Pittwater Online News

Dealing With Dampness Inside The Home

These DIY ideas were first run in March of this year. Requests for a rerun, as we all try to keep on top of black mould, hopefully may help lessen the problem after the next scrub down of walls.

This week a look at how to prevent and treat dampness to keep your home free from ''creeping dank'' and the problems associated with this, including how this may impact on your and your family's health. Many of us, after the last few weeks of heavy rains, may have use of these tips. 

Prevention combined with removal works best. The key is keeping the house dry and free of dust, ensuring adequate ventilation does not trap moisture, and oiling furniture to prevent dust sticking. 

Make sure you:

• fix leaks, including roofs and walls as well as plumbed appliances such as dishwashers
• increase ventilation and air circulation with windows and fans
• use extractor fans when cooking, bathing or drying laundry
• use a dehumidifier
• clean condensation from inner windows.

However, with so much water even the best maintained homes will have a few problems. Open windows when it's not raining to allow breeze to run through and remove damp air. Keep your home as dust free as possible so mould spores don't have too much to latch onto. If you do find mould spots popping up, use a good white vinegar (4 parts water to one part vinegar) and microfibre cloth to remove them.  If you're going to use bleach, protective equipment is recommended: PVC or nitrate rubber gloves; safety glasses; and safety shoes. Make sure the area is well-ventilated while you are cleaning with bleach, and use a mask to stop inhalation of noxious fumes. Clove oil is also great for dealing with mould.

Below runs an overview of how to deal with the main areas your home will be impacted during this long wet season.

Penetrating Damp

Penetrating damp is caused by water seeping through the walls at any point (as opposed to rising damp, which is confined to the lower part of ground-floor walls). You may see damp patches appear when strong winds drive rain against the wall of your house, and disappear when the weather improves.

A semi-permanent damp patch can be caused by a leaking gutter or a crack in the brick mortar. If a whole wall is showing signs of damp, it may mean that old bricks have lost their weatherproof facings and become porous.

Penetrating damp is less likely to affect your home if it has cavity walls. If water does cross the cavity, it's usually because mortar has spread onto a wall tie.

Old bricks can become porous and let water penetrate though the wall. Replace the bricks, or repoint and treat the area with an exterior silicone water-repellent fluid.   

Cracks in brickwork or damaged pointing in the joints will allow water through to your wall too. Where this appears have a look at the exterior of the structure and replace the damaged bricks and fill any gaps in the mortar.

If the brickwork is secure, mortar on a wall tie in the cavity could be bridging the gap and allowing water to cross to the inner wall. The only way to solve this is to remove some bricks, inspect the cavity and rake out or chip off any mortar on the wall ties.

Rising Damp

Rising damp is confined to the lower part of walls (up to a height of about one metre) and to solid floors, and is caused by water soaking up from the ground.

If you have a modern house, it will be protected by a waterproof barrier that's built into the walls 150mm above the ground (the damp-proof course) and another one that's laid under concrete floors (the damp-proof membrane). 

If there's a gap or breach in your damp-proof barrier, water from the ground can be drawn up into the structure of your house. This can happen if the plastic membrane under your floor has been torn (by sharp stones, for instance).

If you live in an old house built without a damp-proof barrier, it could well suffer from rising damp. While the problem is made worse by wet weather, it never completely dries out even in summer. If you spot signs of rising damp, you may need to call in professional help to find out the cause and remedy it.

One way you can protect your home from this is to ensure there is no build up of earth against your exterior walls; this will cause water to breach your damp-proof course and let water seep through. You'll need to remove the earth and let your wall dry out.

You can also ensure an adequate flow of air ventilates the area beneath your floor by installing an Edmonds Ecofan.

Preventing Flooding around your home

As severe wet weather appears to be occurring more often, and more forecast before Autumn and Winter are through, homes are prone to flooding.

A few measures you can take to prevent this around the home:

• Keep your gutters and downpipes clear of any leaves and debris.
• If surface water isn’t draining properly you may have a blocked Stormwater drain – check these to clear of debris washed into and if the problem persists and you have pools that don’t disperse, it is time to contact your plumber before the problem becomes worse. 
• Ensure outside ground surfaces slope away from your house’s walls. 

Condensation 

The warmth inside a home will cause moisture to evaporate into the air. If you always keep your windows and doors shut, fresh air can't replace this water-laden air.

When humid air comes into contact with a cold surface, it cools and condenses - depositing droplets of water. In cold weather, the temperature of your external walls and windows is lower than the air indoors - so moisture will condense and run down your window panes, and into your gyprock, window ledges and even affect wooden architraves at the base of glass doorways.

Dampness occurring in a modern house in good condition is usually due to condensation. To reduce it, you can extract the moist air with an extractor fan, reduce the moisture in the air by improving your ventilation and install insulation so the inner surfaces of your walls and windows don't get so cold. Cleaning extractor fans and vents will maximise their function of removing moisture from interior rooms.

Damp rooms in Winter occurs when a room gets too cold and the air can't absorb the moisture. By turning up the heating the air can absorb more moisture. Ensure rooms continue to have ventilation during these months so the damp air can escape as well. 

If there's widespread damp or mould on your upstairs walls and ceilings a lack of ceiling ventilation or insulation can be the problem. To remedy this, you'll need to have insulation installed and check the air vents for your ceiling are not blocked. 

If you have a persistent problem with mould in some areas of your home, year round whether from humidity in warm months and condensation during cooler months, it may be a good idea to apply a mould-resistant paint to these surfaces to prevent mildew. Make sure you clean the areas you are going to repaint well first or the mould will leach through your new work.

There are a great range of dehumidifiers available that will extract moisture from these rooms, and many of these also ‘clean’ the air, great for a damp salty air environment like ours – just remember some portable versions need to have their water tanks emptied regularly – you will be surprised how much accumulates and how quickly.

A few other simple ways of keeping dampness down within the home are to:

• Open windows when there is no rain and some breeze. This will increase airflow through the house, which will reduce humidity. 
• Externally vent all water-vapour producing appliances such as washing machines, clothes dryers, showers and stoves. Venting into the roofspace can cause condensation problems, especially when the house has a metal roof. 
• Install extractor fans in the kitchen, bathroom and laundry. 
• Cover pans when cooking and let steam escape by opening a window or using an extractor fan. 
• Dry clothes outdoors whenever possible. 
• Keep furniture away from walls to improve air flow in the room. 
• Don’t fill your cupboards to bursting point, especially those where cloth is stored. 
• Close kitchen and bathroom doors to prevent steam travelling into colder rooms. 
• Wipe surfaces when moisture settles to stop mould forming.

Damp spots appearing on ceilings and becoming black with mould indicate there is a lack of ventilation in your roof cavity (the space between tiles and ceiling), a cracked or leaking tile (see re-point your roof) or that guttering may be leaking or that the flashing may have cracked or become dislodged, allowing water through. You'll need to refit the loose flashing, or replace it if it’s damaged with the same type of flashing or a self-adhesive flashing strip.

Cleaning debris from your guttering regularly and apply a sealant to small areas that have deteriorated or aren’t sealed properly and replacing those that are beyond repair will prevent water being funneled into the roof cavity.

Reference

1. Indirect health effects of relative humidity in indoor environments. A V Arundel, E M Sterling, J H Biggin, and T D Sterling. Environmental Health Perspectives. 1986 Mar; 65: 351–361. Retrieved from: www.ncbi.nlm.nih.gov/pmc/articles/PMC1474709

2. Mould - NSW Dept. of Health at: https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx