How Long should I run a Dehumidifier after a Flood? - Mould & Air Quality Testing


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How Long should I run a Dehumidifier after a Flood?

  • Posted by: Alex Wilkie

If you don’t run the dehumidifier long enough, you risk mould growth, if you run it too long, you may risk damaging and warping building materials due to over drying.

Lets say your home has a burst pipe and you have sucked up all the water with an extraction machine or wet dry vac. After this is done, there is still residual moisture which remains sitting in the carpet, underlay and building materials. The issue here is if they are not dried, you are likely to have mould growth and therefore indoor air quality problems in your property. The solution is to hire or purchase a dehumidifier to remove the residual moisture from the building materials and only remove the dehumidifiers once all materials have been moisture tested as dry.

We stock the Delmhorst and GE Protimeter moisture meters for this purpose. Beware here of cheap moisture meters, they can give incorrect readings and cost you more money due to damage caused by not drying materials properly.

You will need to take readings around the area to see how far the water has actually spread. You can take a reference check of the moisture readings in a dry area as a reference of what the dry moisture reading should be. If it reads above this, then the material is likely to be wet.

Once you have determined the size of the spread, you can now use drying equipment. If you have foam underlay it is likely you will need to cut it out and dry it separately or replace it. It is very difficult to dry foam underlay in place. Once you have removed the underlay you can now run air movers to blow air underneath or above the carpet to dry the carpet and the sub-floor.

This is where your dehumidifiers will be useful. You will need to run the dehumidifiers in the room to expel the moist air from the materials. It should be continually run for 24 hours a day until the walls, floor and carpet are dried. This would usually take around 3 – 4 days on average. Be sure to be use your Delmhorst of GE Protimeter to moisture test the materials to ensure they are dry.

If you have any problems with this, be sure to call us so that we can be of assistance.