Two words you never want to hear spoken about an Oriental rug. Dry rot causes the natural fibers found in hand made Persian rugs to become brittle and break apart. Before a rug enters the irreversible stage of dry rot there will be signs of mold or mildew. If you are able to catch those two stages early enough you may be able to save your carpet by hiring a professional cleaner. However once a carpet has dry rot there is no coming back. It occurs most often in Oriental rugs with cotton foundations, but is not unheard of in those with wool foundations.
What Causes Dry Rot?
Dry rot is caused by either too much moisture, or too little. Moisture can come from flooding, leaks in roofs or walls, leaking plant pots (more common than you think) and a rug being stored improperly in a high humidity environment. For example an extreme case would be a rug wrapped in plastic and stored in a damp basement. Over-watering plants can be a problem but some plant pots can have condensation build up over time on the underside which will also cause mold, mildew and eventually rot. Pet urine stains can also be a culprit. It may take anywhere from a few years of exposure without remediation to 40 years. Bleach used on cotton fringe can also cause premature rot.
Signs of Dry Rot
Mold or dark areas on your carpet are cause for concern. Inspect your rug frequently if there is a source of water on or near it such as a plant, litter boxes, water bowls for pets, etc. If there is dry rot it will feel stiff to the touch and sound like wood when knocked on. The rug may have rips, tears or slits due to damage. If the rug is folded or bent a certain way, you may hear ripping or cracking sounds from the brittle foundation threads snapping.
If caught early you may be able to take your carpet to an Oriental rug cleaning expert who could remediate the mold or mildew before it becomes dry rot. If your carpet already has dry rot a repair person would determine what to do on a case by case basis. If the affected area is small and the rug is valuable they may suggest a reweave or patch. If the affected area is large and the rug is not the most desirable they may suggest throwing it away or finding a use for the areas that are not damaged such as pillows. Petroleum and Keratin products have been shown to improve Oriental rugs with dry rot (although there is no sure cure to dry rot).
Preventing Dry Rot
1. Inspect your rugs thoroughly
2. Clean your rugs annually
3. Rotate your rugs
4. Store your rugs properly
5. Elevate potted plants on your rug, or find different spots to put them.