Salt test may indicate rising damp

Salt tests determine the presence of nitrates and chlorides

All you need to do a salt test is the correct amount of two chemicals packed in sachets for each test, a bottle of distilled water, and two measuring beakers. The test is very simple and takes just a few minutes. A colour change will indicate whether or not certain nitrates and chlorides are present.

You can test a sample of the wall covering or plaster by removing it from the wall and mixing it with distilled water to form a solution. You add chemicals in the form of pill, one nitrate 1 tablet to a 10cc vial of distilled water. This turns the solution yellow. Then you add a nitrate 2 tablet, shake for 30 seconds and leave to stand for 5 minutes. If nitrates are present, the solution will change colour, brown for traces of nitrate, red for significant amounts of nitrate. If the solution remains yellow, nitrates are not present.

To test for chlorides you add one chloride tablet to the 50cc solution and shake the container until the tablet dissolves. If the solution is brown, there are no chlorides present but if the solution turns yellow, it means the solution contains chlorides.

The diagnosis of the origin of salts should not be made on the presence of salt alone, but considering other information available such as the moisture distribution within the building. A high reading of nitrates may signify that evaporation of soil water has continued for a long time. Soil salts are hygroscopic which means they absorb water directly from the air.

Be careful to distinguish nitrates in tap water from rising damp

However, when running the test, you must be careful because tap water often has nitrates in it too. For this reason, it is advisable to test your tap water first to establish a baseline nitrate level before testing your walls for rising damp. If the level in your plaster or wall covering is higher than the level in your tap water, this suggests you have rising damp caused by soil water on the surface of your walls.

You also need to take care when choosing your nitrate test kit. The most common kit is the Protimeter kit but the solution it provides simply reacts to nitrates present. Some of the other kits provide a colour chart such as a test kit manufactured by Salifert so you can compare the colour of the solution mixed with tap water and compare this with the solution mixed with wall coverings.

Salt tests are just a small part of the wide range of services that CPL t/a Rainbow Restoration can offer to customers. With nearly 20 years of experience, we provide fire and smoke damage cleanup and restoration, flood and water damage cleanup and restoration, media blasting, biohazards removal and leak detection, to help you to get your property back to pre-incident condition. Give us a call to find out more.