and do not cure the problem – in fact they may make things worse by encouraging stagnant air and mould spore growth. Try to get to the cause.
• In those properties with cavities, the installation of cavity wall insulation will keep the house considerably warmer and will help prevent condensation.
• Ceilings under the roof should not suffer too much from condensation providing adequate roof insulation is fitted.
• Where ceilings have a high gloss finish, consider covering with cork or fibre tiles; alternatively wooden panelling can be installed.
• Solid floors (i.e. a slab of concrete) are often cold because of their large thermal mass (they take a long time to warm up). Even vinyl floor tiles tend to be cold, however there are a number of 'warm' flooring materials available such as cork or cushion tiles. Thin wood flooring can be fitted on most existing solid floors.

Removal of Mould, and Cleaning-up after Water Leaks and Floods.

It is very important to clean up and dry-out the property immediately after water damage caused by flooding, water leaks and condensation, before mould spores have a chance to accumulate and grow.

• Identify and eradicate any sources of moisture.
• Mould cannot exist and grow without moisture. Therefore you must first find and eradicate the source as described above.
• Completely remove and dispose of mould-contaminated materials.

Find any mould on porous items that may have absorbed moisture. In particular, insulation, plaster, carpeting and other floor coverings, ceiling tiles, wood, clothing and textiles, furniture and furnishings, and paper.

If you see evidence of mould, these items should be bagged in plastic and removed. Porous materials that may have been in contact with sewage should also be bagged and removed. Non-porous materials can be saved if they are properly cleaned and dried.

 

Drying out all materials that are wet.

Do this as soon as you possibly can. After the floodwaters have receded, or when you have cured the leak or high humidity problems, damp and water-soaked building materials and household items can be a significant ongoing source of moisture, promoting the growth of mould.

These should be dried or removed from the building if possible. For severe moisture problems, use space heaters and dehumidifiers and move wet items away from walls and off floors.

Equipment rental companies hire space heaters, fans and dehumidifiers, but to avoid spreading mould spores, do not operate fans if visible mould is already present.

Cleaning non-porous or semi-porous items.

It is possible for mould to grow on hard materials like plastic, concrete, glass, or metal, but this can usually be removed with careful cleaning.

Solid wood items can also be salvaged through cleaning, if they are structurally sound.

Mould spores and particles can cause health problems even if they’re dormant, and they can be quickly reinvigorated of the wet or damp conditions return in the future. So, when you clean an item, the aim is to completely remove all of the mould contamination.

• For heavily contaminated items, begin by using a high suction industrial vacuum cleaner (not a conventional household vacuum) to remove as much contamination as possible.
• Carefully damp-wipe the items, to remove as much surface contamination as possible. Rinse wipes often with clean water. Dispose of your wipes and rinse water frequently – they will now be contaminated with mould.
• Thoroughly scrub all contaminated surfaces. Use a stiff brush, hot water, and a non-ammonia soap/detergent or commercial cleaner.
• Collect excess cleaner and cleaning water using a wet/dry vacuum cleaner, a mop or sponge.
• Finally, rinse the surface or items and the clean-up the whole area with clean water. Collect and fully dispose of the excess rinse water, and dry everything out as quickly as possible.

Disinfect surfaces.

After you have removed all visible mould from contaminated surfaces, a disinfectant may be used to kill some of the mould that may still be present. Disinfection should not be a substitute for cleaning and removal of mould. However, it’s essential for items that have been in contact with sewage. If you disinfect, follow these guidelines:

• Use 1/4 to 1/2 cup of bleach per gallon of water and apply to surfaces where mould growth was visible before cleaning. You can apply with a spray, sponge, or some other suitable method.
• Collect any excess bleach solution with a wet/dry vacuum cleaner, sponge or mop but do not rinse or wipe the bleach solution from the items or surfaces being treated — allow it to dry on the surface.